Application of Wavelet Packet Transform to Acoustic Emission Source Location in Thin Plates
نویسندگان
چکیده
To improve the accuracy of acoustic emission (AE) source location, the wavelet packet transform is proposed to process the AE signals in this paper. The AE waves change shape due to the dispersion characteristics when they propagate in thin plates. Therefore, with the conventional method for AE source location by calculating arrival time differences based on the threshold crossing, the result is greatly affected by the level of threshold voltage and the measured value of wave velocity. To solve this problem, the wavelet packet transform was employed to isolate a single frequency from the output waveform of each sensor. Then the time differences due to propagation of this frequency component and the velocity of this frequency component were used for the location analysis. With this method the location error caused by the dispersion characteristics was decreased. Experiments using a pencil lead break as the AE source were carried out on a composite plate. The results proved this method is efficient.
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