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Fast and Efficient: Integrated Fatigue Analysis in PERMAS

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Fast and Efficient: Integrated Fatigue Analysis in PERMAS - Development Preview - Jakob Häckh, Steinbeis Transferzentrum Andreas Schünemann, Intes GmbH
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Page 1: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Fast and Efficient:Integrated Fatigue Analysis in

PERMAS- Development Preview -

Jakob Häckh, Steinbeis Transferzentrum

Andreas Schünemann, Intes GmbH

Page 2: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Motivation

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 2

Fatigue in PERMAS - WHY?

• Fully integrated Stress/Fatigue evaluation in PERMAS

• Highly performant implementation (optimized memory/runtime efficiency, parallelized)

• Classical approach via nodal stresses or SPR stresses/gradients

• avoids stress export/import; no external tool necessary

• GUI support by VisPER for pre and post processing

Options for further development

e.g. Optimization & Fatigue (Damage as design objective or constraint)

Cooperation of Intes with Steinbeis Verkehrszentrum:

Transfer of Know How WinLIFE → PERMAS

Implementation directly in PERMAS(no code integration)

Combination:

Intes FEM/HPC capabilities

+ WinLIFE Fatigue expertise

Page 3: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Content

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 3

• Introduction to Fatigue

• The Fatigue Software WinLIFE

• Advantages of Direct Integration

• The Gain of Performance

• Comparison of Results

• Conclusion

Page 4: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Why do I need a Fatigue Life Calculation?

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 4

After approximately 20 000 km, the aluminum frame of a mountain bike broke.

ICE accident in Eschede:A broken wheel tire gets blocked in a track switch and derails the train

Page 5: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

The Basis is the SN-curve Test

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 5

time t

Stre

ss S

So

Sm

Su

ΔS

Sa

R = S u / S oSa

1. Stress cycle

K Z DNa ND

D

Z

K

S a

K = Low Cycle FatigueZ = High Cycle FatigueD = Very High Cylce Fatigue

Slope k Yield strength

Fatigue strength

Fatigue limit

Stre

ss a

mp

litu

de

S a[N

/mm

2]

stress cycle (log.)

Page 6: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Load -> Damage Amount

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 6

Page 7: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Rainflow Counting

A rainflow counting is an evaluation algorithm used to reduce a random stress-time history to a damage-equivalent stage collective. This can be used as a basis for a strength assessment by comparison with a corresponding Wöhler line.

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 7

Page 8: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Process of a Fatigue Life Calculation

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 8

BASIC Calculation methods of winLIFE:

• Fatigue strength verification and static verification according to FKM

• Static superposition of load cases by scaling• Mostly used method• High calculation speed• up to 200 loads histories• Non-linearity can be taken into account by dividing structure into substructures• Necessary condition: All natural frequencies of the structure > 3*f_exitation

• Modal superposition• Nonlinear calculation

Page 9: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

winLIFE 2021

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 9

winLIFE 2021

Founded 1989 from Prof. Dr. G. Willmerding -> LIFE (Lebensdauer (Fatigue) Information Finite Elemente)-> renamed 1993 in TvLIFE -> 1996 renamed in winLIFE

Established for ofer 30 years with over 250 Installation worldwide

8 Moduls: FKM, BASIC, MULTIAXIAL, GEARWHEEL&BEARING, CRACKGROWTH, RANDOM, STATISTIC, VIEWERAll current theories implemented

Our customer: Astrium, Audi, Arctic Cat, ALKO-Kober, Bayer, Bertrandt, Bosch, Bosch Rexroth, Borg-Warner, Doosan (Korea) EDF, ENO, Enercon, FAG, Fendt, Daimler, Eickhoff, Hitachi, IVECO, Komatsu, Krauss Maffei Wegmann, Kögel, Lürssen Werft, LBF, MAN, Müller Weingarten, MUZ Engineering, Porsche, Pfleiderer Verkehrstechnik Rheinmetall, Neumann & Esser, Terex, TEMIC, ZF, Zelter, Zollern

More details see Lecture of 6th PERMAS Technology day 2019 or www.stz-verkehr.com a product of:

Page 10: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Content

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 10

• Introduction to Fatigue

• The Fatigue Software WinLIFE

• Advantages of Direct Integration

• The Gain of Performance

• Comparison of Results

• Conclusion

Page 11: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Process of Fatigue Analysis

Standard workflow in industry:

- Two separated software- Two independent analyses

- Two different input syntaxes

- Inefficient data handling- File i/o is slow

- Disc space required

- Only stresses at nodes are transferred

- All other valuable information is thrown away and not used

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 11

FE Analysis

Fatigue

FKM

Model

Stress

Damage

Process Disc Space

Page 12: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Common Software „Integration“

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 12

FE Analysis

Fatigue

FKM

Model

Stress

Damage

Process Disc SpaceSimple put together of both software under an uniform cover:

- From outside: one software- Still two independent software kernels

+ one input syntax

- Maybe better data handling- Depends on software company

- Functionality added for advertising brochures

- Some advantages, but not a break through

- Significant possible benefits not implemented

Page 13: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

INTES Integration Approach

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 13

PERMASFE Analysis

FatigueFKM

Model

Stress

Damage

Process Disc SpaceINTES advanced integration approach means:

Implementation of fatigue analysis in PERMAS

+ One software+ One input syntax

+ Efficient data handling+ Common data, no export/import of stress

+ Usage of PERMAS HPC strength:+ Parallelization, data management, …

+ Usage of PERMAS internal model knowledge and of already computed information/results

+ E.g. stress gradients, normal directions, …

+ Knowledge (theory and long time experience) of experts (Steinbeis-Transferzentrum, winLIFE)

Significant advantages implemented: • Simplified, more reliable process• Breakthrough in process acceleration

Page 14: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Potential Advantages in Future

Significant advantages of integrated

• Fatigue analysis and

• Optimization

are door opener for further process improvements in future.

These innovations support your innovations towards best performance of your products!

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 14

FE Analysis

Fatigue

FKM

Model

Stress

Damage

Classic Development Process

Red

esig

n

PERMASFEM

FatigueOPT

Model

Damage

Advanced Process

Optimization

Page 15: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Fatigue Input in DAT File

Examples for preliminary PERMAS data file keywords

• Parameter for the SN-Curve which describes the magnitude of an alternating stress versus the number of cycles to failure (developed by August Wöhler):

$FATIGUE SNCURVE METHOD = PARAM NSET = FAT1 SNCNAME = C45R

! DwTw S02 IL Rm SD K ND M

1.73 500.0 1 700.0 250.0 5.0 1000000 0.15

• Description of roughness for the effect on the fatigue strength:

$FATIGUE NODEPROP TYPE = ROUGHNESS PDEF = NODE

! Node/NSET roughness

1234567 0.15

FRONT 0.05

… …

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 15

Page 16: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Fatigue Analysis in UCI File

• Simple extension of the UCI

• Just an additional result request with parameters required

• Based on nodal point stress results (explicit generate is optional)

UCI file excerpt:

ACTivate SITuation = STATIC_FAT

STATIC

GENerate Nodal Point STRESS

GENerate FATIGUE FLSET = FAT1 SURFACE = 102 NCUT = 50 RFLDIM = 200 STRESS = NORMAL

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 16

EXEC

Page 17: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Performance

FE Model Size:

1506000 Nodes

1250000 Elements

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 17

1147s

Stress import

+ External Fatigue

Analysis

Export

Stress

Static

Fatigue Analysis

Stress

Static

1139s

795s ↔ 528s

➔ PERMAS fatigue analysis is even faster than the stress export!

Export Size:

Stresses: 48 GB (.bof)

Damage: 1.7 MB (.post.gz)

Page 18: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Performance: Parallelization

Fatigue settings for rainflow method

Rough sketch

Standard

High Quality

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 18

10 cutting planes40 rainflow stress classes

Fatigue Runtime parallel GFlop/sspeedup

267s 4.3 4.7

531s 8.9 6.5

544s 10.9 19.6

40 cutting planes200 rainflow stress classes

200 cutting planes1000 rainflow stress classes

Hardware: 1 Socket, 18 cores, 192GB memory

Page 19: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Performance: Parallelization

Fatigue settings for rainflow method

Rough sketch

Standard

High Quality

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 19

10 cutting planes40 rainflow stress classes

Fully parallelized ➔ Higher result quality at small additional runtime

40 cutting planes200 rainflow stress classes

200 cutting planes1000 rainflow stress classes

Hardware: 1 Socket, 18 cores, 192GB memory

Fatigue Runtime parallel GFlop/sspeedup

267s 4.3 4.7

531s 8.9 6.5

544s 10.9 19.6

Page 20: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 20

Planetary Gear Carrier

713377 Nodes

486355 Elements

16504 Fatigue Nodes

Rainflow method with

931 time steps

40 cutting planes

200 stress classes

Page 21: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 21

Planetary Gear Carrier

Kinematic conditions Loads

radial

radial +

tangential

axial

3 x 45 kN → 4725 Nm

Page 22: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 22

Planetary Gear Carrier

Kinematic conditions Loads

radial

radial +

tangential

axial

3 x 45 kN → 4725 Nm

Page 23: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 23

Planetary Gear Carrier: Load Spectrum

Load Pattern → Load Collective

LPAT 1

3 x 45 kN → 4725 Nm

Factor Loading cycles

1.0 3

0.9 21

0.8 63

0.7 105

0.6 273

Page 24: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 24

Planetary Gear Carrier: Stress Results

Stress peaks

Page 25: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 25

Planetary Gear Carrier: Damage Results

PERMAS WinLIFE

Page 26: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 26

Planetary Gear Carrier: Damage Results

PERMAS WinLIFE

Page 27: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 27

Planetary Gear Carrier: Damage Results

PERMAS WinLIFE

Results are equivalent!

Page 28: Fast and Efficient: Integrated Fatigue Analysis in PERMAS

Conclusion

PERMAS Tech Meetings - 22 April 2021 Häckh/Schünemann: Fast and Efficient: Fatigue Analysis in PERMAS 28

• Finite Element Analysis and Fatigue Analysis are based on the same model, but the established processes are to complex and time consuming:

• Integration is a logical step

• Integration of fatigue analysis in PERMAS is in development

• The validity of the solution has been shown

• Deep integration of fatigue code leads directly to significant advantages:• Simplified, more reliable process

• Breakthrough in process acceleration – shown: effort fatigue analysis ≈ effort stress calculation

• Further possibilities in future:• Improve the process from expensive redesign to fast optimization

• Get better damage results by using more and more accurate FE-Solver information


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