Squeal prediction on a simplified brake system by complex eigenvalues analysis

Brake noise is an example of noise caused by vibration induced by friction forces. During brake operation, the friction between the pad and the disc can induce a dynamic instability in the system. The onset of squeal is supposed to occur in linear conditions, during braking phase. A complex eigenvalues analysis of the finite element model of a simplified brake apparatus is here adopted to investigate the squeal occurrence. Several experimental tests are performed to reproduce different squeal frequencies and to study the dynamics of the system in function of driving parameters. The paper shows a good agreement between the dynamic behaviour predicted by the parametrical complex eigenvalues analysis on the model and the dynamic and squeal behaviour measured on the experimental set-up. The simple dynamics of the system allows distinguishing three main substructures: disc, caliper and pad. A clear distinction between squeal events involving the modes of the caliper or of the pad is highlighted.