College of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, China.
Sensors (Basel). 2020 Jun 2;20(11):3151. doi: 10.3390/s20113151.
As an impact-source-localization technique, Lamb waves are commonly used to detect low-velocity impact in composite structures. However, the performance of Lamb waves is susceptible under deformation conditions. In this paper, a novel approach combined the Toeplitz approximation method (TAM) and multiple-signal classification (MUSIC) (TAM-MUSIC) to improve impact-source-localization (angle and distance in polar coordinates) accuracy under deformation conditions. The method divided a two-dimensional search of direction and distance into two one-dimensional searches. The impact direction was calculated by the TAM, which was introduced into the steering vector of MUSIC to estimate the distance by scanning the whole monitoring area. An epoxy laminate plate experiment showed that the phase and amplitude of uniform linear-array signals had different average plate curvature that led to poor impact-source-localization accuracy using the MUSIC method. TAM provided high-resolution direction-finding capability, suitable for the pretreatment of Lamb waves. Results showed that the present method, with a small amount of computation and low memory requirement, had higher location-estimation accuracy than that of traditional methods under deformation conditions.
作为一种冲击源定位技术，兰姆波常用于检测复合材料结构中的低速冲击。然而，兰姆波的性能在变形条件下容易受到影响。本文提出了一种新的方法，将 Toeplitz 逼近法（TAM）和多重信号分类（MUSIC）（TAM-MUSIC）相结合，以提高变形条件下冲击源定位（极坐标中的角度和距离）的准确性。该方法将二维方向和距离搜索分解为两个一维搜索。通过 TAM 计算冲击方向，将其引入 MUSIC 的导向矢量中，通过扫描整个监测区域来估计距离。环氧树脂层压板实验表明，均匀线列信号的相位和幅度具有不同的平均板曲率，这导致使用 MUSIC 方法时冲击源定位精度较差。TAM 提供了高分辨率的测向能力，适合兰姆波的预处理。结果表明，与传统方法相比，该方法在变形条件下具有计算量小、内存需求低的优点，具有更高的定位估计精度。
