Effect of strain hardening in elastic-plastic transition behavior in a hemisphere in contact with a rigid flat

An axisymmetrical hemispherical asperity in contact with a rigid flat is modeled for an elastic-plastic material on the lines of the Kogut-Etsion Model (KE Model) and the Jackson-Green Model (JG Model). The present work extends the previous KE and JG works, accounting for the effect of realistic material behavior in terms of the varying yield strengths and the isotropic strain hardening behavior. The predicted results show that the transition behavior of the materials from the elastic-plastic to the fully plastic case is influenced by the yield strength and the tangent modulus (Et) and such transition do not take place at specific values of interference ratios as suggested by the KE model. New empirical relations are proposed to determine the contact load and the contact area based on the analysis. Numerical results from the finite element modeling are also validated with an experimental ball on flat configuration approach. (c) 2008 Elsevier Ltd. All rights reserved.