Simplified J-Evaluation method for flaw evaluation at high temperature - part 1: systematization of evaluation method

摘要

J-integral is an effective inelastic fracture parameter for the flaw evaluation of cracked components at high temperature. The evaluation of J-integral for arbitrary crack configuration and arbitrary loading condition can be generally accomplished by detailed numerical analysis such as finite element analysis, howeve,r it is time-consuming and requires a high degree of expertise for its implementation. Therefore, it is important to develop simplified J-estimation techniques from the viewpoint of indstrial requirements. In this study, a simplified J-evaluation method is proposed to estimate the J-integral and its variant types of parameters; J-integral to describe ductile crack propagation, and fatigue J-integral range and creep J-integral to describe creep-fatigue crack propagation behavior. This paper presents the systematization of the simplified J-evaluation method incorporated with the reference stress method and the concept of elastic follow-up, then proposes a comprehensive evaluation procedure. The verification of the proposed method is presented in Part II(Shimakawa et al., 2000) of this paper.