Conical indentation of strain-hardening solids

Conical indentation of strain hardening solids is examined within the spherical cavity expansion simulation pattern in finite strain plasticity. Analysis accounts for elastic compressibility and arbitrary strain hardening. Unlike existing studies of indentation processes that assume a definite yield point, the present formulation applies also to smooth elastoplastic transition. Approximate hardness formulae are derived, at different levels of accuracy, and compared with available finite element calculations. Effects of pile-up, or sink-in, and external friction have been ignored. It is suggested that test data over a range of cone angles can be used to reconstruct the axial stress-strain curve. The relation between cavitation and conical indentation is discussed. It is shown that the cylindrical Tresca cavitation yield stress serves as a natural scaling stress in estimating hardness of strain hardening solids. (C) 2007 Elsevier Masson SAS. All rights reserved.