Numerical solution to contact stresses developed during the spherical indentation of elastoplastic solids

This chapter presents a numerical solution (finite element method, FEM) to the contact stresses developed during the nanoindentation of elastoplastic solids. By simulating the indentation processes of elastoplastic materials under a spherical indenter, various contact properties (actual contact depth, contact radius, and contact stress) at the indenter-solid interface are computed. Results show that the FEM solutions are superior to the analytical solutions since they take into account the material pile-ups occurred around the indenter. For materials whose strain hardening index exceeds a threshold (n>0.25), the FEM and analytical solutions predict the same contact stresses.