配管内面の窪み状欠陥に対する高周波ガイド波に関する検討

抄録

It is time-consuming to inspect long pipes in power generation facilities using conventional ultrasonic testing techniques because scanning is necessary. Ultrasonic guided waves potentially provide an attractive solution to this problem because they can propagate several meters once they are excited at one location on the structure. This paper addresses the propagation of high frequency guided wave in a plate and in a pipe, and its interaction with localized wall-thinning on internal surface due to corrosion or erosion. Guided waves were generated in a stainless steel plate and a carbon steel pipe with thickness of 10mm, respectively. The pipe whose diameter is 318 mm contains artificial concave defects with different sizes in order to simulate localized wall-thinning on internal surface. A 2D finite element model was used to simulate wave propagation within the plate, and the characteristics of guided waves were also studied using a 2 MHz conventional transducer. The high frequency guided waves were explored for their capability of detecting and sizing defects.