Relationship between Stress Intensity Factors and Residual Stress Distributions Evaluated from Discontinuous Displacements along a Mixed-Mode Crack.

Abstract

n linear fracture mechanics, stress intensity factors controlling the fracture behavior of materials are calculated from stress distributions acting on the crack surfaces, with the aid of superposition even for remote applied stresses. A method of evaluating such stress distributions has been proposed by the authors. It is assessed from each mode-discontinuous displacement along a crack with mode I and II components. In this study, the previous calculation method restricted within constant sress fields was developed to nonuniform stress fields so as to be applied to fatigue cracks with residual stresses in the wake of the propagation. By using this method, local stress distributions controlling the crack deformation and stress intensity factors KI and KII for the fatigue crack were predicted under a mixed-mode stress condition, and effects of residual stresses near the fatigue crack on the mode II crack deformation were discussed.