a sim academy webinar glued contact 100304 v2

8/3/2019 A Sim Academy Webinar Glued Contact 100304 v2

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MD Nastran Assembly Modeling Using ContactFast Assembl Modelin & inte rated Global / Local Anal sis

rom oarse… … o e ne an … … o ve



MSC.Software Confidential

Introduction

• Name• Dominick Lauzon, ing

• oca on : on rea , ana a

• Background• ~4 Years as Application Engineer at MSC Software

• Previously : 11 years as structural analyst at SPAR/EMS/MDA in Montreal for Space hardwareand Subsystems

• Experience

• Statics, Dynamics, Random, Shock, Acoustics & Hardware Testing• Thermoelastic and Thermal Correlation

• Composites, Honeycomb and other thin shell applications

• Teaching (MSC Training & 5 years of Space Technologies at Polytechnique)

• Linear and Non-Linear Contact

• SimXpert Template Automation

• m anager mu at on ata rocess anagement• Contact

• Office : 514.908.7312

• Email : [email protected]

2




2D Glued Contact To Address True Industrial Problems

In new simulation wa s…

• Creation of Large Assemblies

• Several industrial challenges can be observed where countless hours are spentali nin nodes and s littin meshes to assess structural erformance of

assemblies• Adjoining incongruent meshes coming from different sources is VERY time consuming

• HARD to make early design assessment (stiffness, frequency response, etc…)

• Performing integrated Global-Local Assemblies

• Traditional Local studies implies creation of multiple local refined meshes

• Time consuming effort to extract locations, remesh, numbering, post-processing…

• Requires management of multiple independent local models

• Risks of load transfer error or approximation

• Limitations in dynamics (frequency response and transient)

• Challenge observed in various industries• Airframers (Airplanes, Helicopters, Space Systems, etc…)

• Trains, Shipbuilding, Containers, Electronics, Manufacturing, etc…

3




2D Glued Contact To Address True Industrial Problems

Industr Statement

“ ,have saved between 2 or 3 weeks of remeshing to match

nodes between parts due to some design changes.” -Guy Lamontagne, Airframe Structures, Bell Helicopter Mirabel

4




MD Nastran Touching Contact

• Details

• Touching Contact Between Bodies

• How did ou do it before?

• Assumptions on Design using MPCs• Over-conservative stiffness

• Conservative bolted joint Assemblies

• Difficulty to converge using CGAPs• Need congruent Meshing

• Large displacement/sliding at GAPs prevents convergence

• Why is it better?

• Fast and Easy Contact Detection Setup

• Accurate Stiffness & Loads Transfer• Avoid * oin -throu h* situations in linear statics

Predicts Realistic Contact & Stiffening Effects

• Representative heel-and-toe simulation

• Enables preload and interference fit in linear statics

• Application•

• Aircrafts, Cars, Ship Hulls, Trains Enables Bolt Preloading and Interference Fit




MD Nastran Glued Contact

• Details

• Glued Contact Between Bodies

• How did ou do it before?

• Create Separate Detailed Models, MeshTransitions, Making Nodes Coincident…

• Manually Intensive Process

Refined Model

• Manually Intensive Process

• Resolve Outside the Assembly Model

• Why is it better?

• Fast and Easy Setup

•

Expedite Assembly & Local Meshing

• Application• Expedite Creation of Large FEM Assemblies

• Aircrafts, Cars, Ships, Trains

• • Electronics

• Perform fully integrated Global/Local StudiesIntegrated Global Local Analysis




Assembly Modeling : Key Benefit Areas for Glued Contact

Expedited Assembly & Local Meshing

• Increased productivity due to and removal ofmundane tasks

• Eas to use and setu

Integrated Global Local Analysis

• Elimination of the need make independent models orcomponent/subsystem reduction

•

• Contact analysis carried out by a broader

engineering team• Accurate physics representation and reduction in

design conservatism

stiffness is conserved

• Models can be run in Dynamics

9/27/20117




Assembly Modeling : More Self-Glueing Considerations

Expedited Assembly

• Multiple adjoining mesh with non-congruent nodes

• ONLY 1 Contact Body Created

Other Assembly Considerations and Benefits

• Different Meshing Techniques Offered : Glued, Congruent

• Mass is exactly the same when sandwich are the same

• Table of Contact to Self-Glued

• Ignore Thickness Option Used for Shell Edge-Edge• Eigenvalue Assessment done in seconds

• Concept is scalable to large assemblies

• Significant Gain on Meshing Time from CAD source

• No need to adjust geometry to match (extend, break…)

• 1st and 2nd Bending Modes are 0.08% and 0.62% off

• .Mode does not exist with glued model





• Use Case Example: Wing Rib

• Wing Assembly Level Global Local Analysis Using Glued Contact

Wing Assembly Displacement FieldWing Assembly Integrated Global Local Model

Displacement Field Comparison Stress Field in the Rib Detailed Sectionetween ue an u y eta e ect ons





• Use Case Review for Demonstration

• Defining Glued Contact on Bodies to Quickly Assemble Models and avoidunnecessary nodal congruency as well as incorporating local components can bebeneficial in many situations

• The following example considers:

• A Coarse 2D Shell Aircraft

• Local Fuselage Section Model

oarse

• e a e on- ongruen s

• Local Refinements of Access Doors

• In this example, we will use:

• Edge to Edge (Fine to Coarse Boundaries)

• Face to Face (Ribs to Skins with Physical Offset)

• Self-Glued Contact

• 2D Ribs Assembly, Fine Fuselage with Access Doors2 s





• Live Demonstration Using Patran 2010





• Use Case Example: Aircraft Loads & Detailed Stress Assembly• Wing Assembly Level Global Local Analysis Using Glued Contact

Coarse MeshAnd 1D BeamsCongruent

Detailed MeshAnd 2D Beams

-& Glued

rcra ssem y sp acemen e o ercra oa s o e w n egra e e a e ress omponen

Mode 8 Deformed Shape ComparisonBetween Glued and Congruent Section

Mode 8 Strain Energy Density Fieldin the Fuselage Detailed Section





• Other Use Case Example: Electronic (PC Board Assembly)

• PCB Assembly Level Global Local Analysis Using Glued Contact

PCB Modal Results (Modes 1,2,3)PCB Assembly Integrated Global Local Model (Detailed 3D Chip)

2D PCB and 3D Chi Stress Field Includin Full D namic Res onse Su ortRepresentative Physical Stiffness of PCB (Frequency Domain and Random)




MD Nastran Glued Contact• Conclusion

• Contact Body Definition is fast and simple with virtually no computing time impact

• Glued Assemblies can realistically help expediting meshes with:

• on nes

• Replace 1000s of fasteners (like riveted joints – alternative to connector elm’s)• Assemble dissimilar meshes without need of nodal congruence at interfaces

• Assemble offset shells to avoid tedious eometr editin to match midsurfaces

• Respect physical representation

• No compromise on mass and stiffness

• Less design conservatism

• Enables integrated global-local in the same assembly model

• No need to make independent models or SuperElement reduction required

• Boundary stiffness is conserved

• Resulting Loads at the local model boundary can be generated

• Glued Models can be run in all Nastran Linear Solutions (Modal, Transient, etc…)

• Time Savings enable engineers to spend more time Improving and OptimizingDesigns rather than spending most of their time on meshing



, ,THAT FAST and THAT EASY !

Photo : Vicky Welsh

15



On Curved Panel with Ribs

16





• Use Case Review

•

avoid unnecessary nodal congruency as well as incorporating localcomponents can be beneficial in many situations

• The following example considers:

• A Coarse 2D Shell Curved Panel• Detailed 2D T-Ribs

• Local Study of Window

• Local Study of Mounting Strips

2D Ribs

Coarse

• In this example, Key considerationsFine





• Step 1 – Patran Database

• Open the Model Database in Patran

• Groups are created to facilitate contact body creation

• OR

• Create a new Database, import the nastran bdf file and run the group from File / Session / Play…

• opt ona ss gn group co ors

• Utilities / Group / Group Colors…

• Display / Entity Colors / Group





• Step 2 ContactBody Definition

a. Select Groua

and Post…

b. Select only theRibs Group

c. Press« Apply »

b

c





• Step 2 Contact Body Definition

a. From the Ribbon Menu, Select Loads/BCs c

.

ab

c. Set the O tion to « Deformable Bod »

d. Enter 2D Ribs as Set Name

e. Specify 2D Target Element Typed

e. «

f





• Step 2 Contact BodyDefinition

a) In the Select A licationRegion, Select « FEM »

b) Select the 2D ribs from thevieport by dragging a

aw n ow

c) Click on Add

d) Ensure the Master Region b

element Ids

e) Press OK

•

d

e

Loads/BCs form

• Ensure the 2D Ribs contactis lited in the « existingsets » list.





• Contact Body Definition Precisions

• Patran Body Creation Order is Important

,

contact bodies must defined in a specific order, ideally from fine to coarse• In the contact table, Patran displays contact bodies by alphanumerical

order which does not relate to the Nastran BCBODY ID which isimportant for proper contact detection

• Example resulting contact table if the creation order (incorrect) is:

• 1-coarse, 2-ribs, 3-fine





• Step 2 Contact BodyDefinition

• Repeat the process for the two

b

c

other deformable contact

bodies in the following order :• Panels Fine

• Including Window d

• Shells Coarse

• Verify contact bodies are all

defined select « Plot Contours »

b) Set Object to « Contact »

c) Select Option « DeformableBody»

d) Highlight all existing setse) Toggle Entity Highlight and

Group Color to find bestdisplay

• Press « Apply » at the bottomof the form

e





• Step 3 Setup Loads &Boundary Conditions

a) Create a Displacement

a

o a oun ary

condition at the top andbottom edge of thecoarse shells

b) Define the Name of theboundary condition« Pinned BC »

c) Click on « Input Data… »

d

d) Enter < 0.,0.,0.> in theTranslations input field

e) Press OKb

ress pp y

g) Verify the BoundaryConditions are createdas shown

c

e f




MD Nastran Glued Contact• Step 3 Setup Loads &

Boundary Conditionsa) Create a Displacement Nodal

boundary condition at the top and a

bottom edge of the coarse shells

b) Define the Name of the boundarycondition « Internal Pressure »

c) Set the Target Element Type to« 2 D »

d) Click on « Input Data… »

e) Enter 100. in the Bot SurfPressure

f) Click on « Select ApplicationRe ion…»

eg

g) Select the Coarse and fine shellsincluding the window by dragginga slection window in the viewport

h) Press « Add » and ensure theselection ets in the A lication

b

Region Boxi) Press OK / OK / Apply

di1

i3





• Step 3 Setup Loads & Boundary Conditions

• Verify pressure directions and element normals to ensure consistency in the elementorientations, for glueing, loads application and post-processing




MD Nastran Glued Contact a

• Step 4 Setup the LinearStatic Contact Analysis

a) Pick Analysis from thr d

b) Under the Analysis menu,

provide a Job Name for theanalysis

« »

f

…

d) In the Subcases sub-menu,pick the « default » in theavailable subcases list to set

it as the active Loads and

b

e

BCs Set

e) Click on « SubcaseParameters »

f) In the Subcase Parametersw n ow, c c on « on ac

Table… » to define thecontact specifics betweeneach bodty pairs

c





• Step 5 Define the ContactPairs Specifics (Part 1-2)

a) Set the Panels_Fine to to _

« Glue » by clicking multiple

times until the letter « G »appears

b) Set the Distance tolerance to

a

e

0.02 to ensure detection ofthe face-to-face contactaround the curvature (Ribs

are offsetted by the shell b-

c) Set the Contact Detection toAutomatic

d) Turn ON the Retain Momentc

d

e) Define the SAME OPTIONSfor the Shells_Coarse to2D_Ribs contact pair(similar surface to surfacecontact requirements)




MD Nastran Glued Contact• Step 5 Define the Contact

Pairs Specifics (Part 3)a) Set the Panels_Fine to to

Shells Coarse air in the _ matrix to « Glue » by clicking

multiple times until the letter« G » appears

b) Set the Distance tolerance to

a

. to ensure etect on othe coarse to fine meshcurvature gap on the windowedges (largest gap is0.0024

b

c) Set the Contact Detection toAutomatic

d) Turn ON the Retain Momentoption

cd

e) Click on Optionsf) Toggle ON both « Ignore

Thickness » options to avoidimproper edge-to-edge

f

en ng react ons

g) Press OK / OK / OK / Apply gg

MSC S f C fid i l





• Edge to Edge ContactPrecisions

•

Contact :• Should Carry Bending Moment

=

• Must Ignore Shell Thickness

• This is to prevent secondary

bottom surfaces

• Moment is properly carried fromthe neutral axis (sufficient)

• Select Options:• Ignore Thickness

• Refer to QRG:

» , =

MSC Software Confidential





• Step 6 Request GridPoint Forces Output

a) Under the Analysisb

menu c on« Subcases… »

b) In the Subcases sub-menu, pick the

d

« default » in theavailable subcases list

c) Click on « Output

Requests… »

d) In the Select ResultType, click on « GridPoint Force Balance… »to re uest nodal forces

c

and perform FreebodyDiagrams

e) Press OKa

ress pp y f

MSC Software Confidential





• Step 7 Submit the Job toNastran

a) In the Analysis Menu, click“ ”…

b) Pick the “Default” subcase

from the top window

c) Ensure the “Default”

b

d) Press OK

e) Press Apply

• Step 8 Import the resultsFile

• In the Analysis Menu, click onset the Action to “AccessResults”

c

• Press “Apply”

• The Patran default is to lookfor the corresponding resultsfiles matching the Job Name

a

e

d





MD Nastran Glued ContactContact

Status

• Step 9 - Reviewing Results

• If Grid Point Forces are Requested, Local Meshing Boundary forces can

• Note that Glued Contact Status output *IS NOT AVAILABLE TODAY*(only available for touching contact, expected in MD R4 and SimXpert)

Displacement Field ComparisonBetween Glued and Fully Detailed Models

Freebody Forces at the Local ModelBoundary And Stress Field on the Refined Window

a sim academy webinar glued contact 100304 v2

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