Remaining life assessment and optimal design of statically indeterminate pipe system with circumferential crack

This paper examines the J-R curve theory in elastic-plastic fracture mechanics and crack extension resistance in order to analyze the large-scale yielding of statically indeterminate pipe structure with a circumferential crack. The dJ/da characteristic can be utilized to measure that the crack is stable ductile fracture or unstable ductile fracture and to analyze the crack growth rate. The total propagation time of the crack until collapse can be computationally estimated by numerical analysis that is presented in this paper. The further analysis of dJ/da and optimization is to maximize the crack propagation time during the crack growth before reaching plastic collapse. Both of the center-point crack and end-point crack are investigating cases for analyzing the mechanics and engineering design. These analysis and design strategies developed in this paper are useful for the safety performance of a structural pipe under crack deformation.