EFFECTS OF MULTI-SCALE STRUCTURE AND FRACTAL DIMENSION ON THE FRICTION MECHANISM IN ROUGH SURFACES UNDER HORIZONTAL DYNAMIC EXCITATION

Abstract

Tribological information obtained for contacts with multiple-asperity interaction is a challenging task. In this work, the friction mechanism that is developed between rough interfaces with asperities of different geometry and different scales, submitted to cyclic loading, is studied. In order to analyze numerically the behavior of the asperities, fractal interpolation functions are used for the simulation of the interfaces and the deformations of the asperities are assumed to go through elastic to plastic deformations. In the sequence, the fractal interfaces are submitted to different acceleration histories until the plastification of the asperities and the sliding of interfaces. The dynamic response of the system is computed by using finite element modeling (FEM) technique on the basis that the opposite sides of the interfaces present the same multi-scale structure. From the study, it becomes obvious that sliding instabilities characterize the problem and the fractal dimension of the interface together with the multi-structure of the asperities, the normal pressure and the dynamic excitation play important roles in determining the dynamic friction coefficient, which in this work is studied macroscopically.