应用小波谱白化法对木材表面声发射源直线定位算法的改进  

Improvement of Linear Positioning of Acoustic Emission Source on Wood Surface by Wavelet Spectral Whitening

作　　者：李晓崧 邓婷婷[2] 王明华 李明[1] Li Xiaosong;Deng Tingting;Wang Minghua;Li Ming(Southwest Forestry University,Kunming 650224,P.R.China)

机构地区：[1]西南林业大学机械与交通学院,昆明650224 [2]西南林业大学,昆明650224

出　　处：《东北林业大学学报》2021年第6期102-106,共5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：针对信号噪声显著影响木材表面声发射(AE)源定位精度的问题,提出了一种应用小波谱白化与信号互相关分析的木材表面AE源直线定位算法。首先,依据ASTM-E976标准采用折断铅芯的方式在木材表面产生模拟声发射源,在试件表面相距固定距离的两个位置采集AE信号,采样频率设定为500 kHz。然后,提出一种应用信号相关度的自适应小波重构算法,用于降低噪声影响并重构AE波形,为了补偿AE传播过程高频部分的衰减,提出了一种小波谱白化重构算法。最后,通过信号相关性分析,计算AE信号到达两个传感器的时差,进而计算AE信号的传播速度,并依据直线定位法计算AE源的位置。试验结果表明:使用原始、自适应小波重构、小波谱白化重构的3种AE信号进行AE源定位时,两组试验的误差分别为42.9%、25.1%、2.5%和37.7%、35%、4.1%。AE信号重构算法将直接影响定位算法精度,特别是使用小波谱白化法能够显著提高AE源定位算法精度。Aiming at the problem that the signal noise significantly affects the positioning accuracy of the acoustic emission source on the wood surface,we proposed a linear positioning algorithm for the AE source on the wood surface using wavelet whitening and signal cross-correlation analysis.First,according to the ASTM-E976 standard,a simulated lead emission source was generated on the wood surface by breaking the lead core,and the AE signal was collected at two positions at a fixed distance from the sensor surface of the test piece,and the sampling frequency was set to 500 kHz.Then,an adaptive wavelet reconstruction algorithm based on signal correlation was proposed to reduce the influence of noise and reconstruct the AE waveform.In order to compensate the attenuation of the high frequency part of the AE propagation process,a wavelet spectrum whitening reconstruction algorithm was proposed.Finally,by signal correlation analysis,the time difference between the AE signals reaching the two sensors was calculated,and then the propagation speed of the AE signal was calculated,and the position of the AE source was calculated according to the linear positioning method.The test results show that when using three kinds of AE signals of original,adaptive wavelet reconstruction and wavelet spectrum whitening reconstruction to locate the AE source,the errors of the two groups of experiments were 42.9%,25.1%,2.5% and 37.7%,35%,and 4.1%.The AE signal reconstruction algorithm would directly affect the accuracy of the positioning algorithm,especially using the wavelet spectrum whitening method can significantly improve the accuracy of the AE source positioning algorithm.

关 键 词：声发射 小波谱白化法 自适应小波重构法 信号相关分析法 

分 类 号：S781.38[农业科学—木材科学与技术]