A novel method to extract the equi-biaxial residual stress and mechanical properties of metal materials by continuous spherical indentation test

Abstract

In this present paper, a novel method was proposed to extract the equi-biaxial residual stress, yield strength and strain hardening exponent of metal materials from the load-displacement curve by continuous spherical indentation test. A representative strain independent on strain hardening exponent was introduced to establish the relationship between residual stress, material properties and indentation parameters by dimensional analysis. The representative strain and dimensionless function at different penetration depths were determined through analyzing the results obtained from finite element (FE) simulations. Then based on the reverse analysis algorithm, three unknown parameters were estimated from the corresponding dimensionless functions. The optimal combination of three different indentation depths was confirmed by comparing the relative errors of each dimensionless equation at different depths. At last the effectiveness and reliability of the proposed method were verified by analyzing the numerical simulation data and the actual results of two typical materials (S45C and API X42).