COMPARISON OF THROUGH-WALL-CRACKED PIPE AND COMPACT TENSION SPECIMEN CYCLIC J-R CURVES

摘要

As part of the IPIRG-1 program, a series of nominal 6-inch diameter, Schedule 120, circumferential through-wall-cracked (TWC) cyclic pipe experiments were conducted. An A106 Grade B carbon steel and a TP304 stainless steel pipes were used. These tests were conducted in displacement control at various cyclic load ratios. From these experiments, it was found that the apparent fracture toughness of the material was severely degraded at a stress ratio of -1. As part of the IPIRG-2 program, a series of cyclic compact tension (C(T)) specimen experiments were conducted. The C(T) specimens were manufactured from the same heat of pipe as the TWC pipes, and similar loading conditions were used. The purpose of this investigation was to determine if the small-scale specimen results showed the same amount of toughness degradation and whether these results could be used to make accurate predictions of the cyclic circumferential TWC pipe moments. Cyclic J-R curves from both the pipe and C(T) experiments were compared and a series of fracture predictions using the cyclic C(T) results were compared to the circumferential TWC experimental moments. The results show that the cyclic C(T) and TWC pipe experiments produced the same relative amount of toughness degradation at a stress ratio of-1. Also, using the cyclic C(T) results in a series of fracture prediction models provided reasonable predictions of the cyclic moment response for the circumferential TWC pipe.