Disc Brake Squeal Investigation and Friction Characterization Using Wavelet Transform 2005-01-0789

We propose a method based on wavelet transform for the investigation of disc brake squeal and characterization of contact forces between disc and pad. It is shown experimentally that friction coefficient is time dependent and can be considered as a combination of a deterministic component superimposed by a random one. Discrete wavelet transform (DWT) is applied to decompose, filter, and separate deterministic and random frequency components in time domain. Parameters such as power spectral density and probability density function of the random components are determined. Wavelet modulus and wavelet ridge are used to investigate the spectral properties of the pad acceleration and contact forces. Instantaneous frequencies components and correlations with modal characteristics of the disc and pad are identified.