Element analysis of instrumented sharp indentations into pressure-sensitive materials

Finite element analysis was carried out to investigate the conical indentation response of elastic-plastic solids within the framework of the hydrostatic pressure dependence and the power law strain hardening. A large number of 40 different combinations of elasto-plastic properties with n ranging from 0 to 0.5 and sigma(y)/E ranging from 0.0014 to 0.03 were used in the computations. The loading curvature C and the average contact pressure pave were considered within the concept of representative strains and the dimensional analysis. Dimensionless functions associated with these two parameters were formulated for each studied value of the pressure sensitivity. The results for pressure sensitive materials lie between those for Von Mises materials and the elastic model.