Ae monitor unit

TLDR: In this article, the phase difference between the receiving detection output of an acoustic emission (AE) sensor 11b and the receiving detecting output of a sensor 11a which is delayed in delay circuit 13 of phase deciding part 15 by prescribed time T1 is decided by deciding circuit 14.

Abstract: PURPOSE:To make it possible to change arbitrarily a monitor section without change of the arrangement interval of sensors, by delaying one of detection outputs of two sets of acoustic emission (AE) sensors by a prescribed time and by deciding the phase difference between this output and the other by comparison CONSTITUTION:The phase difference between the receiving detection output of AE sensor 11b and the receiving detection output of AE sensor 11a which is delayed in delay circuit 13 of phase deciding part 15 by prescribed time T1 is decided by deciding circuit 14, and circuit 14 generates a decision pulse only when the phase of the delayed detection output advances, and generation position P of the AE wave signal is detected by signal processing circuit 16 to monitor the AE wave signal Consequently, only when distance D1 from sensor 11a to detection point P is shorter than distance D1 from sensor 11b, the position of detection point P is detected, and the monitor region is limited to prevent the influence of noise and so on In this case, detection points different in distances D1 and D2 can be determined on the basis of expressions I and II by changing time T1, and the monitor section can be changed arbitrarily without change of the arrangement position of sensors Here, V is the AE wave propagation speed, and L is the delay equivalent distance