Oblique effects on J integral of cracked plate under plastic fatigue loading based on inelastic Fe analysis

This paper describes the features of J integrals for cracked plates under plastic loading. The inelastic FE analysis incorporating the accurate constitutive equation provides the detailed inelastic deformations, and leading to show the J integral for cracked plates. The FE analysis can give the detailed inelastic deformations so as to produce the accurate J integral. In the present paper, the plate having the straight crack located in the center of the plate, and the plate with one circular hole in the center having the crack at the hole side extending vertically with a slightly oblique direction. The loadings are assumed to be both of monotonic and cyclic force-controlled loading and cyclic displacement-controlled loading. The strain and stress contours are obtained, and effects of different types of force and displacement-controlled loading are investigated in relation to J integral development. The effects of oblique cracks, which are observed in the fatigue test at the elevated temperature, will also be studied from the detailed FE analysis