OS6-2 ガイド波を用いた局所減肉検査における測定パラメータの検討(OS6 設備診断・運用保全技術,循環型社会における動力エネルギー技術)

Abstract

In order to detect small local wall thinnings, it is strongly expected to excite guided waves with higher frequency. In this report, the analysis of wave propagation in a plate with thickness of 10mm is performed with the finite element method and is verified with a plate specimen with the same thickness, which shows that it is possible to excite guided waves to propagate in such a plate at the frequency of 2MHz when a shear oblique transducer with refraction angle of 45 degrees is used. The detection of artificial defects introduced in the plate specimen is performed by guided waves with frequency of 2MHz. The SN ratio of the reflected echo from these defects at the frequency of 2MHz is larger at least 5.6dB than that at the frequency of 0.3MHz reported previously, which results in detecting small defects easily that is difficult for guided waves with frequency of 0.3MHz.