ACOUSTIC EMISSION LOCATOR OF DEFECT IN A CLOSED STRUCTURE

摘要

Three acoustic emission sensors placed at 120 deg. intervals around the periphery of the tube are followed by amplifiers and comparators supplied from a common DC potentiometer. The outputs of the three comparators are applied to logic circuits which encode the order of arrival of an acoustic wave, originating from a flaw, at the respective emission sensors. The logic outputs control the pulsation and phasing of four waveform generators connected to deflection electrodes acting on the two beams of the oscilloscope, so that the traces rotate in opposite directions.