基于光纤光栅阵列和MVDR算法的声发射定位

基于光纤光栅(FBG)传感器网络构建了声发射检测系统,并提出了最小方差无失真响应(MVDR)的声发射源定位方法。构建的系统由7个FBG传感器组成传感器线阵列,采用未经平坦的放大自发辐射(ASE)光源边缘滤波实现信号解调。利用Shannon小波变换从频散复杂的声发射信号中提取窄带信号,并基于MVDR算法扫描整个监测区域获取空间谱。根据空间谱函数计算输出值,并将计算的输出值作为像素值。最后,通过提取空间谱中的最大值的坐标确定声发射源的位置。在LY12铝合金板上进行了实验验证。结果表明,该方法在400mm×400mm的区域内,声发射定位的最大误差为9.4mm,平均误差为7.2mm,耗时小于3s。该系统具有较高的实时性和定位精度,是一种声发射源定位的新方法。

Acoustic emission location based on FBG array and MVDR algorithm

An Acoustic Emission(AE) detection system based on a Fiber Bragg Grating(FBG) network was constructed and an AE location system by using Minimum Variance Distortionless Response(MVDR) algorithm was designed. In this system, linear FBG array constituted by seven FBGs was used to detect AE signals, and the edge filter technology using an unflatted Amplified Spontaneous Emission(ASE) source was applied to signal demodulation. Shannon wavelet transform was employed in extracting narrow signals of AE signals with complex frequency dispersion and the spatial spectrum could be obtained by canning over the monitoring area with the MVDR algorithm. The spatial spectrum function was used to calculate output values and the values were used as pixels. Finally, the AE source location was determined by the peak of spatial spectrum of MVDR. The system was verified on a LY12 aluminum alloy plate. The result shows that the maximum error and average error are 11.4 mm and 8.2 mm in a 400 mm×400 mm monitoring area, respectively, and the average consumed time is less than 3 s. The system has higher real time ability and location accuracy, and is a new AE location technology.