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Chapter 2: Building A ModelPatran Interface to MSC Nastran Preference Guide

2Building A Model

Introduction to Building a Model 6

Currently Supported MSC Nastran Input Options 8

Adaptive (p-Element) Analysis with the MSC Nastran Preference 23

Coordinate Frames 31

Finite Elements 32

Material Library 59

Element Properties 100

3Beam Modeling 227

Loads and Boundary Conditions 236

Load Cases 270

Defining Contact Regions 271

Rotor Dynamics 274

Patran Interface to MSC Nastran Preference GuideIntroduction to Building a Model

6

2.1 Introduction to Building a ModelThere are many aspects to building a finite element analysis model. In several cases, the forms used to create the finite element data are dependent on the selected analysis code and analysis type. Other parts of the model are created using standard forms.

The Analysis option on the Preferences menu brings up a form where the user can select the analysis code (e.g., MSC Nastran) and analysis type (e.g., Structural).

The analysis code may be changed at any time during model creation.This is especially useful if the model is to be used for different analyses in different analysis codes. As much data as possible will be converted if the analysis code is changed after the modeling process has begun. The analysis option defines what will be presented to the user in several areas during the subsequent modeling steps.

These areas include the material and element libraries, including multi-point constraints, the applicable loads and boundary conditions, and the analysis forms. The selected Analysis Type may also affect the

7Chapter 2: Building A ModelIntroduction to Building a Model

allowable selections in these same areas. For more details, see The Analysis Form (Ch. 2) in the Patran Reference Manual.

To use the Patran MSC Nastran Applicatithis should be set to MSC Nastran.

Indicates the file suffixes used in creatingMSC Nastran input and output files.

The currently supported Analysis Type foNastran are Structural, Thermal and Expl

Patran Interface to MSC Nastran Preference GuideCurrently Supported MSC Nastran Input Options

8

2.2 Currently Supported MSC Nastran Input OptionsThe following tables summarize all the various MSC Nastran commands supported by the Patran MSC Nastran Application Preference. The tables indicate where to find more information in this manual on how the commands are supported

Table 2-1. Supported File Management Commands

Entry Description

ASSIGN An ASSIGN command is used to assign a particular name (job name + user specified MSC Nastran results suffix) to the MSC Nastran OUTPUT2 file to be created during the analysis.

Table 2-2. Supported Executive Control Commands

Entry Pages

ECHO Solution Parameters, 298

SOL Solution Types, 291

TIME Solution Parameters, 298

Table 2-3. Supported Case Control Commands

Entry Pages

ACCELERATION Frequency Response, 317, Transient Response, 320

ACFPMRESULTS Advanced Output Requests, 450

ACPOWER Advanced Output Requests, 450

ADACT Analysis Definition, 27, Subcase Parameters, 388

ADAPT Element and p-Formulation Properties, 25,3D - Solid - Homogeneous - P-Formulation, 217

DATAREC Analysis Definition, 27

DISPLACEMENT Advanced Output Requests, 450

ELSDCON Advanced Output Requests, 450

ESE Advanced Output Requests, 450

FATIGUE Advanced Output Requests, 450

FORCE Advanced Output Requests, 450

FREQUENCY Frequency Response, 317

GPSTRESS Advanced Output Requests, 450

INTENSITY Advanced Output Requests, 450

MAXLINES Solution Parameters, 298

MPCFORCES Advanced Output Requests, 450

9Chapter 2: Building A ModelCurrently Supported MSC Nastran Input Options

OLOAD Advanced Output Requests, 450

SPCFORCES Advanced Output Requests, 450

STRAIN Advanced Output Requests, 450

Table 2-4. Supported Bulk Data Entries

Entry Pages

ADAPT 3D - Solid - Homogeneous - P-Formulation, 217

BEGIN AFPM 2D - Shell - Field Point Mesh, 176

BEGIN BULK SUPER Select Superelements, 383

CACINF3 2D - 2D Solid - Acoustic Infinite, 206

CACINF4 2D - 2D Solid - Acoustic Infinite, 206

CBARAO 1D Element Properties, 112

CBAR 1D Element Properties, 112

CBEAM 1D - Beam - Lumped Section (CBEAM/PBCOMP), 125, 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127

CBEND 1D - Beam - Curved with General Section (CBEND), 121, 1D - Beam - Curved with Pipe Section (CBEND), 123

CDAMP1 0D - Grounded Scalar Damper (CDAMP1/CDAMP1D), 110

CDAMP2 Entity Selection Form, 574, Elements and Element Properties, 582

CELAS1 0D - Grounded Scalar Spring (CELAS1/CELAS1D), 109

CELAS2 Entity Selection Form, 574, Elements and Element Properties, 582

CGAP 1D - Gap - Adaptive / Non Adaptive (CGAP), 141

CHEXA 3D - Solid - Homogeneous - Standard Formulation, 214

CIFQUAD 2D - 2D Solid - Plane Strain - Interface, 192

CIFQDX 2D - 2D Solid - Axisymmetric - Interface, 205

CIFHEX 3D - Solid - Interface, 223

CIFPENT 3D - Solid - Interface, 223

CMASS1 1D - Scalar Mass (CMASS1), 143, 0D - Grounded Scalar Mass (CMASS1), 107

CMASS2 Entity Selection Form, 574, Elements and Element Properties, 582

CONM1 0D - Coupled Point Mass (CONM1), 106

CONM2 0D - Lumped Point Mass (CONM2), 108

CONROD 1D - Rod - General Section - CONROD, 136

Table 2-3. Supported Case Control Commands

Entry Pages


10

CPENTA 3D - Solid - Homogeneous - Standard Formulation, 214

CQUAD4 2D Element Properties, 153,

CQUAD8 2D Element Properties, 153,

CQUADR 2D - Shell - Homogeneous - Revised Formulation, 156, 2D - Shell - Thin - Laminate - Revised Formulation, 164, 2D - Shell - Thin - Equivalent Section - Revised Formulation, 168, 2D - Bending Panel - Revised

Formulation, 179, 2D - Membrane - Revised Formulation, 209

CROD 1D - Rod - General Section (CROD) - Standard Formulation, 135

CSHEAR 2D - Shear Panel, 212

CTETRA 3D - Solid - Homogeneous - Standard Formulation, 214

CTRIAX6 2D - 2D Solid - Axisymmetric - Standard Formulation, 197

CTUBE 1D - Rod - Pipe Section (CTUBE), 137

CVISC 1D - Damper - Viscous (CVISC), 140

DCONST Objectives & Constraints, 501

DOPTPRM Optimize, 498, Toptomize, 500

DPHASE Object Tables, 243

DRESP1/2 Objectives & Constraints, 501

DTI, SETREE Select Superelements, 383

DTI,UNITS Fatigue Parameters Subform, 349

DYNRED Dynamic Reduction Parameters, 307

EIGB Buckling Eigenvalue Extraction, 310, Real Eigenvalue Extraction, 305

EIGC Complex Eigenvalue Extraction, 315

EIGR Real Eigenvalue Extraction, 305

EIGRL Real Eigenvalue Extraction, 305

EXTSEOUT External Superelement Specifications, 288

FEFACE Element Creation, 24

FEEDGE Element Creation, 24

FORCE Force, 245

FREQ1 Frequency Response, 317

FTGDEF Output Request Form Options, 453

FTGEVNT Define Fatigue Load Sequences, 487

FTGLOAD Define Fatigue Load Sequences, 487

FTGPARM Fatigue Parameters Subform, 349


Entry Pages


FTGSEQ Define Fatigue Load Sequences, 487

GMBC Displacement / Velocty / Acceleration, 243

GRAV Inertial Load, 251

MOMENT Force, 245

MAT1 Linear Elastic, 73





MATFTG Stress-Life (SN) and Strain Life (eN), Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible), 66,

Stress-Life (SN) and Strain Life (eN), Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible), 92

MCOHE Cohesive, 94

MPC Explicit MPCs, 40

NLPARM Nonlinear Static Subcase Parameters, 390

OUTPUT Analysis Definition, 27, Advanced Output Requests, 450

PACINF 2D - 2D Solid - Acoustic Infinite, 206

PARAM,AUTOSPC Solution Parameters, 298

PARAM,INREL Solution Parameters, 298

PARAM,ALTRED Solution Parameters, 298

PARAM,COUPMASS Solution Parameters, 298

PARAM,K6ROT Solution Parameters, 298

PARAM,WTMASS Solution Parameters, 298

PARAM,GRDPNT Solution Parameters, 298

PARAM,LGDISP Nonlinear Static, 300, Nonlinear Transient, 323

PARAM,G Complex Eigenvalue, 312, Frequency Response, 317, Transient Response, 320, Nonlinear Transient, 323

PARAM,W3 Transient Response, 320, Nonlinear Transient, 323

PARAM,W4 Transient Response, 320, Nonlinear Transient, 323

PARAM, POST Results Output Format, 379

PBAR 1D - Beam - General Section (CBAR) - Standard Formulation, 112

PBCOMP 1D - Beam - Lumped Section (CBEAM/PBCOMP), 125


Entry Pages


12

PBEAM 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127

PBEAM71 Adaptive Mesh Post-Processing, 446

PBEAMD Adaptive Mesh Post-Processing, 446

PBELTD Adaptive Mesh Post-Processing, 446

PBEND 1D - Beam - Curved with General Section (CBEND), 121, 1D - Beam - Curved with Pipe Section (CBEND), 123

PCOHE 2D - 2D Solid - Plane Strain - Interface, 192

PCOMP 2D - Shell - Thin - Laminate Plate- Standard Formulation, 162, 2D - Shell - Thin - Laminate - Revised Formulation, 164

PDAMP 0D - Grounded Scalar Damper (CDAMP1/CDAMP1D), 110

PELAS 0D - Grounded Scalar Spring (CELAS1/CELAS1D), 109

PELAS1 Adaptive Mesh Post-Processing, 446

PFTG 2D - Shell - Thin - Homogeneous - Standard Formulation, 153

PGAP 1D - Gap - Adaptive / Non Adaptive (CGAP), 141

PLOAD1 Distributed Load, 253

PLOAD2 Pressure, 246

PLOAD4 Pressure, 246

PLOADX1 Pressure, 246

PLOTEL 1D - PLOTEL, 144

PLPLANE 2D - 2D Solid - Plane Strain - Standard Formulation, 183

PLSOLID 3D - Solid - Homogeneous - Hyperelastic, 219

PMASS 1D - Scalar Mass (CMASS1), 143

POINT Element Creation, 24, 3D - Solid - Homogeneous - P-Formulation, 217

PROD 1D - Rod - General Section (CROD) - Standard Formulation, 135

PSHEAR 2D - Shear Panel, 212

PSHELL 2D - Shell - Thin - Homogeneous - Standard Formulation, 153, 2D - Shell - Homogeneous - Revised Formulation, 156, 2D - Shell - Thin -

Homogeneous - P-Formulation, 158, 2D - Shell - Thin - Homogeneous - Linear Discrete Kirchhoff, 160, 2D - Shell - Thin - Laminate Plate- Standard Formulation, 162, 2D - Shell - Thin - Laminate - Revised Formulation, 164, 2D - Shell - Thin - Equivalent Section - Standard Formulation, 166, 2D - Shell - Thin - Equivalent Section - Revised

Formulation, 168, 2D - Shell - Thin - Equivalent Section - P-Formulation, 170

PSHELL1 Adaptive Mesh Post-Processing, 446


Entry Pages


PSHELLD Adaptive Mesh Post-Processing, 446

PSOLID 3D - Solid - Homogeneous - Standard Formulation, 214

PSPRMA Adaptive Mesh Post-Processing, 446

PTUBE 1D - Rod - Pipe Section (CTUBE), 137

PBEAM 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127

PVAL Element and p-Formulation Properties, 25, 3D - Solid - Homogeneous - P-Formulation, 217

PVISC 1D - Damper - Viscous (CVISC), 140

RBAR RBAR MPCs, 43

RBE1 RBE1 MPCs, 45

RBE2 RBE2 MPCs, 47

RBE3 RBE3 MPCs, 48

RFORCE Inertial Load, 251

RROD RROD MPCs, 49

RSPLINE RSPLINE MPCs, 50

RTRPLT RTRPLT MPCs, 51

SESET Select Superelements, 383, Translation Parameters, 285

SET1 Output Request Form Options, 453

SET4 Output Request Form Options, 453

SETREE Select Superelements, 383

SPC1 Displacement / Velocty / Acceleration, 243

SPCD Displacement / Velocty / Acceleration, 243

TABLFTG Define Fatigue Load Sequences, 487

TEMP Temperature, 248

TEMPF Temperature, 248

TEMPRB Temperature, 248

TEMPP1 Temperature, 248

TIC Initial Displacement, 251, Initial Velocity, 252

TSTEP Transient Response, 320

TSTEPNL Nonlinear Transient, 323, Nonlinear Transient Subcase Parameters, 394

UDNAME Define Fatigue Load Sequences, 487

VCCT Crack (VCCT), 265


Entry Pages


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MSC Nastran Implicit Nonlinear (SOL 400/600)The following Bulk Data entries are supported for SOL 400/600 analyses.


3D Contact Region

BCBODY Defines a flexible rigid contact body in 2D or 3D.

BCBOX* Defines a 3D contact region.

BCHANGE Changes definitions of contact bodies.

BCMATL* Defines a 3D contact region by element material.

BCMOVE Defines movement of bodies in contact.

BCPARA Defines contact parameters.

BCPROP* Defines a 3d contact region by element properties.

BCTABLE Defines a contact table.

BSURF Defines a contact body or surface by element IDs.

GMNURB 3D contact region made up of NURBS.

BCTABL1 Defines a Contact Table (New Form).

BCONECT Defines the Touching and Touched Contact Bodies.

BCONPRG Geometric Contact Parameters of Touching Bodies.

BCONPRP Physical Contact Parameters of Touching Bodies.

BCBODY1 Flexible or Rigid Contact Body in 2D and 3D (New Form).

BCBDPRP Contact Body Parameters.

BCRIGID Defines a Rigid Contact Body.

BCRGSRF Rigid Contact Body Surface List.

BCPATCH Defines a Rigid Contact Body Made up of Quadrilateral Patches.

BCNURB2 Defines a 2D Rigid Contact Body Made up of NURBS.

BCNURBS Defines a Rigid Contact Body Made up of NURBS.

BCTRIM Defines the Geometry of Trimming Curves.

BCONTACT Initiates and controls 3D contact in SOLs 101, 400, and 700. It can refer to BCTABL1, BCONECT or BCTABLE Bulk Data entry.


16

Initial Conditions

IPSTRAIN* Defines initial plastic strain values.

ISTRESS* Defines initial stress values.

MARCIN Insert a text string in MSC.Marc.

MARCOUT Selects data recovery output.


Materials

Note: * Not supported in initial release of Patran (2004).

MATEP Elasto-plastic material properties.

MATF Specifies material failure model.

MATG* Gasket material properties.

MATHE Hyperelastic material properties.

MATHP Hyperelastic material properties.

MATHED Damage model properties for hyperelastic materials.

MATORT Elastic 3D orthotropic material properties.

MATTEP Thermoelastic-Plastic material properties.

MATTG* Temperature variation of interlaminar materials.

MATTHE Thermo hyperelastic material.

MATTORT* Thermoelastic orthotropic material

MATTVE* Thermo-visco-elastic material properties

MATVE* Viscoelastic material properties

MATVP Viscoplastic or creep material properties


18

Solution Control

NLAUTO Parameters for automatic load/time stepping.

NLDAMP Defines damping constants.

NLSTRAT Strategy Parameters for nonlinear structural analysis.

PARAMARC Parallel domain decomposition.

RESTART Restart data.


Element Properties

NTHICK Defines nodal thickness values for beams, plates, and/or shells.


20

MSC Nastran Explicit Nonlinear (SOL 700)The following Bulk Data entries are supported for SOL 700 analyses.

Materials

MATD001 Isotropic Elastic material for beam, shell and solid.

MATD003 Isotropic and kinematic hardening plasticity.

MATD005 Isotropic materials to model soil and foam.

MATD006 Isotropic viscoelastic material.

MATD007 Isotropic material to model nearly incompressible continuum rubber.

MATD012 Isotropic plasticity for 3D solids.

MATD014 Isotropic materials to model soil and foam with failure.

MATD015 Isotropic Johnson/Cook strain and temperature sensitive plasticity.

MATD019 Isotropic strain rate dependent material.

MATD020 Isotropic rigid material.

MATD022 Orthotropic material with optional brittle failure for composites.

MATD024 Isotropic elasto-plastic material with stress x strain curve and strain rate dependency.

MATD026 Anisotropic honeycomb and foam material.

MATD027 Isotropic material to model rubber using two variables.

MATD028 Isotropic elasto-plastic material for beam and shell.

MATD030 Isotropic superelastic material.

MATD031 Isotropic material to model rubber using the Frazer-Nash formulation.

MATD032 Orthotropic laminated glass material.

MATD057 Isotropic material to model highly compressible low density foams.

MATD058 *MAT_LAMINATED_COMPOSITE_FABRIC

MATD062 Isotropic material to model viscous foams.

MATD063 Isotropic material to model crushable foams.

MATD064 Isotropic elasto-plastic material with a power law hardening.

MATD067 *MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM

MATD068 *MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM

MATD069 *MAT_SID_DAMPER_DISCRETE_BEAM

MATD070 *MAT_HYDRAULIC_GAS_DAMPER_DISCRETE_BEAM

MATD071 *MAT_CABLE_DISCRETE_BEAM

MATD073 *MAT_LOW_DENSITY_VISCOUS_FOAM


Loads and Boundary Conditions

Elements and Properties

MATD074 *MAT_ELASTIC_SPRING_DISCRETE_BEAM

MATD076 *MAT_GENERAL_VISCOELASTIC

MATD083 *MAT_FU_CHANG_FOAM

MATD087 *MAT_CELLULAR_RUBBER

MATD093 *MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM

MATD094 *MAT_INELASTIC_SPRING_DISCRETE_BEAM

MATD095 *MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM

MATD097 *MAT_GENERAL_JOINT_DISCRETE_BEAM

MATD100 Isotropic spotweld material.

MATD103 Anisotropic viscoplastic material.

MATD119 *MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM

MATD121 *MAT_GURSON_RCDC

MATD126 *MAT_MODIFIED_HONEYCOMB

MATD20M *MAT_RIGID

MATDB01 *MAT_SEATBELT

MATDS01 *MAT_SPRING_ELASTIC

MATDS02 *MAT_DAMPER_VISCOUS

MATDS03 *MAT_SPRING_ELASTOPLASTIC

MATDS04 *MAT_SPRING_NONLINEAR_ELASTIC

MATDS05 *MAT_DAMPER_NONLINEAR_VISCOUS

MATDS06 *MAT_SPRING_GENERAL_NONLINEAR

MATDS07 *MAT_SPRING_MAXWELL

MATDS08 *MAT_SPRING_INELASTIC

MATDS13 *MAT_SPRING_TRILINEAR_DEGRADING

MATDS14 *MAT_SPRING_SQUAT_SHEARWALL

MATDS15 *MAT_SPRING_MUSCLE

TIC3 Defines initial rotational field.

WALL Defines planar rigid wall.

CDAMP1D Scalar damper connection for SOL 700

CELAS1D Scalar spring connection for SOL 700.


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Solution Controls

Form Parameters

Execution Control Parameters

DYSTATIC, DYBLDTIM, DYINISTEP, DYTSTEPERODE, DYMINSTEP, DYMAXSTEP, DYSTEPFCTL, DYTERMNENDMAS, DYTSTEPDT2MS

General Parameters DYLDKND, DYCOWPRD, DYCOWPRP, DYBULKL, DYHRGIHQ, DYRGQH, DYENERGYHGEN, DYSHELLFORM, DYSHTHICK, DYSHNIP

Contact Parameters DYCONSLSFAC, DYCONRWPNAL, DYCONPENOPT, DYCONTHKCHG, DYCONENMASS, DYCONECDT, DYCONIGNORE, DYCONSKIPTWG

Binary Output Database File Parameters

DYBEAMIP, DYMAXINT, DYNEIPS, DYNINTSL, DYNEIPH, DYSTRFLG, DYSIGFLG, DYEPSFLG, DYRLTFLG, DYENGFLG, DYCMPFLG, DYIEVERP, DYDCOMP, DYSHGE, DYSTSSZ, DYN3THDT

DAMPGBL Dynamic relaxation control.

23Chapter 2: Building A ModelAdaptive (p-Element) Analysis with the MSC Nastran Preference

2.3 Adaptive (p-Element) Analysis with the MSC Nastran PreferenceIn Version 68 of MSC.Nastran, MSC introduced p-adaptive analysis using solid elements. The Patran MSC Nastran Preference provides support for this new capability. There are some fundamental differences in approach to model building and results import for p-element analyses; this section will serve as a guide to these.

MSC.Nastran Version 69 extends the Version 68 capabilities for p-adaptive analysis in two areas. Shell and beam elements have been added and p-shells and p-beams can be used for linear dynamic solution sequences. Patran Version 6.0 supports both of these capabilities.

Patran Interface to MSC Nastran Preference GuideAdaptive (p-Element) Analysis with the MSC Nastran Preference

24

Element Creation

MSC Nastran supports adaptive, p-element analyses with the 3D-solid CTETRA, CPENTA, and CHEXA elements; 2D-solid TRIA, and QUAD elements; shells TRIA, and QUAD elements; beams BAR elements. Patran and MSC Nastran allow TET4, TET10, TET16, TET40, WEDGE6, WEDGE15, WEDGE52, HEX8, HEX20, and HEX64 for p-adaptive analysis for 3D-solids; TRIA3, TRIA6, TRIA7, TRIA9, TRIA13, QUAD4, QUAD8, QUAD9, QUAD12, and QUAD16 for p-adaptive analysis for 2D-solids and membranes; TRIA3, TRIA6, TRIA7, TRIA9, TRIA13, QUAD4, QUAD8, QUAD9, QUAD12, and QUAD16 for p-adaptive analysis for shells; BAR2, BAR3, and BAR4 for p-adaptive analysis for beams. The preferred approach, when beginning a new model, is to use the higher-order elements--HEX64, WEDGE52, TET40, and TET16, or TRIA13 and QUAD16, or BAR4. The support for lower-order elements is provided primarily to support existing models. The higher-order cubic elements allow more accurate definition of the geometry and more accurate postprocessing of results from the MSC Nastran analysis.The translator generates the appropriate MSC Nastran FEEDGE and POINT entities for all curved edges on the p-elements. Models with HEX64 and WEDGE52 elements are easily created with the Patran Iso Mesher; models with TET16 elements can be created with the Tet Mesher. Models with QUAD16 and TRIA13 elements can be created using the Iso Mesher or the Paver.

For p-elements, Patran generates cubic edges to fit the underlying geometry. The cubic edge consists of two vertex grid points and two points in between. Adjacent cubic edges are not necessarily C1 continuous. If the original geometry is smooth, the cubic edges may introduce kinks which cause false stress concentrations. Then, the p-element produces unrealistic results especially for thin curved shells.

In Version 7 of Patran, for cubic elements, the two midside nodes on each edge are adjusted so that the edges of adjacent elements are C1 continuous. The adjustment is done in the Pat3Nas translator. After the Pat3Nas translator is executed, the location of the two midside nodes in the Patran database has changed. The user is informed with a warning message. The user can turn the adjustment of midside nodes ON and OFF with the environment variable PEDGE_MOVE. By default, the midside nodes are adjusted to make the adjacent elements C1 continuous. For PEDGE_MOVE set to OFF, the points on a cubic edge are not adjusted.

Patran generates the input for MSC Nastran. For cubic edges, FEEDGE Bulk Data entries with POINTs are written. By default, the location of the two POINTs is moved to 1/3 and 2/3 of the edge in MSC Nastran. The points generated by Patran must not be moved. Therefore, a parameter entry PARAM, PEDGEP, 1 is written by Patran. PEDGEP=1 indicates that incoming POINTs are not moved in MSC Nastran. The default is PEDGEP= 0, MSC Nastran will move the two POINTs to 1/3 and 2/3 of the edge. The C1 continuous cubic edges improve the accuracy of p-element results.

In the Version 69 Release Guide, a cylinder under internal pressure was tested to determine the quality of shell p-elements for curved geometry. The accuracy of the results was very good when exact geometry was used. With C1 continuous edges we recover the same quality of results within single precision accuracy.


Element and p-Formulation Properties

Both element and p-formulation properties are defined using the Element Properties application by choosing Action: Create, Dimension: 1D/2D/ or 3D, Type: Beam/Shell/Bending Panel/2D Solid/Membrane/ or Solid, and p-Formulation on the main form. Most of the properties are optional and have defaults; the material property name is required.

Two properties that may need to be defined are Starting P-orders and Maximum P-orders. These properties specify the polynomial orders for the element interpolation functions in the three spatial directions. Although these are integer values, in Patran, each property is defined using the Patran vector definition. At first, this may seem peculiar, but it gives the user access to many useful tools in the Patran system for defining and manipulating these properties. Typically, a user would define these properties with a syntax like <3 4 2> to prescribe polynomial orders of 3, 4, and 2 in the X, Y, and Z directions. Patran will convert these values to floating point <3. 4. 2.>, but the Patran MSC Nastran Preference will interpret them. This vector syntax is convenient primarily because it allows these properties to be defined using the Fields application. In a case where the material properties are constant over the model, but it is desirable to prescribe a distribution of p-orders, vector fields can be defined and specified in a single property definition. The Patran MSC Nastran Preference will provide additional help for this modeling function. At the end of an adaptive analysis, when results are imported, vector, spatial fields will optionally be created containing the p-orders used for each element for each adaptive cycle. To repeat a single adaptive cycle, it is necessary only to modify the element properties by selecting the appropriate field.

A common use of the Maximum P-orders property is in dealing with elements in the vicinity of stress singularities. These singularities may be caused by the modeling of the geometry (e.g., sharp corners), boundary conditions (e.g., point constraints), or applied forces (e.g., point forces). Sometimes it is easier to tell the adaptive analysis to “ignore” these singular regions than it is to change the model. This can be done by setting the Maximum P-orders property for elements in this region to low values (e.g., <1 1 1> or <2 2 2>. These elements are sometimes called “sacrificial” elements.


26

Loads and Boundary Conditions

It is well known in solid mechanics that point forces and constraints cause the stress field in the body to become infinite. In p-adaptive analyses, care must be taken in finite element creation and loads application to ensure that these artificial high-stress regions don’t dominate the analysis.

Generally, the best results are obtained with distributed loads (pressures) or distributed displacements. There are two options under Loads/BCs for applying distributed displacements. The Element Uniform and Element Variable types under Displacements allow displacement constraints to be applied to the faces of solid elements. If the elements are p-elements, the appropriate FEFACE and GMBC entries are produced. If applied to non-p-elements, the appropriate SPC1 or SPCD entries are produced.

Several new loads and boundary conditions support the p-shell and p-beam elements. Distributed loads can be applied to beam elements or to the edge of shell elements. Pressure loads can be applied to the faces of p-shell elements. Temperature loads can be applied to either the nodes or the elements.


Analysis Definition

Adaptive linear static and normal modes analyses are supported in Version 68 of MSC.Nastran; both solution types are supported by the Patran MSC Nastran Preference. Only a few parameters on the Analysis forms may need to be changed for p-element analyses. If running a version of MSC.Nastran prior to Version 68.2 (i.e., Version 68, or 68.1), the OUTPUT2 Request option on the Translation Parameters form must be set to Alter File in order to process the results in Patran. The Solution Parameters forms for the linear static and normal modes analyses contain a Max p-Adaptive Cycles option, which is defaulted to 3. The Subcase Parameters form under Subcase Create has options to limit the participation of this subcase in the adaptive error analysis. Finally, the Advanced Output Requests form under Subcase Create has an option to define whether results are to be produced for all adaptive cycles or only every nth adaptive cycle.


28

Results Import and Postprocessing

Two different approaches are provided for postprocessing results from MSC Nastran p-element analyses. Both approaches rely on MSC Nastran creating results for a “VU mesh” where each p-element is automatically subdivided into a number of smaller elements. In the standard approach with the default MSC Nastran VU mesh (3 x 3 x 3 elements) for solids, (3 x 3 elements) for shells and (3 elements) for beams, the results will automatically be mapped onto the Patran nodes and elements during import. This mapping will occur for all 10, Patran solid element topologies mentioned above. The most accurate mapping and postprocessing takes place when results are mapped to the higher-order Patran elements.

When the adaptive analysis process increases the p-orders in one or more elements beyond 3, the 3 x 3 x 3 VU mesh, mapping, and postprocessing may not be sufficiently accurate. The Patran MSC Nastran Preference provides a second approach to handle this situation. In this case, a user can specify a higher-order VU mesh (e.g. 5 x 5 x 5) on the MSC Nastran OUTRCV entry and then import both model data and results entities into a new, empty Patran database. In this case, the VU mesh and results are imported directly, rather than mapped and can be post-processed with greater accuracy. The OUTRCV entry is currently supported only with the Bulk Data Include File option on the Translation Parameters form.

It should be noted that, with this import mode, displays of element results (e.g., fringe plots) may be discontinuous across parent, p-element boundaries. This occurs because the VU grids generated by MSC Nastran are different in each p-element. Along element boundaries there are coincident nodes and a result associated with each one. The user should not try to perform an Equivalence operation to remove these coincident nodes. If this is done, subsequent postprocessing operations will likely be incorrect.

For both postprocessing options, a result case is created for each adaptive cycle in the analysis. The result types in this result case will depend on specific options selected on the Output Request form. By default, the Adaptive Cycle Output Interval option is equal to zero. This means that output quantities specific to p-elements will be written only for the last cycle. If postprocessing of results from intermediate cycles is desired, the Adaptive Cycle Output Interval option should be set equal to one.

One of the key uses of output from intermediate adaptive cycles is in examining the convergence of selected quantities (e.g., stresses). This can be done using the X-Y plotting capability under the Results application.


Potential Pitfalls

There are several areas where a user can encounter problems producing correct p-element models for MSC Nastran. One is the incorrect usage of the midside nodes in the Patran higher order-elements. These nodes are used in p-element analysis only for defining the element geometry; analysis degrees of freedom are not associated with these nodes. Therefore it is illegal, for example, to attach non p-elements to assign loads or boundary conditions to these nodes. One way this can occur inadvertently is if a nodal force is applied to the face of a Patran solid. This force is interpreted as a point force at every node (including the midside nodes) on the face of the solid. For the p-elements, this is not valid. This type of load should instead be applied as an element uniform or element variable pressure.


30

Adaptive Analysis of Existing Models

Modifying an existing solid model for adaptive, p-element analysis is relatively straightforward. The first step is to read the NASTRAN input file into Patran using the Analysis/Read Input File option. The model may contain any combination of linear or quadratic tetra, penta, or hexa elements. The second step is to use the Element Props/Modify function to change the Option for all solid properties from Standard Formulation to P-Formulation. The element properties form for p-formulation solids has many options specific to p-element analysis; but they all have appropriate defaults. This property modification step is the only change that must be made before submitting the model for analysis.

Often, however, as discussed in Potential Pitfalls, 29, it is appropriate to modify the types of loads and boundary conditions applied to the model. For example, in non p-element models, displacement constraints are applied using MSC Nastran SPC entries at grid points. In p-element analyses, element-oriented displacement constraints are more appropriate. Existing displacement LBCs can be modified using the Loads/BCs/Modify/Displacement option. For an SPC type of displacement constraint, the LBC type is nodal. For a p-element analysis, Element Uniform or Element Variable displacement constraints are more appropriate. The application region must be changed from a selection of nodes to a selection of element faces. As described above, nodal forces can be troublesome in p-element analyses. If possible, it is beneficial to redefine point forces as pressures acting on an element face. If this is not possible, an alternative is to limit the p-orders in the elements connected to the node with the point force; this can be done by defining a new element property for these elements and defining the Maximum P-orders vector appropriately. Element pressures, inertial loads, and nodal temperatures defined in the original model need not be changed for the p-element analysis.

31Chapter 2: Building A ModelCoordinate Frames

2.4 Coordinate FramesCoordinate frames will generate a unique CORD2R, CORD2C, or CORD2S Bulk Data entry, depending on the specified coordinate frame type. The CID field is defined by the Coord ID assigned in Patran. The RID field may or may not be defined, depending on the coordinate frame construction method used in Patran. The A1, A2, A3, B1, B2, B3, C1, C2, and C3 fields are derived from the coordinate frame definition in Patran.

Only Coordinate Frames that are referenced by nodes, element properties, or loads and boundary conditions can be translated. For more information on creating coordinate frames see Creating Coordinate Frames (p. 393) in the Geometry Modeling - Reference Manual Part 2.

To output all the coordinate frames defined in the model whether referenced or not, set the environment variable “WRITE_ALL_COORDS” to ON.

Patran Interface to MSC Nastran Preference GuideFinite Elements

32

2.5 Finite ElementsThe Finite Elements Application in Patran allows the definition of basic finite element construction. Created under Finite Elements are the nodes, element topology, multi-point constraints, and Superelement.

For more information on how to create finite element meshes, see Mesh Seed and Mesh Forms (p. 25) in the Reference Manual - Part III.

NodesNodes in Patran will generate unique GRID Bulk Data entries in MSC Nastran. Nodes can be created either directly using the Node object, or indirectly using the Mesh object. Each node has associated Reference (CP) and Analysis (CD) coordinate frames. The ID is taken directly from the assigned node

33Chapter 2: Building A ModelFinite Elements

ID. The X1, X2, and X3 fields are defined in the specified CP coordinate frame. If no reference frame is assigned, the global system is used. The PS and SEID fields on the GRID entry are left blank.

ElementsThe Finite Elements Application in Patran assigns element connectivity, such as Quad4, for standard finite elements. The type of MSC Nastran element to be created is not determined until the element properties are assigned (for example, shell or 2D solid). See the Element Properties Form, 100 for details concerning the MSC Nastran element types. Elements can be created either directly using the Element object, or indirectly using the Mesh object

The analysis frame (CD of the GRID) is the coordinate system in which the displacements, degrees of freedom, constraints, and solution vector are defined. The coordinate system in which the node location is defined (CP of the GRID) can be either the reference coordinate frame, the analysis coordinate frame, or a global reference (blank), depending on the value of the forward translation parameter “Node Coordinates.”


34

Mesher is used to specify how the element mesh is to be created; for example, IsoMesh, Paver. The type of geometry (for example, simple (green) or complex (magenta) surface) may determine the choice of the mesher.

Elem Shape is used to specify the shape of the elements created by meshing. For example, the shape for a 2D element can be either triangular or quadralateral.

Beginning IDs for nodes and elements to be created.

List of surface IDs of surfaces to be meshed. For example Surface 1, 2, 3, or Surface 1:3.

The value of Global Edge Length specifies the approximate size of the elements created when meshing.

The button Select Existing Prop... is used to select an existing element property (for example, 2D Shell) that will be assigned to the elements created by meshing.

The button Create New Property is used to create an element property that will be assigned to the elements that will be created by meshing. During creating the element property no application region can be specified; it is specified automatically using all the elements created by meshing.

This type of form is used to create a 1D, 2D, or 3D element mesh.

This “ghosted” area will become dark when an element property is selected.


Multi-point ConstraintsMulti-point constraints (MPCs) can also be created from the Finite Elements Application. These are special element types that define a rigorous behavior between several specified nodes. The forms for creating MPCs are found by selecting MPC as the Object on the Finite Elements form. The full functionality of the MPC forms are defined in Create Action (FEM Entities).

Used to specify the ID to associate to the MPC when it is created.


36

MPC Types

To create an MPC, first select the type of MPC to be created from the option menu. The MPC types that appear in the option menu are dependent on the current settings of the Analysis Code and Analysis Type preferences. The following table describes the MPC types which are supported for MSC Nastran.

MPC Type Analysis Type Description

Explicit Structural Creates an explicit MPC between a dependent degree of freedom and one or more independent degrees of freedom. The dependent term consists of a node ID and a degree of freedom, while an independent term consists of a coefficient, a node ID, and a degree of freedom. An unlimited number of independent terms can be specified, while only one dependent term can be specified. The constant term is not allowed in MSC Nastran.

RSSCON Surf-Vol

Structural Creates an RSSCON type MPC between a dependent node on a linear 2D plate element and two independent nodes on a linear 3D solid element to connect the plate element to the solid element. One dependent and two independent terms can be specified. Each term consists of a single node.

Rigid (Fixed) Structural and Explicit Nonlinear

Creates a rigid MPC between one independent node and one or more dependent nodes in which all six structural degrees of freedom are rigidly attached to each other. An unlimited number of dependent terms can be specified, while only one independent term can be specified. Each term consists of a single node. There is no constant term for this MPC type.

RBAR Structural and Explicit Nonlinear

Creates an RBAR element, which defines a rigid bar between two nodes. Up to two dependent and two independent terms can be specified. Each term consists of a node and a list of degrees of freedom. The nodes specified in the two dependent terms must be the same as the nodes specified in the two independent terms. Any combination of the degrees of freedom of the two nodes can be specified as independent as long as the total number of independent degrees of freedom adds up to six. There is no constant term for this MPC type.

RBE1 Structural Creates an RBE1 element, which defines a rigid body connected to an arbitrary number of nodes. An arbitrary number of dependent terms can be specified. Each term consists of a node and a list of degrees of freedom. Any number of independent terms can be specified as long as the total number of degrees of freedom specified in all of the independent terms adds up to six. Since at least one degree of freedom must be specified for each term there is no way the user can create more that six independent terms. There is no constant term for this MPC type.


RBE2 Structuraland Explicit Nonlinear

Creates an RBE2 element, which defines a rigid body between an arbitrary number of nodes. Although the user can only specify one dependent term, an arbitrary number of nodes can be associated to this term. The user is also prompted to associate a list of degrees of freedom to this term. A single independent term can be specified, which consists of a single node. There is no constant term for this MPC type.

RBE3 Structuraland Explicit Nonlinear

Creates an RBE3 element, which defines the motion of a reference node as the weighted average of the motions of a set of nodes. An arbitrary number of dependent terms can be specified, each term consisting of a node and a list of degrees of freedom. The first dependent term is used to define the reference node. The other dependent terms define additional node/degrees of freedom, which are added to the m-set. An arbitrary number of independent terms can also be specified. Each independent term consists of a constant coefficient (weighting factor), a node, and a list of degrees of freedom. There is no constant term for this MPC type.

RROD Structural Creates an RROD element, which defines a pinned rod between two nodes that is rigid in extension. One dependent term is specified, which consists of a node and a single translational degree of freedom. One independent term is specified, which consists of a single node. There is no constant term for this MPC type.

RSPLINE Structural Creates an RSPLINE element, which interpolates the displacements of a set of independent nodes to define the displacements at a set of dependent nodes using elastic beam equations. An arbitrary number of dependent terms can be specified. Each dependent term consists of a node, a list of degrees of freedom, and a sequence number. An arbitrary number of independent nodes (minimum of two) can be specified. Each independent term consists of a node and a sequence number. The sequence number is used to order the dependent and independent terms with respect to each other. The only restriction is that the first and the last terms in the sequence must be independent terms. A constant term, called D/L Ratio, must also be specified.



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RTRPLT Structural Creates an RTRPLT element, which defines a rigid triangular plate between three nodes. Up to three dependent and three independent terms can be specified. Each term consists of a node and a list of degrees of freedom. The nodes specified in the three dependent terms must be the same as the nodes specified in the three independent terms. Any combination of the degrees of freedom of the three nodes can be specified as independent as long as the total number of independent degrees of freedom adds up to six. There is no constant term for this MPC type.

Cyclic Symmetry

Structural Describes cyclic symmetry boundary conditions for a segment of the model. If a cyclic symmetry solution sequence is chosen, such as “SOL 114,” then CYJOIN, CYAX and CYSYM entries are created. If a solution sequence that is not explicitly cyclic symmetric is chosen, such as “SOL 101,” MPC and SPC entries are created. Be careful, for this option automatically alters the analysis coordinate references of the nodes involved. This could erroneously change the meaning of previously applied load and boundary conditions, as well as element properties.

Sliding Surface

Structural Describes the boundary conditions of sliding surfaces, such as pipe sleeves. These boundary conditions are written to the NASTRAN input file as explicit MPCs. Be careful, for this option automatically redefines the analysis coordinate references of all affected nodes. This could erroneously alter the meaning of previously applied load and boundary conditions, as well as element properties.

RBAR1 Structural This is an alternate (simplified) form for RBAR. Creates an RBAR1 element, which defines a rigid bar between two nodes, with six degrees of freedom at each end. Each dependent term consists of a node and a list of degrees of freedom, while the independent term consists only of a node (with all six degrees of freedom implied). The constant term is the thermal expansion coefficient, ALPHA.



RTRPLT1 Structural Alternative format to define a rigid triangular plate element connecting three grid points. Creates an RTRPLT1 element, which defines a rigid triangular plate between three nodes. Each dependent term consists of a node and a list of degrees of freedom, while the independent term consists only of the node (with all six degrees of freedom implied). The constant term is the thermal expansion coefficient, ALPHA.

RJOINT Structural Creates an RJOINT element, which defines a rigid joint element connecting two coinciding grid points. Each dependent term consists of a node and a list of degrees of freedom, while the independent term consists only of a node (with all six degrees of freedom implied). There is no constant term for this MPC type.



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Degrees of Freedom

Whenever a list of degrees of freedom is expected for an MPC term, a listbox containing the valid degrees of freedom is displayed on the form.

The following degrees of freedom are supported by the Patran MSC Nastran MPCs for the various analysis types:

Explicit MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and Explicit is the selected type. This form is used to create an MSC Nastran MPC Bulk Data entry. The difference in explicit MPC equations between Patran and MSC Nastran will result in the A1 field of the MSC Nastran entry being set to -1.0.

Degree of freedom Analysis Type

UX Structural

UY Structural

UZ Structural

RX Structural

RY Structural

RZ Structural

Note: Care must be taken to make sure that a degree of freedom that is selected for an MPC actually exists at the nodes. For example, a node that is attached only to solid structural elements will not have any rotational degrees of freedom. However, Patran will allow you to select rotational degrees of freedom at this node when defining an MPC.


Holds the dependent term information. This term will define the fields for G1 and C1 on the MPC entry. Only one node and DOF combination may be defined for any given explicit MPC. The A1 field on the MPC entry is automatically set to -1.0.

Holds the independent term information. These terms define the Gi, Ci, and Ai fields on the MPC entry, where i is greater than one. As many coefficient, node, and DOF combinations as desired may be defined.


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Rigid (Fixed)

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and Rigid (Fixed) is the selected type. This form is used to create an MSC Nastran RBE2 Bulk Data entry. The CM field on the RBE2 entry will always be 123456.

Holds the dependent term information. This term defines the GMi fields on the RBE2 entry. As many nodes as desired may be selected as dependent terms.

Holds the independent term information. This term defines the GN field on the RBE2 entry. Only one node may be selected.


RBAR MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RBAR is the selected type. This form is used to create an MSC Nastran RBAR Bulk Data entry and defines a rigid bar with six degrees of freedom at each end. Both the Dependent Terms and the Independent Terms lists can have either 1 or 2 node references. The total number of referenced nodes,


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however, must be 2. If either or both of these lists references 2 nodes, then there must be an overlap in the list of referenced nodes.

Holds the dependent term information. Either one or two nodes may be defined as having dependent terms. The Nodes define the GA and GB fields on the RBAR entry. The DOFs define the CMA and CMB fields.

Holds the independent term information. Either one or two nodes may be defined as having independent terms.The Nodes define the GA and GB fields on the RBAR entry.The DOFs define the CNA and CNB fields.


RBE1 MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RBE1 is the selected type. This form is used to create an MSC Nastran RBE1 Bulk Data entry.


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Holds the dependent term information. Defines the GMi and CMi fields on the RBE1 entry. An unlimited number of nodes and DOFs may be defined here.

Holds the independent term information. Defines the GNi and CNi fields on the RBE1 entry. The total number of Node/DOF pairs defined must equal 6, and be capable of representing any general rigid body motion.


RBE2 MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RBE2 is the selected type. This form is used to create an MSC Nastran RBE2 Bulk Data entry.

Holds the dependent term information. This term defines the GMi and CM fields on the RBE2 entry. As many nodes as desired may be selected as dependent terms.

Holds the independent term information. This term defines the GN field on the RBE2 entry. Only one node may be selected.


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RBE3 MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RBE3 is the selected type. This form is used to create a MSC Nastran RBE3 Bulk Data entry.

Holds the dependent term information. Defines the GMi and CMi fields on the RBE3 entry. The first dependent term will be treated as the reference node, REFGRID and REFC. The rest of the dependent terms become the GMi and CMi components.

Holds the independent term information. Defines the Gi, j, Ci, and WTi fields on the RBE3 entry.


RROD MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RROD is the selected type. This form is used to create an MSC Nastran RROD Bulk Data entry.

Holds the dependent term information. Defines the GB and CMB on the RROD entry. Only one translational DOF may be referenced for this entry.

Holds the independent term information. Defines the GA field on the RROD entry. The CMA field is left blank.


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RSPLINE MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RSPLINE is the selected type. This form is used to create an MSC Nastran RSPLINE Bulk Data entry. The D/L field for this entry is defined on the main MPC form. This MPC type is typically used to tie together two dissimilar meshes.

Holds the independent term information. Terms with the highest and lowest sequence numbers must be independent.

Holds the dependent term information.

Determines what sequence the independent and dependent terms will be written to the RSPLINE entry.


RTRPLT MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RTRPLT is the selected type. This form is used to create an MSC Nastran RTRPLT Bulk Data entry.

Holds the dependent term information. Defines the GA, GB, GC, CMA, CMB, and CMC fields of the RTRPLT entry.

Holds the independent term information. The total number of nodes referenced in both the dependent terms and the independent terms must equal three. There must be exactly six independent degrees of freedom, and they must be capable of describing rigid body motion. Defines the GA, GB, GC, CNA, CNB, and CNC fields of the RTRPLT entry.


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Cyclic Symmetry MPCs

The Cyclic Symmetry MPC created by this form will be translated into CYJOIN, CYAX, and CYSYM entries if cyclic symmetric is the selected type, see Solution Parameters, 298, or into SPC and MPC entries if the requested type is not explicitly cyclic symmetric.

If the type selected is Cyclic Symmetry, the type of symmetry will always be rotational.NOTE: MPC option will automatically overwrite the analysis coordinate references on all the nodes belonging to the Dependent and Independent Regions. Be careful that this does not erroneously change the meaning of previously applied loads and boundary conditions, or element properties.

Side 1 of the CYJOIN entries.

Any node lying on the Z axis will be automatically written to the CYAX entry.

Side 2 of the CYJOIN entries.


Sliding Surface MPCs

The Sliding Surface MPC created by this form will be translated into explicit MPCs in the NASTRAN input file.

If a Sliding Surface type is used, note that this MPC option will automatically overwrite the analysis coordinate references on all the nodes belonging to the Dependent and Independent Regions. Be careful that this does not erroneously change the meaning of previously applied loads and boundary conditions, or element properties.


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RBAR1 MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RBAR1 is the selected type. This form is used to create an MSC Nastran RBAR1 Bulk Data entry..


RTRPLT1 MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RTRPLT1 is the selected type. This form is used to create an MSC Nastran RTRPLT1 Bulk Data entry..


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RJOINT MPCs

This subordinate MPC form appears when the Define Terms button is selected on the Finite Elements form and RJOINT is the selected type. This form is used to create an MSC Nastran RJOINT Bulk Data entry..


SuperelementsIn superelement analysis, the model is partitioned into separate collections of elements. These smaller pieces of structure, called Superelement, are first solved as separate structures by reducing their stiffness matrix, mass matrix, damping matrix, loads and constraints to the boundary nodes and then combined to solve for the whole structure. The first step in creating a superelement is to create a Patran group (using Group/Create) that contains the elements in the superelement. This group is then selected in the Finite Elements application on the Create/ Superelement form.

List of existing superelements.

The group containing all the elements that define a superelement. Note that the group must contain elements not just nodes. If a group does not contain elements, it will not show up in the Element Definition Group listbox.

Brings up an optional subordinate form that allows a user to select boundary nodes of the superelement. By default, the common nodes between the elements in the group and the rest of the model are selected as the boundary nodes.


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Select Boundary Nodes

Allows for manual selection of boundary nodes.

Remove selected nodes from the Selected Boundary Nodes box.

Add selected nodes to the Selected Boundary Nodes box.

59Chapter 2: Building A ModelMaterial Library

2.6 Material LibraryThe Materials form appears when the Material toggle, located on the Patran application selections, is chosen. The selections made on the Materials menu will determine which material form appears, and ultimately, which Nastran material will be created.

The following pages give an introduction to the Materials form and details of all the material property definitions supported by the Nastran Preference.

Only material records that are referenced by an element property region or by a laminate lay-up are translated. References to externally defined materials result in special comments in the input Nastran file, e.g., materials that property values that are not defined in Patran.

The forward translator performs material type conversions when needed. This applies to both constant material properties and temperature-dependent material properties. For example, a three-dimensional orthotropic material that is referenced by CHEXA elements is converted into a three-dimensional anisotropic material.

Materials Application FormThis form appears when Materials is selected on the main menu. The Materials form is used to provide options to create the various Nastran materials.

Patran Interface to MSC Nastran Preference GuideMaterial Library

60

This toggle defines the basic material directionality and can be set to Isotropic, 2D Orthotropic, 3D Orthotropic, 2D Anisotropic, 3D Anisotropic, Fluid, Cohesive, or Composite. For Explicit Nonlinear additional materials can be defined.

Defines the material name. A unique material ID will be assigned during translation.

Lists the existing materials with the specified directionality.

Describes the material that is being created.

Generates a form that is used to define the material properties. See Material Input Properties Form, 61.

Generates a form that is used to indicate the active portions of the material model. By default, all portions of a created material model are active.


Material Input Properties FormThe Input Properties form is the form where all constitutive material models are defined for each material created. Multiple constitutive models can be created for each material created by pressing the Apply button on the main Materials form with the proper widgets set on this form. Multiple constitutive models of the same type are not allowed. The list of existing constitutive models are shown in the bottom list box. A list of valid constitutive models is given in the table below.

Set the Constitutive Model here. Press the Apply button on the main Materials application form to create a constitutive model for the given material. Multiple constitutive models can be created for the same material.

Enter the property values in the databoxes. If a value can be temperature, model, strain rate, or strain dependent, a separate listbox will appear to select a field. These fields must be created in the Fields application as Material type fields.

This is a list of current constitutive models. Use the Change Material Status button to turn them on/off from translation into the Nastran input deck.


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Material Constitutive ModelsThe following table outlines the options when Create is the selected Action.

Object Option 1 Option 2 Option 3 Option 4 Option 5

Isotropic • Linear Elastic

• Nonlinear Elastic

• Hyperelastic • Nearly Incompressible

• Test Data • Mooney Rivlin Order:

1

2

3

• Coefficients • Mooney Rivlin

• Ogden

• Foam

• Arruda-Boyce

• Gent

Order:

1

2

3

4

5

• User Sub. (UELASTOMER)

• Foam_Invariants

• Foam_Principals

• Foam_Invariants (Dev. Split)

• Foam_Principals

(Dev. Split)

• Rubber_InvariantBased

• Rubber_Principal Stretch

0

• Elastoplastic • Stress/Strain Curve

• von Mises

• Tresca

• Mohr-Coulomb

• Drucker-Prager

• Isotropic

• Kinematic

• Combined


• Parabolic Mohr-Colomb

• Buyukozturk Concrete

• Oak Ridge National Labs

• 2-1/4 Cr-Mo ORNL

• Reversed Plasticity ORNL

• Fully Alpha Reset ORNL

• Generalized Plasticity

• Isotropic

• Kinematic

• Combined

• Piecewise Linear

• Cowper-Symonds

• None • Power Law

• Power Rate Law

• Johnson-Cook

• Kumar

• Hardening Slope

• von Mises

• Tresca

• Mohr-Coulomb

• Drucker-Prager

• Isotropic

• Kinematic

• Combined

• Perfectly Plastic

• Parabolic Mohr-Colomb

• Buyukozturk Concrete






• None • Piecewise Linear

• Cowper-Symonds



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• Rigid Plastic • None • Power Law

• Power Rate Law

• Johnson-Cook

• Kumar

Piecewise-Linear

Piecewise LinearCowper-Symonds

• Failure • n/a

• Hill

• Hoffman

• Tsai-Wu

• Maximum Strain

• Failure1/2/3 • Maximum Stress

• Maximum Strain

• Hoffman

• Hill

• Tsai-Wu

• Hashin

• Puck

• Hashin-Tape

• Hashin-Fabric

• User Sub. UFAIL

• No Progressive

• Standard

• Gradual Selective

• Immediate Selective



• Creep • Tabular Input

• Creep Law 111

• Creep Law 112

• Creep Law 121

• Creep Law 122

• Creep Law 211

• Creep Law 212

• Creep Law 221

• Creep Law 222

• Creep Law 300

• User Sub.(CRPLAW)

• MATVP

• Hypoelastic • Isotropic

• User Defined

• Gradient Only

• Gradient and Rotation

• Gradient and Stretch Ratio

• All Input

• All Input (mid increment)

• All Input (end increment)

• User Defined

• User Defined

• Isotropic

• Gradient Only

• Gradient and Rotation

• Gradient and Stretch Ratio

• All Input

• All Input (mid increment)

• All Input (end increment)

• Viscoelastic • No Function

• Williams-Landel-Ferry

• Power Series Expansion



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• Stress-Life (SN) and Strain Life (eN), Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible)

• Derived

• Standard Parameters

• Bastenaire Parameters

• Tabular

• Alloy

• Aluminium

• Cast Iron

• Cast Steel

• Stainless Steel

• Wrought Steel

• Misc. Steel

• Other

• Various metals

2D Orthotropic • Linear Elastic

• Failure • Stress

• Strain

• n/a

• Hill

• Hoffman

• Tsai-Wu

• Maximum Strain

• Failure1/2/3 • See Isotropic Entry

• Elastoplastic • Stress/Strain Curve

• von Mises

• Tresca

• Mohr-Coulomb

• Drucker-Prager






• Isotropic

• Kinematic

• Combined

• Piecewise Linear

• Cowper-Symonds

• Hardening Slope

• von Mises

• Tresca

• Mohr-Coulomb

• Drucker-Prager

• Isotropic

• Kinematic

• Combined



• Perfectly Plastic

• von Mises






• None • Piecewise Linear

• Cowper-Symonds

• Creep • MATVP

• Viscoelastic • See Isotropic Entry

3D Orthotropic • Linear Elastic

• Elastoplastic • See 2D Orthotropic Entry

• Failure1/2/3 • See 2D Orthotropic Entry

• Creep • See 2D Orthotropic Entry

• Viscoelastic • See Isotropic Entry

2D Anisotropic • Linear Elastic


• Failure • See Isotropic Entry

• Failure1/2/3 • See Isotropic Entry - progressive failure not supported

3D Anisotropic • Linear Elastic


• Failure1/2/3 • See 2D Orthotropic Entry - progressive failure not supported

• Creep • See Isotropic Entry

Fluid • Linear Elastic

Cohesive • Bilinear • Secant • No

• Yes

• Automatic

• User Defined

• Keep

• Exponential • Secant • No

• Yes

• Automatic

• User Defined

• Keep

• Linear-Exponential

• Secant • Yes • Automatic

• User Defined

• Keep



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Additional materials for Explicit Nonlinear (SOL 700) are listed in the following table.

• User Sub. (UCOHESIVE)

• Secant • No

• Yes

• None • Keep

Composite • Laminate

• Rule of Mixtures

• HAL Cont. Fiber

• HAL Disc. Fiber

• HAL Cont. Ribbon

• HAL Disc. Ribbon

• HAL Particulate

• Short Fiber 1D

• Short Fiber 2D



Isotropic • Linear Elastic • Linear Elastic (MAT1)

• Solid

• Fluid

• Elastoplastic • Plastic Kinematic(MAT3)

• Iso.Elastic Plastic(MAT12)

• Rate Dependent (MAT19)

• Bilinear

• Piecewise Linear (MAT24)

• Biliear

• Linearized

• Table

• Cowper Symonds

• General

• Rate Sensitive (MAT64)

• Powerlaw

• Resultant (MAT28)

• Shape Memory (MAT30)

• With Failure (MAT13)

• Power Law (MAT18)

• Ramberg-Osgood (MAT80)


• Hydro (MAT10) • Linearized

• Viscoelastic • Viscoelastic (MAT6)

• Rigid • Material Type 20 • No Constraints

• Global Directions

• Local Directions

• MATRIG (Rigid Body Properties)

• Geometry

• Defined

• No Constraints

• Global Directions

• Local Directions

• Johnson Cook • Material Type 15 • No iteractions

• Accurate

• Minimum Pressure

• No Tension, Min. Stress

• No Tension, Min. Pressure

• Rubber • Frazer Nash (MAT31)

• Coefficient

• Least Square Fit

• Respect

• Ignore

• Blatz-Ko (MAT7)

• General Viscoelastic (MAT76)

• Cellular Rubber (MAT87)

• Mooney Rivlin (MAT27)

• Arruda-Boyce (MAT127)

• Coeff.

• Least Square

• Hyperelastic (MAT77)

• Coefficients

• Least Square Fit 1/2/3

• Simplified • Tension-Compresion Load

• Compression Load

• Tension-Compression Identical

• True Strain

• Engineering Strain Rate

• Simple Average

• 12 Point Average

• Foam • Soil and Foam (MAT5/14)

• Active (MAT14)

• Inactive (MAT 5)

• Allow Crushing

• Reversible

• Low Density Urethane (MAT57)

• Fu Chang Foam (MAT83)

• Bulk Viscosity Inactive

• Bulk Viscosity Active

• No Tension

• Maintain Tension



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• Low Density Urethane (MAT57)



• No Tension

• Maintain Tension

• With Relaxation curve

• No Relaxation Curve

• Viscous Foam (MAT62)

• Crushable (MAT63)

• Elastoviscoplatic • With Damage (MAT81)

• Strain Damage

• Orthotropic

• RCDC

• Bilinear

• Linearized

• Table

• Cowper Symonds

• General

• Discrete Beam • Nonlinear Elastic Discrete Beam (MAT67)

• Nonlinear Plastic Discrete Beam (MAT68)

• Side Impact Dummy (SID) Damper Discrete Beam (MAT69)

• Hydraulic Gas Damper Discrete Beam (MAT70)

• Cabel Discrete Beam (MAT71)

• Elastic Spring Discrete Beam (MAT74)

• Elastic 6 DOF Spring Discrete Beam (MAT93)

• Inelastic Spring Discrete Beam (MAT94)

• Inelastic 6 DOF Srping Discrete Beam (MAT95)

• General Joint Discrete Beam (MAT97)

• Spring Damper • Nonlinear 6 DOF Discrete Beam (MAT119)

• General Nonlinear 1 DOF Discrete Beam (MAT121)

• Follow Loading Curve

• Follow Unloading Curve

• Follow Unloading Stiffness

• Follow Quadratic Unloading



• Elastic Spring (MATDS01)

• Viscous Damper (MATDS02)

• Elastic Spring (MATDS03)

• Nonlinear Elastic Spring (MATDS04)

• Nonlinear Viscous Damper (MATDS05)

• General Nonlinear Spring (MATDS06)

• Spring Maxwell (MATDS07)

• Inelastic Spring (MATDS08)

• Tri-linear Degrading (MATDS13)

• Squat Shear Wall (MATDS14)

• Muscle (MATDS15)

• Seat Belt • Seat Belt (MATB01)

• Spotweld • MATDSW1 • DF

• MATDSW2 • DFRES

• DFRESNF

• DFRESNFP

• MATDSW3 • DFSTR

• MATDSW4 • DFRATE

• MATDSW5 • DFNS

• DFSIF

• DFSTRUC

2D Orthotropic • Glass (Laminated)

• Laminated Glass (MAT32)

• Glass

• Polymer

• Composite • Enh. Composite Damage

• Tsai-Wu Theory

• Chang-Chang Theory

• Linear Elastic • Linear Elastic (MAT2)

• Composites and Fabrics

• Composites and Fabrics (MAT58)

• Zero

• One

• Two

• Three

• 0.0

• 1.0

• -1.0

3D Orthotropic • Honeycomb • Composite Honeycomb (MAT26)





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• Composite • Composite Damage (MAT22)

• Composite Failure (MAT59)

• Faceted

• Ellipsoidal


• Modified Honeycomb

• Modified Honeycomb (MAT126)



• LCA .LT. 0

• LCA .GT. 0

• Zero

• One

• Two

2D Anisotropic • Viscoplastic • Viscoplastic (MAT103)

• Shell • From Curve

• Manual Entry


3D Anisotropic • Viscoplastic • Viscoplastic (MAT103)

• Brick • From Curve

• Manual Entry




Linear Elastic

The Input Properties form displays the following for linear elastic properties. The translator produces MAT1 entries for isotropic materials, MAT8 entries for 2D orthotropic materials, MAT3 entries using axisymmetric solid elements or MAT9 entries using 3D solid elements (CHEXA, CPENTA, CTETRA) for 3D orthotropic materials, MAT2 entries for 2D plane stress - 2D anisotropic materials, and MAT9 entries for 3D anisotropic materials. For temperature dependencies, the corresponding MATTi entries are written referencing TABLEMi entries. Temperature dependency is defined using material fields defined under the Fields application. SOL 600 jobs using 3D Orthotropic material the MATORT entry is written

SOL 400 jobs using 3D Orthotropic MATORT materials are shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists for a 3D Orthotropic MATORT material, the MATUDS entry is written to activate user subroutine orient in conjunction with MATORT.

.

Isotropic Description

Elastic Modulus Elastic modulus, E, (Young’s modulus). Can be temperature dependent.

Poisson Ratio Poisson’s ratio (NU). Can be temperature dependent. Should be between -1.0 and 0.5.

Shear Modulus Shear modulus (G). Can be temperature dependent.

Density Density (RHO). Can be temperature dependent.

Thermal Expansion Coefficient Thermal coefficient of expansion (A). Can be temperature dependent.

Structural Damping Coefficient Structural damping coefficient (GE). Can be temperature dependent.

Reference Temperature Reference temperature (TREF).

2D/3D Orthotropic Description

Elastic Modulus ii Modulus of elasticity in 1-, 2-, and 3-directions. Can be temperature dependent.

Poisson Ratio ij Poisson’s ratio for uniaxial loading in the three different directions. Can be temperature dependent.

Shear Modulus ij In-plane and transverse shear moduli in ij planes. Can be temperature dependent.


Thermal Expansion Coefficient ii Thermal coefficients of expansion in the three directions. Can be temperature dependent.


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2D/3D Anisotropic Description

Stiffness ij Elements of the 6x6 symmetric material property matrix in the material coordinate system. Can be temperature dependent.


Thermal Expansion Coefficient ij Thermal coefficients of expansion. Can be temperature dependent.



2D/3D Orthotropic Description


Nonlinear Elastic

The Input Properties form displays the following for nonlinear elastic properties. Use this form to define the nonlinear elastic stress-strain curve on the MATS1 entry. A stress-strain table defined using the Fields application can be selected on this form. Based on this information the translator will produce MATS1 of type NLELAST and TABLES1 entries. This is used primarily for SOL 106 and 129. This option is not supported by SOL 600. Use an elastoplastic constitutive model instead.

Isotropic Description

Stress/Strain Curve Defines the nonlinear elastic stress-strain curve. You must select a field from the listbox. It can be strain and/or temperature dependent. Tabular definition of the stress-strain curve via the Fields application using a material field of strain should follow the specifications as outlined by Nastran. The first point of the material field should be the origin and the second point must be at the initial yield point. This material curve is elastic, meaning that in both loading and unloading the material behavior follows the stress-strain curve as defined. It is not recommended that both nonlinear elastic and elastoplastic constitutive models be active or defined for the same material. For work hardening, use the Elastoplastic constitutive model. See the Nastran Quick Reference Guide for more details.


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Hyperelastic

The Input Properties form displays the following for hyperelastic properties. Use this form to define the data describing hyperelastic behavior of a material. This data is placed on MATHP and TABLES1 entries or on the MATHE entry for SOL 600.

If you select Test Data as the Data Type, the Input Options form reverts to the form used for non-SOL 600 solutions and data is placed on a MATHP entry (Mooney-Rivlin strain energy model). To use test data for MATHE/SOL 600 runs, use the Experimental Data Fitting features under the Tools menu to determine the coefficients and enter them manually.

If Coefficients is selected as the Data Type, use the form to describe the strain energy potential. The Mooney Rivlin model can be written out as a MATHP or MATHE entry for SOL 600. Make sure you use the one that is consistent with the solution to be run. Ogden, Foam, Arruda-Boyce, and Gent models are used for SOL 600 MATHE entries only.

Test Data - Mooney Rivlin Description

Tension/Compression TAB1 All data provided must reference a strain dependent field defining the test data. Please refer to the Nastran Quick Reference Guide for descriptions of each of these tabular inputs.

Equibiaxial Tension TAB2

Simple Shear Data TAB3

Pure Shear Data TAB4

Pure Volume Compression TABD

Mooney Rivlin (MATHP) Description

Distortional Deformation Coefficients, Aij Material constants related to distortional deformation. The Order of the Polynomical determines the number of coefficients required as input.

Volumetric Deformation Coefficients, Di Material constants related to volumetric deformation. The Order of the Polynomial determines the number of coefficients required as input.

Density RHO Defines the mass density which is an optional property.

Volumetric Thermal Expansion Coefficient AV Coefficient of volumetric thermal expansion.

Reference Temperature TREF Defines the reference temperature for the thermal expansion coefficient.

Structural Damping Coefficient GE Structural damping element coefficient.


Mooney Rivlin (MATHE) Description

Strain Energy FunctionC10, C01, C11, C20, C30

Strain energy densities as a function of the strain invariants in the material. May vary with temperature via a defined material field. This option consolidates several of the hyperelastic material models, including Neo-Hookean (C10 only), Mooney-Rivlin (C10 & C01), and Full Third Order Invariant (all coefficients).

Density RHO Defines the mass density

Thermal Expansion Coefficient Defines the instantaneous coefficient of thermal expansion. This property is optional. May vary with temperature via a defined material field.

Bulk Modulus K Defines the Bulk Modulus.


Structural Damping Coefficient GE Structural damping element coefficient.

Ogden Description


Density RHO Defines the material mass density.

Coefficient of Thermal Expansion

Defines the instantaneous coefficient of thermal expansion. This property is optional. May vary with temperature via a defined material field


Modulus k in the Ogden equation. The number of

moduli required as input is dependent on the Order of the Polynomial.

Exponent k in the Ogden equation. The number of

exponents required as input is dependent on the Order of the Polynomial.

Foam Description


Density RHO Defines the material mass density.

μk

αk


78

Thermal Expansion Coefficient Defines the instantaneous coefficient of thermal expansion. This property is optional. May vary with temperature via a defined material field


Modulus n in the Foam equation. The number of moduli

required as input is dependent on the Order of the Polynomial.

Deviatoric Exponent n in the Foam equation. The number of


Volumetric Exponent n in the Foam equation. The number of


Foam Description

un

αn

βn


If you select User Sub. (UELASTOMER) as the Data Type, use the form to describe the User Strain Energy Function (Model = GHEMi) (SOL 400 only) and data is placed on a MATHE entry. GHEM1, GHEM2, GHEM3, GHEM4, GHEM5 and GHEM6 models are used for SOL 400 MATHE entries only. This material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine uelastomer in conjunction with MATHE.

Arruda- Boyce Description

NKT Chain density times Boltzmann constant times temperature. May vary with temperature via a defined material field.

Chain Length Average chemical chain cross length. May vary with temperature via a defined material field.


Density RHO This defines the material mass density.

Thermal Expansion Coefficient Defines the instantaneous coefficient of thermal expansion. This property is optional. May vary with temperature via a defined material field


Gent Description

Tensile Modulus Defines standard tension modulus (E). May vary with temperature via a defined material field.

Maximum 1st Invariant Defines . May vary with

temperature via a defined material field.


Density RHO This defines the material mass density.

Coefficient of Thermal Expansion

Defines the coefficient of thermal expansion.


I1*

I1*

I1 3–=


80

Foam-Invariants (GHEM1) / Foam-Principals (GHEM2) / Foam-Invariants (Dev. Split) (GHEM3) / Foam-Principals (Dev. Split) (GHEM4) / Rubber-Invariant Based (GHEM5) / Rubber-Principal Stretch (GHEM6)

Description


Density RHO Defines the mass density

Thermal Expansion Coeff Defines the coefficient of thermal expansion.

Reference Temp. TREF Defines the reference temperature for the thermal expansion coefficient.

Structural Damp. Coeff. GE Defines the structural damping coefficient.


Elastoplastic

The Input Properties form displays the following for elastoplastic properties. Use this form to define the data describing plastic behavior of a material. The stress-strain curve data is input via a material property field of strain and placed on MATS1 and TABLES1 entries. The data input should be the true equivalent stress vs. equivalent total strain. Other options are placed on the MATEP entry and are valid only for SOL 400 & 600. Note that the existence of both an elastoplastic and nonlinear elastic constitutive models in the same material is not recommended.

Stress/Strain Curve Description

Yield Function Yield function (YF) criterion:

von Mises, Tresca, Mohr-Coulomb, & Drucker-Prager supported on MATS1 entry. All others are for SOL 600 and placed on the MATEP entry. SOL 400 only supports von Mises.

Hardening Rule Hardening Rule (HR). These are Isotropic, Kinematic, and Combined isotropic and kinematic and are placed on the MATS1 entry or MATEP entry depending on solution sequence and yield function selected. Hardening rules Power Law, Rate Power Law, Johnson-Cook, Kumar are available when no Yield Function is specified. This is used for SOL 600 only on MATEP entry.

Strain Rate Method Selects an option for strain-rate dependent yield stress used in SOL 600. Cowper-Symonds requires input of Denominator C and Inverse Exponent P.

Stress/Strain Curve This data must reference a strain dependent field. It can also be temperature and strain rate dependent. LIMIT1 in MATS1 determined from supplied tabular field of stress-strain curve. Data is placed on TABLES1 entry.

Internal Friction Angle Defined for Mohr-Coulomb and Drucker-Prager yield function placed on the MATS entry LIMIT2.

Yield Point

Stress at Yield

Initial yield stress.

Beta Parameter beta for parabolic Mohr-Coulomb or Buyukozturk concrete models. Placed on the MATEP entry.

10th Cycle Yield Stress Equivalent 10th cycle tensile yield stress for Oak Ridge National Labs models (ORNL). Placed on the MATEP entry.


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Denominator C

Inverse Exponent P

Constants for the Cowper-Symonds strain rate method.

Coefficient A / B / C / Bi

Exponent M / N

Coefficient and exponent data for Power Law, Rate Power Law, Johnson-Cook, and Kumar hardening rules.

initial Strain Rate

Room Temperature

Melt Temperature

Additional data input for the Johnson-Cook hardening rule.

Hardening Slope Description

Yield Function Yield function (YF) criterion:

von Mises, Tresca, Mohr-Coulomb, & Drucker-Prager supported on MATS1 entry.

Hardening Rule Hardening Rule (HR). These are Isotropic, Kinematic, and Combined isotropic and kinematic and are placed on the MATS1 entry.

Strain Rate Method No strain rate methods are available for the Hardening Slope data.

Hardening Slope Work hardening slope (H) - slope of stress versus plastic strain. Defined in units of stress. For an elastic-perfectly plastic case, use the Perfectly Plastic data input option.

Internal Friction Angle Defined for Mohr-Coulomb and Drucker-Prager yield function placed on the MATS entry LIMIT2.

Yield Point Initial yield stress.

Perfectly Plastic Description

Yield Function See the Stress / Strain Curve table above. All options are identical except there must be a yield function selected.

Hardening Rule None are available since no hardening is possible for a perfectly plastic material.

Stress/Strain Curve Description


See the Nastran Quick Reference Guide for more information about the necessary data for MATS1 and MATEP entries.

Strain Rate Method Piecewise linear or Cowper-Symonds are available.

Yield Point Initial yield stress.

All other data input is described in the Stress/Strain Curve table above.

Rigid Plastic Description

Yield Function No yield functions are available as the material is defined as rigid and then plastic, so no yield is possible.

Hardening Rule See the Stress / Strain Curve table above. Valid options are the Power Law, Power Rate Law, Johnson-Cook, Kumar, and Piecewise Linear.

Strain Rate Method Piecewise linear or Cowper-Symonds are available only if the Piecewise Linear hardening rule is selected.

Stress/Strain Curve Necessary only when not using one of the power law hardening rules (Piecewise-Linear). This data must reference a strain dependent field. It can also be temperature and strain rate dependent. LIMIT1 in MATS1 determined from supplied tabular field of stress-strain curve. Data is placed on TABLES1 entry.

All other data input is described in the Stress/Strain Curve table above. Rigid Plastic is only used in SOL 600 and only for isotropic materials.

Perfectly Plastic Description


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Failure

The Input Properties form displays the following for failure material models. Note that this failure model is for non-SOL 400/600/700 solutions. See Failure 1/2/3 for SOL 400/600/700.

No Composite Failure Theory Description

Tension Stress Limit Stress limits for tension, compression, and shear used to compute margins of safety in certain elements. They have no effect on the computational procedures.

Compression Stress Limit

Shear Stress Limit

Failure criteria for the isotropic and two-dimensional orthotropic and anisotropic materials appear in the ST, SC, and SS fields on MAT1 and MAT2 entries and the Xt, Xc, Yt, Yc, and S fields on the MAT8 entry.

Composite Failure Theory:

Hill, Hoffman, Tsai-Wu, Maximum

Description

Failure Limits For 2D orthotropic on the MAT8 entry, the limits can be defined as stress or strain allowables. This is not applicable to isotropic and anisotropic materials.

Tension Stress Limit Stress limits for tension, compression, and shear are the same as those defined for non-composite failure.Compression Stress Limit

Shear Stress Limit

Bonding Shear Stress Limit Allowable shear stress of the bonding material. SB field on the PCOMP entry.

Failure criteria for the isotropic and two-dimensional orthotropic and anisotropic materials appear in the ST, SC, and SS fields on MAT1 and MAT2 entries and the Xt, Xc, Yt, Yc, and S fields on the MAT8 entry unless composites are being used in which case the data is written to the PCOMP entry as necessary.


Failure 1, Failure 2, Failure 3

The Input Properties form displays the following for failure material models used in SOL 400 and 600. Solution sequences other than SOL 400/600/700 should use the Failure constitutive model above instead. Up to three failure constitutive models can be defined for any one material. Failure 1 must exist in order for Failure 2 and 3 to be recognized and translated into the proper MATF and MATTF entries. Temperature dependent properties as defined by material fields are translated onto the MATTF entry. Note also that only Failure 1 allows for definition of progressive failure. Failure models 2 and 3 take on whatever progressive failure is defined in Failure 1. Different failure criterion may exist between all three in the same material definition.

The table below outlines the allowable properties. All values are real, 0.0, or left blank with no defaults unless otherwise indicated. Which properties are available is dependent on the Failure Criterion selected. The following Failure Criteria are available:

• Maximum Stress

• Maximum Strain

• Hill

• Hoffman

• Tsai-Wu

• Hashin

• Puck

• Hashin-Tape

• Hashin-Fabric

• User Sub. UFAIL

If you select User Sub. UFAIL as the Failure Criteria, the form with the Progressive Failure Option and no properties displays. Use the form to specify the Progressive Failure Option. The data is placed on a MATF entry. For SOL 400 jobs, this material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine ufail (if Progressive Failure Option is set to None) / uprogfail (if Progressive Failure Option is set to Progressive Failure / Gradual / Immediate) in conjunction with MATF.


86

Property Description

Progressive Failure Options Progressive failure options are None, standard Progressive Failure, Gradual or Immediate selective progressive failure for SOL 600. SOL 400 does not support progressive failure models and will ignore this setting if set to anything other than None. Only failure indices are computed when no progressive failure is specified. Anisotropic materials do not support progressive failure.

Tension Stress Limit X / Y /ZTension Strain Limit X / Y / Z

Compression Stress Limit X / Y / ZCompression Strain Limit X / Y / Z

Shear Stress Limit XY / YZ / ZXShear Strain Limit XY / YZ / ZX

Tension, compression, and shear stress or strain limits used in the Maximum Stress or Strain, Hill, Hoffman, and Tsai-Wu failure criteria.

Shear Stress Bond (SB) Allowable shear stress of bonding material between layers for composites only. This is used in SOL 600 only and is ignored for SOL 400.

Failure Index Failure index used for Hill, Hoffman, and Tsai-Wu criteria.

Interactive Strength XY / YZ / ZX Interactive strength constants for specified plane used in the Tsai-Wu criterion.

Max Fiber / Matrix TensionMax Fiber / Matrix Compression

Max Tape Fiber TensionMax Tape Fiber Compression

Max 1st Fiber Tension / CompressionMax 2nd Cross Fiber Tension / Compression

Max Thickness TensionMax Thickness Compression

Definable stress limits for Hashin, Puck, Hashin-Tape, and Hashin-Fiber criteria.

Layer Shear StrengthTransverse Shear Strength YZ / ZX

Shear stress limits for Hashing, Puck, Hashin-Tape, and Hashin-Fiber criteria.

Slope P12C / P12T / P23C / P23T of Fracture Envelope

Slopes of the failure envelope used in Puck failure criterion.


Deactivate Tension X / Y/ ZDeactivate Compress X / Y / ZDeactivate Shear XY / YZ / ZX

Deactivate Elements

Deactivate Fiber / Matrix TensionDeactivate Fiber /Matrix CompressionDeactivate Matrix TensionDeactivate Matrix Compression

If any value other than blank or 0.0 is entered for progressive failure options Gradual and Immediate, failed elements are deactivated (placed ICi fields in MATF entry). See the Nastran Quick Reference Guide for information.

Residual Stiffness FactorMatrix Compression FactorShear Stiffness FactorE33 Fiber Failure FactorShear Fiber Failure Factor

Reduction fractions or factors. Values can be between 0.0 and 1.0. Used only for Gradual or Immediate progressive failure modes (placed on Ai fields in MATF entry). See the Nastran Quick Reference Guide for more information.



88

Creep

The Input Properties form displays the following for creep models.

User Sub.(CRPLAW)

Use this form to define the creep law using user subroutine crplaw for SOL 400 runs. This data is written to the MATVP entry in primary format. For SOL 400 jobs, this material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine crplaw in conjunction with MAT1.

Tabular Input Description

Data defined by the use of this form to define the primary stiffness, primary damping, and secondary damping for a creep model with tabular input appears on the CREEP entry for non-SOL 600 runs. Only isotropic materials use this data input method.

Creep Law ijk Description

Use this form to define the coefficients for one of many empirical creep models available appears on the CREEP entry for non-SOL 600 runs. Only isotropic materials use this creep definition.

MATPV Description

Use this form to define either the coefficients and exponents for creep model or provide tabular field data to define Temperature vs. Creep Strain, Creep Strain Rate vs. Stress, Strain Rate vs. Creep Strain, or Time vs. Creep Strain in SOL 600 runs. This data is written to the MATVP entry. If tabular data is provided, this data is written to TABLEM1 entries. It is not recommended to mix the exponents and coefficients and tabular data. Use one or the other.


Hypoelastic

The Input Properties form displays the following to define user-defined generic material properties for hypoelastic material models in SOL 400 only. The data is placed on MATUSR entry. This material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine hypela2 in conjunction with MATUSR.


Coordinate System (IPREF)

Coordinate System (IPREF) options are Isotropic and User Defined

Kinematic Flag (IKINEM) Kinematic Flag (IKINEM) options are Gradient Only, Gradient and Rotation, Gradient and Stretch Ratio, All Input, All Input (mid increment) and All Input (end increment)


Thermal Expansion Coeff Thermal coefficient of expansion (A1). Can be temperature dependent. Not show if coordinate system is User Defined.

Thermal Expansion Coeff (A1)

Thermal coefficient of expansion (A1). Can be temperature dependent. Not show if coordinate system is Isotropic.






Structural Damping Coeff Structural damping coefficient (GE). Can be temperature dependent.



Shear Stress Limit


90

User Defined

The Input Properties form displays the following to define user-defined generic material properties for user defined material models in SOL 400 only. The data is placed on MATUSR entry. This material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine umat in conjunction with MATUSR.


Coordinate System (IPREF)

Coordinate System (IPREF) options are Isotropic and User Defined

Kinematic Flag (IKINEM) Kinematic Flag (IKINEM) options are Gradient Only, Gradient and Rotation, Gradient and Stretch Ratio, All Input, All Input (mid increment) and All Input (end increment)


Thermal Expansion Coeff Thermal coefficient of expansion (A1). Can be temperature dependent. Not show if coordinate system is User Defined.








Structural Damping Coeff Structural damping coefficient (GE). Can be temperature dependent.



Shear Stress Limit


Viscoelastic

The Input Properties form displays the following for viscoelastic models. This material model is only used in SOL 600 runs and all data is placed on the MATVE, MATTVE entries. Linear elastic or hyperelastic constitutive models for isotropic or anisotropic materials must exist in addition to the viscoelastic model.


92

Stress-Life (SN) and Strain Life (eN),Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible)

These constitutive models are used for defining fatigue material properties in order to run an MSC Nastran Embedded Fatigue analyses using statics, normal modes and modal transient response. All parameters defined here are placed on the MATFTG bulk data entry.

With the Stress-Life (SN) constitutive model you can:

• Derive S-N curves by specifying the type of metal, the ultimate tensile strength (UTS), and Young’s Modulus (defined in the Linear constitutive model).

• Enter standard parameters to define an S-N curve

• Enter Bastenaire parameters to define an S-N curve

• Tabularly define multiple S-N curves by the selection of a pre-defined field. See Fields Create (Material Property, Tabular Input) (Ch. 6) in the Patran Reference Manual). One or more tabular S-N curves can be defined that were derived from either constant mean stress or constant R-Ratio (minimum stress/maximum stress). The fields must be of type Life(N) as the independent variable. Also Haigh curves can be defined using the same mechanism where each curve is derived at a constant life value. Although the field in this case must also be of type Life(N), the y-values are defined as mean stress vs. x-values of stress amplitude. The Value 1, 2, 3, etc. fields are used to input the constant mean, constant R-ratio, or constant life value at which the selected field (curve) was created.

With the Strain-Life (eN) constitutive model you can:

• Derive strain-life (ε-N) and cyclic stress-strain (ε−σ) curves by specifying the type of metal, the ultimate tensile strength (UTS), and Young’s Modulus (defined in the Linear constitutive model).

• Enter standard parameters to define an the strain-life and cyclic stress-strain curves

With the Spot Weld Top and Bottom Sheet constitutive models you can:

• Define Standard S-N curves for fatigue analysis of spot welds by specifying the type of metal (steel or aluminum), the ultimate tensile strength (UTS), and Young’s Modulus (defined in the Linear constitutive model).

• Manually enter standard parameters to define an S-N curve for the top and bottom sheets manually

• Please note the following: Three (3) S-N curves are allowed for fatigue analysis of spot welds. One to define the spot weld nugget (center), and one each for the top and bottom sheet. If all locations use the same S-N curve, only the Stress-Life constitutive model needs to be defined. If the nugget and top/bottom sheet S-N curves differ, then it is necessary to define both the nugget as a standard Stress-Life constitutive model and the sheet(s) as a Spot Weld Top/Bottom Sheet constitutive model(s). If the top sheet is defined but not the bottom, or vice-versa, both take on the defined definition. If top and/or bottom are defined, but not a standard Stress-Life constitutive model for the nugget, then the nugget takes on the properties of the top sheet (or bottom if top is not defined).


With the Seam Weld Stiff and Flexible constitutive models you can:

• Define Standard S-N curves for fatigue analysis of seam welds by specifying the type of metal (steel or aluminum), the ultimate tensile strength (UTS), and Young’s Modulus (defined in the Linear constitutive model).

• Manually enter standard parameters to define an S-N curve for the stiff and flexible curves manually

• Please note the following: Two (2) S-N curves are allowed for fatigue analysis of seam welds. One to define the stiff (bending ratio=0) and one for the flexible (bending ratio=1) properties. The analysis interprets between the two based on the actual bending ratio. If both are the same, only the Stress-Life constitutive model needs to be defined. If one is defined but not the other, then the undefined properties are taken from the standard Stress-Life constitutive model. If the stiff definition is defined but not the other, or vice-versa, but no standard Stress-Life constitutive model is defined, then the same properties are used for both.

For all these methods of input, a conversion factor can be supplied. This conversion factor operates only on the stress parameters of the defined curves and is used to allow input of the parameters on these constitutive models in stress units other than the consistent model units. For example, if the consistent model units are in PSI (for stresses), then a factor off 145.0377 could be entered that would allow the stress parameters to then be entered in MPa. (Note that this only applies to parameters on these constitutive models and not for, say, the linear constitutive model where E is defined.)

In order to run a successful MSC Nastran Embedded Fatigue analysis, at least one of the above constitutive model must be defined for the elements of interest. An output request for fatigue life must be made (see Output Requests, 448). An S-N (standard, spot or seam weld) or ε-N analysis must be turned on when setting up the analysis (see Solution Parameters, 298 for Linear Static, Normal Modes, or Transient Response). And a cyclic loading sequence must be defined (see Subcase Select, 485) above the subcase level. Optionally, various fatigue parameters can be defined as element properties such as surface finish (see Element Properties, 100) for shell and solid elements only.

For more detail on how to set up and perform an MSC Nastran Embedded Fatigue analysis using Patran, please see the MSC Nastran Embedded Fatigue User’s Manual. For details on the MATFTG entry, please see the MSC Nastran Quick Reference Guide.


94

Cohesive

The Input Properties form displays the following for viscoelastic models. This material model is only used in SOL 400 runs and all data is placed on the MCOHE entry. This material is used with interface elements only (PCOHE/CIFQUAD/CIFQDX/CIFHEX/CIFPENT).

There are three standard models available, which are discussed below.

The strain measures of the interface elements are the relative displacements between the top and the bottom edges (2D) or faces (3D). In 2D, there are two strain components: one normal and one shear. In 3D, there are three components: one normal and two shear. The relative displacements are combined in an equivalent value and the constitutive behavior of the interface elements is defined in terms of an equivalent traction as a function of the equivalent relative displacement. The area below the traction-displacement curve is called the cohesive energy (which is also called the critical energy release rate). The names of the three standard cohesive material models refer to the shape of the traction-displacement curve. They have in common that the initial response is elastic or reversible and upon reaching a critical opening displacement, the response is irreversible, which is manifested by a reducing traction and increasing damage in the interface elements (delamination). The models have thefollowing characteristics:

Exponential model: entirely defined by an exponential function; the necessary material properties are the cohesive energy (Gc) and the critical opening displacement (vc).

Linear model: both the reversible and the irreversible part of the traction-displacement curve are linear; the necessary material properties are the cohesive energy (Gc), the critical opening displacement (vc) and

the maximum opening displacement (vm), beyond which the traction is reduced to zero.

Linear-exponential model: the reversible part of the traction-displacement curve is linear, where the irreversible part is described by an exponential function; the necessary material properties are the cohesive energy (Gc), the critical opening displacement (vc) and the exponential decay factor (q).

Since the exponential model has only two basic parameters, it does not offer the possibility to shift the critical opening displacement without changing the maximum traction (assuming that the cohesive energy remains constant). The other models do offer this possibility, where the irreversible behavior of the linear-exponential model is based on a continuously differentiable curve.

Sometimes cohesive materials are defined by the cohesive energy and the maximum traction (tc), instead

of the critical or maximum opening displacement. See the MSC Nastran Quick Reference Manual for the relationships to convert such data. Note that for the linear model one still has to select the critical opening displacement

Note that for the linear model one still hs to select the critical opening displacment and for the linear-exponential model the decay factor. They can be used to influence the reversible response.


Models Description

Bilinear

Exponential

Linear-Exponential

User Sub. (UCOHESIVE)

Constitutive Models for Cohesive Material.

The "User Sub.(UCOHESIVE)" model is applicable for MSC Nastran (SOL400) Preference. If selected, the MATUDS entry for MTYPE - MCOHE and UNAME - ucohes is written. The data is placed on MCOHE entry with MODEL set to -1. This material is shown for selection when setting up the UDS Map (See User Defined Services, 346). If UDS Map exists, the MATUDS entry is written to activate user subroutine ucohes in conjunction with MCOHE.

Stiffness Matrix Description

Secant

Tangent

Only Secant is currently valid for MSC Nastran.

The contribution to the global system matrix can be based on either a modified tangent or secant matrix. The former will usually result faster convergence, but may cause a non-positive definite matrix if the irreversible part of the traction-displacement curve is reached.

Viscous Energy Dissipation Description

No or Yes Since upon the onset of delamination the FE analysis may become instable, one can activate some viscous damping. The idea of this damping model is that an extra viscous traction is added to the regular traction. This viscous traction is a function of the rate of the equivalent displacement, a reference value of the rate of the equivalent displacement, the maximum traction and the viscous energy factor:


96

Reference Rate Description

None

Auto

User Defined

If Viscous Energy Dissipation is "No", then this value is "None".

The reference value can be entered by the user, but can also be calculated by the program as the largest relative displacement rate in any interface element as long as the response is reversible.

Fully Damages Elements Description

Keep This is currently not applicable for MSC Nastran.

If an interface element is fully damaged, so if all the integration points have reached the maximum damage, one can deactivate this element. In a contact analysis, this implies that the outer boundary of a contact body is newly determined. The user can decide to either leave deactivated interface elements on the post file or to exclude them from the post file.


Input Parameters Description

Cohesive Energy This can also refer a Temperature/Strain/Strain-Rate field.

Critical Opening Displacement Enter a opening displacmenet values

Maximum Opening Displacement Used for "Bilinear" model only

Shear-Normal Stress Ratio The ratio of the maximum stress in shear and the maximum stress in tension

Compression Stiffening Factor Stiffening factor in compression

Viscous Energy Dissipation Factor for viscous energy dissipation. This is activated only if, Viscous Energy Dissipation option is set to "Yes".

Reference Rate Reference rate of relative displacement. This is used if Viscous Energy Dissipation option is set to "Yes" and Reference Rate option is set to "User Defined"

Exponential Decay Factor Used for Linear-Exponential model only

Thermal Conductance This can also refer a Temperature/Strain/Strain-Rate field. Used for thermal/coupled analysis only.


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Composite

The Composite forms provide alternate ways of defining the linear elastic properties of materials. All the composite options, except for Laminated Composite, will always result in a homogeneous elastic material in MSC Nastran.

When the Laminated Composite option is used to create a material and this material is then referenced in a “Revised or Standard Laminate Plate” element property region, a PCOMP entry is created. However, if this material is referenced by a different type of element property region, for example, “Revised or Standard Homogeneous Plate,” then the equivalent homogeneous material properties are used instead of the laminate lay-up data. Only materials created through the Laminated Composite option should be referenced by a “Revised or Standard Laminate Plate” element property region. Refer to Composite Materials Construction (p. 116) in the Patran Reference Manual.

Laminated

This subordinate form appears when the Input Properties button is selected on the Materials form, Composite is the selected Object, and Laminate is the selected Method. Use this form to define the laminate lay-up data for a composite material. If the resulting material is referenced in a “Revised or Standard Laminate Plate” element property region, then an MSC Nastran PCOMP entry containing the lay-up data is written. If the resulting material is referenced by any other type of element property region, the equivalent homogeneous properties of the material are used

The difference between the "Total" option and the "Total - %thicknesses" option is that the former requires that the user give actual thickness values of each ply and the latter requires each ply thickness to be given as a percentage of the total layup thickness. This is the prefered method when applying the composite material to solid (CHEXA) elements or 2D solid element (axisymmetric, plane strain).


.

Patran Interface to MSC Nastran Preference GuideElement Properties

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2.7 Element PropertiesThe Element Properties form appears when the Element Properties toggle, located on the Patran main form, is chosen.There are several option menus available when creating element properties. The selections made on the Element Properties menu will determine which element property form appears, and ultimately, which MSC Nastran element will be created.

The following pages give an introduction to the Element Properties form, and details of all the element property definitions supported by the Patran MSC Nastran Preference.

Element Properties FormThis form appears when Element Properties is selected on the main menu. There are four option menus on this form. Each will determine which MSC Nastran element type will be created and which property forms will appear. The individual property forms are documented later in this section. For a full description of this form, see Element Properties Forms (p. 67) in the Patran Reference Manual.

101Chapter 2: Building A ModelElement Properties

The following table outlines the option menus when Analysis Type is set to Structural.

Use this option menu to define the element’s dimension. The options are:

0D (point elements)1D (bar elements)2D (tri and quad elements)3D (tet, wedge, and hex elements)

This option menu depends on the selection made in the Dimension option menu. Use this menu to define the general type of element, such as:Mass versus Grounded SpringShell versus 2D_Solid

These option menus may or may not be present, and their contents depend heavily on the selections made in Dimension and Type. See Table 2-1 for more help.

This button is used to quickly edit an element property; for example change the shell thickness.

This is used to specify element properties; for example shell thickness, or material orientation.

This is used to specify the region (area) of geometry or elements that are to be included in the property definition.


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Table 2-1 Structural Element Property Options

Dimension Type Option 1 Option 2 Option 3

0D • Mass • Coupled page 106

• Grounded page 107

• Lumped page 108

• Grounded Spring page 109

• Grounded Damper page 110

• Grounded Bush • Grounded page 111


1D • Beam • General Section • Standard page 112

• P-Formulation page 117

• Linear/Cubic Closed Section page 119

• Linear-Shear page 120

• Curved w/General Section page 121

• Curved w/Pipe Section page 123

• Lumped Section page 125

• Tapered Section • Standard page 127

• P-element page 129

• General Section • Standard page 130

• Linear/Cubic Closed Section page 132

• Linear/Cubic Open Section page 133

• Linear-Shear page 134

• Rod • General Section • Standard page 135

• CONROD page 136

• Pipe Section page 137

• Spring page 138

• Damper • Scalar page 139

• Viscous page 140

• Gap • Adaptive page 141

• Non-Adaptive page 141

1D Mass page 143

PLOTEL page 144

Bush • Scalar page 145

• 2D Linear/Non Linear page 147

Spot Weld Connector page 149

Fastener Connector page 150




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2D • Shell • Thin • Homogeneous • Standard page 153

• Revised page 156


• Linear Discrete Kirchhoff page 160

• Laminate • Standard page 162


• Equivalent Section • Standard page 166



• Thick • Standard page 172

• Reduced Integration page 174

• Field Point Mesh page 176

• Bending Panel • Standard page 177



• 2D-Solid • Plane Strain • Standard page 183

• Reduced page 185



• Hyperelastic page 189

• Laminated Composite page 190

• Incompressible page 191

• Interface page 192

• Plane Stress • Standard page 193






2D • 2D-Solid • Axisymmetric • Standard page 197


• Twist page 200


• Laminated Composite page 202

• PLPLANE page 203



• Acoustic Infinite page 206

• Membrane • Standard page 207



• Shear Panel

3D • Solid • Homogeneous • Standard page 214




• Solid Shell page 220


• Laminate page 222

• Gasket


• Body Pair • Geometric page 224

• Physical page 226




106

0D Element Properties

0D - Coupled Point Mass (CONM1)

This describes the Input Properties available from the Element Properties form when the following options are chosen.

Use this form to create a CONM1 element. This defines a 6 x 6 symmetric mass matrix at a geometric point of the structural model. This is a list of Input Properties available for creating a CONM1 element that were not shown on the previous page. Use the menu scroll bar on the Input Properties form to view these properties.

Action Dimension Type Option(s) Topologies

CreateModify

0D Mass Coupled Point/1

Prop Name Description

Mass Orientation CID/CG

Defines the orientation of the 1-2-3 axes of the mass matrix. The value is a reference to an existing coordinate frame. The 1-2-3 axes will be aligned with the X-Y-Z axes of the specified coordinate system. If a non rectangular coordinate system is specified, the system will be evaluated into a local rectangular system, which is then used to orient the mass matrix. This property is the CID field on the CONM1 entry. This property is optional.

Mass Component i,j Defines the values of the mass matrix. These are the Mij fields on the CONM1 entry. These properties can either be real values or references to existing field definitions. Each of these properties are optional; however, at least one must be defined.


0D - Grounded Scalar Mass (CMASS1)


Use this form to create a CMASS1 element and a PMASS property. This defines a scalar mass element of the structural model. Only one node is used in this method, and the other node is defined to be grounded.


CreateModify

0D Mass Grounded Point/1


Mass Defines the translation mass or rotational inertia value to be applied. This is the M field on the PMASS entry. This property can be either a real value or a reference to an existing field definition. This property is required.

Dof at Node 1 Defines which degree of freedom this value will be attached to. This property can be set to UX, UY, UZ, RX, RY, or RZ and defines the setting for the C1 field on the CMASS1 entry. This property is required.


108

0D - Lumped Point Mass (CONM2)


Use this form to create a CONM2 element. This defines a concentrated mass at a geometric point of the structural model.


CreateModify

0D Mass Lumped Point/1


Mass Defines the translational mass value to be used. This is the M field on the CONM2 entry. This property can either be a real value or a reference to an existing field definition. This property is required.

Mass Orientation CID/GG

Defines the orientation of the 1-2-3 axes of the mass matrix. This is a reference to an existing coordinate frame. The 1-2-3 axes will be aligned with the X-Y-Z axes of the specified coordinate system. If a nonrectangular coordinate system is specified, the system will be evaluated into a local rectangular system, which is then used to orient the mass matrix. This is the CID field on the CONM2 entry. If the Value Type is set to Vector then the components of the vector define the center of gravity of the mass in the basic coordinate system and the field for CID is translated as -1. This property is optional.

Mass Offset Defines an offset from the specified node to where the lumped mass actually is to exist in the structural mode. This vector is defined in the Mass Orientation coordinate system. Defines the X1, X2, and X3 fields on the CONM2 entry. This property is optional.

Inertia i,j Inertia i,j defines the rotation inertia properties of this lumped mass. These properties are the Iij fields on the CONM2 record. These values can be either real values or references to existing field definitions. These values are optional.


0D - Grounded Scalar Spring (CELAS1/CELAS1D)


Use this form to create a CELAS1 or CELAS1D (for SOL 700) element and a PELAS property. This defines a scalar spring element of the structural model. Only one node is used in this method. The other node is defined to be grounded.


CreateModify

0D Grounded Spring Point/1


Spring Constant Defines the coefficient to be used for this spring. This is the K field on the PELAS entry. This can either be a real value or a reference to an existing field definition. This property is required.

Damping Coefficient Defines what damping is to be included. This is the GE field on the PELAS entry. This property can either be a real value or a reference to an existing field definition. This property is optional.

Stress Coefficient Defines the relationship between the spring deflection and the stresses within the spring. This property is the S field on the PELAS entry and can either be a real value, or a reference to an existing field definition. This property is optional.

Dof at Node 1 Defines which degree of freedom this value is to be attached to. This can be set to UX, UY, UZ, RX, RY, or RZ. This property defines the setting of the C1 field on the CELAS1 entry. This property is required.

User Def CS Number Number of a User Defined Coordinate system, used only for Explicit Nonlinear (SOL 700). This property is optional.


110

0D - Grounded Scalar Damper (CDAMP1/CDAMP1D)


Use this form to create a CDAMP1 or CDAMP1D (for SOL 700) element and a PDAMP property. This defines a scalar damper element of the structural model. Only one node is used in this method. The other node is defined to be grounded.


CreateModify

0D Grounded Damper Point/1


Damping Coefficient Defines the force per unit velocity value to be used. This property is the B field on the PDAMP entry and can either be a real value or a reference to an existing field definition. This property is optional.

Dof at Node 1 Defines which degree of freedom this value is to be attached to. This property can be set to UX, UY, UZ, RY, or RZ and defines the setting for the C1 field on the CDAMP1 entry. This property is required.

User Def CS Number Number of a User Defined Coordinate system, used only for Explicit Nonlinear (SOL 700). This property is optional.


0D - Grounded Bush (CBUSH/PBUSH)

This describes the Input Properties available from the Element Properties form and the following options are chosen.

This is a list of Input Properties available. Use the menu scroll bar on the Input Properties form to view all of these properties. This creates CBUSH/PBUSH entries.


CreateModify

1D Bush Grounded Bar/2


Bush Orientation System CID specifies the Grounded Bush Orientation System. The element X,Y, and Z axes are aligned with the coordinate system principal axes. If the CID is for a cylindrical or spherical coordinate system, the grid point specified locates the system. If CID = 0, the basic coordinate system is used.

Spring Constant iStiff. Freq Depend i

Defines the stiffness associated with a particular degree of freedom. This property is defined in terms of force per unit displacement and can be either a real value or a reference to an existing field definition for defining stiffness vs. frequency.

Stiff. Force/Disp i Defines the nonlinear force/displacement curves for each degree of freedom of the spring-damper system.

Damping Coefficient iDamp. Freq Depend i

Defines the force per velocity damping value for each degree of freedom. This property can be either a real value or a reference to an existing field definition for defining damping vs. frequency

Structural DampingStruc. Damp Freq Depend

Defines the non-dimensional structural damping coefficient (GE1). This property can be either a real value, or a reference to an existing field definition for defining damping vs. frequency.

Stress Recovery TranslationStress Recovery Rotation

Stress recovery coefficients. The element stress are computed by multiplying the stress coefficients with the recovered element forces.

Strain Recovery TranslationStrain Recovery Rotation

Strain Recovery Coefficients. The element strains are computed by multiplying the strain coefficients with the recovered element strains.


112


1D - Beam - General Section (CBAR) - Standard Formulation


Use this form to create CBAR elements with a PBAR or PBARL property. A CBARAO entry will be generated if any Station Distances are specified. This defines a simple beam element in the structural model. If used in a SOL 400 run, a PBARN1 entry may also be written with the LC option written to the BEHi field.

Most of the beam properties that appear on all beam/bar input property forms are listed here. Only those applicable to the element type being created will appear on the input properties form.

Action Dimension Type Option 1 Option 2 Topologies

CreateModify

1D Beam General Section Standard Formulation

Bar 2

Note: .Patran will check the element associativity to other elements sharing this property set and will not export user defined pin unless the user includes an asterisk (*) in the string, in which case Patran will export the defined pin flags for all elements in the property set.


Section Name Specifies a beam section previously created using the beam library

Allows you to define a bar/beam section either by Dimensions (PBARL/PBEAML) or by Properties (PBAR/PBEAM). If Dimensions is choosen, the MSC Nastran’s built-in section library (Version 69 and later), PBARL/PBEAML, (for the standard Beam Library) or PBRSECT/PBMSECT (for an Arbitrary section) will be used to define the bar/beam. If Properties is chosen, the standard bar/beam properties, PBAR/PBEAM will be used to define the beam section. If the Dimensions Option is set to Dimensions, the Translation Parameters Version must be set to version 69 or later.

Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. This property defines the value to be used in the MID field on the PBAR/PBEAM entry. This property is required.


Bar Orientation Defines the local element coordinate system to be used for any cross-sectional properties. This orientation will define the local XY plane, where the x-axis is along the beam. This orientation defines the value for the X1, X2, X3, or G0 fields on the CBAR/CBEAM entry. This property is required.

Specifies how the bar orientation is defined:

Vector – Specified using a vector

Node Id – Specified using an existing node in the beam XY plane

When the value type is Vector, it is always input in either the Patran global or some other Patran user defined coordinate system (i.e. <0 1 0 Coord 5>).

Reference Coordinates Specifies the MSC Nastran coordinate system in which the bar/beam orientation vector will be written to the CBAR/CBEAM entry:

Analysis - Displacement Coordinate System at GA

Coord 0 - Basic Coordinate System

If Analysis is specified, a G will be written to the first position of the OFFT value on the CBAR/CBEAM entry. If Coord 0 is specified, a B will be written.

Note: The reference coordinate system specified does not affect how the input is interpreted within Patran. Only how it is written to the CBAR/CBEAM entry.

Offset @ Node 1Offset @ Node 2

Defines the offset from the nodes to the actual centroids of the beam cross section. These orientations are defined as vectors. These properties, after any necessary transformations, become the W1A, W2A, W3A, W1B, W2B, and W3B fields on the CBAR/CBEAM entry.

These properties are optional.

Vector – Specified using a vector

This is the only method available. The Reference Coordinate System controls how the vector input is interpreted in Patran.



114

Reference Coordinates Specifies the MSC Nastran coordinate system in which the offset vectors will be written to the CBAR/CBEAM entry and how the vector input will be interpreted in Patran:

Analysis - Displacement Coordinate Systems at GA and GB

Element - Element Coordinate System

If Analysis is specified, a G will be written to the second or third position of the OFFT value on the CBAR entry. Within Patran, the vector will be interpreted to be in either the Patran global or some other Patran user defined coordinate system (i.e. <0 1 0 Coord 5>). If Element is specified, an E will be written to the second or third position of the OFFT value on the CBAR entry. Within Patran, the vector will be interpreted to be in the Element coordinate system.

Pinned DOFs @ Node 1Pinned DOFs @ Node 2

These degrees of freedom are in the element local coordinate system. Values that can be specified are UX, UY, UZ, RX, RY, RZ, or any combination. These properties are used to remove connections between the node and selected degrees of freedom at the two ends of the beam. This option is commonly used to create a pin connection by specifying RX, RY, and RZ to be released. Defines the setting of the PA and PB fields on the CBAR/CBEAM record. These properties are optional.

Note that if pinned DOF releases are defined within a property set, but the end nodes of the beams are connected to beams of a different property set, then no pinned DOFs will be written for those beams (PA or PB will be left blank). To override this and force the pin flags to be written per the property set, use an "*" after the specification for the DOFs. (This may be problematic if the property sets defined different pin DOFs.) For example, if rotation about the 2nd DOF is to be freed, specify "RY*." These values must be typed into the data box. Although there is a pull down menu next to the data box showing the valid selections, you will have to type the values in if more than one DOF or the "*" is to be specified. Specifying the "*" by itself does nothing.

Area Defines the cross-sectional area of the element. This is the A field on the PBAR/PBEAM entry. This value can be either real values or a reference to an existing field definition. This property is required.



Inertia i,j Defines the various area moments of inertia of the cross section. These are the I1, I2, and I12 fields on the PBAR/PBEAM entry. These values can be either real values or references to existing field definitions. These values are optional.

Torsional Constant Defines the torsional stiffness of the beam. This is the J field on the PBAR/PBEAM entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Shear Stiff, YShear Stiff, Z

Defines the shear stiffness values. These are the K1 and K2 fields on the PBAR/PBEAM entry. These values can be either real value or references to existing field definitions. This property is optional.

Shear Relief YShear Relief Z

Defines the shear relief coefficients due to taper. These are the S1 and S2 fields on the PBEAM entry. These values can either be real values or references to existing field definitions. These properties are optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is defined in terms of mass per unit length of the beam. This is the NSM field on the PBAR/PBEAM entry. This value can be either a real value or reference to an existing field definition. This property is optional.

NSM Inertia @ Node 1NSM Inertia @ Node 2

Specified the nonstructural mass moments of inertia per unit length about the nonstructural mass center of gravity at each end of the element. These properties are the NSI(A) and NSI(B) fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.

Y of NSM @ Node 1Z of NSM @ Node 1Y of NSM @ Node 2Z of NSM @ Node 2

Defines the offset from the centroid of the cross section to the location of the nonstructural mass. These values are measured in the beam cross-section coordinate system. These are the M1(A), M2(A), M1(B), and M2(B) fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.

Y of Point CZ of Point CY of Point DZ of Point DY of Point EZ of Point EY of Point FZ of Point F

Indicates the stress recovery. They define the Y and Z coordinates of the stress recovery points across the section of the beam, as defined in the local element coordinate system. These are the C1, C2, D1, D2, E1, E2, F1, and F2 fields on the PBAR entry. These values can be either real values or references to existing field definitions. These properties are optional.



116

Y of NA @ Node 1Z of NA @ Node 1Y of NA @ Node 2Z of NA @ Node 2

Defines the offset from the shear center of the cross section to the location of the neutral axis. These values are measured in the beam cross-section coordinate system. These are the N1(A), N2(A), N1(B), and N2(B) fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.

[Contact Beam Radius] This allows the equivalent radius for beam-to-beam contact to be different for each beam cross section. The MSC Nastran entry BCBMRAD is written to the .bdf file. The BCBMRAD entry format is different for SOL 400 and SOL 600. You must turn on beam-to-beam contact under the Analysis application (contact parameters / contact detection) for this parameter to be written.

Section Integration Used only for Sol 400. Value is written to the SECT field of the PBARN1/PBEMN1 entry.

Nonlinear Formulation This optional property word can take on any of the three values Automatic, Large Strain, or Small Strain and is only recognized for implicit nonlinear (SOL 400) analyses. Automatic is the default if not specified and determines if large or small strain is appropriate based on the existence of an elastoplastic material constitutive model and/or if the elements are contained in a contact body. If appropriate, the PBARN1/PBEMN1 entry is written for this property set. Large Strain forces the PBARN1/PBEMN1 entry to be written, regardless; and Small Strain forces it not to be written, regardless. In addition, if large strain is forced or detected, the usage of NLMOPTS, LRGSTRN,0 or 1 is written based on the setting on the Load Increment Parameters form when defining a Subcase. See Static Subcase Parameters for Implicit Nonlinear Solution Type, 408.

Create SectionsI C L ..., Beam Library

Activates the Beam Library forms. These forms will allow the user to define beam properties by choosing a standard cross section type and inputing dimensions.

Weld Nugget DiameterTop/Bot Sheet Thickness

These optional properties are used for defining spot weld parameters (weld diameter and connecting sheet thicknesses) in an MSC Nastran Embedded Fatigue analyses of spot welds for statics, normal modes and modal transient response. All parameters defined here are placed on the PFTG bulk data entry. For the sheet thickness, enter two values separated by spaces. If only one is provided both top and bottom thickness retain the same value for both. If not defined, the thicknesses are determined from the connecting sheet properties. If the diameter is left blank, a diameter is determined through a look up table based on the minimum thickness of the connecting sheets.



1D - Beam - General Section (CBEAM) - P-Formulation


Use this form to create CBEAM elements with a PBEAM or PBEAML property along with the P-formulation entries ADAPT and PVAL. This form defines a simple beam element in the structural model for an adaptive, p-element analysis.

Please see the description of properties listed in 1D - Beam - General Section (CBAR) - Standard Formulation, 112 for the generic properties needed for any beam/bar definition. Additional properties for P-formulation are listed here.


CreateModify

1D Beam General Section P-Formulation Bar 2/3/4

Note: .Patran will check the element associativity to other elements sharing this property set and will not export user defined pin unless the user includes an asterisk (*) in the string, in which case Patran will export the defined pin flags for all elements in the property set.


Starting P-orders and

Maximum P-orders

Polynomial orders for displacement representation within elements. Each contains a list of three integers referring to the directions defined by the P--order Coordinate System (default elemental). Starting P-orders apply to the first adaptive cycle. The adaptive analysis process will limit the polynomial orders to the values specified in Maximum P-orders. These are the Polyi fields on the PVAL entry.

P-order Coord. System The three sets of three integer p-orders above refer to the axes of this coordinate system. By default, this system is elemental. This is the CID field on the PVAL entry.

Activate Error Estimate Flag that controls whether or not this set of elements participates in the error analysis. This is the ERREST field on the ADAPT entry.

P-order Adaptivity Controls the particular type of p-order adjustment from adaptive cycle to cycle. This is the TYPE field on the ADAPT entry.

Error Tolerance The tolerance used to determine if the adaptive analysis is complete. By default this value is equal to 0.1. This is the ERRTOL field on the ADAPT entry.


118

Stress Threshold Value Elements with von Mises stress below this value will not participate in the error analysis. By default this value is equal to 0.0. This is the SIGTOL field on the ADAPT entry.

Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis.By default this value is equal to1.0E-8. This is the EPSTOL field on the ADAPT entry.



1D - Beam - General Section (CBAR) - Linear/Cubic Closed Section


Use this form to create CBAR elements with a PBAR or PBARL property and associated PBARN1 to define nonlinear, large displacement, large strain behavior for use in SOL 400. A PBARN1 entry is written with LCC option written to the BEHi field. A CBARAO entry will be generated if any Station Distances are specified. This defines a simple beam element in the structural model.

Please see the description of properties listed in 1D - Beam - General Section (CBAR) - Standard Formulation, 112 for the generic properties needed for any beam/bar definition. Properties specific to defining this beam behavior are listed here.


CreateModify

1D Beam General Section Linear/Cubic Closed Section

Bar 2


Section Integration Used only for Sol 400. Value is written to the SECT field of the PBARN1/PBEMN1 entry. Asmeared cross section or a numerically integrated cross section can be defined.


120

1D - Beam - General Section (CBAR) - Linear-Shear


Use this form to create CBAR elements with a PBAR or PBARL property and associated PBARN1 to define nonlinear, large displacement, large strain behavior for use in SOL 400. A PBARN1 entry is written with LS option written to the BEHi field. A CBARAO entry will be generated if any Station Distances are specified. This defines a simple beam element in the structural model.



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1D Beam General Section Linear-Shear Bar 2




1D - Beam - Curved with General Section (CBEND)


Use this form to create CBEND elements with a PBEND property. This form defines a curved beam element of the structural model. The CBEND element has several ways to define the radius of the bend and the orientation of that curvature.This element always uses the method of defining the center of curvature point (GEOM=1). An alternate property of the Curved Pipe element also exists.

Properties specific to defining this beam behavior are listed here.


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1D Beam Curved w/General Section Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. This property defines the setting of the MID field on the PBEND entry. This property is required.

Center of Curvature Vector

Defines the center of curvature of the pipe bend. It is done by either specifying a vector from the first node of the element or by referencing a node. The CBEND element in MSC Nastran has several ways to define the radius of the pipe bend and the orientation of that curvature. This defines the settings of the X1, X2, X3, and G0 fields of the CBEND entry. This property is required.

Radial Bar OffsetAxial Bar Offset

Defines the offset from the nodes to the actual centroids of the beam cross section. These properties define the settings of the RC and ZC fields on the PBEND entry. These values can either be real values or references to existing field definitions. This property is optional.

Area Defines the cross-sectional area of the element. This property is the A field on the PBEND entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Inertia 1,1Inertia 2,2

Defines the various area moments of inertia of the cross section. These properties are the I1 and I2 fields on the PBEND entry. These values can either be real values or references to existing field definitions. These values are optional.

Torsional Constant Defines the torsional stiffness of the beam. This is the J field on the PBEND entry. This value can be either a real value, or a reference to an existing field definition. This property is optional.


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Shear Stiff, RShear Stiff, Z

Defines the shear stiffness values. These properties are the K1 and K2 fields on the PBEND entry. These values can be either real values or references to existing field definitions. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit length of the beam and is the NSM field on the PBEND entry. This value can be either real value or a reference to an existing field definition. This property is optional.

Radial NA Offset Defines the radial offset of the geometric centroid from the end nodes. Positive values move the centroid of the section towards the center of curvature of the pipe bend. This property is the DELTAN field on the PBEND entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

R of Point CZ of Point CR of Point DZ of Point DR of Point EZ of Point ER of Point FZ of Point F

These properties are for stress recovery. They define the R and Z coordinates of the stress recovery points across the section of the beam, as defined in the local element coordinate system. These properties are the C1, C2, D1, D2, E1, E2, F1 and F2 fields on the PBEND entry. These values can be either real values or references to existing field definitions. These properties are optional.



1D - Beam - Curved with Pipe Section (CBEND)


Use this form to create CBEND elements with a PBEND property. This defines a curved pipe or elbow element of the structural model. The internal pressure is defined as part of the element definition because, for pipe elbows, the internal pressure affects the element stiffness.

Properties specific to defining this beam behavior are listed here.


Create 1D Beam Curved W/Pipe Section Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. Defines the MID field on the PBEND entry. This property is required.

Center of Curvature Vector Defines the center of curvature of the pipe bend. This can be done either by specifying a vector from the first node of the element or by referencing a node. The CBEND element in MSC Nastran has several ways to define the radius of the pipe bend and the orientation of that curvature. Defines the settings of the X1, X2, X3, and G0 fields on the CBEND entry. This element in Patran always uses the method of defining the center of curvature point (GEOM=1). This value is required.

Radial Bar OffsetAxial Bar Offset

Defines the offset from the nodes to the actual centroids of the pipe cross section. These are the RC and ZC fields on the PBEND entry. These values can either be real values or references to existing field definitions. These properties are optional.

Mean Pipe Radius Indicates the distance from the centroid of the pipe cross section to mid-wall location. This is the r field on the PBEND entry. This value can either be a real value or a reference to an existing field definition. This property is required.

Pipe Thickness Indicates the wall thickness of the pipe. This is the t field on the PBEND entry. This value can be either a real value or a reference to an existing field definition. This property is required.

Internal Pipe Pressure Indicates the static pressure inside the pipe elbow. This is the P field on the PBEND entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


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Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit length of the beam and is the NSM field on the PBEND entry. This value can either be a real value or a reference to an existing field definition. This property is optional.

Stress Intensification Indicates the desired type of stress intensification to be used. This is a character string value. This property is the FSI field on the PBEND entry. Valid settings of this parameter are General, ASME, and Welding Council.



1D - Beam - Lumped Section (CBEAM/PBCOMP)


Use this form to create CBEAM elements with a PBCOMP property. This defines a beam element of constant cross section, using a lumped area element formulation.The orientation vector can be defined as either a vector or a reference to an existing node in the XY plane.



Create 1D Beam Lumped Section Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. This defines the setting of the MID field on the PBCOMP entry. This property is required.

Area Defines the cross-sectional area of the element. This is the A field on the PBCOMP entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is defined in terms of mass per unit length of the beam. This is the NSM field on the PBCOMP record. This value can be either a real value or a reference to an existing field definition. This property is optional.


Defines the shear stiffness values. These are the K1 and K2 fields on the PBCOMP entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Y of NSMZ of NSM

Defines the offset from the centroid of the cross section to the location of the nonstructural mass. These values are measured in the beam cross-section coordinate system. These properties are the M1 and M2 fields on the PBCOMP entry. These values can be either real values or references to existing field definitions. These properties are optional.


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Symmetry Option Specifies which type of symmetry is being used to define the lumped areas of the beam cross section. This is a character string parameter. The valid settings are No Symmetry, YZ Symmetry, Y Symmetry, Z Symmetry, or Y=Z Symmetry. This defines the setting of the SECTION field on the PBCOMP entry. This property is optional.

Ys of Lumped AreasZs of Lumped Areas

Defines the locations of the various lumped areas. These are defined in the cross-sectional coordinate system. These properties define the Yi and Zi fields on the PBCOMP entry. These values are lists of real values. These properties are optional.

Area Factors Defines the Fraction of the total area to be included in this lumped area. The sum of all area factors for a given section must equal 1.0. If the data provided does not meet this requirement, the values will all be scaled to the corrected value. These properties define the values for the Ci fields on the PBCOMP entry. These values are lists of real values. These properties are optional.



1D - Beam - Tapered Section (CBEAM) - Standard Formulation


Use this form to create CBEAM elements with a PBEAM or PBEAML property. This defines a beam element with varying cross sections. The difference between defining a tapered section and a constant section is the ability to define station locations along the beam and various values at those stations as a real list. Real lists are entered by separating values in the databoxes by spaces or commas. There should be the same number of values in each data box corresponding to the number of stations. If less values are entered than the number of stations, the missing values will take on the last value entered. A general section beam can also be used to define a tapered section beam. See 1D - Beam - General Section (CBEAM) - Standard Formulation, 130.



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1D Beam Tapered Section Standard Formulation

Bar 2


Station Distances Defines stations along each beam element where the section properties will be defined. The values specified here are fractions of the beam length. These values, therefore, are in the range of 0. to 1. These values define the settings of the X/XB fields on the PBEAM record. These values are real values. These properties are optional. Enter them as a list each value being separated by a space.

Cross-Sect. Areas Defines the cross-sectional area of the element. This property defines the settings of the A fields on the PBEAM record. This value can be either a real value, or reference to an existing field definition or entered as a list. This property is required.

Inertias i,j Defines the various area moments of inertia of the cross section. These defines the settings of the I1, I2, and I12 fields on the PBEAM entry. These values are real values entered as a list. These properties are optional.

Torsional Constants Defines the torsional stiffness parameters. This property defines the J fields on the PBEAM entry. This is a list of real values, one for each station location. This property is optional.


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Ys of C PointsZs of C PointsYs of D pointsZs of D PointsYs of E PointsZs of E PointsYs of F PointsZs of F Points

Defines the Y and Z locations in element coordinates, relative to the shear center for stress data recovery. These define the C1, C2, D1, D2, E1, E2, F1, and F2 fields on the PBEAM entry. These are lists of real values, one for each station location. These properties are optional.

Nonstructural Masses Defines the mass not included in the mass derived from the material of the element. This is defined in terms of mass per unit length of the beam. This property is the NSM field on the PBEAM entry. This is a list of real values, one for each station location. This property is optional.


Defines the shear stiffness values. These properties are the K1 and K2 fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.

Shear Relief YShear Relief Z

Defines the shear relief coefficients due to taper. These are the S1 and S2 fields on the PBEAM entry. These values can either be real values or references to existing field definitions. These properties are optional.

Warp Coeff. @ Node 1Warp Coeff. @ Node 2

Specifies the warping coefficient at each end of the element. These properties are the CW(A) and CW(B) fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.

Y of NA @ Node 1Z of NA @ Node 1Y of NA @ Node 2Z of NA @ Node 2

Defines the offset from the centroid of the cross section to the location of the neutral axis. These values are measured in the beam cross section coordinate system and are the N1(A), N2(A), N1(B), and N2(B) fields on the PBEAM entry. These values can be either real values or references to existing field definitions. These properties are optional.



1D - Beam - Tapered Section (CBEAM) - P-Formulation


Use this form to create CBEAM elements with a PBEAM or PBEAML property along with the P-formulation entries ADAPT and PVAL. This defines a beam element with varying cross sections. The difference between defining a tapered section and a constant section is the ability to define station locations along the beam and various values at those stations as a real list. Real lists are entered by separating values in the databoxes by spaces or commas. There should be the same number of values in each data box corresponding to the number of stations. If less values are entered than the number of stations, the missing values will take on the last value entered.

Please see the description of properties listed in 1D - Beam - General Section (CBAR) - Standard Formulation, 112 for the generic properties needed for any beam/bar definition.

Additional properties for P-formulation are listed described in 1D - Beam - General Section (CBEAM) - P-Formulation, 117.

Property values that can accept real lists for definig the taper of the beam are described in 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127.


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1D Beam Tapered Section P- Formulation Bar 2


130

1D - Beam - General Section (CBEAM) - Standard Formulation


Use this form to create CBEAM elements with a PBEAM or PBEAML property. This defines a beam element with varying cross sections. This set of options provides a method of creating beam models with warping due to torsion. The capabilities of this beam properties formulation option are similar to those of the “Tapered Section” formulation, except that warping due to torsion is handled more conveniently. If SOL 400 is used and non-linear formulations set, a PBEMN1 entry is written with BEAM option written to the BEHi field and LC written to the INTi field.

Please see the description of properties listed in 1D - Beam - General Section (CBAR) - Standard Formulation, 112 for the generic properties needed for any beam/bar definition. Also see 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127 for a description of defining tapered beam properties. Properties specific to defining this beam behavior are listed here.

Warping due to torsion is enabled by generating MSC Nastran SPOINTs to contain the warping degrees of freedom. These SPOINTs are not actually present in the Patran database, and there is no way to recover any results for these SPOINTs. They are created during analysis deck translation, and provide the means to communicate to MSC Nastran the continuity and constraint properties of the warping degrees of freedom in the model. These attributes of continuity and constraint are implied in the Patran database through the composition of the element properties application region and the set of options selected. These continuity and constraint attributes apply to both warping SPOINTs and end release flags. This connection of these attributes to the composition of the application region is new since Patran 2001r3, and represents a change in behavior from previous versions of Patran. The general rules of implied continuity are as follows.


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1D Beam General Section (CBEAM)

Standard Formulation

Bar 2


Warping Option This specifies how contraints should be applied to the warping SPOINTs of unmatched ends within the application region (see continuity rules above). The choices available include “A free B free”, “A fixed B fixed”, “A free B fixed”, “A fixed B free”, or “None”. The choice of “None” is used to disable warping altogether for the current element property set, in which case no SPOINTs will be generated or constrained. Only unmatched ends within the application region will be eligible for constraining, and whether or not a constraint is applied will depend on the option selected, and whether the unmatched end is “End A” or “End B” of its beam element. If no selection is made for this element property, “A free B free” is selected by default.


1. Within the application region, two beam elements are taken to be continuous if a GRID ID at an end of one of the beam elements matches a GRID ID at one of the ends of the other beam element. If a third beam element in the same application region also contains the same GRID ID, it is assumed that none of the beam elements is continuous at this location. This condition is known as a “multiple junction”. Similarly, if none of the other beam elements in the application region contain a matching GRID ID, the corresponding end of the beam element is taken to be not continuous. This condition is known as an “unmatched end”.

2. If warping is enabled, then all instances of beam element continuity must have the matching GRID ID located at “End A” of one of the beam elements and at “End B” of the other. “End A” and “End B” positions are determined by the order of GRID IDs specified in the element connectivity array, and the positive direction of the x-axis of the element coordinate system points from “End A” to “End B”. If warping is not enabled, this restiction does not apply. If warping is enabled, any violation of this requirement will result in a failure to complete the translation of the finite element model. In this event, the user will have to reverse the direction of the improperly oriented beam elements and initiate the translation again.

3. When warping is enabled, all positions of beam element continuity within an application region will be represented by a single SPOINT at each of these positions, which will be generated at the time of analysis deck translation and will appear on the CBEAM entries for the appropriate end of both of the beam elements that are continuous at each location. If any end release codes have been prescribed for the application region, they will not be applied at locations of beam element continuity. This is new for Patran 2001r3. For earlier versions of Patran, end release codes would be applied to all elements of the application region, regardless of continuity.

4. When warping is enabled, individual SPOINTs are generated for all beam ends that are not continuous. This applies to both “multiple junctions” and “unmatched ends”.

5. The specified end release codes are applied to all discontinuous beam element ends in the application region, whether “multiple junction” or “unmatched end”, with the applied end release codes dependent on what has been prescribed for “End A” and “End B” for the application region. If no end release codes have been prescribed for the application region, none are generated.

6. When warping is enabled, and for unmatched ends only (not multiple junctions), constraints applied to the SPOINTs are specified by the “warping option” specified in the element properties form. For example, if “A free B fixed” has been selected and the unmatched end is “End A” of its beam element, it will not be constrained. If it is “End B” of its element, it will be constrained. The warping SPOINT for a beam element end involved in a multiple junction will not be constrained under any circumstances. If the user wishes to constrain warping for a beam element involved in a multiple junction, he will have to do so by splitting the application region in such a way that the beam element end becomes an “unmatched end” within its new application region.

7. Warping is considered to be enabled when a value has been specified for the warping coefficient at either end of the beam element. When the user selects the “Beam Library” option, values for the warping coefficient get computed autamatically, and thus warping is implicitly enabled. If the user wishes to disable warping while using the Beam Library option, he must choose “None” as his “Warping Option” on the “Input Properties ...” form.


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1D - Beam - General Section (CBEAM) - Linear/Cubic Closed Section


Use this form to create CBEAM elements with a PBEAM or PBEAML property and associated PBEMN1 to define nonlinear, large displacement, large strain behavior for use in SOL 400. A PBEMN1 entry is written with BEAM option written to the BEHi field and LCC written to the INTi field.

Please see the description of properties listed in 1D - Beam - General Section (CBEAM) - Standard Formulation, 130 for the generic properties needed for any beam/bar definition. Properties specific to defining this beam behavior are listed here.


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1D Beam General Section (CBEAM)

Linear/Cubic Closed Section

Bar 2




1D - Beam - General Section (CBEAM) - Linear/Cubic Open Section


Use this form to create CBEAM elements with a PBEAM or PBEAML property and associated PBEMN1 to define nonlinear, large displacement, large strain behavior for use in SOL 400. A PBEMN1 entry is written with BEAM option written to the BEHi field and LCO written to the INTi field



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Bar 2




134

1D - Beam - General Section (CBEAM) - Linear-Shear


Use this form to create CBEAM elements with a PBEAM or PBEAML property and associated PBEMN1 to define nonlinear, large displacement, large strain behavior for use in SOL 400. A PBEMN1 entry is written with BEAM option written to the BEHi field and LS written to the INTi field



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Bar 2




1D - Rod - General Section (CROD) - Standard Formulation


Use this form to create a CROD element and a PROD property. This defines a tension-compression-torsion element of the structural model.


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1D Rod General Section Standard Formulation

Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This defines the setting of the MID field on the PROD entry. This property is required.

Area Defines the cross-sectional area of the element. This is the A field on the PROD entry. This value can be either a real value or a reference to an existing field definition. This property is required.

Torsional Constant Defines the torsional stiffness of the beam. This is the J field on the PROD entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Torsional Stress Coefficient Defines the coefficient to determine the torsional stress. This is the C field on the PROD entry. This property can be either a real value or a reference to an existing field definition. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit length of the beam. This is the NSM field on the PROD entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Contact Beam Radius Defines the radius of the beam for beam to beam contact in SOL 600/400.


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1D - Rod - General Section - CONROD

This describes the Input Properties available from theElement Properties form when the following options are chosen.

Use this form to create a CONROD element. This defines a tension-compression-torsion element of the structural model.


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1D Rod General Section CONROD Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. This defines the setting of the MID field on the CONROD entry. This property is required.

Area Defines the cross-sectional area of the element. This property is the A field on the CONROD entry. This value can be either a real value or a reference to an existing field definition. This property is required.

Torsional Constant Defines the torsional stiffness of the beam. This property is the J field on the CONROD entry. This value can either be a real value or a reference to an existing field definition. This property is optional.

Torsional Stress Coefficient Defines the coefficient to determine the torsional stress. This property is the C field on the CONROD entry and can either be a real value or a reference to an existing field definition. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit length of the beam and is the NSM field on the CONROD entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


1D - Rod - Pipe Section (CTUBE)


Use this form to create a CTUBE element and a PTUBE property. This defines a tension-compression-torsion element with a thin-walled tube cross section.


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1D Rod Pipe Section Bar 2


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. This property defines the setting of the MID field on the PTUBE entry. Either select from the list using the mouse, or type in the name. This property is required.

Outer Diameter @ Node 1Outer Diameter @ Node 2

Defines the tube outer diameters at each end of the element. These are the OD and OD2 fields on the PTUBE entry. These values can either be real values or references to existing field definitions. The outer diameter at Node 1 property is required. The outer diameter at Node 2 Property is optional.

Pipe Thickness Specifies the wall thickness of the pipe. This is the T field on the PTUBE entry. This value can either be a real value or a reference to an existing field definition. This property is required.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit length of the beam and is the NSM field on the PTUBE entry. This value can be either a real value or reference to an existing field definition. This property is optional.


138

1D - Spring (CELAS1)


Use this form to create a CELAS1 or CELAS1D (for SOL 700) element and a PELAS property. This defines a scalar spring of the structural model.


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1D Spring Bar/2


Spring Constant Defines the coefficient to be used for this spring. This property is the K field on the PELAS entry and can be either a real value or a reference to an existing field definition. This property is required.

Damping Coefficient Defines what damping is to be included. This property is the GE field on the PELAS entry and can be either a real value or a reference to an existing field definition. This property is optional.

Stress Coefficient Defines the relationship between the spring deflection and the stresses within the spring. This property is the S field on the PELAS entry and can be either a real value or a reference to an existing field definition. This property is optional.

Dof at Node 1Dof at Node 2

Defines which degree of freedom this value is to be attached to at each node. The degree of freedom can be set to UX, UY, UZ, RX, RY, or RZ. These properties define the settings of the C1 and C2 fields on the CELAS1 entry. These properties are required.

User Defined Coordinate System Number

Number of a User Defined Coordinate system, used only for Explicit Nonlinear (SOL 700). This property is optional.


1D - Damper - Scalar (CDAMP1)


Use this form to create a CDAMP1 or CDAMP1D (for SOL 700) element and a PDAMP property. This defines a scalar damper element of the structural model.


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1D Damper Scalar Bar/2


Damping Coefficient Defines the force per unit velocity value to be used. This is the B field on the PDAMP entry and can either be a real value or a reference to an existing field definition. This property is optional.


Defines which degree of freedom this value will be attached to at each node. This can be set to UX, UY, UZ, RX, RY, or RZ. These define the settings of the C1 and C2 field on the CDAMP1 entry. These properties are required.

User Defined Coordinate System Number

Number of a User Defined Coordinate system, used only for Explicit Nonlinear (SOL 700). This property is optional.


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1D - Damper - Viscous (CVISC)


Use this form to create a CVISC element and a PVISC property. This defines a viscous damper element of the structural model.


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1D Damper Viscous Bar 2


Extensional Viscous Coefficient

This is the C1 field on the PVISC entry. This property can either be a real value or a reference to an existing field definition. This property is optional.

Rotational Viscous Coefficient

This is the C2 field on the PVISC entry. This property can either be a real value or a reference to an existing field definition. This property is optional.


1D - Gap - Adaptive / Non Adaptive (CGAP)


Use this form to create a CGAP element and a PGAP property. This defines a gap or frictional element of the structural model for non-linear analysis.


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1D Gap Adaptive

Nonadaptive

Bar 2


Gap Orientation Defines the local element coordinate system for this element that can be defined in one of three ways. If the two end nodes of the gap are not coincident, then the Gap Orientation can reference a vector or a node ID. This local x-axis would then run between the two end nodes and the orientation information would define the local xy plane. However, if the two end nodes are coincident, then the Gap Orientation refers to an existing coordinate system definition and will be used as the local element coordinate system. This Gap Orientation defines the settings of the X1, X2, X3, G0, and CID fields on the CGAP entry. This property is required.

Initial Opening Defines the initial opening of the gap element. The nodal coordinates are only used to define the closure direction. This property is the U0 field on the PGAP entry and can be either a real value or a reference to an existing field definition. This property is optional.

Preload Defines an initial preload across an initially closed gap. For example, this can be used for initial thread loading. If the gap is initially open, setting this value to the initial opening stiffness will improve the solution convergence. This is the F0 field on the PGAP entry and can either be a real value or a reference to an existing field definition. This property is optional.

Closed StiffnessOpen Stiffness

Defines the artificial stiffness of the gap when the gap is open or closed. The closed stiffness should be chosen to closely match the stiffness of the surrounding elements. The open stiffness should be approximately 10 orders of magnitude less. These properties are the Ka and Kb fields on the PGAP entry and can either be real value or references to existing field definitions. The closed stiffness property is required. The opened stiffness property is optional.


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Sliding Stiffness Defines the artificial shear stiffness of the element when the element is closed. This is the Kt field on the PGAP entry. This property can be either a real value or a reference to an existing field definition. This property is optional.

Static Friction Defines the static friction coefficient. This property is the MU1 field on the PGAP entry. This value is optional and can be a real scalar or a spatially varying real scalar field. Not applicable for Nonadaptive model.

Kinematic Friction Defines the kinematic friction coefficient. This property is the MU2 field on the PGAP entry. This value is optional and can be a real scalar or a spatially varying real scalar field. Not applicable for Nonadaptive model.

Max Penetration Defines the maximum allowable penetration. This property is the TMAX field on the PGAP entry. This value is optional and can be a real scalar or a spatially varying real scalar field.

Max Adjust Ratio Defines the maximum allowable adjustment ratio. This property is the MAR field on the PGAP entry. This value is optional and can be a real scalar or a spatially varying real scalar field. Not applicable for Nonadaptive model.

Penet. Lower Bound Defines the lower bound for the allowable penetration. This is the TRMIN field on the PGAP entry. This value is optional and can be a real scalar or a spatially varying real scalar field. Not applicable for Nonadaptive model.

Friction Coeff. y

Friction Coeff. Z

Defines the coefficient of friction when sliding occurs along this element in the local y and z directions. These are the MU1 and MU2 fields on the PGAP entry and can be either real values or references to existing field definitions. These properties are optional.



1D - Scalar Mass (CMASS1)


Use this form to create CMASS1 elements and a PMASS property. This defines a scalar mass element of the structural model.


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1D 1D Mass Bar/2


Mass Defines the translation mass or rotational inertia value to be applied. This property is the M field on the PMASS entry and can either be a real value or a reference to an existing field definition. This property is required.


Defines which degree of freedom this value will be attached to at each node. These can be set to UX, UY, UZ, RX, RY, or RZ and defines the settings of the C1 and C2 field on the CMASS1 entry. These properties are required.


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1D - PLOTEL


Use this form to create PLOTEL elements. No actual properties are needed to define this property set. These elements are written to the MSC Nastran input deck for MSC Nastran plotting purposes only and are not structural in nature and not used by the actual analysis.


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1D PLOTEL Bar/2


1D - Bush (CBUSH)


CBUSH/PBUSH/PBUSHT element property sets are created with this option for defining a scalar bush joint, which is a generalized spring-damper structural element. If frequency dependent or nonlinear force deflection properties are supplied, the PBUSHT entry will be written. Otherwise it will not be written. This is a list of Input Properties available. Use the menu scroll bar on the Input Properties form to view these properties.


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1D Bush Scalar Bar/2


Bush Orientation Element orientation strategy keys off of CID specification. If CID is blank, the element x-axis lies along the line which joins the elements grid points (GA, GB Element Properties/Application Region). The X-Y plane is determined by specifying the Bush Orientation. If a vector input is given, these components define an

orientation vector from the first grid point (GA) of the element in the displacement coordinate system at that point (GA). If the Bush Orientation references a grid point ID (Value), this orientation point forms an orientation vector which extends from the first element grid point to the orientation point.

If a CID ≥ 0 is specified for Bush Orientation System, the element X,Y, and Z axes are aligned with the coordinate system principal axes. If the CID is for a cylindrical or spherical coordinate system, the first elemental grid point (GA) is used to locate the system. If CID = 0, the elemental coordinate system is the Basic Coordinate System.

If no orientation is specified in any form, the element x-axis is along the line which connects the element’s grid points. The material property inputs for this condition must be limited to simple axial and torsional stiffness and damping (k1,k4,B1,B4).

Offset Location Offset Location (0.0 ≤ s ≤ 1.0) specifies the spring-damper location along the line from GRIDGA to GRIDGB by setting the fraction of the distance from GRIDGA. s=0.50 centers the spring-damper.

Offset Orientation System Specifies the coordinate system used to locate the spring-damper offset when it is not on the line from GRIDGA to GRIDGB.

v


146

Offset Orientation Vector Provides the location of the spring-damper in space relative to the offset coordinate system. If the offset orientation system is -1 or blank, the offset orientation vector is ignored.

Spring Constant iStiffness Frequency Depend i

Defines the stiffness associated with a particular degree of freedom. These are the Ki fields of the PBUSH entry. This property is defined in terms of force per unit displacement and is defined as a real value A reference to an existing field definition for defining stiffness vs. frequency writes the TKIDi fields in the PBUSHT entry.

Stiffness Force/Displacement i Defines the nonlinear force vs deflection curves for each degree of freedom of the spring-damper system. These are the TKNIDi fields of the PBUSHT entry.

Damping Coefficient iDamping Frequency Depend i

Defines the force per velocity damping value for each degree of freedom. These are the Bi fields of the PBUSH entry. A reference to an existing field definition for defining damping vs. frequency writes the TBIDi fields in the PBUSHT entry.

Structural DampingStructural Damping Frequency Depend i

Defines the non-dimensional structural damping coefficient (GEi fields of the PBUSH entry). A reference to an existing field definition for defining damping vs. frequency writes the TKGEIDi fields to the PBUSHT entry.

Stress Recovery TranslationStress Recovery RotationStrain Recovery TranslationStrain Recovery Rotation

Stress and Strain Recovery Coefficients. The element stress are computed by multiplying the stress coefficients with the recovered element forces. The element strains are computed by multiplying the strain coefficients with the recovered element strains. This defines the SA, ST, EA & ET fields on the PBUSH entry.

Force-Deflection Curve Rule Force deflection curve rule - writes FDC field of PBUSHT. See the MSC Nastran Quick Start manual for details.

Fuse Behavior Fuse behavior. Writes the FUSE field of PBUSHT

Fuse Direction Fuse direction. Writes the DIR field of PBUSHT.

Fuse Failure Mode Failure mode. Writes the OPTION field of PBUSHT.

Lower Failure BoundUpper Failure Bound

Lower and Upper failure bound. Writes the LOWER and UPPER fields of the PBUSHT entry.

FRATE-K Drop Scale Factor Fuse stiffness retention factor. Writes the FSRS field of the PBUSHT entry.

Grid A Rotation Large rotation flag. Writes the LRGR field of the PBUSHT entry.



1D- Bush (CBUSH2D/PBUSH2D)

This describes the Input Properties available from the Element Properties form and the following options are chosen.

This creates CBUSH2D/PBUSH2D entries. Following is a list of Input Properties available. Use the menu scroll bar on the Input Properties form to view these properties.


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1D Bush 2D Linear/Non Linear Bar/2


Bush Orientation String pull down indicating the plane must be supplied as the XY, YZ, or ZX plane of the given coordinate system.

Orientation System Coordinate in which Orientation plane is defined. Select data box to allowed graphical selection of coordinate.

Stiffness K11 Nominal stiffness in T1 rectangular direction. Required!

Stiffness K22 Nominal stiffness in T2 rectangular direction. Required!

[Damping B11] Nominal damping in T1 rectangular direction. Default = 0.0

[Damping B22] Nominal damping in T2 rectangular direction. Default = 0.0

[Force M11] Nominal acceleration-dependent force in T1 rectangular direction. Default = 0.0

[Force M22] Nominal acceleration-dependent force in T2 rectangular direction. Default = 0.0

[Inner Journal Diameter BDIA] Inner journal diameter. Real > 0.0

[Damper Length BLEN] Damper length. Required if inner journal diameter given! Real > 0.0

[Damper Radial Clearance BCLR] Damper radial clearance. Required if inner journal diameter given! Real > 0.0

[Solution Option SOLN] Pulldown String - Solution Option: Long or Short (Default = Long)

[Lubricant viscosity VISCO] Lubricant viscosity. Required if inner journal diameter given! Real > 0.0

[Lubricant Vapor Pressure PVAPCO] Lubricant vapor pressure. Required if inner journal diameter given! Real.

[Number of Lubricant Ports NPORT] Integer pull down: Number of lubricant ports. 1 or 2


148

[Boundary Pressure for Port 1] Boundary pressure for port 1. Required if NPORT = 1. Real >= 0.0

[Angular Positions for Port 1] Angular position for port 1. (0.0<=Real<=360.0). Required if NPORT = 1.

[Frequency Dependent] Specifies if element is frequency dependent or not for USD support. String - Yes/No. No = default.



1D - Spot Weld Connector (CWELD)


If you supply "General" for the "Connection Type" of a "Spot Weld Connector" element property, then field 9 (TYPE) for the PWELD bulk data entry in the BDF file will be blank instead of "SPOT". When this field is set to "SPOT", Nastran does extra verifications to avoid excessive stiff of soft connections.

Note that spot weld (CWELD/PWELD ) properties are created automatically (or pre-existing properties selected) when creating Spotwelds through the Finite Elements application. Therefore no application region is required (or presented) in the element properties application when defining or modifying spotweld properties because the existence of the spotweld itself is the application region for the property set. Property values may be modified in this form, but the property set will remain associated with the connector elements they were originally created with. If you wish to modify the property set a connector is associated with, do this in the Finite Element application using the Modify / Connector action.

For MSC Nastran Embedded Fatigue analyses of spot welds for statics, normal modes and modal transient response the spot weld diameter is placed on the PFTG bulk data entry. The top and bottom sheet thicknesses are determined from the connecting sheet properties automatically by Nastran.

In order to run a successful MSC Nastran Embedded Fatigue analysis, an S-N or ε-N constitutive model (or both) must be defined for the elements of interest (see Stress-Life (SN) and Strain Life (eN), Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible), 92). An output request for fatigue life must be made (see Output Requests, 448). A spot weld fatigue analysis must be turned on when setting up the analysis (see Solution Parameters, 298 for Linear Static, Normal Modes, or Transient Response). And a cyclic loading sequence must be defined (see Subcase Select, 485) above the subcase level.


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1D Spot Weld Connector Connector


150

1D - Fastener Connector (CFAST)


Note that fastener properties (CFAST/PFAST) are created automatically (or pre-existing properties selected) when creating Fasteners through the Finite Elements application. Therefore no application region is required (or presented) in the element properties application when defining or modifying fastener properties because the existence of the fastener itself is the application region for the property set. Property values may be modified in this form, but the property set will remain associated with the connector elements they were originally created with. If you wish to modify the property set a connector is associated with, do this in the Finite Element application using the Modify / Connector action.

Once a connector is created, its properties can be modified in this, the Element Properties application or by modifying the connector in the Finite Elements application. Aconnector can be created and a new property set and values specified, in which case the new property set will be created. Modifying a connetor in the Finite Elements application will allow you to select/change to an existing property set or change the values of the property set, in which case overwrite permission is requested.

Fastener Stiffness Formulas

Specifying a formula will automatically calculate the connector stiffness based on the connector properties, its material, and the sheet thicknesses and materials, thus minimizing the need for manual calculation. The formula value can be any of the following:

NoneDouglasHuth Hi-Lok in CFRPHuth Hi-Lok in metalHuth solid rivet

None requires that you manually supply the stiffness. Specifying any other value will ignore any stiffness values input manually and will overwrite them.

Stiffness coefficients for the CFAST element are calculated in different steps. Generally, either Douglas or three derivatives of Huth formulas are used. Regardless of the selected formula, the axial stiffness is always calculated the same way:


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1D Fastener Connector Connector

kEf

14---πd

2

L-----------------=


The stiffness is inserted into the KT1 parameter of the PFAST entry. The length of the fastener will be determined by summation of the thickness of the two connected shell elements.

The Douglas formula is*:

where

The formula according to Huth is*:

wher n = 1 or 2 for single or double shear, respectively, and

In the case of composites, the Douglas and Huth formulas have to be used twice. First, the overall (engineering) Young’s modulus has to be calculated for both directions (E11 and E22), which then has to

be applied to the formulas. In this case, the shear stillness of the fastener is direction dependent. For composites or anisotrophic material, the material tensors of the two connected shell elements have to be transformed into the coordinate system of the CFAST element before the Douglas or Huth formula is applied. The resulting stiffness is applied to the KT2 and KT3 parameters on the PFAST entry.

A B

For Aluminium Rivet 5.0 0.8

For Steel Bolt 1.67 0.86

a b

Hi-Lok in CFRP 0.6667 4.2

Hi-Lok in metal 0.6667 3.0

Solid Rivet 0.4 2.2

k1c---=

cA

dEf--------- B

1t1E1------------ 1

t2E2------------+

+=

k1c---=

ct1 t2+

2d---------------

abn--- 1

t1E1----------- 1

nt2E2-------------- 1

2Eft1------------- 1

2nEft2-----------------+ + +

=


152

* The following symbols are used in the formulas:

Note: The calculated stiffness will be applied in the fastener connector element coordinate system based on the specification or non-specification of a defined coordinate system. If no coordinate system is supplied, the elemental system used is defined by the MCID = -1 method described in the MSC Nastran Quick Reference Guide for the PFAST entry. The stiffnesses are determined with this setting and MCID = -1 is written to the PFAST entry. MFLAG is ignored in this case. If a coordinte system is specified then the fasterer coordinate system is determined with the MCID >= 0 method described in the MSC Nastran Quick Reference Guide for the PFAST entry. The stiffnesses are determined and MCID is written to the PFAST entry with the specified coordinate ID. MFLAG = 0 (relative) is used in this case to calculate the stiffnesses.

Caution: Once a formula is used to create stiffness properties, the formula and material used remain associated to the property but the stiffnesses are calculated on translation and not stored in the Stiffness Values slot. Any values in the Stiffness Values databox are ignored when a formula is specified.

Symbol Meaning

Ef Young’s modulus of fastener

d Diameter of fastener

L Length of fastener, evaluated from the FE model

E1 Young’s modulus of first property connected to the fastener

t1 Thickness of first property connected to the fastener

E2 Young’s modulus of second property connected to the fastener

t2 Thickness of second property connected to the fastener



2D - Shell - Thin - Homogeneous - Standard Formulation

This describes the Input Properties available from the Element Properties form when the following options are chosen:

Use this form to create CQUAD4, CTRIA3, CQUAD8, or CTRIA6 elements with a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank to achieve the requested behavior.

Action Dimension Type Option 1 Option 2 Option 3 Topologies

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2D Shell Thin Homogenous Standard Formulation

Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select one from the list using the mouse or type in the name. This defines the settings of the MID1, MID2, MID3, and MID4 fields on the PSHELL entry. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CQUADi or CTRIAi entry. This scalar value can either be a constant value in degrees, a vector, or a reference to an existing coordinate system. This property is optional.

Thickness Defines the thickness, which will be uniform over each element. This value can either be a real value or a reference to an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CQUAD4/8 and CTRIA3/6 entries and/or the T field on the PSHELL entry. This property is required.

Nonstructural Mass Defines the mass not derived from the material of the element. This is defined in terms of mass per unit area of the element. This is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


154

Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CQUAD4/8 entry and can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the bottom and top most extreme fibers, respectively. These properties define the Z1 and Z2 fields on the PSHELL entry and can be either real values or references to existing field definitions. This property is optional.

Nonlinear Formulation This optional property word can take on any of the three values Automatic, Large Strain, or Small Strain and is only recognized for implicit nonlinear (SOL 400) analyses. Automatic is the default if not specified and determines if large or small strain is appropriate based on the existence of an elastoplastic material constitutive model and/or if the elements are contained in a contact body. If appropriate, the PSHLN1/2 entry is written for this property set. Large Strain forces the PSHLN1/2 entry to be written, regardless; and Small Strain forces it not to be written, regardless. In addition, if large strain is forced or detected, the usage of NLMOPTS, LRGSTRN,0 or 1 is written based on the setting on the Load Increment Parameters form when defining a Subcase. See Static Subcase Parameters for Implicit Nonlinear Solution Type, 408.



LayerSurface FinishReduction Factor KfScale FactorOffsetRoughness FactorTreatment FactorShape FactorWeld LocationWeld Type

These optional properties are used for defining fatigue properties in an MSC Nastran Embedded Fatigue analyses using statics, normal modes and modal transient response. All parameters defined here are placed on the PFTG bulk data entry.

In order to run a successful MSC Nastran Embedded Fatigue analysis, an S-N or ε-N constitutive model (or both) must be defined for the elements of interest (see Stress-Life (SN) and Strain Life (eN), Spot Weld (Top and Bottom Sheet), Seam Weld (Stiff and Flexible), 92). An output request for fatigue life must be made (see Output Requests, 448). An S-N or ε-N analysis must be turned on when setting up the analysis (see Solution Parameters, 298 for Linear Static, Normal Modes, or Transient Response). And a cyclic loading sequence must be defined (see Subcase Select, 485) above the subcase level.

For more detail on how to set up and perform an MSC Nastran Embedded Fatigue analysis using Patran, please see the MSC Nastran Embedded Fatigue User’s Manual. For details on the PFTG entry, please see the MSC Nastran Quick Reference Guide.

Weld TypeWeld Location

These optional properties are used for defining seam weld type and element location on the weld in an MSC Nastran Embedded Fatigue analyses of seam welds for statics, normal modes and modal transient response. All parameters defined here are placed on the FTGDEF bulk data entry. See the above entry also.



156

2D - Shell - Homogeneous - Revised Formulation


Use this form to create CTRIAR or CQUADR elements with a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank to achieve the requested behavior.


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2D Shell Thin Homogenous Revised Formulation

Tri 3Quad 4


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the settings of the MID1, MID2, MID3, and MID4 fields on the PSHELL entry. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CQUADi or CTRIAi entry. This scalar value can either be a constant value in degrees, a vector, or a reference to an existing coordinate system. This property is optional.

Thickness Defines a uniform thickness, which will cover each element. This property defines the T1, T2, T3, and T4 fields on the CQUADR or CTRIAR entry and/or the T field on the PSHELL entry and can be either a real value or a reference to existing field definition. This property is required.

Nonstructural Mass Defines the mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit area of the element. and this is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers. These properties are the Z1 and Z2 fields on the PSHELL entry and can be either real values or references to existing field definitions. These properties are optional.



LayerSurface FinishReduction Factor KfScale FactorOffsetRoughness FactorTreatment FactorShape FactorWeld TypeWeld Location

See 2D - Shell - Thin - Homogeneous - Standard Formulation, 153



158

2D - Shell - Thin - Homogeneous - P-Formulation


Use this form to create CQUAD4 or CTRIA3 elements with a PSHELL property along with the P-formulation entries ADAPT and PVAL. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.The p-formulation shell element is supported in MSC.Nastran Version 69 or later.


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2D Shell Thin Homogenous P- Formulation Tri 3/6/7/9/13Quad 4/8/12/16



Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are two ways to assign this definition: (1) reference a coordinate system, then the projected x-axis of the coordinate system is the material x-axis (2) define a constant angle offset from the projected x-axis of the basic system.This defines the setting of the THETA or MCID field on the CQUAD4 or CTRIA3 entry. This property is optional.

Thickness Defines a uniform thickness, which will cover each element. This property defines the T1, T2, T3, and T4 fields on the CQUAD4 or CTRIA3 entry and/or the T field on the PSHELL entry and can be either a real value or a reference to existing field definition. This property is required.

Nonstructural Mass Defines the mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit area of the element and this is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CQUAD4 or CTRIA3 entry and can be either a real value or a reference to an existing field definition. This property is optional.


Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers, respectively. These properties define the Z1 and Z2 fields on the PSHELL entry and can be either real values or references to existing field definitions. This property is optional.


Maximum P-orders

Polynomial orders for displacement representation within elements. Each contains a list of three integers referring to the directions defined by the P--order Coordinate System (default elemental). Starting P-orders apply to the first adaptive cycle. The adaptive analysis process will limit the polynomial orders to the values specified in Maximum P-orders. These are the Polyi fields on the PVAL entry.


Activate Error Estimate Flag that controls whether or not this set of elements participates in the error analysis. This is the ERREST field on the ADAPT entry.




Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis.By default this value is equal to1.0E-8. This is the EPSTOL field on the ADAPT entry.



160

2D - Shell - Thin - Homogeneous - Linear Discrete Kirchhoff

This describes the Input Properties available from the Element Properties form when the following options are chosen

Use this form to create CTRIA3 or CQUAD4 elements with a PSHELL/PSHLN1 property. The appropriate fields on the PSHELL entry are filled in or left blank to achieve the requested behavior. This property set is meant to be used with SOL 400 exclusively. The DCT option is written to the DCTN entry in the BEHi field and the LDK option to the INTi field to define this element formulation.


CreateModify

2D Shell Thin Linear Discrete Kirchhoff

Tri 3Quad 4


Material NameBending MaterialShear Material

Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select one from the list using the mouse or type in the name. This defines the settings of the MID1, MID2, MID3, and MID4 fields on the PSHELL entry. At least the first property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CTRIA3/CQUAD4 entry. This scalar value can either be a constant value in degrees, a vector, or a reference to an existing coordinate system. This property is optional.

Thickness Defines the thickness, which will be uniform over each element. This value can either be a real value or a reference to an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CTRIA3/CQUAD4 entry and/or the T field on the PSHELL entry. This property is required.



Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CTRIA3/CQUAD4 entry and can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Dist. 1

Fiber Dist. 2




162

2D - Shell - Thin - Laminate Plate- Standard Formulation


Use this form to create CTRIA3, CTRIA6, CQUAD4, or CQUAD8 elements with a PCOMP or PCOMPG property. A PCOMPG will be written if global plies have been defined in the associated composite material.


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2D Shell Thin Laminate Standard Formulation

Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type the name in. The specified material must be a laminate material. The data in this material definition defines the settings of the MIDi, Ti, and THETAi fields on the PCOMP entry. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This property defines the setting of the THETA or MCID field on the CTRIA3, CTRIA6 CQUAD4, or CQUAD8 entry. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is the NSM field on the PCOMP entry. This property is defined in terms of mass per unit area of the element and can be either a real value or a reference to an existing field definition. This property is optional.

PlateOffset Defines the offset of the element‘s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


Laminate Options Laminate option placed on the LAM field of the PCOMP/PCOMPG entry. No option implies all plies must be specified and all stiffness terms developed. MEM - all plies are specified but only membrane terms are computed. BEND - all plies specified but only bending terms computed. SMEAR - all plies specified, stacking sequence ignored and TS/T and 12I/T**3 terms set to zero. SMCORE - all plies specified with the last ply specifying core properties and the previous plies specifying face sheet properties. See the Nastran Quick Reference Guide for more details.

Bonding Shear Writes the SB field of the PCOMP entry.

Reference TemperatureDamping Coefficient

TREF is written to PCOMP from the value defined on the first MAT8 entry defined in the composite, or in other words, from the material of the first ply in the layup. The value of GE is written to PCOMP as the sum of all GE values on all plies, scaled based on the percentage thickness of each ply. To get values for TREF and GE from the PCOMP entry, the 2D/Shell/Thin/Laminate/Standard and Revised formulations need to have property words used to define these values. If the values are not defined then the values are retrieved from the MAT8 material card.




164

2D - Shell - Thin - Laminate - Revised Formulation


Use this form to create CQUADR or CTRIAR elements with a PCOMP or PCOMPG property. A PCOMPG will be written if global plies have been defined in the associated composite material.


CreateModify

2D Shell Thin Laminate Revised Formulation

Tri 3Quad 4


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. The specified material must be a laminate material in Patran. The data in this material definition defines the settings of the MIDi, Ti, and THETAi fields on the PCOMP entry. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CTRIAR or CQUADR entry. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is the NSM field on the PCOMP entry. This property is defined in mass per unit area, of the element. This value can be either a real value or a reference to an existing field definition. This property is optional.

PlateOffset Defines the offset of the element‘s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CTRIAR, or CQUADR entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


Laminate Options Laminate option placed on the LAM field of the PCOMP/PCOMPG entry. No option implies all plies must be specified and all stiffness terms developed. MEM - all plies are specified but only membrane terms are computed. BEND - all plies specified but only bending terms computed. SMEAR - all plies specified, stacking sequence ignored and TS/T and 12I/T**3 terms set to zero. SMCORE - all plies specified with the last ply specifying core properties and the previous plies specifying face sheet properties. See the Nastran Quick Reference Guide for more details.

Bonding Shear Writes the SB field of the PCOMP entry.

Reference TemperatureDamping Coefficient

TREF is written to PCOMP from the value defined on the first MAT8 entry defined in the composite, or in other words, from the material of the first ply in the layup. The value of GE is written to PCOMP as the sum of all GE values on all plies, scaled based on the percentage thickness of each ply. To get values for TREF and GE from the PCOMP entry, the 2D/Shell/Thin/Laminate/Standard and Revised formulations need to have property words used to define these values. If the values are not defined then the values are retrieved from the MAT8 material card.




166

2D - Shell - Thin - Equivalent Section - Standard Formulation


Use this form to create CTRIA3, CTRIA6, CQUAD4, or CQUAD8 elements with a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


CreateModify

2D Shell Thin Equivalent Section

Standard Formulation

Tri 3/6Quad 4/8


Membrane MaterialBending MaterialShear MaterialCoupling Material

Defines the materials to be used to describe the membrane, bending, shear, and coupling behavior of the element. A list of all materials currently in the database is displayed when data is entered. These properties define the settings of the MID1, MID2, MID3, and MID4 fields on the PSHELL entry. Either select from the list using the mouse or type in the name. These properties are optional.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA field on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry. This scalar value can be either a constant value or a reference to an existing coordinate system. This property is optional.

Thickness Defines the uniform thickness for each element. This property defines the setting of the Ti, T2, T3, and T4 fields on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry and/or the T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is required.

Bending Stiffness Defines the bending stiffness parameter. This is the 12I/T3 field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Thickness Ratio Defines the ratio of transverse shear thickness to the membrane thickness. This property is the TS/T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is defined in terms of mass per unit area of the element. This property is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This property is the ZOFFS field on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Distance 1

Fiber Distance 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers, respectively. These properties are the Z1 and Z2 fields on the PSHELL entry. These values can be either real values or references to existing field definitions. These properties are optional.






168

2D - Shell - Thin - Equivalent Section - Revised Formulation


Use this form to create a CTRIAR or CQUADR element and a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


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Revised Formulation

Tri 3Quad 4


Membrane MaterialBending MaterialShear Material

Defines the materials to be used to describe the membrane, bending, shear, and coupling behavior of the element. A list of all materials currently in the database is displayed when data is entered. These properties define the settings of the MID1, MID2, MID3, and MID4 fields, on the PSHELL entry. Either select from the list using the mouse or type in the name. These properties are optional.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This property defines the setting of the THETA field on the CQUADR or CTRIAR entry. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Thickness Defines the uniform thickness, which will be used for each element. This property defines the setting of the Ti, T2, T3, and T4 fields on the CTRIAR or CQUADR entry and/or the T field on the PSHELL entry. This value can be either a real value or a references to an existing field definition. This property is required.

Bending Stiffness Defines the bending stiffness parameter. This property is the 12I/T3 field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Thickness Ratio Defines the ratio of transverse shear thickness to the membrane thickness. This is the TS/T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This property is defined in terms of mass per unit area of the element. This is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Distance 1

Fiber Distance 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers respectively. These properties are the Z1 and Z2 fields on the PSHELL entry. These values can be either real values or references to existing field definitions. These properties are optional.






170

2D - Shell - Thin - Equivalent Section - P-Formulation


Use this form to create a CQUAD4, or CTRIA3 element and a PSHELL property along with the P-formulation entries ADAPT and PVAL. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior. The p-formulation shell element is supported in MSC.Nastran Version 69 or later.

.


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P- Formulation Tri 3/6/7/9/13Quad 4/8/12/16


Membrane MaterialBending MaterialShear MaterialCoupling Material

Defines the materials to be used to describe the membrane, bending, shear, and coupling behavior of the element. A list of all materials currently in the database is displayed when data is entered. These properties define the settings of the MID1, MID2, MID3, and MID4 fields, on the PSHELL entry. Either select from the list using the mouse or type in the name. These properties are optional.

Material Orientation Angle

Defines the basic orientation for any non-isotropic material within the element. There are two ways to assign this definition: (1) reference a coordinate system, then the projected x-axis of the coordinate system is the material x-axis (2) define a constant angle offset from the projected x-axis of basic system.This property is optional.

Thickness Defines the uniform thickness, which will be used for each element. This property defines the setting of the Ti, T2, T3, and T4 fields on the CTRIA3 or CQUAD4 entry and/or the T field on the PSHELL entry. This value can be either a real value or a references to an existing field definition. This property is required.

Bending Stiffness Defines the bending stiffness parameter. This property is the 12I/T3 field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Thickness Ratio Defines the ratio of transverse shear thickness to the membrane thickness. This is the TS/T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.



Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CQUAD4 or CTRIA3 entry and can be either real value or reference to an existing field definition. This property is optional.

Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers, respectively. These properties define the Z1 and Z2 fields on the PSHELL entry and can be either real value or references to existing field definitions. This property is optional.

Starting P-orders and Maximum P-orders

Polynomial orders for displacement representation within elements. Each contains a list of three integers referring to the directions defined by the P-order Coordinate System (default elemental). Starting P-orders apply to the first adaptive cycle. The adaptive analysis process will limit the polynomial orders to the values specified in Maximum P-orders. These are the Polyi fields in the PVAL entry.


Activate Error Estimate Flag controlling whether this set of elements participates in the error analysis. This is the ERREST field in the ADAPT entry.


Error Tolerance The tolerance used to determine if the adaptive analysis is complete. By default, equal to 0.1. This is the ERRTOL field on the ADAPT entry.

Stress Threshold Value Elements with von Mises stress below this value will not participate in the error analysis. By default, equal to 0.0. This is the SIGTOL field on the ADAPT entry.

Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis. By default, equal to1.0E-8. This is the EPSTOL field on the ADAPT entry.



172

2D - Shell - Thick - Standard Formulation


Use this form to create CQUAD4 elements with a PSHELL/PSHLN1 property. The appropriate fields on the PSHELL entry are filled in or left blank to achieve the requested behavior. This property set is meant to be used with SOL 400 exclusively. The DCT option is written to the PSHNL1 entry in the BEHi field and the L option to the INTi field to define this element formulation.


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2D Shell Thick Standard Formulation

Quad 4




Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CQUAD4 entry. This scalar value can either be a constant value in degrees, a vector, or a reference to an existing coordinate system. This property is optional.

Thickness Defines the thickness, which will be uniform over each element. This value can either be a real value or a reference to an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CQUAD4 entry and/or the T field on the PSHELL entry. This property is required.


Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CQUAD4 entry and can be either a real value or a reference to an existing field definition. This property is optional.


Fiber Dist. 1

Fiber Dist. 2






174

2D - Shell - Thick - Reduced Integration


Use this form to create CQUAD4 or CQUAD8 elements with a PSHELL/PSHLN1 property. The appropriate fields on the PSHELL entry are filled in or left blank to achieve the requested behavior. This property set is meant to be used with SOL 400 exclusively. The DCT option is written to the PSHNL1 entry in the BEHi field and the LRIH or QRI option to the INTi field to define this element formulation.


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2D Shell Thick Reduced Integration

Quad 4/8




Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the THETA or MCID field on the CQUAD4/8 entry. This scalar value can either be a constant value in degrees, a vector, or a reference to an existing coordinate system. This property is optional.

Thickness Defines the thickness, which will be uniform over each element. This value can either be a real value or a reference to an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CQUAD4/8 entry and/or the T field on the PSHELL entry. This property is required.



Plate Offset Defines the offset of the element’s reference plane from the plane defined by the nodal locations. This is the ZOFFS field on the CQUAD4/8 entry and can be either a real value or a reference to an existing field definition. This property is optional.

Fiber Dist. 1

Fiber Dist. 2




176

2D - Shell - Field Point Mesh


Use this form to create a CTRIA3, CQUAD4 elements for creating acoustic field point mesh for an exterior acoustics analysis. No property cards are created. The material referenced should be the same as that defined for the 3D solid elements and exterior acoustic infinite elements used to define the surrounding fluid environment of the structure, although no actual materials is written. In order to recover results on these meshes, you must set the output request ACFPFRESULT.

Each acoustic field point mesh defined is written to a seperate section of the bulk data using the BEGIN AFPM=id.


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2D Shell Field Point Mesh Tri 3Quad 4


Material Name Defines the material to be used. See the discussion above.


2D - Bending Panel - Standard Formulation


Use this form to create a CTRIA3, CTRIA6, CQUAD4, or CQUAD8 element and a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


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2D Bending Panel Standard Formulation Tri 3/6Quad 4/8



Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This property defines the setting of the THETA or MCID field on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Thickness Defines the uniform thickness for each element. This defines the T1, T2, T3, and T4 fields on the CQUAD4/8 and CTRIA3/6 entries and/or the T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is required.

Nonstructural Mass Defines the mass not derived from the material of the element. This property is defined in mass per unit area of the element and is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


178

Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers respectively. These properties define the Z1 and Z2 fields on the PSHELL entry and these values can be either real values or references to existing field definitions. These properties are optional.

LayerSurface FinishReduction Factor KfScale FactorOffsetRoughness FactorTreatment FactorShape Factor




2D - Bending Panel - Revised Formulation


Use this form to create a CTRIAR or CQUADR i and a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


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2D Bending Panel Revised Formulation Tri 3Quad 4




Thickness Defines the uniform thickness, which will be used for each element. This defines the T1, T2, T3, and T4 fields on the CTRIAR or CQUADR entry and/or the T field on the PSHELL entry. This value can be either a real value or a reference to an existing field definitions. This property is required.

Nonstructural Mass Defines the mass not included in the mass derived from the material of the element. This is defined in terms of mass per unit area of the element. This is the NSM field on the PSHELL entry. This value can either be real values or a reference to and existing field definition. This property is optional.


180

Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers, respectively. These properties are the Z1 and Z2 fields on the PSHELL entry. These values can be either real values or references to existing field definitions. This property is optional.





2D - Bending Panel - P-Formulation


Use this form to create CTRIA3, or CQUAD4 elements with a PSHELL property along with the P-formulation entries ADAPT and PVAL. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior. The p-formulation shell element is supported in MSC.Nastran Version 69 or later.


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2D Bending Panel P- Formulation Tri 3/6/7/9/13Quad 4/8/9/12/16



Material Orientation AngleMaterial Coordinate System

Defines the basic orientation for any non-isotropic material within the element. There are two ways to assign this definition: (1) reference a coordinate system, then the projected x-axis of the coordinate system is the material x-axis or (2) define a constant angle offset from the projected x-axis of basic system.This property defines the setting of the THETA or MCID field on the CQUAD4 or CTRIA3 entry. This property is optional.

Thickness Defines the uniform thickness, which will be used for each element. This defines the T1, T2, T3, and T4 fields on the CQUAD4 or CTRIA3 entry and/or the T field on the PSHELL entry and this value can be either a real value or a reference to an existing field definition. This property is required.


Fiber Dist. 1

Fiber Dist. 2

Defines the distance from the element’s reference plane to the top and bottom most extreme fibers, respectively. These properties define the Z1 and Z2 fields on the PSHELL entry. These values can be either real values or references to existing field definitions. These properties are optional.


182


Maximum P-orders

Polynomial orders for displacement representation within elements. Each contains a list of three integers referring to the directions defined by the P-order Coordinate System (default elemental). Starting P-orders apply to the first adaptive cycle. The adaptive analysis process will limit the polynomial orders to the values specified in Maximum P-orders. These are the Polyi fields on the PVAL entry.

P-order Coord. System The three sets of three integer p-orders above refer to the axes of this coordinate system. By default this system is elemental. This is the CID field on the PVAL entry.

Activate Error Estimate Flag controlling whether this set of elements participates in the error analysis. This is the ERREST field on the ADAPT entry.




Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis. By default this value is equal to1.0E-8. This is the EPSTOL field on the ADAPT entry.



2D - 2D Solid - Plane Strain - Standard Formulation


Use this form to create a CTRIA3, CTRIA6, CQUAD4, or CQUAD8 element and a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested plane strain behavior for non SOL 400 runs. For SOL 400 runs a PLPLANE and PSHLN2 entry are written instead based on the setting of the Nonlinear Formulation.


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2D 2D Solid Plane Strain Standard Formulation

Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID1 field on the PSHELL entry. The MID2 field on the PSHELL entry will be set to -1 to define plane strain behavior. This property is required.

Plane of Deformation Leave blank for default or select an option. Writes to the CID field of the PLPLANE entry. Select coordinate frame from which to specify plane of deformation. For SOL 400 plane strain/axisymmetric runs, outputs are in this CID system and elements must lie in XY plane of this CID frame.

Output Locations Location of stress and strain output. the options are “GAUS” (default) or “GRID.” this defines the STR field on the PLPLANE entry.


184

Nonlinear Formulation This optional property word can take on any of the three values Automatic, Large Strain, or Small Strain and is only recognized for implicit nonlinear (SOL 400) analyses. Automatic is the default if not specified and determines if large or small strain is appropriate based on the existence of an elastoplastic material constitutive model and/or if the elements are contained in a contact body. If appropriate, the PSHLN2 entry is written for this property set. Large Strain forces the PSHLN2 entry to be written, regardless; and Small Strain forces it not to be written, regardless. In addition, if large strain is forced or detected, the usage of NLMOPTS, LRGSTRN,0 or 1 is written based on the setting on the Load Increment Parameters form when defining a Subcase. See Static Subcase Parameters for Implicit Nonlinear Solution Type, 408.





2D - 2D Solid - Plane Strain - Reduced Integration

This describes the Input Properties available from the Element Properties form when the following options are chosen. Information on this form is used to create input for a nonlinear analysis:

Use this form to create CQUAD4 or CQUAD8 elements and a PLPLANE property. Fo SOL 400 a PSHLN2 is also written with the PLSTRN option for the BEHi field and LRIH or QRI option for the INTi field to define reduced integration formulation.


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2D 2D Solid Plane Strain Reduced Integration

Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID field on the PLPLANE entry. This property is required.




186

2D - 2D Solid - Plane Strain - Revised Formulation


Use this form to create CTRIAR or CQUADR element with a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


CreateModify

2D 2D Solid Plane Strain Revised Formulation

Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID1 field on the PSHELL entry. The MID2 field on the PSHELL entry will be set to -1 to define plane strain behavior. This property is required.




2D - 2D Solid - Plane Strain - P-Formulation


Use this form to create a CQUAD4 or CTRIA3 element and a PSHELL property along with the P-formulation entries ADAPT and PVAL. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior. The p-formulation shell element is supported in MSC.Nastran Version 69 or later.

Additional properties on the form which do not appear on the previous page are:


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2D 2D Solid Plane Strain P- Formulation Tri 3/6/7/9/13Quad 4/8/9/12/16


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse, or type in the name. This property defines the setting of the MID1 field on the PSHELL entry. This property is required. The MID2 field on the PSHELL entry will be set to -1 to define plane strain behavior.

Material Orientation AngleMaterial Coordinate System

Defines the basic orientation for any non-isotropic material within the element. There are two ways to assign this definition: (1) reference a coordinate system, then the projected x-axis of the coordinate system is the material x-axis (2) define a constant angle offset from the projected x-axis of basic system. This defines the setting of the THETA or MCID field on the CQUAD4 or CTRIA3 entry. This property is optional.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is defined in mass per unit area of the element. This is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Starting P-orderMaximum P-order




188





Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis. By default this value is equal to 1.0E-8. This is the EPSTOL field on the ADAPT entry.



2D - 2D Solid - Plane Strain - Hyperelastic Formulation


Use this form to create CQUAD, CQUAD4, CQUAD8, CTRIA3, or CTRIA6 element with a PLPLANE property.


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2D 2D Solid Plane Strain Hyperelastic Formulation

Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID field on the PLPLANE entry. This property is required should have a hyperelastic constitutive model associated with the selected material..

Plane of Deformation Identification number of a coordinate system defining the plane of deformation. This defines the CID field on the PLPLANE entry. Select coordinate frame from which to specify plane of deformation. For SOL 400 plane strain/axisymmetric runs, outputs are in this CID system and elements must lie in XY plane of this CID frame.



190

2D - Plane Strain - Laminated Composite


Use this form to create CQUAD4 or CQUAD8 elements and a PLCOMP property.

The DIRECT field of PLCOMP cards is negative for the "Total" option where ply thicknesses are the actual thicknesses and positive for the "Total - %thicknesses" option where ply thicknesses are defined as percentages of the total ply stack thickness.


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2D 2D Solid Plane Strain Laminated Composite

Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the PLCOMP entry to be used. This property is required. The material selected must be a composite material.

Thickness Direction 2D Defines element edge used as base ply orientation. See discussion above. Positive or negative value placed on the DIRECT field of the PLCOMP entry.

Out-of-Plane Thickness Value is placed on the THICKOP field of the PLCOMP entry.


2D - 2D Solid - Plane Strain - Incompressible


Use this form to create incompressible axisymmetric CTRIA3 elements and a PLPLANE/PSHLN2 property (SOL 400 only). If not SOL 400 or no nonlinear behavior is detected, the PSHLN2 is likely not to be written. Only Tri 3 elements are valid for this formulation. This put IPS in the BEHi field of the PSHLN2 to indicate the axisymmetric incompressible formulation.


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2D 2D Solid Plane Strain Incompressible Tri 3


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the MID on the PLPLANE/PSHLN2 entry to be used. This property is required.


Output Locations Defines where the output for these elements are to be reported. This property can be set to either Gauss or Grid and is the STR field on the PLPLANE entry. This property is optional.


192

2D - 2D Solid - Plane Strain - Interface


Use this form to create planar interface CIFQUAD elements and a PCOHE property (SOL 400 only). This input data creates interface elements that are generally zero-thickness elements that bond two meshes together and are used in the Cohesive Zone Modeling Technique (CZMT) to simulate delamination or crack growth.


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2D 2D Solid Plane Strain Interface Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the PCOHE entry to be used. This property is required. The material selected should be a cohesive material.

Interface Integration Scheme

Leave blank for default or select an option. Writes to the INT field of the PCOHE entry.

Output Locations Defines where the output for these elements are to be reported. This property can be set to either Gauss or Grid and is the OUTPUT field on the PCOHE entry. This property is optional.

Stiffnes Matrix Scheme Writes selected scheme to the SECANT field of the PCOHE entry.

Thickness Required for plane stress only and is written on the PCOHE entry in the T field. This the only difference between plane strain versus plane stress interface elements.


2D - 2D Solid - Plane Stress - Standard Formulation


This element is meant for use with SOL 400 only (MSC Nastran 2010 or greater). Use this form to create a CTRIA6 (CTRIA3 not supported), CQUAD4/8 element and a PLPLANE plus PSHLN2 entries are based on the setting of the Nonlinear Formulation. The PSTRS option is written in the BEHi field of the PSHLN2 entry to indicate this formulation type.


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2D 2D Solid Plane Stress Standard Formulation

Tri 6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This defines the setting of the MID field on the PLPLANE for SOL 400 runs. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the TH field on the element entry. This scalar value can be either a constant value or a reference to an existing coordinate system. This property is optional.

Thickness Required for plane stress and is written on the PSHLN2 entry in the T field.


194





2D - 2D Solid - Plane Stress- Reduced Integration


Use this form to create CQUAD4 or CQUAD8 elements and a PLPLANE property. Fo SOL 400 a PSHLN2 is also written with the PSTRS option for the BEHi field and LRIH or QRI option for the INTi field to define reduced integration formulation.


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2D 2D Solid Plane Stress Reduced Integration

Quad 4/8



Thickness Required for plane stress and is written on the PSHLN2 entry in the T field.




196

2D - 2D Solid - Plane Stress - Interface


Use this form to create planar interface CIFQUAD elements and a PCOHE property (SOL 400 only). This input data creates interface elements that are generally zero-thickness elements that bond two meshes together and are used in the Cohesive Zone Modeling Technique (CZMT) to simulate delamination or crack growth.


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2D 2D Solid Plane Stress Interface Quad 4/8







Thickness Required for plane stress only and is written on the PCOHE entry in the T field. This is the only difference between a plane stress versus a plane strain interface element.


2D - 2D Solid - Axisymmetric - Standard Formulation


Use this form to create a CTRIAX6 axisymmetric solid element for non SOL 400 runs. This defines an isoparametric and axisymmetric triangular cross section ring element with midside nodes for non SOL 400 runs. For SOL 400 runs, CQUADX and/or CTRIAX entries and a PLPLANE and PSHLN2 entry are written instead based on the setting of the Nonlinear Formulation.


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2D 2D Solid Axisymmetric Standard Formulation

Tri 3/6Quad 4/8


Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the TH field on the CTRIAX6 entry. This scalar value can be either a constant value or a reference to an existing coordinate system. This property is optional.

Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This defines the setting of the MID field on the CTRIAX6 for non-SOL 400 runs or the PLPLANE for SOL 400 runs. This property is required.


198





2D - 2D Solid - Axisymmetric - Reduced Integration


Use this form to create CQUADX elements and a PLPLANE property. Fo SOL 400 a PSHLN2 is also written with the AXSOLID option for the BEHi field and LRIH or QRI option for the INTi field to define reduced integration formulation.


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2D 2D Solid Axisymmetric Reduced Integration

Quad 4/8






200

2D - 2D Solid - Axisymmetric - Twist


Use this form to create CQUADX elements and a PLPLANE property. Fo SOL 400 a PSHLN2 is also written with the AXSOLID option for the BEHi field and LT or QT option for the INTi field to define this type of formulation.


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2D 2D Solid Axisymmetric Twist Quad 4/8






2D - 2D Solid - Axisymmetric - Hyperelastic Formulation


Use this form to create CQUADX or CTRIAX elements and a PLPLANE property.


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2D 2D Solid Axisymmetric Hyperelastic Formulation

Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID field on the PLPLANE entry. This property is required and should have a hyperelastic constitutive model associated with the selected material.

Output Locations Leave blank for default or select an option. Writes to the CID field of the PLPLANE entry. Select coordinate frame from which to specify plane of deformation. For SOL 400 plane strain/axisymmetric runs, outputs are in this CID system and elements must lie in XY plane of this CID frame.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the TH field on the CTRIAX/CQUADX entries. This scalar value can be either a constant value or a reference to an existing coordinate system. This property is optional.


202

2D - 2D Solid - Axisymmetric - Laminated Composite


Use this form to create axisymmetric CQUADX elements and a PLCOMP composite property. The DIRECT field of the PLCOMP card is negative for the "Total" option where ply thicknesses are the actual thicknesses and positive for the "Total - %thicknesses" option where ply thicknesses are defined as percentages of the total ply stack thickness when creating the composite material in the Material application.


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2D 2D Solid Axisymmetric Laminated Composite

Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the PLCOMP entry to be used. This property is required. The material selected must be a composite material.

Thickness Direction 2D Defines element edge used as base ply orientation. See discussion above. Positive or negative value placed on the DIRECT field of the PLCOMP entry.

Out-of-Plane Thickness Not used for axisymmetric elements. Value is placed on the THICKOP field of the PLCOMP entry.


2D - 2D Solid - Axisymmetric - PLPLANE


Use this form to create standard axisymmetric solid elements for non SOL 400 runs with CTRIAX or CQUADX with PLPLANE property or PLPLANE/PSHLN2 for SOL 400 runs. This defines an isoparametric and axisymmetric cross section ring element with or without midside nodes. If not SOL 400 or no nonlinear behavior is detected, the PSHLN2 is likely not to be written. This put AXSOLID in the BEHi field of the PSHLN2 to indicate the axisymmetric formulation for SOL 400.


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2D 2D Solid Axisymmetric PLPLANE Tri 3/6Quad 4/8


Material Name For SOL600 solutions use the PLPLANE option and any material type. For non-SOL600 runs, use the Hypereleastic option with Mooney-Rivlin materials.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This defines the setting of the TH field on the CTRIAX/CQUADX entries. This scalar value can be either a constant value or a reference to an existing coordinate system. This property is optional.



204

2D - 2D Solid - Axisymmetric - Incompressible


Use this form to create incompressible axisymmetric CTRIAX elements and a PLPLANE/PSHLN2 property (SOL 400 only). If not SOL 400 or no nonlinear behavior is detected, the PSHLN2 is likely not to be written. Only Tri 3 elements are valid for this formulation. This put IAX in the BEHi field of the PSHLN2 to indicate the axisymmetric incompressible formulation.


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2D 2D Solid Axisymmetric Incompressible Tri 3


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the MID on the PLPLANE/PSHLN2 entry to be used. This property is required.


Output Locations Defines where the output for these elements are to be reported. This property can be set to either Gauss or Grid and is the STR field on the PLPLANE entry. This property is optional.


2D - 2D Solid - Axisymmetric - Interface


Use this form to create CIFQDX elements and a PCOHE property (SOL 400 only). This input data creates interface elements that are generally zero-thickness elements that bond two meshes together and are used in the Cohesive Zone Modeling Technique (CZMT) to simulate delamination or crack growth.


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2D 2D Solid Axisymmetric Interface Quad 4/8








206

2D - 2D Solid - Acoustic Infinite

These elements are used in exterior acoustic analysis (frequency response) and placed on the outside of the solid mesh representing the fluid (coincident with the outside surface). The must share the same nodes as the solid mesh. They simulate the fluid proprties reaching to infinity beyond the boundary of the solid mesh representing the fluid. The surfaces that these elements connect to must be convex. However it is not necessary that the surface be smooth. They also take on the same fluid proprties as the solid fluid mesh.

Use this form to create a CACINF3, CACINF4 elements and a PACINF property. The appropriate fields on the PACINF entry are filled in or left blank in order to achieve the requested behavior.


CreateModify

2D 2D Solid Acoustic Infinite Tri 3, Quad 4


Material Name Defines the material to be used. This material is generally the same material used to define the solid fluid mesh in an exterior acoustics analysis (MAT10). The same material should also be referenced when using acoustic field point meshes.

Radial Interpolation Order Interger value that defines the radial interpolation order, which must be defined and greater than zero.

Pole of Infinite Elements The pole of the acoustic infinite elements. This must be coorinate location defined in the global Patran coordinate system. A node ID can also be selected graphically.


2D - Membrane - Standard Formulation


Use this form to create a CTRIA3, CTRIA6, CQUAD4, or CQUAD8 element and a PSHELL/PSHLN1 property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


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2D Membrane Standard Formulation Tri 3/6Quad 4/8


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the settings of the MID1 field on the PSHELL entry. This property is required.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1)reference a coordinate system, which is then projected onto the element. (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This property defines the setting of the THETA or MCID field on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Thickness Defines the uniform thickness that will be used for each element. This value can either be a real value or reference an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CTRIA3, CTRIA6, CQUAD4, or CQUAD8 entry and/or the T field on the PSHELL entry. This property is required.

Nonstructural Mass Defines the mass not derived from the material of the element. This property is defined in mass per unit area of the element and is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


208






2D - Membrane - Revised Formulation


Use this form to create a CTRIAR or CQUADR element and a PSHELL property. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior.


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2D Membrane Revised Formulation Tri 3Quad 4


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This defines the settings of the MID1 field on the PSHELL entry. This property is required.


Thickness Defines the uniform thickness that will be used for each element. This value can be either a real value or a reference to an existing field definition. This property defines the T1, T2, T3, and T4 fields on the CTRIAR or CQUADR entry and/or the T field on the PSHELL entry. This property is required.

Nonstructural Mass Defines the mass not derived from the material of the element. This property is defined in terms of mass per unit area of the element and is the NSM field on the PSHELL entry. This value can be either a real value or a reference to an existing field definition. This property is optional.




210

2D - Membrane - P-Formulation


Use this form to create a CQUAD4 or CTRIA3 element and a PSHELL property along with the P-formulation entries ADAPT and PVAL.. The appropriate fields on the PSHELL entry are filled in or left blank in order to achieve the requested behavior. The p-formulation shell element is supported in MSC Nastran Version 69 or later.

:


CreateModify

2D Membrane P- Formulation Tri 3/6/7/9/13Quad 4/8/9/12/16


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID1 field on the PSHELL entry. This property is required.

Material OrientationMaterial Coordinate System

Defines the basic orientation for any non-isotropic material within the element. There are two ways to assign this definition: (1) reference a coordinate system, then the projected x-axis of the coordinate system is the material x-axis or (2) define a constant angle offset from the projected x-axis of basic system. This property defines the setting of the THETA or MCID field on the CQUAD4 or CTRIA3 entry. This property is optional.

Starting P-ordersMaximum P-orders


P-order Coord. System The three sets of three integer p-orders above refer to the axes of this coordinate system. By default this system is elemental. This is the CID field on the PVAL entry.






Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis. By default this value is equal to 1.0E-8. This is the EPSTOL field on the ADAPT entry.



212

2D - Shear Panel


Use this form to create a CSHEAR element and a PSHEAR/PSHEARN property. This defines a shear panel element of the structural model.


CreateModify

2D Shear Panel Quad/4


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This defines the settings of the MID field on the PSHEAR entry. This property is required.

Thickness Defines the uniform thickness, which will be used for each element. This defines the T field on the PSHEAR entry. This property is required. This value can be either a real value or a reference to an existing field definition.

Nonstructural Mass Defines mass not included in the mass derived from the material of the element. This is defined in mass per unit area of the element. This is the NSM field on the PSHEAR entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Extensional Stiffness 12 Defines the effectiveness factor for extensional stiffness along the 1-2 and 3-4 sides. This is the F1 field on the PSHEAR entry. This value can be either a real value or a reference to an existing field definition. This property is optional.

Extensional Stiffness 14 Defines the effectiveness factor for extensional stiffness along the 2-3 and 1-4 sides. This is the F2 field on the PSHEAR entry. This value can be either a real value or a reference to an existing field definition. This property is optional.


Nonlinear Formulation This optional property word can take on any of the three values Automatic, Large Strain, or Small Strain and is only recognized for implicit nonlinear (SOL 400) analyses. Automatic is the default if not specified and determines if large or small strain is appropriate based on the existence of an elastoplastic material constitutive model and/or if the elements are contained in a contact body. If appropriate, the PSHEARN entry is written for this property set. Large Strain forces the PSHEARN entry to be written, regardless; and Small Strain forces it not to be written, regardless. In addition, if large strain is forced or detected, the usage of NLMOPTS, LRGSTRN,0 or 1 is written based on the setting on the Load Increment Parameters form when defining a Subcase. See Static Subcase Parameters for Implicit Nonlinear Solution Type, 408.





214


3D - Solid - Homogeneous - Standard Formulation


Use this form to create CHEXA, CTETRA, or CPENTA elements with a PSOLID/PSLDN1 property for Standard Formulations. A PSLDN1 entry is written for use in SOL 400 only. See the nonlinear formulation property description below.


CreateModify

3D Solid Homogeneous Standard Formulation

Tet 4/10Wed 6/15Hex 8/20


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the settings of the MID field on the PSOLID entry or references a PCOMP entry in the case of a composite material. This property is required.

Material Orientation Defines both the orientation of referenced nonisotropic materials and solid element results. This can be set to Global, Elemental, or to a specific coordinate frame reference and defines the CORDM field on the PSOLID entry. The default is Global. Nonlinear stresses and strains are output in the Elemental system regardless of the setting.

Integration Network Defines the type of integration network to be used. This property is the IN field on the PSOLID entry and can be set to Bubble, Two, or Three. This property is optional.

Integration Scheme Defines the integration scheme to be used. This property is the ISOP field on the PSOLID entry and can be set to Reduced or Full. This property is optional.

Output Locations Defines where the output for these elements are to be reported. This property can be set to either Gauss or Grid and is the STRESS field on the PSOLID entry. This property is optional.


Nonlinear Forumulations (SOL 400)

This optional property word can take on any of the three values Automatic, Large Strain, or Small Strain and is only recognized for implicit nonlinear (SOL 400) analyses. Automatic is the default if not specified and determines if large or small strain is appropriate based on the existence of an elastoplastic material constitutive model and/or if the elements are contained in a contact body. If appropriate, the PSLDN1 entry is written for this property set. Large Strain forces the PSLDN1 entry to be written, regardless; and Small Strain forces it not to be written, regardless. In addition, if large strain is forced or detected, the usage of NLMOPTS, LRGSTRN,0 or 1 is written based on the setting on the Load Increment Parameters form when defining a Subcase. See Static Subcase Parameters for Implicit Nonlinear Solution Type, 408.



Weld Nugget DiameterTop/Bot Sheet Thickness

These optional properties are used for defining spot weld parameters (weld diameter and connecting sheet thicknesses) in an MSC Nastran Embedded Fatigue analyses of spot welds for statics, normal modes and modal transient response. All parameters defined here are placed on the PFTG bulk data entry. See the above entry also. For the sheet thickness, enter two values separated by spaces. If only one is provided both top and bottom thickness retain the same value for both. If not defined, the thicknesses are determined from the connecting sheet properties. If the diameter is left blank, a diameter is determined through a look up table based on the minimum thickness of the connecting sheets. To use a solid HEX element as a spot weld, the top face must be connect to the top sheet and the bottom face must be connected to the bottom sheet using RBE3 elements.



216

3D - Solid - Homogeneous - Reduced Integration


Use this form to create CHEXA, or CTETRA elements with a PSOLID/PSLDN1 property for Reduced Integration. This element is typically only used with SOL 400 and nonlinear analysis. If defined for other solution sequences, a standard formulation will be written instead. Tet 4 elements are not valid. The SOLID option is written to the BEHi field and LRIH or QRI options are written to the INTi field of the of the PSLDN1 entry to indicate reduced integration.


CreateModify

3D Solid Homogeneous Reduced Integration

Tet 10Hex 8/20


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the settings of the MID field on the PSOLID entry. This property is required.




3D - Solid - Homogeneous - P-Formulation

This describes the Input Properties available from the Element Properties form when the following options are chosen:

Use this form to create CHEXA, CTETRA, or CPENTA elements with a PSOLID property along with the P-formulation entries ADAPT and PVAL.


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3D Solid Homogeneous P-Formulation Tet 4/10/16Wed 6/15/24/52Hex 8/20/32/64


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID field on the PSOLID entry. This property is required.

Material Orientation Defines orientation for the referenced material. This property can be set to Global, Elemental or to a user-defined coordinate system and defines the CORDM field on the PSOLID entry. The default is Global. This property is optional.

Starting P-ordersMinumum P-ordersMaximum P-orders

Polynomial orders for displacement representation within elements. Each contains a list of three integers referring to the directions defined by the P-order Coord. System (default elemental). Starting P-orders apply to the first adaptive cycle. The adaptive analysis process will limit the polynomial orders to the values specified in Maximum P-orders. These are the Polyi fields on the PVAL entry.

P-order Coordinate System The three sets of three integer p-orders above refer to the axes of this coordinate system. By default, this system is elemental. This is the CID field on the PVAL entry.



Error Tolerance The tolerance used to determine if the adaptive analysis is complete. By default the value is equal to 0.1. This is the ERRTOL field on the ADAPT entry.

Stress Threshold Value Elements with von Mises stress below this value will not participate in the error analysis. By default the value is equal to 0.0. This is the SIGTOL field on the ADAPT entry.


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Strain Threshold Value Elements with von Mises strain below this value will not participate in the error analysis. By default the value is equal to 1.0E-8. This is the EPSTOL field on the ADAPT entry.


Integration Scheme Defines where the output for these elements are to be reported. This can be set to either Gauss or Grid. This property is the STRESS field on the PSOLID entry. This property is optional.



3D - Solid - Homogeneous - Hyperelastic


Use this form to create CHEXA, CTETRA, or CPENTA elements with a PLSOLID property to define a fully nonlinear hyperelastic solid. This is meant to work with SOL 106 and not SOL 400. For SOL 400, use standard elements with hyperelastic material properties.


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3D Solid Homogeneous Hyperelastic Formulation

Tet 4/10Wed 6/15Hex 8/20


Material Name Defines the material to be used. The material must have a hyperelastic constitutive model defined so the PLSOLID can reference a MATHP entry. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the setting of the MID field on the PLSOLID entry. This property is required.

Output Locations Location of stress and strain output. the options are GAUS (default) or GRID. this defines the STR field on the PLSOLID entry.

Nonlinear Formulation This parameter is ignored. Use this property set with SOL 106 only.


220

3D - Solid Shell - Homogeneous - Standard Formulation


Use this form to create CHEXA elements with a PSOLID/PSLDN1 property for Solid-Shell Formulations. A Solid Shell definition is identical to a Standard Formulation in that it also creates the elements plus a PSOLID property, but is meant for use in SOL 400 only and creates the additional PSLDN1 entry (the nonlinear formulation property does not need to be defined and is not included on the Input Properties form). The SLCOMP value is written to the BEHi field of the PSLDN1 option to indicate a solid continuum composite element type and the ASTN option written to the integration code field if assumed strain is requested. Only Hex 8 elements are valid for this element property.


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3D Solid Homogeneous Solid Shell Hex 8





Integration Scheme Defines the integration scheme to be used. This property is the ISOP field on the PSOLID entry and can be set to Reduced or Full. This property is optional.


SCOMP IntegrationScheme Defines the Integration Scheme requested for the solid continuum composite elements.


3D - Solid - Homogeneous - Incompressible


Use this form to create CTETRA elements with a PSOLID/PSLDN1 property for incompressible elements. This element is typically only used with SOL 400 and nonlinear analysis. If defined for other solution sequences, a standard formulation will be written instead. Tet 4 elements are the only valid elements. The ISOL option is written to the BEHi field and L option is written to the INTi field of the of the PSLDN1 entry to indicate incompressible.


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3D Solid Homogeneous Incompressible Tet 4






222

3D - Solid - Laminate


Use this form to create CHEXA elements and a PCOMP (SOL 600 and non SOL 400) or PCOMPLS (SOL400) property. Note that only Assumed Strain is allowed for HEX8 elements only when ply stack direction is in Z-element diretion and the ply thicknesses have been defined as percent thicknesses. Any other combination will revert the integration scheme to the Nastran default for linear or quadratic elements. For SOL 600, the MSTACK option is also written.


CreateModify

3D Solid Laminate Hex 8/20


Material Name Defines the material to be used. A list of all materials currently in the database is displayed when data is entered. Either select from the list using the mouse or type in the name. This property defines the PCOMP or PCOMPLS entry to be used. This property is required. The material selected should be a composite.

Material Orientation Defines the basic orientation for any non-isotropic material within the element. There are three ways to assign this definition: (1) reference a coordinate system, which is then projected onto the element, (2) define a vector that will be projected onto the element, or (3) define a constant angle offset from the default element coordinate system. This scalar value can either be a constant value or a reference to an existing coordinate system. This property is optional.

Laminate Option Defines available laminate options MEM, BEND, SMEAR, SMCORE (see MSC Nastran QRG for definitions written to PCOMP only (non SOL 400).

Thickness Direction 3D Defines element face used as base ply orientation. For [Thickness Direction 3D]

"Nastran Elem X" -- this corresponds to 1-4-8-5

"Nastran Elem Y" -- this corresponds to 2-1-5-6

"Nastran Elem Z" -- this corresponds to 1-2-3-4

SCOMP Integration Scheme

SOL 400 - Writes the SLCOMP option to the PCOMPLS entry for defining assumed strain.


3D - Solid - Interface


Use this form to create CIFHEX or CIFPENT elements and a PCOHE property (SOL 400 only). This input data creates interface elements that are generally zero-thickness elements that bond two meshes together and are used in the Cohesive Zone Modeling Technique (CZMT) to simulate delamination or crack growth.


CreateModify

3D Solid Interface Wed 6/15Hex 8/20








224

3D - Body Pair- Geometric

This describes the Input Properties available from the Element Properties form when the following options are chosen..

Use this form to create the geometric properties of contact body pair.

Parameters

Action Dimension Type Option(s)

CreateModify

3D Body Pair Geometric


Distance Tolerance (ERROR)

Distance below which a node is considered touching a body. If left blank, calculation is automatic.

Bias Factor (BIAS) Contact tolerance bias factor. Overrides any value set elsewhere.

Interference Closure (CINTERF)

Interference closure amount, normal to the contact surface. For values > 0.0, overlap between bodies. For values <0.0, gap between bodies.

Slide Off Distance (SLIDE) Delayed slide off distance. Not used unless Delayed Slide Off is activated. A node sliding on a segment will slide off only if it passes a node or edge at a sharp corner over a distance larger than this distance. The default is related to the dimensions of the contacted segment by a 20% increase of its isoparametric domain.

Hard-Soft Ratio (HARDS) Hard-soft ratio. Only used if double-sided contact with automatic constraint optimization.

Glued Contact (IGLUE) Flag to activate glued contact. Otherwise it is assumed touching contact. To fully deactivate contact, the user should remove the Body Pair from the Load Case.

Retain Gaps/Overlaps (IGLUE)

Existing initial gaps or overlaps between nodes and the contacted body are not removed.

Retain Moment (IGLUE) Insures full moment carrying glue when shells contact.

Allow Separation (JGLUE) Allows separation of a node if ON based on whether a Separation Threshold has been set or Breaking Glue parameters are set.

Stress free InitCont (ICOORD)

Coordinates of nodes in contact are adjusted to cause an initial stress free condition.

Delayed Slide Off (ICOORD)

Extends the tangential error tolerance at sharp corners of deformable bodies to delay sliding off a contacted segment.


Options

Contact Detection (ISEARCH)

Contact searching order for deformable contact bodies. (Node to Segment only.) Double sided searches from Slave to Master starting from the lowest body ID, then reverses the order. Single Sided is from Slave to Master. Automatic, the program decides based on smallest element edge at outer boundaries (or thickness in case of shell elements).

Penetration Dist (AUGDIST)

Penetration distance beyond which an augmentation will be applied for segment-to-segment contact.

Normal Penalty Fact (PENALT)

Augmented Lagrange penalty factor used by segment-to-segment contact algorithm. The default is derived from default contact characteristic distances.

Tan Penalty Factor (TPENALT)

Augmented Lagrange penalty factor for sticking part of friction used by the segment-to-segment contact algorithm. The default is the Normal Penalty Factor divided by 1000.

Slip Distance (STKSLP) Maximum allowable slip distance for sticking, beyond which there is no sticking and only sliding exists. Used by segment-to-segment contact algorithm only.

Stick/Slip (TAUGMNT) Flag for augmentation for the slicking part of friction in a segment-to-segment contact analysis.


Note: If individual property name is left empty then the new contact property created will have it’s name ‘pairname_p’ for physical property and ‘pairname_g’ for geometrical property.

Rigid/Shell Contact Options - Slave (COPTS)

Detects the top and/or bottom of shell elements with or without consideration of the thickness for slave body. For rigid elements, any value except Exclude will be treated as inclusion of rigid surfaces in the contact algorithm.

Rigid/Shell Contact Options - Master (COPTM)

Detects the top and/or bottom of shell elements with or without consideration of the thickness for master body. For rigid elements, any value except Exclude will be treated as inclusion of rigid surfaces in the contact algorithm.

Edge Contact Options - Slave (COPTS)

Detects beams/bars and/or free and hard shell edges for slave body.

Edge Contact Options - Master (COPTM)

Detects beams/bars and/or free and hard shell edges for master body.


226

3D - Body Pair- Physical

This describes the Input Properties available from the Element Properties form when the following options are chosen..

Use this form to create the physical properties of contact body pair.

Action Dimension Type Option(s)

CreateModify

3D Body Pair Physical


Separation Threshold (FNTOL)

Separation force, stress, or fraction above which a node separates from a body. The value is dependent on whether the separation flag on the BCPARA entry, IBSEP, is set to absolute /relative forces/stresses. Segment to segment contact always uses relative stress. This is set on the Contact Control Parameters form.

Friction Coefficient (FRIC) Friction coefficient. Can reference a temperature dependent non-spatial field.

Fric Stress Limit (FRLIM) Friction stress limit. Used only with Coulomb friction bilinear model.

Breaking Glue (BKGL) Activate breaking glue for node to segment contact. Not supported for segment to segment contact. Must define maximum normal and tangential stress and corresponding exponents. Default = No

Max Normal Stress (BGSN) Maximum normal stress for breaking glue. Not supported when using segment to segment contact. Default = 0.0

Max Tan Stress (BGST) Maximum tangential stress for breaking glue. Not supported when using segment to segment contact. Default = 0.0

Breaking Glue - 1 Exp (BGM)

First exponent for breaking glue. Not supported when using segment to segment contact. Default = 2.0

Breaking Glue - 2 Exp (BGN)

Second exponent for breaking glue. Not supported when using segment to segment contact. Default = 2.0

227Chapter 2: Building A Model3Beam Modeling

2.8 3Beam ModelingModeling structures composed of beams can be more complicated than modeling shell, plate, or solid structures. First, it is necessary to define bending, extensional, and torsional stiffness that may be complex functions of the beam cross sectional dimensions. Then it is necessary to define the orientation of this cross section in space. Finally, if the centroid of the cross section is offset from the two finite element nodes defining the beam element, these offsets must be explicitly defined. Fortunately, Patran provides a number of tools to simplify these aspects of modeling.

Cross Section DefinitionThe cross section properties are defined on the element property forms shown on pages 1D - Beam - General Section (CBAR) - Standard Formulation, 112 and 1D - Beam - Tapered Section (CBEAM) - Standard Formulation, 127. The properties can be entered directly into the data boxes labeled Area, Inertia i,j, Torsional Constant, etc. or by pushing the large I-beam icon on these forms to access the Beam Library form. The Beam Library forms are a much more convenient way of defining properties for standard cross sections and are shown below.

Patran Interface to MSC Nastran Preference Guide3Beam Modeling

228

Create Action

The first step in using the beam library is to select the section icon for the particular cross section desired (e.g. I-section).Then the dimensions for each of the components of the beam section must be entered.


Enter the dimensions of the beam section here, referring to the beam section icon.

Current beam section as selected from the section library icon palette. The required dimensions are shown.

Beam section library icon palette. Select the icon representing the desired section.

Beam section name to be created.

Calculates the beam properties based on the current dimensions and displays an image of the scaled section along with the properties.

List of existing beam sections. This list can be filtered to contain only the section names of interest using the filter mechanism.

These forward and backward arrows provide access to additional beam section icons.

Writes the current beam properties to a report file.


230

Finally, a section name must be entered and the Apply button pushed. The other options available with the beam library are documented in the Patran Reference Manual, see Tools>Beam Library (p. 528) in the Patran Reference Manual. Once one or more beam sections have been defined, these can be selected in the section data box on the element properties form.


Supplied Functions

I-Beam - Six dimensions -- lower flange thickness (t1), upper flange thickness (t2),lower flange width (w1), upper flange width (w2), overall height (H), and web thickness (t)-- allows for symmetric or unsymmetrical I-beam definition.

Angle - Open section, four dimensions -- overall height (H), overall width (W), horizontal flange thickness (t1), vertical flange thickness (t2).

Tee - Four dimensions -- overall height (H), overall width (W), horizontal flange thickness (t1), vertical flange thickness (t2).

Solid-Rod - Solid section, one dimension -- radius (R).

Box-Symmetric - Closed section, four dimensions -- overall height (H), overall width (W), top and bottom flange thicknesses (t1), side flange thicknesses (t2).

Tube - Closed section, two dimensions -- outer radius (R1), inner radius (R2).

Channel - Open section, four dimensions -- overall height (H), overall width (W), top and bottom flange thicknesses (t1), shear web thickness (t).

Bar - Solid section, two dimensions -- height (H) and width (W).


232

Cross Section OrientationThe Bar Orientation data box on the Input Properties form is used to define how the y-axis of the beam cross section is oriented in space. By default the Value Type is Vector. This tells MSC ⁄Nastran that the cross section y-axis lies in the plane defined by the beam’s x-axis (the line connecting the two node points) and this vector. The Value Type pop up menu may be changed to Node ID. In this case the y-axis lies in the plane defined by the x-axis and the selected node.

Box-Unsymmetrical - Closed section, six dimensions -- overall height (H), overall width (W), top flange thickness (t1), bottom flange thickness (t2), right side flange thickness (t3), left side flange thickness (t4).

Hat - Four dimensions -- overall height (H), top of hat flange width (W), bottom of hat flange width for one side (W1), thickness (t).

H-Beam - Four dimensions -- overall height (H), width between inner edges of vertical flanges (W), horizontal shear web thickness (t), and thickness of one vertical flange (W1/2).

Cross - Four dimensions -- overall height (H), vertical flange thickness (t), horizontal flange thickness (t2), length of free horizontal flange for one side (W/2).

Z-Beam - Four dimensions -- overall height (H2), height of vertical flange between as measured between horizontal flanges, length of free horizontal flange for one side (W), thickness (t1).

Hexagonal - Solid section, three dimensions -- overall height (H), overall width (W), horizontal distance from side vertex to top or bottom surface vertex along the common edge (i.e., diagonal edge hypotenuse times the cosine of the exterior diagonal angle).


When the Value Type is Vector and the Bar Orientation data box is selected the following select box appears on the screen.

After the orientation has been defined, there are two ways to verify its correctness in Patran. The first option is in the Element Properties application. By selecting the Show Action, the Definition of X Y Plane property, and Display Method Vector Plot, the vectors defining the orientation will be shown on the model. A second option can be used when the Beam Library has been used to define the beam cross section. There is an option on the Display form Display>LBC/Element Property Attributes (p. 407) in the Patran Reference Manual called Beam Display. The menu allows different display options for displaying an outline of the defined cross section on the model in the correct location and orientation.

Users should be aware of one difference between the Patran and MSC Nastran definitions for cross section orientation. In Patran the orientation is completely independent of the analysis coordinate system at the beam nodes. In MSC Nastran, the orientation vector is assumed to be defined in the same system as the analysis system at the first node of the beam. In Patran it is perfectly permissible to define the orientation in a different coordinate system from that analysis system. When the NASTRAN input file is generated, the necessary transformation of this vector to the analysis system at node 1 will be performed.

These select tools provide different options for defining vectors. They are discussed in more detail in the Select Menu (p. 35) in the Patran Reference Manual.

These three tools define the orientation vector as the 1 (x), 2(y), or 3(z) axis of a selected coordinate system. This is a convenient way to specify the orientation when it is aligned with one of the three axes of a rectangular coordinate system. When the system is not rectangular (e.g. cylindrical) these tools may not provide the desired definition because the defined vector does not change direction at different points in space--these tools just provide an alternate way to define a global vector.

This tool may be used to define a general vector with respect to an alternate coordinate system. When this icon is picked, the select menu changes to the one on the right.

These tools provide different ways to define vectors. In addition, the user is requested to select a coordinate system in which this vector is defined. The simplest list processor syntax that appears in the databox for a vector in an alternate coordinate system is <x_component, y_component, z_component> coord cord_id (e.g. <1, 0, 0> coord 3). In many cases it is easy to simply type a definition in this form into the Bar Orientation databox.


234

Cross Section End OffsetsTwo data boxes are provided on the Element Properties, Input Properties form to optionally define an offset from either node 1 to the cross section centroid (Offset @ Node 1) or from node 2 to the cross section centroid (Offset @ Node 2). The same select menu tools are available for defining these vectors. One difference between the orientation definition and the offset definitions, however, is that for the offset the magnitude of the vector is important. Because of this, the select menu tools are usually not very convenient. Typically, offsets are defined by typing the definition (e.g <x, y, z> or <x, y, z> coord n>) into the appropriate data box.

Two options are available for verifying the definitions of offsets; these options are very similar to those for orientations. The Element Properties, Show Action will allow the end offsets to be displayed as vectors on the model. This option is not especially useful because the vector plot shows only the direction of the offset, not the magnitude of the offset. It is usually much more useful to view the Beam Display menu on the Display form Display>LBC/Element Property Attributes (p. 407) in the Patran Reference Manual to select the display option with offsets. The viewport will then show the beam displayed in both the offset and non-offset positions.

Stiffened Cylinder ExampleFigure 2-1 shows a simple example of a circular cylinder stiffened with Z-stiffeners. The cross section was defined by selecting the Beam Library icon on the Element Properties/Input Properties form. The Z cross section was selected on the Beam Library form, the cross section dimensions input, a section name input, and the Apply button pushed. On the Input Properties form, the Use Beam Section toggle is set to ON. The defined section name is selected in the [Section Name] data box. The string <-1.0 0. 0.> coord 1 is typed into the Bar Orientation data box to align the cross section orientation with the radial direction of the global, cylindrical system. Similarly, the strings <-2.0 0.0 0.0> coord 1 and <-2.0 0.0 0.0> coord 1


typed into the Offset @ Node 1 and Offset @ Node 2 data boxes define the end offsets to be radially inward.

Figure 2-1 Stiffened Cylinder

1 R

T

Z

X

Y

Z

Patran Interface to MSC Nastran Preference GuideLoads and Boundary Conditions

236

2.9 Loads and Boundary ConditionsThe Loads and Boundary Conditions form will appear when the Loads/BCs toggle, located on the Patran main form, is chosen. When creating a load and boundary condition there are several option menus. The selections made on the Loads and Boundary Conditions menu will determine which load and boundary conditions form appears, and ultimately, which MSC Nastran loads and boundary conditions will be created.

The following pages give an introduction to the Loads and Boundary Conditions form and details of all the loads and boundary conditions supported by the Patran MSC Nastran Analysts Preference.

Loads & Boundary Conditions FormThis form appears when Loads/BCs is selected on the main menu. The Loads and Boundary Conditions form is used to provide options to create the various MSC Nastran loads and boundary conditions. For a definition of full functionality, see Loads and Boundary Conditions Form (p. 21) in the Patran Reference Manual. Options for defining slide line contact are also accessed from this main Loads and Boundary Conditions form. For more information see Defining Contact Regions, 271.

237Chapter 2: Building A ModelLoads and Boundary Conditions

Defines the general load type to be applied. Object choices are Displacement, Force, Pressure, Temperature, Inertial Load, Initial Displacement, Initial Velocity, Velocity, Acceleration, Distributed Load, CID Distributed Load, Total Load, Contact, Initial Temperature, Planar Rigid Wall and Init.Rotation Field.

Defines what type of region is to be loaded. The available options depend on the selected Object. The general selections can be Nodal, Element Uniform, or Element Variable. Nodal is applied explicitly to nodes. Element Uniform defines a constant value to be applied over an entire element, element face, or element edge. Element Variable defines a value that varies across an entire element, element face, or element edge.

Generates either a Static, 239 or Time Dependent, 241 Input Data form, depending on the current Load Case Type.

Current Load Case type is set on the Load Case menu. When the Load Cases toggle located on the main menu is chosen, the Load Cases menu will appear. Under Load Case Type, select either Static or Time Dependent, then enter the name of the case, and click on the Apply button.


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The following table outlines the options when Create is the selected Action.

* For SOL 700 only.

Object Type

• Displacement / Velocty / Acceleration

• Nodal

• Element Uniform

• Element Variable

• Force • Nodal

• Pressure • Element Uniform


• Temperature • Nodal

• Element Uniform


• Inertial Load • Element Uniform

• Initial Displacement • Nodal

• Initial Velocity • Nodal

• Distributed Load • Element Uniform


• CID Distributed Load • Element Uniform


• Total Load • Element Uniform

• Contact • Element Uniform

• Crack (VCCT) • Nodal

• Initial Plastic Strain • Element Uniform

• Initial Stress • Element Uniform

• Initial Temperature • Nodal

• Planar Rigid Wall * • Nodal

• Init. Rotation Field * • Nodal


Static

This subordinate form appears when the Input Data button is selected on the Loads and Boundary Conditions form and the Current Load Case Type is Static. The Current Load Case Type is set on the Load Case form. For more information see Loads & Boundary Conditions Form, 236. The information on the Input Data form will vary depending on the selected Object. Defined below is the standard information found on this form.


240

Defines a general scaling factor for all values defined on this form. The default value is 1.0. Primarily used when field definitions are used to define the load values.

Input Data in this section will vary. See Object Tables, 243 for detailed information.

When specifying real values in the Input Data entries, spatial fields can be referenced. All defined spatial fields currently in the database are listed. If the input focus is placed in the Input Data entry and a spatial field is selected by clicking in this list, a reference to that field will be entered in the Input Data entry.

Defines the coordinate frame used to interpret the degree-of-freedom data defined on this form. This only appears on the form for Nodal type loads. This can be a reference to any existing coordinate frame definition.

This button will display a Discrete FEM Fields input form to allow field creation and modification within the loads/bcs application. Visible only when focus is set in a databox which can have a DFEM field reference.


Time Dependent

This subordinate form appears when the Input Data button is selected on the Loads and Boundary Condition form and the Current Load Case Type is Time Dependent. The Current Load Case Type is set on the Load Case form. For more information see Loads & Boundary Conditions Form, 236 and Load Cases, 270. The information on the Input Data form will vary, depending on the selected Object. Defined below is the standard information found on this form.


242

Input Data

1Load/BC Set Scale Factor

Spatial Dependence * Time Dependence

Spatial Fields Time Dependent Fields

Coord 0

Analysis Coordinate Frame

OK Reset

Trans Accel (A1,A2,A3)

Rot Velocity (w1,w2,w3)

Rot Accel (a1,a2,a3)

Defines a general scaling factor for all values defined on this form.The default value is 1.0. Primarily used when field definitions are used to define the load values.

When specifying time dependent values in the Input Data entries, time-dependent fields can be referenced. All defined time-dependent fields currently in the database are listed. If the input focus is placed in the Input Data entry and a time-dependent field is selected by clicking in this list, a reference to that field will be entered in the Input Data entry.

Defines the coordinate frame to be used to interpret the degree-of-freedom data defined on this form. This only appears on the form for Nodal type loads. This can be a reference to any existing coordinate frame definition.

Input Data in this section will vary. See Object Tables, 243 for detailed information.

When specifying real values in the Input Data entries, spatial fields can be referenced. All defined spatial fields currently in the database are listed. If the input focus is placed in the Input Data entry and a spatial field is selected by clicking in this list, a reference to that field will be entered in the Input Data entry.

FEM Dependent Data...

This button will display a Discrete FEM Fields input form to allow field creation and modification within the loads/bcs application. Visible only when focus is set in a databox which can have a DFEM field reference.


Object TablesThese are areas on the static and transient input data forms where the load data values are defined. The data fields that appear depend on the selected load Object and Type. In some cases, the data fields also depend on the selected Target Element Type. The following Object Tables outline and define the various input data that pertains to a specific selected object:

Displacement / Velocty / Acceleration

Creates MSC Nastran SPC1 and SPCD Bulk Data for Displacement entries. All non blank entries will cause an SPC1 entry to be created. If the specified value is not 0.0, an SCPD entry will also be created to define the non zero enforced displacement or rotation. Phase angle specifications will create DPHASE entries for all corresponding non blank translational or rotational data in frequency response analysis. Displacement, Velocity and Acceleration LBCs used in frequency response / dynamic analysis also define the RLOAD1 entries with DISP, VELOC, and ACCEL keywords, respectively. For frequency response analysis, the LBCs must reference a frequency range of interest defined as a non-spatial frequency field such that a TABLEDi entry is created. The load case needs to be defined as Time/Frequency dependent to do this. Values given via this option are total enforced values. For relative enforced values used in SOL 400, see the description for the Relative Displacement option below.

Applies a zero or nonzero total displacement boundary condition to the face of solid elements. The primary use of this boundary condition is to apply constraints to p-elements; but it may also be used for standard solid elements. If applied to a p-element solid, the appropriate FEFACE and GMBC entries are created. If applied to a standard solid element, the appropriate SPC1 and SPCD entries are created. In

Object Type Analysis Type Option

DisplacementVelocityAcceleration

Nodal Structural Standard

Input Data Description

Translations (T1,T2,T3) Defines the total enforced translational values. These are in model length units.

Rotations (R1,R2,R3) Defines the total enforced rotational values. These are in radians.

Translational Phase Angles (Tth1,Tth2,Tth3)

Defines the phase angle for out-of-phase loading in frequency response analysis for the translational values. These are in degrees.

Rotational Phase Angles (Rth1,Rth2,Rth3)

Defines the phase angle for out-of-phase loading in frequency response analysis for the rotational values. These are in degrees.

Object Type Analysis Type Dimension

Displacement Element Uniform

Element Variable

Structural 3D


244

frequency response analysis, the phase angles are written as DPHASE entries. See comments above for nodal displacements.

Applies a zero or nonzero relative displacement boundary condition as opposed to a total magnitude. This is used in SOL 400 only with multiple steps and not applicable to other solution sequences. This LBC will be ignored if present in a referenced load case for solution sequences other than SOL 400. The appropriate SPC1 and SPCR entries are created. For example, if a DOF is specified on a SPCR with 0.0 for step 2, the relative displacement of this DOF for step 2 with respective to step 1 is 0.0. The total displacement of step 2 is 0.2 if the solution of step 1 for this DOF is 0.2.


Translations (T1,T2,T3) Defines the enforced translational displacement values. These values are in model-length units.

Translation Phases (Tth1,Tth2,Tth3)

Defines the phase angle for out-of-phase loading in frequency response analysis for the translational displacement values. These are in degrees.

Object Type Analysis Type Option

Displacement Nodal Structural Relative Displacement


Relative Translations (T1,T2,T3) Defines the relative enforced translational displacement values in vector form, each value separated by a comma between the brackets <>. If no enforced translation is to be specified, the particular component should be left blank.

Relative Rotations (R1,R2,R3) Defines the relative enforced rotational displacement values in vector form, each value separated by a comma between the brackets <>. If no enforced rotation is to be specified, the particular component should be left blank.


Force

Creates MSC Nastran FORCE and MOMENT Bulk Data entries. Creates the DPHASE entries in frequency response analysis when specifying phase angles for out-of-phase loading. RLOAD1 entries are created for dynamic analysis and reference the appropriate FORCE entries. For frequency response analysis, the force LBCs must reference a frequency range of interest defined as a non-spatial frequency field such that a TABLEDi entry is created. The load case needs to be defined as Time/Frequency dependent to do this.

Object Type Analysis Type

Force Nodal Structural


Force (F1,F2,F3) Defines the applied forces in the translation degrees of freedom. This defines the N vector and the F magnitude on the FORCE entry.

Moment (M1,M2,M3) Defines the applied moments in the rotational degrees of freedom. This defines the N vector and the M magnitude on the MOMENT entry.

Force Phase Angles (Fth1,Fth2,Fth3)

Defines the phase angle for out-of-phase loading in frequency response analysis for the corresponding force components. These are in degrees.

Moment Phase Angles (Mth1,Mth2,Mth3)

Defines the phase angle for out-of-phase loading in frequency response analysis for the corresponding moment components. These are in degrees.


246

Pressure

Creates MSC Nastran, PLOAD4, PLOADX1, or FORCE Bulk Data entries.

Creates MSC Nastran PLOAD4 Bulk Data entries.

Creates MSC Nastran, PLOAD4, PLOADX1, or FORCE Bulk Data entries.


Pressure Element Uniform Structural 2D


Top Surf Pressure Defines the top surface pressure load on shell elements using a PLOAD4 entry. The negative of this value defines the P1, P2, P3, and P4 values. These values are all equal for a given element, producing a uniform pressure field across that face.

Bot Surf Pressure Defines the bottom surface pressure load on shell elements using a PLOAD4 entry. This value defines the P1 through P4 values.These values are all equal for a given element, producing a uniform pressure field across that face.

Edge Pressure For Axisymmetric Solid elements (CTRIAX6), defines the P1 through P3 values on the PLOADX1 entry where THETA on that entry is defined as zero. For other 2D elements, this will be interpreted as a load per unit length (i.e. independent of thickness) and converted into equivalent nodal loads (FORCE entries). If a scalar field is referenced, it will be evaluated at the middle of the application region.


Pressure Element Uniform Structural 3D


Pressure Defines the face pressure value on solid elements using a PLOAD4 entry. This defines the P1, P2, P3, and P4 values. If a scalar field is referenced, it will be evaluated once at the center of the applied region.


Pressure Element Variable Structural 2D


Creates MSC Nastran PLOAD4 Bulk Data entries.


Top Surf Pressure Defines the top surface pressure load on shell elements using a PLOAD4 entry. The negative of this value defines the P1, P2, P3, and P4 values. If a scalar field is referenced, it will be evaluated separately for the P1 through P4 values.

Bot Surf Pressure Defines the bottom surface pressure load on shell elements using a PLOAD4 entry. This value defines the P1 through P4 values. If a scalar field is referenced, it will be evaluated separately for the P1 through P4 values.

Edge Pressure For Axisymmetric Solid elements (CTRIAX6), defines the P1 through P3 values on the PLOADX1 entry where THETA on that entry is defined as zero. For other 2D elements, this will be interpreted as a load per unit length (e.g., independent of thickness) and converted into equivalent nodal loads (FORCE entries). If a scalar field is referenced, it will be evaluated independently at each node.


Pressure Element Variable Structural 3D


Pressure Defines the face pressure value on solid elements using a PLOAD4 entry. This defines the P1, P2, P3, and P4 values. If a scalar field is referenced, it will be evaluated separately for each of the P1 through P4 values.


248

Temperature

Creates MSC Nastran TEMP Bulk Data entries.

Writes the TEMPP1 entry. For 2D Target Elements, T1/T2 or TBAR/TPRIME are written to the TEMPP1 entry but not both. For Equivalent Section shell properties or shell properties that have Z1/Z2 defined, T1/T2 is written and TBAR/TPRIME left blank on the TEMPP1 entry. Nastran determines the correct TPRIME. For all other shell properties TBAR/TPRIME are written and T1/T2 left blank. TBAR/TPRIME are computed by Patran from T1/T2 using the thickness property value. This is for Element Variable Temperature LBCs. For Element Uniform Temperature LBC, only TBAR is written or necessary. All others fields are left blank.

Creates MSC Nastran TEMPRB Bulk Data entries.

Creates MSC Nastran TEMPP1 Bulk Data entries.


Temperature Nodal Structural


Temperature Defines the T fields on the TEMP entry.


Temperature Element Uniform Structural 1D


Temperature Defines a uniform temperature field using a TEMPRB entry. The temperature value is used for both the TA and TB fields. The T1a, T1b, T2a, and T2b fields are all defined as 0.0.


Temperature Element Uniform Structural 2D


Temperature Defines a uniform temperature field using a TEMPP1 entry. The temperature value is used for the T field. The gradient through the thickness is defined to be 0.0.


Creates MSC Nastran TEMPRB Bulk Data entries.

Creates MSC Nastran TEMPP1 Bulk Data entries.

This option applies only to the P-formulation elements. A TEMPF and DEQATN entry are created for the constant temperature case. A TEMPF and TABLE3D entry are created for the case when a spatial field is referenced. Writes the TEMPP1 entry. For 2D Target Elements, T1/T2 or TBAR/TPRIME are written to the TEMPP1 entry but not both. For Equivalent Section shell properties or shell properties that have Z1/Z2 defined, T1/T2 is written and TBAR/TPRIME left blank on the TEMPP1 entry. Nastran determines the correct TPRIME. For all other shell properties TBAR/TPRIME are written and T1/T2 left blank. TBAR/TPRIME are computed by Patran from T1/T2 using the thickness property value. This is for Element Variable Temperature LBCs. For Element Uniform Temperature LBC, only TBAR is written or necessary. All others fields are left blank.


Temperature Element Variable Structural 1D


Centroid Temp Defines a variable temperature file using a TEMPRB entry. A field reference will be evaluated at either end of the element to define the TA and TB fields.

Axis-1 Gradient Defines the temperature gradient in the 1 direction. A field reference will be evaluated at either end of the element to define the T1a and T1b fields.

Axis-2 Gradient Defines the temperature gradient in the 2 direction. A field reference will be evaluated at either end of the element to define the T2a and T2b fields.


Temperature Element Variable Structural 2D


Top Surf Temp Defines the temperature on the top surface of a shell element. The top and bottom values are used to compute the average and gradient values on the TEMPP1 entry.

Bot Surf Temp Defines the temperature on the bottom surface of a shell element. The top and bottom values are used to compute the average and gradient values on the TEMPP1 entry.


Temperature Element Uniform Element Variable

Structural 1D, 2D, 3D


250


Temperature Defines the temperature or temperature distribution in the element.


Inertial Load

Creates MSC Nastran GRAV and RFORCE Bulk Data entries.

The acceleration and velocity vectors are defined with respect to the input analysis coordinate frame. The origin of the rotational vectors is the origin of the analysis coordinate frame. Note that rotational velocity and rotational acceleration cannot be defined together in the same set.In generating the GRAV and RFORCE entries, the interface produces one GRAV and/or RFORCE entry image for each Patran load set.

Initial Displacement

Creates a set of MSC Nastran TIC Bulk Data entries.


Inertial Load Element Uniform Structural


Trans Accel (A1,A2,A3) Defines the N vector and the G magnitude value on the GRAV entry.

Rot Velocity (w1,w2,w3) Defines the R vector and the A magnitude value on the RFORCE entry.

Rot Accel (a1,a2,a3) Defines the R vector and the RACC magnitude value on the RFORCE entry.


Initial Displacement Nodal Structural


Translations (T1,T2,T3) Defines the U0 fields for translational degrees of freedom on the TIC entry. A unique TIC entry will be created for each non blank entry.

Rotations (R1,R2,R3) Defines the U0 fields for rotational degrees of freedom on the TIC entry. A unique TIC entry will be created for each non blank entry.


252

Initial Velocity

Creates a set of MSC Nastran TIC Bulk Data entries.


Initial Velocity Nodal Structural


Trans Veloc (v1,v2,v3) Defines the V0 fields for translational degrees of freedom on the TIC entry. A unique TIC entry will be created for each non blank entry.

Rot Veloc (w1,w2,w3) Defines the V0 fields for rotational degrees of freedom on the TIC entry. A unique TIC entry will be created for each non blank entry.


Distributed Load

Defines distributed force or moment loading along beam elements using MSC Nastran PLOAD1 entries. The coordinate system in which the load is applied is defined by the beam axis and the Bar Orientation element property. The Bar Orientation must be defined before this Distributed Load can be created. If the Bar Orientation is subsequently changed, the Distributed Load must be updated manually if necessary.

For the element variable type, a field reference is evaluated at each end of the beam to define a linear load variation.

Defines a distributed force or moment load along the edges of 2D elements. The coordinate system for the load is defined by the surface or element edge and normal. The x direction is along the edge. Positive x is determined by the element corner node connectivity. See Patran Element Library (p. 347) in the Reference Manual - Part III. For example, if the element is a CQUAD4, with node connectivity of 1, 2, 3, 4. The positive x directions for each edge would be from nodes 1 to 2, 2 to 3, 3 to 4, and 4 to 1. The z direction is normal to the surface or element. Positive z is in the direction of the element normal. The y direction is normal to x and z. Positive y is determined by the cross product of the z and x axes and always points into the element. The MSC Nastran entries generated, depend on the element type.

For the element variable type, a field reference is evaluated at all element nodes lying on the edge.


Distributed Load Element Uniform Element Variable

Structural 1D


Edge Distributed Load (f1,f2,f3)

Defines the FXE, FYE, and FZE fields on three PLOAD1 entries.

Edge Distributed Moment (m1,m2,m3)

Defines the MXE, MYE, and MZE fields on three PLOAD1 entries.


Distributed Load Element Uniform Element Variable

Structural 2D


Edge Distributed Load (f1,f2,f3)

For axisymmetric solid elements (CTRIAX6), the PA, PB, and THETA fields on the PLOADX1 entry are defined. For other 2D elements, the input vector is interpreted as load per unit length and converted into equivalent nodal loads (FORCE entries).

Edge Distributed Moment (m1,m2,m3)

For 2D shell elements, the input vector is interpreted as moment per unit length and converted into equivalent nodal moments (MOMENT entries).


254

CID Distributed Load

This load is a generalized distributed load whereby directionality is specified by the user in the form a vector where each component of this vector represents the distributed load magnitude for the associated direction. The vector may be constant or a field. This load type is identical to the "Total Load" except the vector components are used as is (i.e., not divided by the area or length of the application region) and that element variable is implemented so that the load can vary across an element.


CID Distributed Load Element Uniform Element Variable

Structural 1D/2D/3D


Load/BC Set Scale Factor Scale factor by which all components of the distributed forces are multiplied.

Distributed Force (Surface and Edge) (F1,F2,F3)

Defines the applied translational distributed force vector with respect to the specified analysis coordinate frame. In general this provides the magnitudes (for each component) of the uniform load per unit length for 1D or edges of 2D elements or the per unit area on 2D or 3D surfaces.

Spatial Fields When specifying real values in the Input Data entries, spatial fields can be referenced. All defined spatial fields currently in the database are listed. If the input focus is placed in the Input Data entry and a spatial field is selected by clicking in this list, a reference to that field will be entered in the Input Data entry.

FEM Dependent Data This button will display a Discrete FEM Fields input form to allow field creation and modification within the loads/bcs application. Visible only when focus is set in a databox which can have a DFEM field reference.

Analysis Coordinate Frame Coordinate Frame in which the three translational distributed forces are defined.


Contact

This form is used to define certain data for the MSC Nastran contact entries. Other data entries for contact are defined under the Analysis Application when setting up a job for nonlinear static or nonlinear transient dynamic analysis. A contact table is also supported; by default, all contact bodies initially have the potential to interact with all other contact bodies and themselves. This default behavior can be modified under the Contact Table form, located on the Solution Parameters subform in the Analysis Application when creating a Load Step.

Note that contact bodies (BCBODY entry) are written to the MSC Nastran input deck in alphanumeric order, deformable bodies first followed by rigid bodies. The only way to control the order in which bodies are written to the input deck is to name them alphanumerically in the order you wish them to be written..

Preview Rigid Body Motion

After defining the Input Properties you can use the Preview Rigid Body Motion to check the movement of the rigid bodies in place. This is an effective tool for verifying the directions for LBCs.

Slideline (SOL 400 and SOL 600)


Contact Element Uniform Structural

Input Description

Penetration Type If the Penetration Type is One Sided, nodes in the Slave Region are not allowed to penetrate the segments of the Master Region. If Symmetric, in addition, nodes in the Master Region are not allowed to penetrate segments of the Slave Region.

Static Friction Coefficient (MU1)

Coefficient of static friction between the two surfaces.

Stiffness in Stick (FSTIF)

FSTIF is a penalty parameter in the contact formulation. The default value is usually adequate.

Penalty Stiffness Scaling Factor (SFAC)

SFAC is a penalty parameter in the contact formulation. The default value is usually adequate.

Slideline Width (W1) Slideline Width is constant along the slideline and is used to determine the area for contact stress calculation. This is the Wi field on the BFRIC entry.

Vector Pointing from Master to Slave Surface

A vector must be defined which lies in the contact plane and points from the Master region to the Slave region. This vector is used to define the coordinate system on the BCONP entry and the BLSEG entries for each region.


256

Deformable Body (SOL 400, SOL 600, and SOL 700 ).

Description

Friction Coefficient (MU)

Coefficient of static friction for this contact body. For contact between two bodies with different friction coefficients, the average value is used.

Define (type of contact) Select 1) Analytic Contact, 2) Contact Area, 3) Exclusion Region, or 4) Glue Deactivation. The Contact Area and Exclusion Region are defined using MSC Nastran entry BCHANGE in the .bdf file, with NODE for Contact Area, and EXCLUDE for Exclusion Region. The Glue Deactivation is defined using MSC Nastran entry UNGLUE.

Boundary Type Select either 1) Analytic, or 2) Discrete. By default, a deformable contact body boundary is defined by the free faces of its elements; this is used by the Discrete option. However, instead of using the free faces of the elements (Discrete), it is possible to use spline surfaces (2D) to represent the outer faces (element faces) of the contact bodies; this is used by the Analytic option. The Analytic option can improve the accuracy of deformable-deformable contact analysis.

C0 Continuity Using this, enforces C0-continuity at edges where the normal vector to the outer contour of the structure indicates a discontinuity. This is enabled for 3D analysis only.

Auto Detect Discontinuities

Select this to cause the automatic detection of any discontinuity.

Feature Angle If the angle between the normals of two touching (adjacent) segments of contact bodies is greater than the Feature Angle, there is a discontinuity there, and the discontinuity (at edge) is preserved.

MFD Increment The MFD file contains the spline surfaces that were created to represent some or all of the outer faces of the contact model. Using this causes the spline surfaces to be written to an MFD file every nth increment. This file is an Patran database, and can be opened with Patran, and the spline surfaces can be compared with the contact model.

Select Discontinuities...

See Select Deactivation Region, 257

Edge Contact... See Edge Contact Subform, 257

Select Contact Area... See Select Contact Area, 257

Select Exclusion Region...

See Select Exclusion Region, 257

Select Deactivation Region...

See Select Deactivation Region, 257


Select Discontinuities Subform.

Edge Contact Subform.

Select Contact Area.

Select Exclusion Region.

Select Deactivation Region

Description

Select (entity type) Choose to either select Geometry or FEM to define any discontinuities.

Detect Discontinuities Click on this button to determine if there are any discontinuities for the entities that define the Application Region.

Define Discontinuities Select entities to define the discontinuities.

Description

Include Outside (Solid Element)

When detecting contact of solid elements (for example, CHEXA elements) use this to include contact of the outside of the elements. For details refer to the BCBODY entry (defines a flexible or rigid contact body in 2D or 3D) of the MSC Nastran QRG. The entry that is used for the BCBODY entry is COPTB (flag that indicates how body surfaces may contact).

Check Layers (Shell Element)

For contact bodies composed of shell elements, this option menu chooses the layers to be checked. Available options are: Top and Bottom, Top Only, Bottom Only. Check Layers and Ignore Thickness combination enters the appropriate flag in the 10th field of the 2nd data block.

Ignore Thickness Turn this button ON to ignore shell thickness. Check Layers and Ignore Thickness combination enters the appropriate flag in the 10th field of the 2nd data block.

Include Edges (Edges) Use this to specify how body surfaces may contact. There are three options, Beam/Bar, Free and Hard Shell, or Both. For details refer to the BCBODY entry (defines a flexible or rigid contact body in 2D or 3D) of the MSC Nastran QRG. The entry that is used for the BCBODY entry is COPTB (flag that indicates how body surfaces may contact).

Description

Select (entity type) Choose to either select Geometry or FEM to define the contact area.

Define Contact Area Select entities to define the contact area.

Description

Select (entity type) Choose to either select Geometry or FEM to define the exclusion region.

Define Exclusion Region

Select entities to define the exclusion region.


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Rigid Body (SOL 600 and SOL 700 only)

The input data form differs for 1D and 2D rigid bodies. One dimensional rigid surfaces are defined as beam elements, or as curves (which may optionally be meshed with beam elements prior to translation) and used in 2D problems. Two dimensional rigid surfaces must be defined as Quad/4 or Tri/3 elements, or as surfaces (which may optionally be meshed with Quad/4 or Tri/3 elements prior to translation) and are used in 3D problems. The elements will be translated as 4-node patches if meshed or as NURB surfaces if not meshed.

Description

Select (entity type) Choose to either select Geometry or FEM to define the glue deactivation region.

Define Deactivated Entities

Select entities to define the entities that are to be un-glued.


Input Description

Flip Contact Side Upon defining each rigid body, Patran displays normal vectors or tic marks. These should point inward to the rigid body. In other words, the side opposite the side with the vectors is the side of contact. Generally, the vector points away from the body in which it wants to contact. If it does not point inward, then use the modify option to turn this toggle ON. The direction of the inward normal will be reversed.

Symmetry Plane This specifies that the surface or body is a symmetry plane. It is OFF by default.

Null Initial Motion This toggle is enabled only for Velocity and Position type of Motion Control. If it is ON, the initial velocity, position, and angular velocity/rotation are set to zero in the CONTACT option regardless of their settings here (for increment zero).

Motion Control

Motion of rigid bodies can be controlled in a number of different ways: velocity, position (displacement), or forces/moments.

Velocity(vector)

For velocity controlled rigid bodies, define the X and Y velocity components for 2D problems or X, Y, and Z for 3D problems.

Angular Velocity (rad/time)

For velocity controlled rigid bodies, if the rigid body rotates, give its angular velocity in radians per time (seconds usually) about the center of rotation (global Z axis for 2D problems) or axis of rotation (for 3D problems).

Friction Coefficient (MU)

Coefficient of static friction for this contact body. For contact between two bodies with different friction coefficients the average value is used.

Rotation Reference Point

This is a point or node that defines the center of rotation of the rigid body. If left blank the rotation reference point will default to the origin.

Axis of Rotation

For 2D rigid surfaces in a 3D problem, aside from the rotation reference point, if you wish to define rotation you must also specify the axis in the form of a vector.

First Control Node This is for Force or SPCD controlled rigid motion. It is the node to which the force or SPCD is applied. A separate LBC must be defined for the force, but the application node must also be specified here. If both force and moment are specified, they must use different control nodes even if they are coincident. If only 1 control node is specified the rigid body will not be allowed to rotate.

Second Control Node

This is for Moment controlled rigid motion. It is the node to which the moment is applied. A separate LBC must be defined for the moment, but the application node must also be specified here. It also acts as the rotation reference point. If both force and moment are specified, they must use different control nodes even if they are coincident.


260

Note: While importing the Nastran Input File, Patran adds a suffix to the names of contact bodies with unique IDs like:

nName-DEFORM.1, name-DEFORM.2, name-RIGID.3

name* - indicates the name of the contact body being imported.


Body Pair

This option defines the parameters for the LBC called Contact -- Body Pair, that consists of two contact bodies as a pair. The Input Data form contains two tabs: Geometric Contact Parameters and Physical Contact Parameters.


262

For display purposes and graphical identification of master/slave relationship, an arrow is drawn from the slave body toward the master body for each created body pair or when LBC markers are redrawn/displayed, similar to that shown here:

Icon Title Description

Geometric Contact Parameters

Input form for defining geometric parameters and contact options of the body pair. For details of the parameters, see: 3D - Body Pair- Geometric, 224

The contact options on this form are divided into two columns one for Body1/Slave and the other for Body2/Master. Select appropriate contact options from the given Rigid/Shell Elements and Edge contact options.

Physical Contact Parameters

Input form for defining physical parameters of contact body pair. For details of the parameters, see: 3D - Body Pair- Physical, 226

For physical contact parameters of Thermal Analysis, see: Body Pair (p. 102) in the Patran Interface to MSC Nastran Thermal.

Slave Body Master Body


Planar Rigid Wall (SOL 700 only)

Two different planar rigid wall options exist:

1. Kinematic rigid wall without friction

2. Penalty method based rigid wall with friction

These are seen as options at the top of the Input Data form. The user must select which wall will be used. Both wall’s position and orientation are defined by selecting a coordinate system which has its origin on the plane and the local z axis as the outward normal from the contact surface. This defines a WALL Bulk Data entry. There are only parameters associated with the penalty based planar rigid wall.

Initial Rotation Field (SOL 700 only)

Defines a velocity field of grid points consisting of a rotation and a traslation specification.

Creates a TIC3 Bulk Data entry.


Planar Rigid Wall Nodal Explicit Nonlinear


Static Friction Coefficient Static coefficient of friction.

Kinetic Friction Coefficient Kinetic coefficient of friction.

Exponential Decay Coefficient Exponential decay coefficient EXP.


Init. Rotation Field Nodal Explicit Nonlinear


Trans Veloc(v1,v2,v3) Defines the initial translational velocity values. These are in model length units per unit time.

Rot Veloc (w1,w2,w3) Defines the initial rotational velocity values. These are in degrees per unit time.

Rotation Center Defines a point at the center of rotation.


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Total Load

Defines a pressure on 1D, 2D, or 3D elements, element faces, surfaces, or curves; or a force on element edges by entering the total desired load. Patran will distribute the load among affected nodes/elements. Total Load will automatically calculate individual Pressure Loads, or Forces as applicable. Alternatively, you can define a variable load using fields.

Total Load = Scale Factor * SQRT (X^2 + Y^2 +Z^2)

When the model is exported to a Nastran input file, Total Load will create one or more entries for PLOAD1 (1D application region), PLOAD4 (2D or 3D application region), or FORCE (element edge application region) in the Bulk Data.

For Total Load applied to element edges, Forcepernode = (Load/Total Length) * (element length/2).


Total Load Element Uniform Structural 1D/2D/ 3D

Input Description

Current Load Case The current load case. You can select it from the list of existing load cases.

Existing Sets Displays existing load sets.

New Set Name Type here the name of new total load set.

Target Element Type Select the target element type: 1D, 2D, or 3D from the drop down option box.

Input Data... Brings up the Input Data form, where you can define Load/BC Set Scale Factor and the loads according to element types.

Select Application Region Brings up the Select Application Region form, where you can specify application region for FEM or Geometric Entities. Total load can also be defined for region or element property.


Crack (VCCT)

This input data creates the VCCT keyword option. Multiple VCCT options are generated for each crack defined. This is valid for MSC Nastran 2010 or higher. VCCT is the Virtual Crack Closure Technique used for evaluating the energy release rates in crack growth analysis.

Definition of a crack has special input data. For crack in 2D solid and shell elements, the crack tip is defined by a single node, thus you simply select a single node as the Appication Region. If you select more than one node, all nodes will be referenced in the VCCT definition but will not be valid and MSC Nastran is likely to exit with an error or ignore all but the first or last node. For cracks in 3D elements, a crack front needs to be define, which is simply a list of nodes defining the crack front. The supported elements are lower- and higher-order 2-D solids and 3-D shells, lower- and higher-order 3-D hexahedral solids, and lower order 3-D tetrahedral solids. For 3-D solids, it is important that a regular mesh around the crack front is used.

Multiple cracks can be defined and results are obtained for each crack separately. Each crack consists of a crack tip node in 2-D for shells and a list of nodes along the crack front for 3-D solids. Shell elements can be used for defining a 2-D style line crack and also be connected to the face of another shell or 3-D solid to form a 3-D style surface crack. These different cases are automatically identified.

For crack propagation, there are two modes of growth: fatigue and direct. For fatigue style, the user specifies a load sequence time period. During the load sequence, the largest energy release rate and the corresponding estimated crack growth direction is recorded. At the end of the load sequence, the crack is grown using the specified method. For direct growth, the crack grows as soon as the calculated energy release rate is larger than the user-specified Gc. Note that Gc can be made a function of the accumulated

crack growth length to model a crack growth resistance behavior.

Crack opening or propagation may be modeled using two techniques. In the first method, the body in which the crack is located is remeshed based upon adaptive global remeshing criteria. This option is currently not available in MSC Nastran. In the second method, the uncracked area is represented by elements with double nodes and ties, RBE2 or RROD or by elements that are glued together via contact definitions.

The Input Data form is specific to the parameters needed for defining crack growth and are listed in this table. The field name of the values/parameters written to the VCCT option as documented in the MSC Nastran Quick Reference Guide is indicated in parenthesis.

Input Data Type Analysis Description

Crack (VCCT) Nodal Structural 2D/3D Defines a crack tip (2D) or a crack front (3D) and its corresponding parameters for crack growth analysis.


266


VCCT Parameter Description

Crack Propagation Type:(ITYPE)

Can be set to None, Fatigue, or Direct.

None means no crack propagation is initially performed.

Fatigue - cracks are grown at the end of each fatigue time period. During this time period the largest energy rate is recorded, together with the corresponding crack growth direction. The largest change in energy release rate is used in Paris’ law (if used) for calculating the crack growth increment. (NOT CURRENTLY SUPPORTED)

Direct - cracks grow when the energy release rate is larger than the user specified crack growth resistance (fracture toughness).

Crack Growth:(IGROW)

This is the method of growing the crack and can be set to Remeshing (desired), Released Glued, or Break Up Mesh.

Remeshing will remesh at the appropriate time during the crack propagation and refine the mesh around the crack tip. It is necessary to set up Global Adaptive remeshing also for this option to work. (NOT CURRENTLY SUPPORTED)

Released Glued will release MPC definitions (tying) and works with glued contact, RBE2/RROD, and tying type 100. This requires that the crack growth direction be known and is somewhat dictated by the mesh.

Break Up Mesh will split element edges. (NOT CURRENTLY SUPPORTED)

Growth Increment Control:(INCM)

This toggle is used for specifying the size of the growth increments to be used for fatigue crack growth. With fixed size the crack growth increment is directly given, while it is calculated with Paris law otherwise. (ONLY FIXED IS CURRENTLY SUPPORTED)

Fatigue Time Period: This value specifies when the crack should grow. Each time the end of the fatigue time period is reached, a crack growth calculation is performed. (NOT CURRENTLY SUPPORTED)

Paris Law Energy Release Rate: If the energy release rate is less than this value there will be no crack growth. (NOT CURRENTLY SUPPORTED)

Paris Law Parameter C: Parameter of Paris’ law (NOT CURRENTLY SUPPORTED)

Paris Law Parameter M: Parameter of Paris’ law (NOT CURRENTLY SUPPORTED)

Minimum Growth Increment: If the calculated crack growth increment is smaller than this value there will be no crack growth. (NOT CURRENTLY SUPPORTED)


268

Direction Method:(METHOD)

This is used for specifying the method for calculating the crack growth direction.

Maximum Hoop Stress - The individual energy release modes are used for calculating the crack growth direction. This method is also called maximum principal stress criterion. See Marc Volume A, chapter 5, section on Fracture Mechanics for details on how this is calculated.

Along Pure Mode - The crack growth direction is given by one of the pure modes I, II or III. The one with the largest absolute value of (with i equal to I, II or III) is used. (NOT CURRENTLY SUPPORTED)

Along Mode I - The crack growth direction is given by the mode I direction, that is, along the x-axis of the crack tip system. Useful when it is known that the crack will growstraight ahead. (NOT CURRENTLY SUPPORTED)

User Defined - The crack growth direction is given directly by means of a vector in the global coordinate system. (NOT CURRENTLY SUPPORTED)

Direction Vector: Direction vector if User Defined Incement Method is specified. (NOT CURRENTLY SUPPORTED)

Crack Growth Criterion: This is used for specifying the criterion for when the crack is growing. (NOT CURRENTLY SUPPORTED)

Total Energy Release Rate - The crack grows when the total energy release rate is larger than the user defined crack growth resistance (often called fracture toughness): G>Gc

Individual Mode - The crack grows when any of the individidual energy release rates is larger than the respective crack growth resistance: GI>GIc or GII>GIIc or GIII>GIIIc

Power Law Mixed Mode - The crack grows when the following mixed mode criterion is fulfilled:

(GI/GIc)n

1 + (GII/GIIc)n

2 + (GIII/GIIIc)n

3 > 1

Reeder Mixed Mode - The crack grows when the Reeder mixed mode criterion is fulfilled. See the Marc documentation for the actual equation.



Crack Growth Increment Size:(CGI)

This sets the fixed crack growth increment. It specifies the length the crack advances during growth. When remeshing based growth is specified the given crack growth increment is directly used when extending the crack.

For the option of releasing tied interface the crack is grown one element edge at the time, and as many edges as needed to reach the specified growth increment are released.

Crack Growth ResistanceResistance Mode IResistance Mode IIResistance Mode III(GC) (GC-II & GC-III)

This sets the crack growth resistance (often denoted fracture toughness) for the current crack. This value is used together with the total energy release rate growth criterion and provides the default for the separate modes: Mode I, Mode II, Mode III

For each of the crack modes one can specify a separate crack growth resistance. The default is to use the value specified above.

These values can be a function of accumlated crack growth (a displacement based non-spatial field), time, or temperature.

n1, n2, n3: These are the values of the exponents for the Power Law Mixed Mode crack growth criterion or the Reeder exponent (n1) for the Reeder Mixed Mode criterion. (NOT CURRENTLY SUPPORTED)

Dependent Fields:(TABCGI, TABGC, TABGC-II & TABGC-III

A list of non-spatial fields is given that can be associated to the Crack Resistance parameters such that they are functions of acculated crack growth, time, or temperature. A displacement based non-spatial field should be created for defining a function based on acculated crack growth. This will write a TABLEMi entry with X values defining the accumulated crack growth as opposed to temperature.


Patran Interface to MSC Nastran Preference GuideLoad Cases

270

2.10 Load CasesLoad cases in Patran are used to group a series of load sets into one load environment for the model. Load cases are selected when defining an analysis job. The usage within MSC Nastran is similar. The individual load sets are translated into MSC Nastran load sets, and the load cases are used to create the SUBCASE commands in the Case Control Section.

For information on how to define multiple static and/or transient load cases, see Load Cases Application (Ch. 5) in the Patran Reference Manual.

271Chapter 2: Building A ModelDefining Contact Regions

2.11 Defining Contact RegionsThe MSC Nastran preference supports 3D slideline contact functionality introduced in MSC.Nastran Version 68. This capability allows the user to model contact between 2D and 3D structural regions or rigid bodies.

This functionality can be accessed by using in the Loads/BCs Application in Patran. After selecting the Contact Object on the main form, the first step is to define the regions that may come into contact. Pushing the Application Region button brings up the following form

Patran Interface to MSC Nastran Preference GuideDefining Contact Regions

272

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Application Region

Geometry Filter

Geometry

Master Surface: Slide Line

Slave Surface: Slide Line

Active Region: Master

Select Curves

Add Remove

Master Region

Slave Region

OK Clear

One or more curves, surface edges, or solid edges are defined for the Master and Slave application regions. The application region can only contain geometric entities. To model contact between FEM entities without associated geometry, curves must first be created from the nodes using the tools available in the Geometry application.

Toggles the select box between Master and Slave regions. The Master and Slave application regions can be defined in either order.

Select the curve or edge.

Adds the entities in the Select Curves databox to either the Master Region or Slave Region depending on the setting of the Active Region option menu.

u

273Chapter 2: Building A ModelDefining Contact Regions

ContactThe second step is to define a set of properties of these contacting surfaces. This is done by pushing the Input Data button on the main Application form to bring up the following subordinate form.

Input Data

Penetration Type: One Sided

Friction Coefficient (MU1)

Stiffness in Stick (FSTIF)

Penalty Stiffness Scaling Factor (SFAC)

1.0

Slideline Width (W1)

A Vector Pointing from Master to Slave Surface

OK Reset

A vector must be defined which lies in the contact plane and points from the Master region to the Slave region. This vector is used to define the coordinate system on the BCONP entry and the BLSEG entries for each region.

If the Penetration Type is One Sided, nodes in the Slave Region are not allowed to penetrate the segments of the Master Region. If Two Sided, in addition, nodes in the Master Region are not allowed to penetrate segments of the Slave Region. This is the PTYPE field on the BCONP entry.

Coefficient of static friction between the two surfaces. This is the MU1 field on the BFRIC entry.

FSTIF on the BFRIC entry and SFAC on the BCONP entry are penalty parameters in the contact formulation. The default values are usually adequate.

Slideline Width is constant along the slideline and is used to determine the area for contact stress calculation. This is the Wi field on the BFRIC entry.

Patran Interface to MSC Nastran Preference GuideRotor Dynamics

274

2.12 Rotor DynamicsThe MSC Nastran Preference supports steady state and transient rotor dynamics, introduced in MSC.Nastran 2004. This capability allows you to model structures with rotating parts, allowing for gyroscopic effects to be included.

Rotor Dynamics are modelled using Rotor and Unbalance entities, created within the Rotor Dynamics... selection under the Tools menu:

275Chapter 2: Building A ModelRotor Dynamics

Rotor Dynamics FormThe Rotor Dynamics form is accessed from the Rotor Dynamics... selection under the Tools menu. This form is used to create, modify, delete, or show Rotors, which define spin properties, including the axis of rotation, spin direction, damping factor, and speed.

CreateModifyDeleteShow

Steady StateTransient

RotorUnbalance (Transient only)

A set of co-linear nodes that make up the rotor model (spin axis). These are the grids in the MSNastran ROTORG Bulk Data entry.

Two nodes defining the spin direction. These are the GRIDA and GRIDB fields in the MSC Nastran RSPINR and RSPINT Bulk Data entries. These nodes must be included in the “Rotor Node List” above.

Rotor structural damping factor (default 0.0). This is the GR field of the MSC Nastran RSPINR and RSPINT Bulk Data entries.

Spin Profile (Steady State)Spin History (Transient)


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Spin Profile FormFor Steady State analyses, the Spin Profile form is used to define the relative spin rates.

Spin History FormFor Transient analyses, the Spin History form is used to define the spin rates.

The unit for the speed entries. RPM for revolutions per minute, or Cycles/Time for frequency. This value defines the SPDUNIT field of the MSC Nastran RSPINR Bulk Data entry, and are translated to either ‘RPM’ or ‘FREQ’.

List of relative spin rates. Entries must be in ascending or descending order. At least one entry required (no default). These values make up the SPEEDi fields of the MSC Nastran RSPINR Bulk Data entry.


Unbalance FormThe Rotor Dynamics Unbalance form is used to create, modify, delete, or show Unbalances, which define unbalance loads for transient analyses in terms of cylindrical system with the rotor axis as the Z axis.

The unit for the speed entries. RPM for revolutions per minute, or Cycles/Time for frequency. This value defines the SPDUNIT field of the MSC Nastran RSPINT Bulk Data entry, and are translated to either ‘RPM’ or ‘FREQ’.

A constant multiplier to be applied to the Time Dependent Field.

A time dependent field that defines the spin rate as a function of time. This field, with the Speed Amplitude applied to it, will be translated into an MSC Nastran TABLED1 Bulk Data entry that is referenced by the RSPINT entry.


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The unbalance is applied to a node, which must be included in a transient rotor. When a transient rotor is selected, the “Node” listbox is populated with nodes from that rotor’s axis. The unbalance node may then be selected from that list, assuring that it belongs to an existing transient rotor.This node defines the GRID field of the MSC Nastran UNBALNC Bulk Data entry.

Displays the Unbalance Properties form to define the remaining parameters for the MSC Nastran UNBALNC Bulk Data entry.

CreateModifyDeleteShow


Unbalance Properties FormThe Unbalance Properties Form is used to define the remaining parameters for the Unbalance.


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Define the MASS, ROFFSET, and ZOFFSET fields of the MSC Nastran UNBALNC Bulk Data entry.For each of these values, either a constant real value may be specified, or a time dependent field my be selected from the list below. Time dependent fields are translated to TABLED1 entries, and referenced by integer ID values in the appropriate UNBALNC fields.Defaults are 1.0 for Radial Offset and 0.0 for Z Offset. There is no default for Mass.

Defines the coordinate system orientation relative to the ACID of the unbalance node (no default).This vector defines the X1, X2, and X3 fields of the MSC Nastran UNBALNC Bulk Data entry.

Angular position, in degrees, of the mass in the unbalance coordinate system (default 0.0). This defines the THETA field of the MSC Nastran UNBALNC Bulk Data entry.

The start and termination times for applying the unbalance load. The default start time is 0.0, while the default termination time is 999999.0. These values define the Ton and Toff fields of the MSC Nastran UNBALNC Bulk Data entry.

Correction flag to specify whether 1) the mass will be used to modify the total mass in the transient response calculations, 2) the effect of the rotor spin rate change will be included in the transient response calculation, or 3) both.Possible values are None, Mass, Speed, or Both (default None).This value defines the CFLAG field of the MSC Nastran UNBALNC Bulk Data entry.


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