FRACTURE ANALYSES OF SURFACE-CRACKED PIPES AND ELBOWS USING THE LINE-SPRING SHELL MODEL/

The line-spring/shell model proposed by Rice and Levy (1972) and furth er modified by Parks and co-workers (1981, 1982, 1995) provides an att ractive and inexpensive alternative to analyzing surface-cracked struc tures. This model idealizes the complex three-dimensional surface crac k problem in a plate-or shell-like structure as a more tractable two-d imensional problem. Though used in some previous studies, this model h as largely been ignored in the study of surface-cracked nuclear piping components. While it is true that the line-spring method has some res trictions, it can provide reasonably accurate predictions of important fracture parameters of cracked components within the domain of its ap plicability. Through some detailed studies of surface-cracked pipes an d elbows, the predictive nature of the line-spring model is demonstrat ed by comparing its predictions with that of a three-dimensional finit e element model as well as with experimental measurements. Excellent c omparisons between the predictions of the line-spring/shell and three- dimensional finite element models are shown not only using the three-d imensional finite element calculations performed by the author, but al so using the three-dimensional calculations performed by two other ind ependent investigators. It is hoped that the results shown in this pap er invalidate the criticisms and reestablish the usefulness and reason able accuracy of the line-spring model, within its domain of applicabi lity, in the analyses of surface-cracked structures. (C) 1998 Elsevier Science Ltd. All rights reserved.