光纤光栅传感网络的冲击定位方法

针对航空航天层合板结构冲击与振动监测的需求,提出一种基于小波包分解方法和分布式光纤光栅传感网络的板状结构低速冲击辨识方法。根据四边固支板结构的承载形式与光纤光栅传感器的感知特性,设计合理的传感器网络布局,再利用快速傅里叶变换(fast Fourier transformation,简称FFT)与小波包分解对光纤光栅传感网络监测到的冲击响应信号进行时频域分析,获取能表征冲击特性的时域特征分解信号。在此基础上,分别计算出每一个特征分解信号与其对应的时域原始信号之间的互相关系数,并将其做为相似度分配权值,分解出所有样本冲击点对应冲击响应信号的特征分解信号,构建样本信息库。利用Haudorff距离计算测试信号与样本信息库各个信号之间的相似度,并根据相似度来确定冲击点的位置坐标。研究表明,该方法能够实现对航空航天层合板结构低速冲击位置的辨识。

Research on Impact Location by Using Fiber Bragg Grating Sensor Network

In view of the demand of monitoring the impact and vibration of laminated composite plates, a new method of low speed impact identification based on wavelet packet decomposition and distributed fiber Bragg grating sensing network is proposed. The sensor network layout is designed according to the load form of clamped plate structure and the sensing characteristics of fiber Bragg grating sensor. Then, the impact response signals monitored by fiber Bragg grating sensor network are analyzed by the fast Fourier transformation and wavelet packet decomposition to obtain the time domain characteristics of impact characteristics. On this basis, the mutual correlation coefficient between each characteristic decomposition signal and its corresponding time domain original signal is calculated to be the weight of the similarity. The characteristics of the impact response signals of all samples are decomposed, and the sample database is constructed. Finally, the location coordinates of impact points are determined according to the similarity calculated based on the Haudorff distance between the test signal and the sample information. The research shows that this method can realize the identification of the low speed impact position on the structure of the laminated plates.