Numerical study of the effect of yield strain and stress ratio on the measurement accuracy of biaxial residual stress in steels using indentation

Abstract

Investigations into engineering structures show that residual stresses in combination with external loads can cause failure in loads which are below the design threshold. As a result, the exact study of the magnitude and distribution of these stresses is an important topic in mechanical engineering. Indentation is a new method for estimating residual stress. To measure non-equibiaxial residual stresses, there is only one reliable method presented by Lee et al. In this paper, the effect of yield stress and different values of residual stress on the accuracy of residual stress measurements in steels with similar work hardening behavior was studied by performing a large number of finite element simulations.Based on these numerical simulations and by studying how the residual stress measurement error of Lee and Kwon’s model changes according the stress ratio and the yield strain, a method is suggested to correct this error and calculate the real amount of non-equibiaxial residual stresses. The procedure is significantly reduces the error of residual stress measurement (from more than 100% to less than 10%) and has been verified by conducting experimental indentation.