On the Three Dimensional J Integral Evaluation in the Inelastic and Transient Stress Fields

In applying the methodology of the fracture mechanics for the reactor technology, the three dimensional evaluation of the parameter of fracture, J integral, is needed because of the complexity of the boundary conditions. Recently several papers have been published on the three dimensional crack problems in the elastic-plastic states, and the numerical methods to evaluate the three dimensional J integral have been studied [1,2]. In general, the reactor vessel is under thermal transient loadings and the cladding is deposited on the inner surface of the vessel wall. Then the general formulation of the three dimensional J integral is not available and some modifications are needed. A paper on transient loading was carried out by Aoki et al [3], and for the multi-phase problem, Kikuchi [4] extended the J integral definition.