Theoretical fringe analysis for a coherent optics method of residual stress measurement

Abstract

In this paper, the theoretical relationships between relieved in-plane displacements and residual stresses, which are needed for data reduction in a moiré interferometric version of hole drilling method, are obtained. The analysis includes the case of linearly varying biaxial stresses. The theoretical relationships are then used for generating on a computer the corresponding moiré interferometric fringe patterns thus simulating the experimental response under known loading conditions. Various effects due to the degree of residual stress biaxiality, the strength of the linear stress term, the direction of sensitivity of the moiré grid, and the value of the Poisson's ratio are illustrated.