Countermeasure Against Squeal in Car Disc Brakes by a Dynamic Absorber

This paper deals analytically and experimentally with the design of a dynamic absorber to quench squeal generated in car disc brakes. Firstly, the design of the dynamic absorber was investigated to quench the frictional vibration due to Coulomb friction of a two-degree-of-freedom block system simplifying disc brakes. The agreement between the analytical and experimental results on the optimal design of the dynamic absorber was confirmed. Next, the optimal design was applied to the disc brake. It was found by the analysis and experiments that the natural frequency of the dynamic absorber should be tuned near the squeal frequency and the damping of the dynamic absorber was not needed to quench squeal. Hence, the optimum design of the dynamic absorber to quench self-excited vibration caused by the asymmetry of stiffness matrix of the system was quite different from that of the forced vibrations.