An improved line contact model for elastic–plastic rough surfaces

Abstract

In contacts of rough surfaces, the real contact area is much smaller and thus the contact pressure can be far beyond the yield strength of solids. Therefore, the influence of plastic deformation should be quite considerable in practice. In this paper, an improved incremental contact model is proposed to examine the elastic–plastic contact between a self-affine fractal rough surface and a rigid flat under the plane strain condition. For different rough surfaces with various material properties, the load-contact area relations predicted by the present model are in accordance with direct finite element simulations, and show a linear dependence within 15% contact fraction. Compared with the solution of purely elastic contact, the existence of plastic deformation results in a lower mean contact pressure over the real contact area. For rough surface with a small yield strain, the mean contact pressure rises with the yield stress in a power law: P/(E^*A_c) ∝ (σ_y/E^*)^0.89. This study provides an efficient method for contact evaluation of elastic–plastic solids with highly anisotropic rough surfaces.