Critical evaluation of the indentation data analyses methods for the extraction of isotropic uniaxial mechanical properties using finite element models

Two different definitions of indentation strain and two different definitions of contact radius are being used in the current literature, leading to inconsistent estimates of mechanical properties (especially plastic properties). In this paper, we critically evaluate the validity of the different definitions of both the indentation strain and the contact radius by applying the protocols on datasets generated from a finite element simulation of spherical indentation. The finite element models allow assignment of a wide range of elastic–plastic properties to the sample while circumventing many of the uncertainties faced in experimental investigations, and thereby offer unique opportunities for critical validation of the different data analysis procedures. In particular, we are able to establish important connections between the indentation stress–strain curves and the conventional uniaxial stress–strain curves.