A contact model for the efficient simulation of abrasive wear of multiphase friction materials

摘要

In this paper we present a routine to predict wear behaviour of multiphase materials commonly used in brake applications. The material selection for friction materials have to take into account numerous influencing factors, partially with strong mutual dependencies. Thus, increasing the life-time based solely on traditional engineering experience is no longer feasible. In order to reduce development cycles in time and cost, a chain of development tools is built, which enables material preselection based on numerical simulations and cost-efficient model tests to reduce the number of prototypes. The wear of the friction materials is determined by its real contact area and thus modelling the contact on the microscale is essential. A statistical numerical model based on the contact mechanics of Greenwood-Williamson is set up for mechanically heterogeneous contacts occurring in inhomogeneous materials. The asperities are assigned to specific material phases whose mechanical response was determined by nano-indentation measurements. External brake conditions like sand particles are incorporated by adapting the contact mechanics model and modifying the contact area and the resulting statistical pressure distribution. These pressure distributions are transferred to a FEM code, which can numerically calculate the wear of the component under various environmental conditions by using wear rates determined for different materials in a model test.