1. Updating and design sensitivity processes applied to drum brake squeal analysis
G. Martin, SDTools, Chassis Brakes International
E. Balmes, SDTools, Arts et Metiers ParisTech/PIMM
T. Chancelier, Chassis Brakes International
G. Vermot-Des-Roches, SDTools
EB2016-SVM-047

2. Introduction Squeal event analysis involves
Experimental
measurements
Finite element
modelling
Experimental Modal Analysis
Operational Deflection Shapes
System behavior understanding
Redesign simulation
Objective : Efficient countermeasure specification

3. Correlation : where is the error?
Identification error
Setup error
Noisy measurements
FEM error
Geometry
Material parameters
Coupling properties

4. Outline Updating protocol Coupling modeling and updating
Assembly modal sensitivity to coupling

5. Application
Experimental observation : squeal occurrences depend on plate subassembly modal properties
Need for understanding of the origin of modal properties dispersion

6. Outline Updating protocol Coupling modeling and updating
Assembly modal sensitivity to coupling

7. Updating protocol Nominal Geometry Measured Geometry
Colocalized transfers
Weight
Topo
Correlation
Geometry
updating
Frequency
Correlation
Material parameters updating
Component A Geometry
Component A Model
EMA
Nominal junction
Shape
Correlation
Contact
updating
Component B Model
Assembly A+B Model

8. Topo correlation correlation by CBI
Geometry updating
Nominal Geometry
Measured Geometry
Up to 2mm gap
11% Volume error
Topo correlation correlation by CBI

9. Geometry updating Bandwidth 0 – 6kHz Shapes differ >3 kHz
Frequencies:
2 % mean error
5 % max error

10. Material parameters updating
Colocalized transfers
Weight
Component A Geometry
Correction of bias induced by geometry
Better correlation
Lower error
Young modulus closer to expected values
Representative model (Experimental frequency dispersion <2%)
Frequency
Correlation

11. Outline Updating protocol Coupling modeling and updating
Assembly modal sensitivity to coupling

12. Coupling updating EMA Plate model Nominal junction Cable guide model
Shape correlation 12

13. Coupling updating +/-10% dispersion for some modes EMA Plate model
Nominal junction
Cable guide model
Shape correlation 13

14. Junction surface definition
Stakes : Impossibility to have a local definition of coupling
(static pressure, roughness, mean behavior over modal trajectory)
Nearly equivalent surface definition adapted to FEM scales :
Evolution of rigid minimal surface + contact stiffness
Minimal surface in contact
Out-of-plane stiffness Kn
In-plane stiffness Kt
Contact stiffness evolution => lower cost

15. Surface / stiffness equivalence
Surface evolution
Stiffness evolution

16. Coupling modeling strategy
Elastic coupling
In-plane Out of plane
Elastic components
Min Surface (Tie)
Multi-model reduction with 4 operating points formed with (nmin,nmax,tmin,tmax)

17. Coupling updating Multi-model reduction : 500.000 DOFs
1600 points in 10min
Clear optimal value

18. Coupling updating n=5.10-7 t=1.10-4 Multi-model reduction :
DOFs
1600 points in 10min
Clear optimal value
Relative to maximum stiffness (1010 N/mm3)
n=5.10-7
t=1.10-4

19. Outline Updating protocol Coupling modeling and updating
Assembly modal sensitivity to coupling

20. Coupling analysis : freq evolution

21. Coupling analysis : freq evolution

22. Coupling analysis : freq evolution

23. Coupling analysis : freq evolution
Rigid plate, deformed cable-guide

24. Junction analysis : freq evolution
Rigid plate, deformed cable-guide
Rigid cable-guide, deformed plate

25. Junction analysis : freq evolution
Rigid plate, deformed cable-guide
Rigid cable-guide, deformed plate
Both deforming
Relative contribution of component mode coupled to rigid assembly (keep inertia effect)

26. Assembly mode with rigid component
Original assembly
Rigid plate
Plate :
Rigid body subspace

27. Assembly mode with rigid component
Original assembly
Rigid plate
Plate :
Rigid body subspace
Assembly mode crossings with coupling stiffness

28. Assembly mode with rigid component
Original assembly
Rigid Cable guide
Cable-guide :
Rigid body subspace

29. Influence of mode crossing
Original assembly
Rigid Cable guide
Cable-guide :
Rigid body subspace
Cable-guide :
Rigid body subspace
Constant plate shape at
Higher frequency at low stiffness
Lower frequency at high stiffness

30. Influence of mode crossing
Low coupling stiffness
Opposition of phase
Higher assembly frequency
High coupling stiffness
In phase
Lower assembly frequency

31. Conclusion - Perspectives
Improved understanding of the dispersion origin
Major impact of geometry updating
Major impact of coupling on modal properties
Introduction of assembly modes with rigid component for sensitivity analysis
Efficient numerical strategies (CMT reduction)
Interactive visualization of the design space (GUI)
Integrate dispersion in the reduced model
Integration in full drum brake model

32. Conclusion - Perspectives
Thank you for your attention !
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