Analytical Correction by Superposition Method for Residual Stress Measured by Surface Removal

Abstract

The measured stress distribution by step-by-step surface removal needs to be corrected by taking into account of the redistribution due to surface removal. In our previous report, we proposed “the direct analysis method”, that is a correction method with the correction matrix obtained by finite element analysis. For the direct analysis method, we prepared multi-layer solids with differential thermal coefficients of expansion, and used the residual stress distribution due to a uniform temperature change in order to determine the correction matrix. However, this method had a problem of poor accuracy where the measured stress was close to zero. In this report, we developed a new correction method “the superposition method” which solves the problem of the direct analysis method, and is applicable to arbitrary stress distributions. For the superposition method, we obtained correction matrices by giving unit pressure to a removal part, focusing on that distressing by surface removal is equivalent to cancel residual stress by giving opposite stress to a removal part. Moreover, we verified validity of the superposition method by comparing with the corrected results by the direct analysis method, and examined the influence of a biaxial stress component.