A Brake Model with Thermoelastic Disc for the Analysis of Vehicle Judder Vibrations

Abstract

Friction braking is necessarily related to high thermal loads which may cause problems such as hot spotting and the associated hot judder phenomenon. The driver may experience brake judder as vibrations in the frequency range below 100 Hz in the steering wheel, brake pedal and floor. It is state-of-the-art to investigate the thermal and thermoelastic behaviour of brakes in elaborate finite element studies, which provide high resolution results but require a high computational effort. As a consequence, thermal and thermoelastic issues could not be considered so far in brake models intended to be used for a system-dynamical analysis of the complete vehicle that may necessary to set up control strategies such as electronic stability programs. With this backgrouns, the article introduces a new method to model brake discs and to account for their thermal amd thermoelastic behaviour while braking in a very efficient way. Effects such as the temperature dependency on friction and the change of contact conditions between the disc and the pad caused by thermal and mechanical influences may be considered with much less computational effort and an acceptable accuracy when compared with the finite element method.