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声发射全波形采集为基于波形分析的声源定位方法提供了可能。声发射源定位方法中最常用的是时差定位方法,因此,时差获取精确与否直接影响定位的精度。借助于小波变换和互相关技术研究声发射信号的时延估计,首先利用小波分析技术对信号进行分解,确定有意义信号的频带宽度,再提取分解后的相应频带的小波系数,利用互相关技术计算出该频带信号到达各传感器的时差,进而利用时差定位法反演声发射源,实现了声发射源更精确的定位。经声发射监测验证结果表明,该时延估计方法能有效地减小声发射源定位的误差,提高声发射源的定位精度,为准确反演声发射源提供了一种有效途径。
Acoustic emission full waveform acquisition provides the possibility of sound source localization based on waveform analysis. Acoustic emission source positioning method is the most commonly used method of time difference positioning, therefore, the accuracy of time-difference access directly affect the positioning accuracy. The time-delay estimation of acoustic emission signal is studied by means of wavelet transform and cross-correlation technique. Firstly, the signal is decomposed by wavelet analysis to determine the bandwidth of the signal of significance, and then the wavelet coefficients of the corresponding frequency band are extracted. By using the cross-correlation technique The time difference between the signals reaching the sensors is calculated, and then the acoustic emission sources are inverted using the time difference positioning method to achieve a more accurate positioning of the acoustic emission sources. The results of acoustic emission monitoring show that the proposed method can effectively reduce the errors of the location of acoustic emission sources and improve the location accuracy of acoustic emission sources. This method provides an effective way to accurately invert acoustic emission sources.