Model updating considering damping effects

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Model updating considering damping effects

  1. 1. Fahrzeugphysik2011 European HyperWorks Technology ConferenceModel updating considering damping effects Charline Bonfils, EDAG GmbH & Co. KGaA Antoine Guellec, AUDI AG
  2. 2. Model updating considering damping effectsIssue Fahrzeugphysik Low-frequency NVH analysis Ways to represent damping in FEM  modal damping  viscous damping  structural damping Damping modelling generally not accurate enough FEM validation using experimental data Interest of optimization: identify model differencesFolie 2 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  3. 3. Model updating considering damping effectsContents: The successive steps of validation Fahrzeugphysik Comparison of the models Test vs. FEM Experiment FEM Simulation Eigen mode comparison Curve comparison Optimization with Optistruct Objective Definition & Design Variables Sensitivity Analysis and ResultsFolie 3 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  4. 4. Model updating considering damping effects Step 1: Comparison of the models (FE vs. Test) Fahrzeugphysik  Total mass TB  Mass distribution Step 2: Eigen modes only platform and body selected → projection on FEM test model correlation model MAC calculation torsionModal Assurance Criterion 4 analysis 3 bending 2 Very good correlation 1 for the global modes 1 2 3 4 measure Folie 4 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  5. 5. Model updating considering damping effectsEigen mode: Torsion Fahrzeugphysik Test FEMFolie 5 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  6. 6. Model updating considering damping effects Step 3: Experimental Transfer Functions  Large number of output points → groups Fahrzeugphysik node 1 node 4 node 2 4 nodes → 4 FRFs / shaker node 3  Mean value of these 4 FRFsX XYZY Reduction to 14 groups / 42 curves Comparison with simulationZ Folie 6 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  7. 7. Model updating considering damping effectsStep 4: FEM Simulation Fahrzeugphysik  Model: TB...  Material Property Definition (MAT1) 1 2 3 4 5 6 7 8 9 MAT1 MID E G NU RHO A TREF GE Young’s Modulus Structural Element Damping coefficient  Modal Frequency Response Analysis (RADIOSS)  FRF computed  Responses: same nodes as in the experiment  Results as curves (using the groups of experiment)Folie 7 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  8. 8. Model updating considering damping effects Step 5: Comparison UPPER BODY Fahrzeugphysik M, K BONNET D REAR DOORCOOLER FLOORFRONTEND DOOR Folie 8 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  9. 9. Model updating considering damping effectsStep 6: Optimization with Optistruct: Objective Fahrzeugphysik Run Type: Sizing Optimization Design Response: DRESP1: acceleration for each node of a group DRESP2: average of these accelerations Objective function: MINMAX command - weighting factor System identification with beta method (DSYSID) - target value - response frequency sub ranges response target values (Ti) target functionFolie 9 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  10. 10. Model updating considering damping effectsStep 7: Optimization with Optistruct: Variables Fahrzeugphysik  Design Variables (DESVAR / DVMREL1) Spot Welds : HEXA solid elements 1 2 3 4 5 6 7 8 9 DESVAR ID LABEL XINIT XLB XUB DELXV DDVAL user-defined name initial move limit ID for discrete values initial value lower/upper bound 1 2 3 4 5 6 7 8 9 DVMREL1 ID TYPE MID MPNAME C0 DVID1 COEF1 DVID2 COEF2 etc.Folie 10 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  11. 11. Model updating considering damping effects Step 8: Sensitivity Analysis and Results Fahrzeugphysik First investigation focus on the most sensitive adhesive lines of windscreenUPPER BODY and side windows FLOORFRONTEND Reconsider damping for glass parts / sealings Folie 11 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  12. 12. Model updating considering damping effects Step 8: Sensitivity Analysis and Results Fahrzeugphysik Second investigation focus on the front area of the carUPPER BODY only spot welds of the front area FLOORFRONTEND Precise localisation by using 1 MID for each element Spot Welds connected elements have to be further investigated Folie 12 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  13. 13. Model updating considering damping effectsConclusion Fahrzeugphysik  Sensitivity analysis helps to highlight the areas with insufficient characterisation of damping  Optimization allows to identify the potential to adjust damping  New measurements for the identified components updated model  New model techniquesFolie 13 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  14. 14. Model updating considering damping effectsAcknowledgements Fahrzeugphysik  Fa. ID, G. Lindner for the experimental analysis  H. Gruber, AltairFolie 14 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  15. 15. Model updating considering damping effectsReferences Fahrzeugphysik  RADIOSS User’s Guide, version 10  Optistruct User’s Guide, version 10  HyperGraph User’s Guide, version 10  Geometry Correlation & MAC Calculation, FE-Graph - User’s Manual, von Mach EngineeringFolie 15 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference
  16. 16. Model updating considering damping effects Fahrzeugphysik Thank you for your attention! Questions?Folie 16 von 17 © Copyright 2010 EDAG GmbH & Co. KGaA. Alle Rechte vorbehalten. Charline Bonfils EDAG, Antoine Guellec AUDI AG, 06-09/11/2011 2011 European HyperWorks Technology Conference

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