Drum Brake Contact Analysis and its Influence on Squeal Noise Prediction P. Ioannidis, P.C Brooks, D.C Barton
University of Leeds
Copyright © 2003 SAE International
A non-linear contact analysis of a leading-trailing shoe drum brake, using the finite element method, is presented. The FE model accurately captures both the static and pseudo-dynamic behaviour at the friction interface. Flexible–to-flexible contact surfaces with elastic friction capabilities are used to determine the pressure distribution. Static contact conditions are established by initially pressing the shoes against the drum. This first load step is followed by a gradual increase of applied rotation to the drum in order to define the maximum reacted braking torque and pseudodynamic pressure distribution at the transition point between sticking and sliding motion. The method clearly illustrates the changes in contact force that take place as a function of the applied pressure, coefficient of friction and initial gap between lining and rotor. These changes in contact area are shown to influence the overall stability and therefore squeal propensity of the brake assembly. Dynamometer tests and experimental modal analysis on individual brake components are used to validate the analytical results.
parameters cause changes to the pressure distribution either directly such as changing the applied pressure or indirectly such as the thermal loading. A drum brake operating temperature of 400ºC for example can cause a typical passenger drum brake diameter to increase by 1 to 1.5 mm . This non uniform thermal expansion of the brake components can lead to alternative contact configurations which will result in variation of the brake factor and may also contribute to squeal generation. Hence, the characterisation of the nature of squeal noise as “fugitive” as documented by many researchers is well justified. The parametric studies reported in this paper concentrate on the...