El Youbi F, Grondel S, Assaad J
IEMN, UMR CNRS 8520, Département OAE, Université de valenciennes et du Hainaut Cambrésis, Le Mont Houy, 59313 Valenciennes, Cedex 9, France.
Ultrasonics. 2004 Apr;42(1-9):803-6. doi: 10.1016/j.ultras.2004.01.070.
This work describes an investigation into the development of a new health monitoring system for aeronautical applications. The health monitoring system is based on the emission and reception of Lamb waves by multi-element piezoelectric transducers (i.e., arrays) bonded to the structure. The emitter array consists of three different elementary bar transducers. These transducers have the same thickness and length but different widths. The receiver array has 32 same elements. This system offers the possibility to understand the nature of the generated waves and to determine the sensitivity of each mode to possible damage. It presents two principal advantages: Firstly, by exciting all elements in phase, it is possible to generate several Lamb modes in the same time. Secondly, the two-dimensional fourier transform (2D-FT) of the received signal can be easily computed. Experimental results concerning an aluminum plate with different hole sizes will be shown. The A0-, S0-, A1-, S1- and S2-modes are generated at the same time. This study shows that the A0 mode seems particularly interesting to detect flaws of this geometrical type.
这项工作描述了对一种用于航空应用的新型健康监测系统的开发研究。该健康监测系统基于粘结在结构上的多元素压电换能器（即阵列）对兰姆波的发射和接收。发射器阵列由三种不同的基本条形换能器组成。这些换能器具有相同的厚度和长度，但宽度不同。接收器阵列有32个相同的元件。该系统提供了了解所产生波的性质以及确定每种模式对可能损伤的灵敏度的可能性。它具有两个主要优点：首先，通过使所有元件同相激励，可以同时产生几种兰姆模式。其次，可以轻松计算接收信号的二维傅里叶变换（2D - FT）。将展示关于具有不同孔径铝板的实验结果。同时产生了A0、S0、A1、S1和S2模式。这项研究表明，A0模式对于检测这种几何类型的缺陷似乎特别有意义。
