電磁超音波センサを用いた最適波形法による鋼管の減肉検査

概要

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Novel technique for detection of thickness reduction in steel pipe is suggested. Velocity of the longitudinal wave, which propagates along length of the pipe, shows the frequency dependence. When the coherent pulse is launched, the dispersion distorts the received signal, the time reversal signal of which can be used as the excitation signal to receive the original coherent pulse. In this study, we first transmit the broadband pulse, being symmetric in the time domain, in the sound section. The time reversal signal is then used as the inspection signal. If the wall thickness is decreased, the consequent change in the dispersion relation reduces the symmetry of the waveform. After verifying the effectiveness of this method by numerical simulation, we apply it to the steel pipe with thin section. To make it possible to generate and detect the longitudinal wave at arbitrary positions, we use the electromagnetic acoustic transducers.
社団法人日本機械学会の論文
2001-07-25