应用小波谱白化对胶合木表面AE源定位算法的改进  

Improvement of AE Source Location of Wood Surface Using Wavelet Spectral Whitening

作　　者：李晓崧 邓婷婷[1] 赖菲 李明[1] Li Xiaosong;Deng Tingting;Lai Fei;Li Ming(Southwest Forestry University,Kunming 650224,P.R.China)

机构地区：[1]西南林业大学,昆明650224

出　　处：《东北林业大学学报》2021年第8期117-121,125,共6页Journal of Northeast Forestry University

基　　金：国家自然科学基金项目(31760182,31100424);云南省教育厅科学研究基金项目(2020Y0376)。

摘　　要：针对声发射(AE)信号在胶合木板表面各向异性传播时的AE源定位问题,提出一种小波谱白化与信号相关性分析相结合的胶合木板表面AE源定位算法。首先,根据ASTM-E976标准在橡木胶合木板表面产生AE源,并在橡木胶合木板表面相距固定距离的4个位置采集原始AE信号,设置采样率为500 kHz。其次,采用小波谱白化算法减少胶层的影响以及合理补偿AE信号的高频缺失,为降低噪声信号的影响,提出一种自适应的小波重构算法。最后,依据试验结果拟合得到AE信号由胶合木板顺纹理方向到横纹理方向的传播速度变化公式,在此基础上根据信号相关性分析法计算信号到达各传感器的传播时差,并采用基于时差的定位算法确定AE源的位置。结果表明:使用原始、自适应小波重构法、小波谱白化法重构的3种AE信号进行定位时,两处AE源的定位结果为100.0%、67.1%、6.0%和41.5%、66.3%、2.8%。AE信号的重构算法直接影响基于时差的AE源平面定位算法精度,特别是使用小波谱白化法能够有效降低噪声信号、胶层的影响,合理补偿AE信号的高频缺失,提升信号分辨率,同时提升计算时差的准确性进而提升AE源定位精度。In order to study the problem of AE source localization when acoustic emission(AE)signals propagate anisotropically on the surface of plywood,an AE source localization algorithm for plywood surface combining wavelet whitening and signal correlation analysis is proposed.First,according to the ASTM-E976 standard,an AE source is generated on the surface of the oak plywood,and the original AE signal is collected at four positions at a fixed distance from the surface of the oak plywood,and the sampling rate is set to 500 kHz.Secondly,in order to reduce the influence of the glue layer and reasonably compensate for the high frequency loss of the AE signal,a wavelet spectrum whitening algorithm is proposed.To reduce the influence of the noise signal,an adaptive wavelet reconstruction algorithm is proposed.Finally,according to the experimental results,the formula for the change of the propagation speed of the AE signal from the grain direction of the plywood along the grain direction to the horizontal grain direction is obtained.The propagation time difference of the signal reaching each sensor is calculated according to the signal correlation analysis method,and the time difference based on the time difference is used.The positioning algorithm determines the location of the AE source.The test results show that when using the original,adaptive wavelet reconstruction method and wavelet spectral whitening method to reconstruct three AE signals for positioning,the positioning results of the two AE sources are 100.0%,67.1%,6.0%and 41.5%,66.3%,2.8%.The reconstruction algorithm of the AE signal directly affects the accuracy of the AE source plane positioning algorithm based on the time difference.In particular,the use of the wavelet spectrum whitening method can effectively reduce the influence of the noise signal and the glue layer,reasonably compensate for the high frequency loss of the AE signal,and improve the signal resolution.At the same time,the accuracy of the calculated time difference is improved for the positioning a

关 键 词：声发射 胶合木板 小波谱白化法 自适应小波重构法 信号相关分析法 AE源平面定位 

分 类 号：S781.38[农业科学—木材科学与技术]