アコースティック・エミッションの波形解析理論とモーメントテンサー解に関する考察(<小特集>信頼性工学小特集)

概要

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The development of mathematical theory of acoustic emission (AE) is summarized, and a waveform analysis of the moment tensor solution is proposed. On the basis of the theory, vertical surface motions (AE) in the disbonding process of stainless overlay were simulated, determining source characteristics from the observation of a micrograph. It is confirmed that a simulated displacement agrees quite well with a detected AE waveform up to the arrival of reflection waves, including the scale of amplitude. To check the effect of the inclined angle on results of the deconvolution analysis, simulated waveforms were deconvoluted with error on the inclination angle. According to the results, unless the inclination angle is correctly known, the source time functions obtained may include considerable error except for a rise time. It imolies that the determination of crack orientation is of significant importance, before attempting the deconvolution analysis. The applicability of the moment tensor solution was investigated by numerical experiments for inclined tensile and shear cracks. Simulated AE waveforms in a half space were employed, and then components were determined within 8% discrepancy. The results of the eigenvalue analysis show a great promise of the moment tensor solution for determining the crack type and the crack orientation.
1987-09-15