Fracture behaviors and acoustic emission characteristics of pipes with local wall thinning

Fracture behaviors of pipes with local wall thinning are very important for the integrity of power plant piping system. The locally wall thinned phenomenon of pipes is simulated as metal loss due to erosion/corrosion (E/C). Acoustic emission (AE) has been widely used in various fields because of its extreme sensitivity, dynamic detection ability and location of growing defects. In this study, monotonic bending tests without internal pressure are conducted on 1.91 inch diameter full-scale carbon steel pipe specimens. Locally wall thinned shapes were machined to be different in size along the circumferential direction of straight pipes. We investigated failure modes of locally wall thinned pipes and evaluated AE signals by AE counts, accumulative counts and time-frequency analysis during the bending test.