Abstract
Keywords:
Drum Brake Squeal, Non-Linear Contact Analysis, Pressure Distribution, Complex Eigenvalue Analysis
ABSTRACT
An integrated finite element approach is presented which is able to accurately simulate the dynamics at the frictional interface of a leading-trailing shoe drum brake and predict the stability of the assembly. The ANSYS Parametric Design Language (APDL) is utilised to build three dimensional models in terms of parameters and therefore generate alternative geometric configurations in the space of minutes. Non-linear contact analysis is carried out by incorporating flexible-to-flexible, non-linear contact surfaces with elastic friction capabilities to predict the pressure distribution under static and pseudo-dynamic conditions. Finally, the non-linear contact elements are replaced by linear “friction springs” over the predicted area of interfacial contact in order to evaluate the unstable modes of vibration of the system within the frequency range 500 to 5000 Hz by means of a complex eigenvalue analysis. The drum brake squeal phenomenon is shown, through a series of parametric simulations, to be a truly three dimensional problem which is dependent upon the applied pressure, initial installation gap and friction coefficient. The unstable modes predicted in this study were all associated with a diametral mode of the drum in conjunction with a torsional mode of either shoe. The results are in good correlation with the results of experimental dynamometer and on-vehicle testing.