| 摘要 |
PURPOSE:To remove automatically an effect of longitudinal wave in acoustic emission (AE) signal, by detecting each peak value arriving time of the AE signal from a plurality of AE sensors. CONSTITUTION:Output signals C, F of voltage comparing circuits 3a, 3b comparing envelope wave detecting signals A, D of the No.1 and the No.2 AE, sensors and their peak-hold signals B, E detect time of arrival at the peak value of A, D signals operating thus timers 4a, 4b. Consequently, when the timers 4a, 4b are brought for instance to a standstill automatically at the specified time and count differences are obtained in a computing member, etc., time differences of peak arrival times of the AE signal by the No.1 and No.2 sensors are obtained. When these time differences are supplied for position display of the AE source as time differences of arrival of AE waves of each AE sensor, an effect of longitudinal wave that appears at the leading part of the AE signal is removed and the same precision of position evaluation can be obtained as the case when the time difference is obtained by detecting leading status of the surface wave.
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