Early Noise Analysis for Robust Quiet Brake Design 2009-01-0858

At the early design stage it is easier to achieve impacts on the brake noise. However most noise analyses are applied later in the development stage when the design space is limited and changes are costly. Early noise analysis is seldom applied due to lack of credible inputs for the finite element modeling, the sensitive nature of the noise, and reservations on the noise event screening of the analysis. A high quality brake finite element model of good components’ and system representation is the necessary basis for credible early noise analysis. That usually requires the inputs from existing production hardware. On the other hand in vehicle braking the frequency contents and propensity of many noise cases are sensitive to minor component design modifications, environmental factors and hardware variations in mass production. Screening the noisy modes and their sensitivity levels helps confirm the major noisy event at the early design stage. A robust design is required to perform the quiet braking consistently through being insensitive to reasonable brake variations. This need calls for an early noise analysis utilizing the stochastic analysis combined with the complex eigenvalue analysis for ensuring the design robustness.

With the original stochastic work developed in GM, this paper documents the experience of an early brake noise analysis for supporting robust quiet design. Three areas are discussed. The first area shows some essentials for building a desirable high quality finite element model. Next, the necessity of a sensitivity check of complex eigenvalue analysis for screening the noise events is presented. Finally, with reasonable analysis criterions specified specifically for the major noise events of interest, the stochastic analysis for confirming the robustness of the brake is presented and discussed.