X-Ray Measurements of Residual Stress in the Whole Cross Section of a Plate

Abstract

Distribution of residual stress in a plate may be determined by the stress analysis using X-ray. In this connection, the present authors propose two kinds of method to obtain two principal components of residual stress in a plate. A plate having residual stress is electrolysed only on one side to remove thin layers successively, and two methods are applied to it for obtaining two principal components of residual stress. One of them consists of that the residual stresses are calculated from the stress distributions in two principal directions measured by using X-ray on the electrolysed surface successively (front surface method). In the other method, residual stress distributions are calculated from the stresses successively measured by using X-ray on the surface opposite to the electrolysed or chemically etched surface (back surface method). In these two methods, theoretical formulas are derived respectively from the corresponding integral equations of Volterra type. As examples of the two methods proposed by the present authors, principal components of residual stress in a thin steel plate are measured, and the results are compared with those obtained by the usual methods, curvature method and strain gauge method.