基于时间反转的玻璃钢复合板材声发射源定位方法

An acoustic emission source location method based on time reversal for glass fiber reinforced plastics plate

玻璃钢复合材料在许多工业领域得到了广泛应用,但是对于该复合材料的声发射动态监测还存在很多问题有待解决。针对玻璃钢复合材料的强各向异性特征,提出一种基于时间反转原理的虚拟加载聚焦增强技术,可应用于声发射源定位。首先按照时间反转原理,推导出虚拟加载过程中的信号聚焦增强技术的理论模型;然后在复合材料上布置传感器阵列,并在监测区域内不同位置进行声速测量,获得材料平均声速为2 432.32 m/s;最后将实验采集的模拟声发射源信号按照理论模型进行处理,计算监测区域内每一个像素点的振动幅值,重建波动幅值图,并以最大幅值处确定为声源位置,同时将波动图经过阈值处理后,可从图中直接看出声发射源的位置。实验结果证明,该方法相对现有声发射仪器,定位精度在4%以内,能够满足工程应用要求。

Glass fiber reinforced plastics(GFRP) has been widely used in many industrial fields. However, there are still many problems to be solved in acoustic emission(AE) dynamic monitoring of the composites. A focusing enhancement technique with virtual loading based on time reversal theory is proposed for the strong anisotropy of GFRP, which can be applied to locate the sound source. First, the theoretical model of signal focusing enhancement technique in the process of virtual loading is derived according to the principle of time reversal. Then, the sensor array are arranged on GFRP, and the sound velocity is measured at different positions in the monitoring area for obtaining the material average sound velocity 2 432.32 m/s. Finally, the simulated AE signals collected in experiment are processed by the proposed model The vibration amplitude of each pixel in the monitoring area is calculated and fluctuation image is reconstructed. The position of the AE source is determined by the maximum amplitude. After threshold processing, the location of AE source can be seen intuitively from the figure. Compared with the existing AE instrument, experimental results show that this method has positioning accuracy within 4%, which can meet the requirements of engineering application.