通过正交异性压电(Orthotropic Piezoelectric Composite Materials,简称OPCM)传感器与普通压电(PZT)传感器的传感特性比较,证明了OPCM传感器对同平面内相互正交的AE信号具有不同的响应特性.基于OPCM传感器的这一特性,将其作为结构健康诊断系统中的声发射传感器,可减少结构侧面等边界反射的影响,有效保留损伤和/或缺陷的有用信息.结合Gabor小波时频分析方法和透射波法,能增强声发射技术探测结构损伤的能力,并减少了测试仪器的通道数量,为实用的结构健康诊断提出了新的思路并建立了相关的理论模型.
By comparing the sensing characteristics of OPCM (OrthOtropic Piezoelectric Composite Materials) sensors with that of PZT sensors, different frequency response characteristics of OPCM sensors to planar orthotropic stress waves are verified by using FEM and experimental results. Based on these characteristics, the OPCM sensors are adopted as acoustic emission sensors in a SHM (Structure Health Monitoring) system to reduce the influence of lateral boundary reflections, etc. and reserve most useful information about damage and/or defects effectively. In addition, the damage detecting capacity of the system is improved and the number of channels of the system is reduced by using Gabor wavelet time-frequency analysis, OPCM sensors and the transmission method. The technique in this paper paves a new way to a practical SHM system, and a corresponding theoretical model is also proposed.