基于菱形光纤布拉格光栅传感阵列的声发射定位技术

Acoustic emission location based on diamond FBG sensor array

声发射技术是结构损伤检测的重要手段,声发射源定位是损伤检测的首要环节。时差定位技术具有快速、高效、精确的特点,以此设计了由菱形阵列光纤布拉格光栅(FBG)传感器构成的声发射定位系统。采用小波变换和传统阈值法提取特征信号,结合互相关法获得传感器间的信号到达时差,然后根据几何定位模型求解非线性方程组得到声源可能存在的位置,最后根据时差的正负特性进一步确定声源的准确位置,有效避免了伪声源的情况。在铝合金板上,以对角线为48 cm×48 cm的监测区域进行了10组测试实验验证,平均误差为1.29 cm。

Acoustic emission（AE） technology is an important method for structural damage detection, and AE source location is the most important part of the damage detection. The TDOA location method has the advantages of fast, high efficient and more accurate. An acoustic emission location system based on diamond Fiber Bragg Grating （FBG） sensor array was designed. Wavelet transform and traditional threshold method were used to extract feature signal, and the cross-correlation method was used to obtain the arrival time difference between different sensors. Then, the possible AE source was determined by solving nonlinear equations of the geometric model. Finally, the actual AE source was determined according to the feature of time difference. This location system can effectively avoid the pseudo AE source. The 10 groups of test data were carried out in the monitoring area with the diagonal of 48 cm× 48 cm of the aluminum alloy plate, and the average error was 1.29 cm.