Determination of the profile of the complete residual stress tensor in a VPPA weld using the multi-axial contour method

Abstract

The multi-axial contour method is a recent development of the contour method of stress measurement. It permits measurement of the 3D residual stress distribution in a body, based on the assumption that the residual stresses are due to an inelastic misfit strain (eigenstrain) that does not change when a sample containing residual stresses is sectioned. The eigenstrain is derived from measured displacements due to residual stress relaxation when the specimen is sectioned. By carrying out multiple cuts, the full residual stress tensor in a continuously processed body can be determined, where the specimen has an initial length-to-width aspect ratio of 2:1. In the present study, first a finite element simulation of the technique was carried out to verify the method numerically. The method was then used to determine the residual stresses in a VPPA-welded sample, and the results were validated by neutron diffraction measurements.