Measuring Material Plastic Properties with Optimized Representative Strain-Based Indentation Technique

Indentation analysis based on the representative strain offers an effective way of obtaining material elastoplastic properties from the reverse analysis of indentation load-displacement curve. In this paper, the formulations of the representative stress and strain are optimized to obtain the best accuracy, while retaining a simple form with only one fitting parameter for determining the yield stress and work hardening exponent. The formulations are valid for a wide parameter space of materials. A simple method of estimating the elastic modulus is also proposed. For ductile materials with relatively small yield strains, the elastic modulus can be estimated from one sharp indentation test, and an explicit analysis may be used to obtain the material plastic properties by using plural sharp indenters.