基于Lamb波频散特性的声发射源平面定位新方法

针对传统的声发射源平面定位中各传感器灵敏度差异和门槛值设置不同对时差定位精度影响较大的问题，通过研究弹性波在薄板中传播的特性即Lamb板波频散特性，借用模态声发射的概念将单个传感器接收到的信号利用Gabor小波时频分析得到不同模态的峰值到达时间，并在引入速度因子概念的基础上，讨论了两种不同的声发射源平面定位方法，即同一频率不同模态的定位方法和同一模态不同频率的定位方法，试验证明两种方法都能得到模拟源的正确定位，不仅从根本上避免了传感器间灵敏度差异对时差定位精度的影响，而且还可以减少平面定位中传感器的数量，避免三角形定位中伪定位的出现，并适用于传统的声发射源平面定位中不易布置传感器阵列的结构健康无损监测。

New Methods of Planar Location of Acoustic Emission Source Based on the Dispersive Characteristics of Lamb Wave

In order to solve the problem that different sensitivities among various sensors and threshold settings have a great influence on the accuracy of arrival time-difference location in traditional location of acoustic emission source, two new approaches of planar location are presented based on the research of dispersive characteristics of Lamb wave, arrival time of different modes determined by using the peak of the magnitude of Gabor wavelet timefrequency analysis on the view of modal acoustic emission and introduced velocity factor. One method of location is based on the same frequency and different modes and the other is based on the same mode and different frequency. The two methods whose accuracy is demonstrated by experiments can solve the proposed problem completely, reduce the number of sensors in planar location, avoid false location in traditional triangular location and be used to monitor structures which are not feasible for the traditional method of source location.