Numerical and experimental study on the effect of considering plastic and elastoplastic deformation of each asperity in dry contact of rough surfaces

Abstract

Contact is one of the main means to transmit force between bodies, and a detailed study of contact mechanics provides the required knowledge toward a realistic prediction of the behavior of contacting bodies. In this study, an approach based on the Greenwood-Williamson model is developed in which all of the contact points on the contacting surfaces are observed momentarily. The surface roughness is experimentally measured. The surface asperities are treated as spline functions, and their properties such as radius of curvature are obtained by differentiating these functions. The response of each individual contact point is evaluated by solving contact equations related to a specific asperity in elastic, elastoplastic, and plastic regimes. The method is therefore called spatially resolved Greenwood-Williamson (SRGW) model. To validate the model, a new technique is used which is based on indentation. A series of indentation experiments are conducted on two contacting surfaces, and the elastic and plastic deformations of the asperities under different loads are measured. The percentage error of the proposed approach is lower compared to other methods such as GW and ZMC, which shows the higher accuracy of this new method. The results show that the presented model can predict experimental results with reasonable accuracy under different contact conditions.