박판 음향방출 위치 표정의 오차해석

Abstract

This paper demonstrates how consideration of the modal nature of AE signals can be used to reduce the number of sensors needed in AE source localization. To this end, the theory of the chirplet transform and modal acoustic emission are used to analyze the propagation of elastic waves in thin plates. First, the chirplet transform and the dispersion curves of the fundamental Lamb wave modes are utilized to separate the first-arrived modes and to estimate the distance between a source and a sensor. Then an analytical model is developed to simulate their late-arrived wave packets. Finally, the correlation between the experimental and the simulated waveform is used to estimate the location of AE source. To validate the proposed source localization algorithm, experiments were performed on a steel plate using the Hsu-Nielsen pencil lead break (PLB) test. Results show that the proposed algorithm can effectively localize AE source regardless of the location of the sources.