A new approach considering the brake pad geometry in brake squeal

Friction-induced vibration can be defined as a type of dynamic instability problem. Generally, engineers and researchers working in the field of noisy disc brakes treat instabilities due to a friction force as self-excited vibrations. The most known case is squealing. For disc brake mechanisms, mode coupling is responsible for generating annoying squeal noise and vibration in brakes. In order to identify whether a system is stable or not, a complex eigenvalue analysis is achieved. In this paper, a new dynamic model of disc brake squeal was developed. The analytical formulation of the dynamic equation of motion was detailed. Moreover, a stability analysis of disc brake vibrations including gyroscopic effect, negative friction slope and mode coupling with non-proportional damping was developed. Then, the disc brake parameters optimization was discussed by studying the influence of the angular velocity, stiffness and damping coefficient of the pad and friction coefficient and, especially, the pad geometry (opening angle). The improved model led to a better understanding of the unwanted squeal phenomenon and to designs targeting their avoidance.