Modelling of sharp indentation experiments: some fundamental issues

Abstract

Correct interpretation of sharp indentation experiments requires a fundamental understanding of the mechanics involved in the process. Such an understanding can only be achieved if an appropriate mechanical model is used to describe the problem. These models can, in rare cases, be purely analytical, but nowadays numerical modelling is a vital part of the mechanical approach. Furthermore, with the development of new materials and nanoindentation devices, material (constitutive) modelling has becomes very important. The aim of the present paper is to present an overview of the modelling of sharp indentation experiments. Indentation of classical Mises elastoplastic behaviour, in particular, will be considered, in addition to indentation modelling of other types of materials. In addition, some fundamental issues in indentation modelling will be discussed. These issues include (1) the influence from large deformations, (2) differences and similarities between cone and pyramid indentation results, (3) the influence of residual stresses, (4) the effective elastic modulus at indentation and (5) the differences and similarities between indentation and scratch results. Most of these results have been published previously in international journals but their implications, in the author's opinion, have not been fully appreciated by the indentation community or, at least, not debated sufficiently.