Reference Stress Approach for Fracture Assessment of Extrados Circumferential Through-Wall Crack at the Interface between Elbow and Pipe Subjected to Internal Pressure

Abstract

The fracture assessment of a cracked component can provide a technical support for an effective maintenance and a prevention of catastrophic accident. The present study applies the reference stress method to extend the J-integral solution from the finite element analysis for the Ramberg-Osgood stress-strain relationship to other types of stress-strain relationship. The problem in this study is an extrados circumferential through-wall crack at the interface between elbow and pipe subjected to internal pressure. The finite element results from the literature were analyzed to determine the optimized reference pressure. The reference-stress-based failure assessment curve which incorporated with the obtained reference pressure can be used to estimate the finite-element-based failure assessment curve with a sufficient accuracy in fracture assessment. The failure load predicted from the reference-stress-based failure assessment curve deviated from that predicted from the finite-element-based failure assessment curve within the range of -7% to 11%.