An Analytical Approach to Model Disc Brake System for Squeal Prediction

Abstract The squeal noise arising due to friction-induced vibrations in brakes continues to be a major challenge for automotive manufacturers. To predict one of the mechanisms behind disc brake squeal, an analytical model is developed for the disc brake system. The brake rotor is represented by a thin plate of equivalent modal characteristics and the backing plates are modeled as thin annular sector plates using Rayleigh-Ritz approach. The two structural models are then coupled using linear elastic springs and Coulomb friction at the interface, and Lagrangian approach is used to derive the equations of motion of the coupled system. The resulting linear equations are solved by using complex eigenvalue analysis. The study shows that squeal is a flutter-type instability caused by coupling between the modes of structural components with very close natural frequencies. The sensitivity to friction material stiffness and the influence of hydraulic cylinder stiffness at backing plates are also discussed.