A critical investigation of the unloading behavior of sharp indentation

Finite element simulations of the indentation of rigid indenter into an elastic-plastic half space have been conducted in order to evaluate the influence of material properties on the unloading response. The emphasis of these results has been to determine the load penetration behavior, the development of the contact area and to estimate the hardness and the modulus from load penetration curves. The material parameters are chosen such that the ratio of hardness H and Young's modulus E varies between 0.01 and 0.1. Most of these materials can be regarded as brittle. Since cracking is excluded from the analysis, the results refer to low load penetration. (C) 1997 Acta Metallurgica Inc.