Optimization process for correlation of experimental and numerical modal analysis

Optimization process for correlation of experimental and numerical modal analysis European HyperWorks Technology Conference EHTC 2011 November 8th ndash 9th 2011 Bonn Germany Dr-Ing Martin H Muumlller-Bechtel Dipl-Ing Simon Tschirpke TECOSIM Technische Simulation GmbH

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Foundation 1992

Business Area TECOSIM is Europersquos largest independent service provider in Computer Aided Engineering (CAE) ndash

the computer-based development and optimization of components structures and products

Markets Original Equipment Manufacturers (OEMs) and suppliers in following industries

- automotive - aerospace - chemical - energy - railway - medical hellip

Vision Global Leader in Computer Aided Engineering

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Turn over (Mio euro) Employees

Fore

cast

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cast

TECOSIM Facts amp Figures

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Aim verification of NVH simulation models

Essential for virtual vehicle development

Complex dependencies to wide range of parameters

Method Usage of optimization for parameter identification

Better correlation in less time

Correlation should consider frequency and mode shape

Relative frequency of simulation mode compared to test

MAC (modal assurance criterion) value for comparison of mode shapes with ai shape vector of test mode i bj shape vector of sim mode j

Problem Definition

jjii

2

ji

jibbaa

baMAC

422

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Typical NVH models coupled structures

Full vehicle modes of suspension engine

Trimmed body coupled masses like cooler battery or mass damper

Body in white with elastically connected subframes

ML BiW with subframe mode 2

Full vehicle mode Subframe mode

Problem Definition

522

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Typical parameters to identify

Coupling element stiffness (bushings engine mount hellip)

Joining technique modeling method dependent properties glue material stiffness weld line thickness

Properties for not exactly known materials like fiber reinforced plastics

hellip

Distribution of masses of hang on parts

Structural glue Laser weld Weld line

Problem Definition

622

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Example model rear subframe out of TEC|BENCHtrade process

Analysis

Purchasing rear subframe

Hardware NVH testing Scanning

Geometry data preparation

FE modeling

FE simulation

722

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Example model rear subframe out of TEC|BENCHtrade process

Initial correlation status

Nearly perfect match for 1st and 2nd mode (MAC gt 099)

Reduced frequency for 5th mode (mass damper effect)

Parameters to identify

Bushing stiffness

Distribution of masses inside rubber bushings

Test 1 2 3 4 5

frequency 7200 10206 17397 18134 21369

correlation status 3 3 0 0 2

MAC value 099 099 030 038 085

rel Frequency 97 103 1 141 86

sim

7 7005 3 0994 0000 0001 0016 0097

8 10536 3 0000 0993 0288 0171 0012

9 13963 0 0044 0000 0000 0013 0673

10 14009 0 0267 0001 0008 0006 0008

11 18402 2 0001 0008 0011 0011 0855

Analysis

822

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Example model rear subframe out of TEC|BENCHtrade process

Criterion for correlation considers frequency AND mode shape

MAC value for comparison of mode shapes

Relative frequency of simulation mode compared to test Fij penalty function with gradient to correlation window plusmn5 mid section uses Runge function

Correlation criterion FijMACij frequency filtered MAC value

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1

12

05 06 07 08 09 1 11 12 13 14 15 16 17 18

Test 1 2 3 4 5

frequency 7200 10206 17397 18134 21369

correlation status 3 3 0 0 0

MAC value 103 102 005 012 058

rel Frequency 97 103 61 141 86

sim

7 7005 3 1029 0000 0000 0000 0001

8 10536 3 0000 1021 0048 0024 0001

9 13963 0 0004 0000 0000 0006 0151

10 14009 0 0023 0000 0004 0002 0002

11 18402 0 0000 0001 0011 0011 0577

Analysis

922

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Example model rear subframe out of TEC|BENCHtrade process

Correlation criterion considers best matching simulation mode

For each test mode take the best matching simulation mode maxfMACi = max(FijMACij)

Optimization objective

Maximize correlation of best matching simulation modes for all test modes maximize

ifMACmax

Test 1 2 3 4 5

frequency 7200 10206 17397 18134 21369

correlation status 3 3 0 0 0

MAC value 103 102 005 012 058

rel Frequency 97 103 61 141 86

sim

7 7005 3 1029 0000 0000 0000 0001

8 10536 3 0000 1021 0048 0024 0001

9 13963 0 0004 0000 0000 0006 0151

10 14009 0 0023 0000 0004 0002 0002

11 18402 0 0000 0001 0011 0011 0577

Test 1 2 3 4 5

frequency 7200 10206 17397 18134 21369

correlation status 3 3 0 0 0

MAC value 103 102 005 012 058

rel Frequency 97 103 61 141 86

sim

7 7005 3 1029 0000 0000 0000 0001

8 10536 3 0000 1021 0048 0024 0001

9 13963 0 0004 0000 0000 0006 0151

10 14009 0 0023 0000 0004 0002 0002

11 18402 0 0000 0001 0011 0011 0577

Σ

max

Analysis

1022

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used TCL programming

Implementation of test data

Reading test data file in csv format

Measurement point IDs (9) Node IDs Nodes SET

Test modes (5) Frequency DTABLE entry (5)

Test modes (5) shape vectors (27) DTABLE entries(135)

Test 1 2 3 4 5

Frequency 7200 10206 17397 18134 21369

amplitude 091433 068783 056059 067002 069682

Shapes 1 024282 003218 -001758 001333 276E-01

046801 -003529 000371 -002999 448E-01

-001334 -031399 -027625 018199 -265E-02

2 004657 007936 002257 000164 201E-02

025833 -001541 002229 -003488 157E-01

-000081 -012870 -031011 034853 606E-04

3 -008430 008442 017604 -016444 -170E-01

000066 005959 000033 000534 -723E-02

Analysis

1122

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used TCL programming

Response definition for simulation modes

EIGRL card with fixed number of modes (15)

Simulation modes (15) Frequency DRESP1 entry (15)

Simulation modes (15) shape vectors (27) DRESP1 entries (405)

Δ Mode specific displacement response not supported by OptiStruct

Solver switched to NASTRAN

Δ Mode specific displacement response not defined in NASTRAN template

Direct programming of NASTRAN code (replacementnas) referencing replacementnas in bulk unsupported section moving of DRESP1 to separate include (waste_basketnas)

Analysis

1222

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

DEQATN 2 f(

+ t001xt001yt001z

+

+ t009xt009yt009z

+ T

+ s001xs001ys001z

+

+ s009xs009ys009z

+ S)=((

+ t001xs001x+t001ys001y+t001zs001z+

+

+ t009xs009x+t009ys009y+t009zs009z

+ )2((

+ t001xt001x+t001yt001y+t001zt001z+

+

+ t009xt009x+t009yt009y+t009zt009z

+ )(

+ s001xs001x+s001ys001y+s001zs001z+

+

+ s009xs009x+s009ys009y+s009zs009z

+ )))

+ MIN((S(095T))4(T(095S))4

+ 02+085(1+25(ST-1)(ST-1)))

Setup of optimization process in HyperWorks

Method used TCL programming

Calculation of single frequency filtered MAC

Definition of DEQATN

Parameters out of DTABLE Test shape (27) test freq (1)

Parameters out of DRESP1 sim shape (27) sim freq (1)

Equation for MAC calculation

Frequency filtered MAC test (5) vs simulation (15) FijMACij DRESP2 (75)

Analysis

1322

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used TCL programming

Selection of best correlating sim mode for each test mode

Definition of DEQATN

Parameters out of DRESP2 test mode related simulation mode filtered MACs (15)

Selection of maximum MAC for each test mode DRESP2 (5)

ΔDRESP2 referencing DRESP2 not supported by NASTRAN template

NASTRAN template modified with specific section out of OptiStruct template

DEQATN 4 f(

+ m1

+

+ m15

+ )=

+ Max(

+ m1

+

+ m15

+ )

Analysis

1422

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used TCL programming

Sum of best correlating frequency filtered MAC values

Definition of DEQATN

Parameters out of DRESP2 maximum MAC for each test mode (5)

sum of maximum MAC for each test mode DRESP2 (1)

DRESP2 referencing DRESP2 now supported by modified NASTRAN template

Definition of design objective

Sum of maximum MAC DESOBJ(MAX) (1)

DEQATN 3 f(

+ m1

+

+ m5

+ )=

+ m1+

+

+ m5

Analysis

1522

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used manual definition

Request for optimization output

Output of responses restricted to frequency and best correlating filtered MAC DSAPRT (1)

Δ DSAPRT not supported by HyperWorks

Manual definition in unsupported section

Definition of responses for output SET (1)

Δ SET of responses not supported in NASTRAN template

Manual definition in unsupported section

Analysis

1622

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Setup of optimization process in HyperWorks

Method used manual definition

Problem specific definition of design variables

Stiffness of frontrear bushing 6DOF DESVAR (12)

Stiffness of rubber bands 3DOF DESVAR (3)

PBUSH-property relations DVPREL (15)

Δ DVPREL for PBUSH not supported by NASTRAN Template

Direct definition of NASTRAN cards (replacementnas) moving of DVPREL to separate include (waste_basketnas)

Mass distribution for bushing bolts DESVAR (4)

PMASS-propery relations DVPREL (4)

Δ DVPREL for PMASS not supported by NASTRAN Template

Direct definition of NASTRAN cards (replacementnas) moving of DVPREL to separate include (waste_basketnas)

Analysis

1722

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Example model rear subframe out of TEC|BENCHtrade process

Optimized correlation status

Nearly perfect match for 1st and 2nd mode (MAC ~ 099)

Improved match of frequency and shape for 5th mode (mass damper effect)

Parameters identified

Bushing stiffness

Distribution of masses inside rubber bushings

Test 1 2 3 4 5

frequency 7200 10206 17397 18134 21369

correlation status 3 3 0 0 2

MAC value 099 099 030 038 085

rel Frequency 97 103 1 141 86

sim

7 7005 3 0994 0000 0001 0016 0097

8 10536 3 0000 0993 0288 0171 0012

9 13963 0 0044 0000 0000 0013 0673

10 14009 0 0267 0001 0008 0006 0008

11 18402 2 0001 0008 0011 0011 0855

3 3 2 2 2

099 099 094 081 081

98 100 126 121 98

7082 3 0994 0000 0001 0016 0096

10210 3 0001 0986 0311 0190 0012

14230 2 0000 0709 0130 0049 0010

17178 0 0000 0399 0019 0004 0302

17326 2 0023 0002 0003 0011 0883

19351 0 0025 0006 0015 0005 0290

20892 3 0024 0006 0009 0009 0814

7

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9

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Analysis

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TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions How does HyperWorks support the process

All keywords necessary for the process are supported by HyperWorks

Tcl programming interface allows for very efficient setup of a huge number of entities

Tcl programming benefits of command logging (used like macro recording for easy access to command syntax)

Different ways of work around

But there is a variety of entities not or not fully supported

Mode specific nodal displacement response missing in OptiStruct not supported in NASTRAN template

DRESP2 referring DRESP2 supported in OptiStruct template but not in NASTRAN template (identical syntax)

DVPREL for PBUSH missing in NASTRAN template

SET definition for DRESP entries missing

Discussions

1922

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions Definition of a complex optimization process

Applicable for a wide range of structures

Enabled by HyperWorks using tcl programming

But there is room for improvements

More consequent support of NASTRAN keywords DRESP2 (just update the template) DVPREL (add further property types PBUSH hellip) SET (add further types DRESP hellip)

Conclusions

2022

TECOSIM

Introduction

Problem Definition

Analysis

Discussions

Conclusions

Perspectives

Solutions

Q amp A

Thank you

Contact TECOSIM Technische Simulation GmbH Dr-Ing Martin Muumlller-Bechtel Tech Manager Virtual Benchmarking Ferdinand-Stuttmann-Straszlige 15 D-65428 Ruumlsselsheim Phone +49 (0)6142 8272-230 Fax +49 (0)6142 8272-249 Mail mmuellerbdetecosimcom

wwwtecosimcom

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