Simulating the Effect of Insulators in Reducing Disc Brake Squeele

Disc brake squeal is a very complicated phenomenon, and the influence of insulators in suppressing squeal is not fully understood. The aim of this paper is increase the understanding of the effect of insulators. A previous paper [1] presented an experimental technique for measuring the frequency- and temperature- dependent properties of viscoelastic materials currently used in insulators. The present work continues by considering the coupled vibrations of the brake pad and insulator. A comparison of natural frequencies found from experimental modal analysis and finite element modeling indicates agreement to with 5%. Experimentally determined modal loss factors of the brake pad vary dramatically with frequency, changing by a factor of 2 over the frequency range 2-11 kHz. A method for including this frequency dependence, as well as the frequency dependence of the insulator material, in state-of-the-art finite element software is proposed. This method uses forced response vectors from the complete frequency-dependent model to construct a reduced-order model with frequency-independent matrices. Agreement between the complete and reduced models is analytically guaranteed and numerically observed at a number of frequencies in the band of interest.