A comparison of 3D finite element simulations for Berkovich and conical indentation of fused silica

Much of our understanding of elastic-plastic contact mechanics as it relates to the interpretation of nanoindentation data comes from two-dimensional, axisymmetric finite element simulations of conical indentation. In many instances, conical results adequately describe real experimental results; however, there are instances where conical simulations fail to capture important behaviour. Three-dimensional finite element simulations of Berkovich triangular pyramidal indentation of fused silica are compared to similar simulations with a 70.3° cone. It is shown that a potentially significant difference between the two indenters exists for the contact areas and contact stiffnesses. Implications for the interpretation of nanoindentation data are discussed.