참조 응력법을 활용한 관통균열이 존재하는 곡관의 J 평가

Reference stress-based approximate J estimation of elbow with intrados circumferential through-wall cracks under in-plane opening bending are reported in this paper. To find the reference stress-based approximate J, non-linear three-dimensional finite element analyses using elastic-perfectly plastic materials are performed. Then validity of that estimation of circumferential through-wall cracked elbow under given condition is evaluated. Also, effects of the elbow geometry and crack lengths are systematically investigated. Results are presented in the failure assessment diagram(FAD) space. If optimized reference moment was taken into consideration, reference stress-based J values are closed together with slight dependency on not only elbow geometry but also crack lengths.