Abstract
In the transportation industry, the development of friction materials is mainly based on an industrial feedback with empirical methodologies. If the use of heterogeneous materials can meet the different features required (high friction, low wear, mechanical strength…), the understanding of the role of each component on the mechanical behavior and so their influence on the dynamical aspect is an essential step to improve the performance of friction materials. Recently (1), it has been shown that surfaces and heterogeneities existing in friction pad are influential on the dynamic excitations and the risk of instabilities. Thus, in this paper, a physical approach is proposed in order to consider explicitly the greatest heterogeneity: the porosity. At first step, a friction pad has been characterized by a topographical study using Xray. This step permit to obtain some informations concerning the porosity (orientation, localization, number, etc.). In a second step, a simplified test bench is modeled using finite element analysis considering initially homogeneous friction material and secondly heterogeneous friction material including the pores. The pores distribution are generated using a representative random fields technique. At conclusion, some difference on dynamical aspect appears between homogeneous and heterogeneous materials.
KEYWORDS Friction induced vibration, Material heterogeneities, Finite element method, Morphological generation.