femfat 5.4 news and more

FEMFAT 5.4News and MoreGaier

Steyr

2019

• VISUALIZER: Animation of equivalent stress and damage, video export

• VISUALIZER: Additional WELD definition settings

• New SPOT method: Assessment of stresses of NASTRAN super-elements

• SPOT additional report file output of fatigue dataset name

• New WELD stress interpolation method: Hot spot stress concept

• STRAIN input file analogous MAX

• SPECTRAL: Improved mean stress influence

• Filter function for group list

• FEMFAT parallelization: Delete automatically temporary files after analysis

• FEMFAT inside ANSYS

• Template for elastomers analysis settings

FEMFAT 5.3.1 available since August 2018

Date: 2019 / Author: Gaier 2© MPT Engineering / Disclosure or duplication without consent is prohibited

Animation of FEMFAT Results

3© MPT Engineering / Disclosure or duplication without consent is prohibited

• Define in FEMFAT a

„DETAILED RESULTS“

nodal group for animation

• Select the new result

category „Animated

Results“ in the Result

Selector dropdown menu

• Color for nodes without

value can be defined also

for animated results

Date: 2019 / Author: Gaier

Animated Results GUI

4© MPT Engineering / Disclosure or duplication without consent is prohibited

• Selectable result types

• Currently selected time step as shown on the geometry

• Options for animating the results

• For Example: run an animation „From“ time step 1 „To“

time step 681 and show every 10th time step

(„Increment“).

• The „Delay“ of 100 [ms] refers to the time interval

between two rendering processes. The Delay does not

include the rendering time.

• Options to circle the animation („Loop“) and save

Screenshots of the shown time steps („Export…“)

• Animation Controls

Date: 2019 / Author: Gaier

Video Export


High

Medium

Low

Equivalent stress

Partial damage

Total damage

Additional Settings for Welding Seam End Definitions


• Spots are mostly represented with simple models

• Usage of detailed spot models without the disadvantages of

“too many DOFs”

• Aim is one FEA for all spots in trimmed BIW(No post-processing of FEA is necessary)

Usage of NASTRAN super-elements

New SPOT Method by Using Nastran Super-ElementsMotivation


Workflow: Usage of Super-Elements


Replace hexas by

super-elements

connected by 4

nodes/sheet via RBE3

Pre-Proc

BIW sheet structure with

hexa elements connected

by RBE3 to sheets

NASTRAN

Op2-file

Post-Proc

Op2-file

Post-

processing

Database with

super-elements

and stiffness

matrices

External super-elements

(Super-elements are imported)

→ supported by FEMFAT

Model with Super-Elements using ANSA


Super-element 4

Super-element 1 Super-element 3

Super-element 2

ANSA creates a hexahedron

element for visualization

ANSA Connection Manager

Results, Global behavior


Model without super-elements,

but with detailed SPOT solid

model connected via RBE3-

elements to shell structure

Model with super-elements

• Advantages– Applicable to all types of spot joints (spot welds, rivets, nails, …)

– Detailed FE-model of notch of spot-> accurate stiffness and stress results

– Assessment of stresses with one master S-N curve independent from load type and direction

– Detection of crack location in detailed FE-model

– Correct superposition of stresses (Maximum stresses of different load cases may be at different locations)

– Detailed FE-model needs to be generated and analyzed only one time-> data (model and stiffness) can be stored in a database

• Disadvantages– Linear model

– Special know-how for applying super-element concept is necessary

– Higher computation effort

– No easy distinction between failure modes (sheet or nugget failure)

Usage of Super-Elements


SPOT Output of Fatigue Dataset Name


VISUALIZER

Joint 1: ConnD (in more than one FEMFAT analysis joint)

Connector Element(s): 1440, 1441, 1446

Stress based Assessment

NodeLab CenterLab Safety Loc. Angle Amplitude MeanStress ElemLab PropID FatigueID

3459 42 3.520e-03 top 90.0 6.589e+04 6.589e+04 2742 1000002 std_spot_stress_fatigue_data_steel

Report File

• Extension of the automatic stress correction

• New formula:

– Standard method:

– New hot spot stress method:

• The hot spot stress concept is applied automatically, if

necessary values are activated in the WELD database

WELD: New Hot Spot Stress Interpolation Method


DAssesspoint.= f (0.5 tNeighbor + tmin)

DAssesspoint = a tNeighbor + b tEvalulated

tEvalulated

tNeighbor

STRAIN Comp Input File .sco


-1

3001

Management of Strain Gage Data of Comp

Text:

Text:

Text:

Text:

---------------------------------------------------

1 -

Mode (CTR, ALL, N2N) : CTR

Gage Type (LIN, R45, R60) : LIN

Element 1 : 80

File Name :

Grid 1 - File Column : 1

Grid 1 - Initial Elongation : 0.000000

Dimension (----, µm/mm, µm/m) : ----

Multiplication Factor : 1.000000

Repetition Factor : 1

---------------------------------------------------

...

---------------------------------------------------

...

-1

-1

3002

Extended Strain Gage Data of Comp

Text:

Text:

Text:

Text:

Material Behaviour - Cyclic Hardening/Softening (ON, OFF) : OFF

Output - Stress Comparison (ON, OFF) : ON

Output - Strain Comparison (ON, OFF) : ON

Signal Length - Finite Element Data [sec] : 1.000000

Signal Length - Measurement Data [sec] : 1.000000

-1

STRAIN Calc Input File .sca


-1

4001

Management of Strain Gage Data of Calc

Text:

Text:

Text:

Text:

---------------------------------------------------

1 -

Gage Type (LIN, R45, R60) : LIN

Notched Structure (YES, NO) : NO

File Name :

Grid 1 - File Column : 1

Grid 1 - Initial Elongation : 0.000000

Dimension (----, µm/mm, µm/m) : ----

Multiplication Factor : 1.000000

Repetition Factor : 1

---------------------------------------------------

2 -

Gage Type (LIN, R45, R60) : R45

Notched Structure (YES, NO) : YES

Select Gradient/Radius (GRAD, RAD): GRAD

Gradient : 0.500000

...

---------------------------------------------------

...

-1

-1

4002

Extended Strain Gage Data of Calc

Text:

Text:

Text:

Text:

Angle between cutting-planes [°] : 10.000000

Number of rainflow-classes : 64

Factor for residue load cycles : 0.500000

-1

SPECTRAL: Improved Mean Stress Influence


Mean stress influence is always

analyzed with R=const option to

ensure an intersection point with

the Haigh-diagram

For constant stress without mean

stress influence two options are

availableA

+ M- M

HAIGH

const

Filter Function for Group List


Without filter With filter

• For saving disk space, a button can be activated to delete all

files in the parallel-subdirectories automatically after a

successful parallel FEMFAT analysis

• Only message (.msg) and report (.pro) files will not be deleted

Parallel Analysis: Remove Temporary Files


FEMFAT inside ANSYS: One continuous workflow

The use of design points and optimization tools is fully supported.

19

All files which are relevant for the simulation are automatically stored and updated

in one folder.Date: 2019 / Author: Gaier © MPT Engineering / Disclosure or duplication without consent is prohibited

Complete Job Definition and Full Result Visualization in ANSYS Mechanical

20Date: 2019 / Author: Gaier © MPT Engineering / Disclosure or duplication without consent is prohibited

• Automatic adjustment of the necessary FEMFAT settings for elastomer components which undergo large deformations– Consistent stress transformation

– Deactivated stress gradient

– Deactivated PLAST

– User defined mean stress

– Normal stress in critical plane

– Miner elementary with R = const.

– 3D-stresses, all nodes

Template for Elastomers Analysis Settings


Increasing fatigue

limit because

polymer chains

orient themselves

towards load

direction and block

cracks.

• New ChannelMAX scratch format based on HDF5:– Flexible database format with direct data access, e.g. for

future developments of sophisticated stress gradient methods

– Less space on hard disk and faster

– Standard format for FEMFAT analysis and VISUALIZER

– General data format applicable also for BASIC, TransMAX, SPECTRAL

– Suitable for future parallelization of scratch and analysis process

• VISUALIZER: Maximum/Minimum Search

• Boundary Layer:– Improved stress gradient analysis

– Display of FEA-stresses at surface and transition in VISUALIZER

• Script for automatic detection of weld lines

• Support Abaqus odb 2018 & 2019

FEMFAT 5.3.2 released in February 2019


Stress Gradient Calculation Problem and Solution

© MPT Engineering / Disclosure or duplication without consent is prohibited

Stress gradient perpendicular to the front

surface is almost zero

Results are too conservative

Solution: Results are Calculate Gradient

in three orthogonal directions

Resulting stress gradient is the length

of the stress gradient vector:

0,01*d

1

2

3

2

3

2

2

2

1'

Date: 2019 / Author: Gaier 23

• weldseamscanner.exe

Weld Seam Scanner


• VISUALIZER: New reliable definition algorithm for double-row welds (overlapped weld, edge joint, laser weld, flared joint, etc.)

• VISUALIZER and WELD: Support of degenerated double-rowed welds

• VISUALIZER: Delete multiple welds with rubberband selection

• VISUALIZER: Simultaneous display of SPOT detailed and base material results

• SPECTRAL analysis of SPOT joints

• SPECTRAL Neuber Correction with PLAST

FEMFAT 5.4 (planned for June 2019)


• Output stress and damage histories as RPC binary files (e.g. for FEMFAT LAB)

• Safety factor analysis: Output of fatigue strength at given cycles(GUI & report file)

• Compressed ANSYS RST Interface

• Performance enhancements forparallel processing

• SPECTRAL interface for PERMAS (based on Medina.bof)

• Job-file: Select material by name

• SPOT parallel analysis: Merge report file

FEMFAT 5.4 (planned for June 2019)


setValue {} {} FatParamMaterial {test}

→ test.esh.tim

→ test.pdh.tim

→ test.tdh.tim

VISUALIZER: New reliable definition algorithm for double-rowed welds

Date: 2019 / Author: Gaier 27© MPT Engineering / Disclosure or duplication without consent is prohibitedEdge Joint

Overlap Joint Laser Joint

Overlap Joint Flared Joint

Complex meshing of connecting sheet (multi-row and triangle elements)

VISUALIZER: Support of degenerated double-rowed welds


Overlap Joint Edge Joint

VISUALIZER: Delete multiple welds


SPECTRAL Analysis of SPOT Joints


SPECTRAL Neuber Correction with PLAST


Dirlik without PLAST PLAST Mean PLAST Mean + Amplitude

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