Fracture Tests of Flat Plate and Pipe With Non-Aligned Multiple Flaws

Fracture tests of flat plates and pipes with non-aligned multiple flaws were conducted to investigate an appropriate flaw characterization rule for ductile fracture evaluation. Worldwide fitness-for-service codes, such as the JSME Code and the ASME Boiler and Pressure Vessels Code provide flaw characterization rules for flaws detected by in-service inspection. Since the flaw characterization rules seems to be determined based on linear-elastic fracture mechanics, developing appropriate rules remains a ductile fracture evaluation issue. Although experimental approaches have been attempted to establish an evaluation method for ductile fractures of non-aligned multiple flaws, further efforts are required. Hence, this study deals with expanding the experimental data of a flat plate subjected to tensile load and a pipe subjected to bending load. Each specimen was given one, two, or three through-wall flaws by electrical discharge machining. The tensile tests of flat plate specimens and the 4-point bending tests of pipe specimens were conducted to observe the collapse behavior and obtain load-displacement relationships. Flaw interactions, which depend on the distances between two flaws, were observed from the test results. The experimental data to investigate an evaluation method were expanded by performing fracture tests on the flat plate and pipe specimens.