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

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

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

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

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

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

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

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

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

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  

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

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

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

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

Surface / stiffness equivalence Surface evolution Stiffness evolution

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)

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

Coupling updating n=5.10-7 t=1.10-4 Multi-model reduction : 500.000 DOFs 1600 points in 10min Clear optimal value   Relative to maximum stiffness (1010 N/mm3) n=5.10-7 t=1.10-4

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

Coupling analysis : freq evolution  

Coupling analysis : freq evolution  

Coupling analysis : freq evolution  

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

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

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)

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

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

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

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  

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

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

Conclusion - Perspectives Thank you for your attention ! Contacts : guillaume.martin@ensam.eu balmes@sdtools.com vermot@sdtools.com thierry.chancelier@chassisbrakes.com www.sdtools.com/Publications.html