A Comprehensive Elastic-Plastic Single-Asperity Contact Model

Abstract

Generally, the contact of rough surfaces is modeled and analyzed through statistical approaches, including microgeometrical measurements and description of the asperities in contact (shape, size, spacing, and asperity height), developing theoretical expressions to describe the mechanical behavior of the asperities in contact, and finally extending it to the whole surface contacts. In some of the main contact models like the Kogut-Etsion model (KE model), Jackson-Green model (JG model), and Shankar-Mayuram model (SM model), an axisymmetrical hemispherical asperity in contact with a rigid flat surface is modeled and analyzed using finite element concepts and the resultant contact parameter relations are extended to rough surface contacts. The present work addresses the complete effect of Poisson's ratio and its influence in sub surface yielding, elastic-plastic transition and inception of fully plastic contact by accounting realistic material behavior which are not covered by the above models. A unified single-asperity model is proposed and, based on the results, empirical relations are developed to predict the contact parameters (dimensionless contact load and contact area), which are then extended to statistical rough surface contacts.