Finite element analysis of wear and its effect on squeal generation

Abstract

In the past, wear at the pad interface of disc brakes has rarely been accounted for in studies of brake squeal using the finite element method, and its effect on disc brake squeal has been investigated largely through experimental methods. In the present paper, wear taking place at this interface over time is simulated using a modified wear rate formula. The surface topographies of two new and unworn pairs of brake pads are measured. The same brake pads are tested under braking applications of three time durations. For each braking application, the static contact pressure distribution is measured using pressure-indicating film. The results are used to compare with the simulated results predicted by the three-dimensional finite element model of a real disc brake. The paper also investigates squeal generation due to the above braking applications using complex eigenvalue analysis that is available in a commercial software package. It is found that the predicted unstable frequency is very close to the observed squeal frequency and that they take place in the same braking duration.