Two-dimensional friction force in brake squeal simulation

摘要

In order to improve the design of disc brakes we currently use Finite Element (FE) and Elastic Multi Body System (EMBS) models. The linear Complex Eigen Value Analysis (CEA) predicts unstable system conditions due to the frictional contact. This linear approach is applicable since we are convinced that mode coupling is the origin of disc brake squeal. Up to the present it was assumed for simulation purposes that friction forces act only in tangential direction. However, our latest measurements exhibit a relative velocity between disc and pad having a significant component in radial direction. Therefore, the paper deals with the impact of the radial component of the friction force upon the disc brake squeal simulation procedure. We carry out the linearisation of the nonlinear 2-dimensional friction force, needed for the CEA. By means of an EMBS model we discuss the result with respect to the friction induced instability.