Numerical and Experimental Parameter Studies on Brake Squeal

This paper deals with the analysis of a complete axle of a passenger car, which shows brake squeal in test runs. The complete brake system including the parts of the corner is studied with two different Finite Element Analysis programs and their brake squeal calculation algorithms. Thereby significant differences between the results of the two simulations and also the experiments are observed. The used element type and the chosen discretisation level influence largely the simulated contact and thereby the overall results. In order to explain these outcomes, the force distribution and the force vectors between disc and pad are analysed. On the one hand tetrahedral elements cause stiffening of the parts and hence of the contact. On the other hand the effort to create hexahedral elements in daily meshing practice is often omitted due to cost reasons. This trend is enforced by the statement of software vendors. They provide algorithms for all kinds of elements for treating contact problems. The influence of different meshing and contact variants and their impact on the results has been analysed. This paper underlines the influence of the contact calculation on brake squeal analysis. Once contact calculation is stabilised, geometric and material parameters could be investigated on their significance on the system behaviour in order to avoid parameter-combinations where the chance to enforce squealing is high. Hence further analyses of the actual system are carried out in order to achieve practical results for the design of a brake system, especially in early design phases.