Theoretical investigations on disc-brake squeal noise

The squeal noise of the brake is a significant problem in vehicles and it has not been solved satisfactorily until recently. It is well known that a squealing brake is more effective than the non-squealing one. However, decreasing this squeal noise during braking is very important for the comfort in driving. A multi-degree-of-freedom mathematical model has been developed to study the effect of different parameters on the brake squeal noise. The model has taken such factors as the distance between clamping bolts of the caliper, the width and thickness of the friction material, which were not included in previous work. The state-space equations developed have been solved using the program MATLAB. The program has been used in this study to calculate the complex eigenvalues, which indicate the natural frequencies and the instability of the system. it is evident from the analysis that squeal noise of the brake decreases with increasing distance between the clamping bolts of the caliper and with the increase in friction material thickness. However the squeal noise increases with increasing the width of the friction material.