Stress Intensity Factor Analysis and Fatigue Behavior of a Crack in the Residual Stress Field of Welding

摘要

This paper deals with the behavior of a crack in the residual stress field induced by butt weld in a wide plate. It is known that the distribution pattern of residual stress is similar regardless of welding process, though the size and the magnitude of the residual stress depend largely on the welding process. Stress intensity factor and stress redistribution induced by the crack extension were calculated for a crack with arbitrary length and location. The stress redistributions caused by crack extension obtained by the present analysis showed good agreement with the experimental data. Fatigue crack propagation behavior in the residual stress field reported by Glinka was also examined from the △K point of view. In this paper, the effect of residual stress on the fatigue crack propagation rate is considered to be the effect of varying mean stress. The concept of △Keff, where the effect of residual stress is accounted as the correction factor by the way of simple superposition, is shown to predict the crack growth rate with sufficient accuracy.