Finite Element Analysis of Conical Indentation: Proposing a Contact Area Independent Procedure Based on Strain Energy Analysis to Estimate Materials Mechanical Properties

A systematic finite element analysis (FEA) of conical indentation in different isotropic elastic-plastic bulk solids was realized. In particular, the relation between the indentation Hardness (H)-to-Reduced Elastic Modulus (Er) ratio and the Elastic (Ue)-to-Total (Ut) strain energy ratio was studied. Results showed a linear dependency between both ratios as predicted by analytical studies, being the proportionality constant mainly dependent on cone semi-angle(𝜃) and material Poisson´s ratio (𝑣). A well-agreement with experimental data reported in the literature was observed for a wide variety of materials. By a simple analysis of the Oliver & Pharr method and our results, we proposed two analytical equations to calculate the H and E parameters overcoming the indenter contact area (AC) dependence in indentation data analysis. AC independent analytical procedures can become interesting to simplify the data analysis and overcome considerable uncertainties due to possible pile-up effects associated to different plastic deformation phenomena.