A Method to Apply the Reference Stress Approach to Simplified Estimates of Inelastic J-integral Under Displacement-Controlled Loading

Abstract

In the assessment of structural integrity and remaining life of a power component operated at high temperatures, evaluation of crack-like damage is frequently required. When estimating crack propagation rates under creep-fatigue loading, J-integral type inelastic fracture mechanics parameters including elastic-plastic J-integral for elastic-plastic body and creep J-integral for creeping body are needed. Although these parameters may be estimated by detailed inelastic finite element analysis of a cracked component, this kind of analysis is usually laboring and costly. Therefore, employing simplified methods such as the reference stress approach is practical. Since the reference stress approach has been developed for an inelastic body subjected to external loading, a method to apply this to a component under secondary stress has not been established. This paper proposes an approach to apply the reference stress method to a cracked component subjected to displacement-controlled loading together with a clear definition of elastic follow-up factor