Institute of Technology and Science, The University of Tokushima, Tokushima 770-8506, Japan.
Ultrasonics. 2012 Apr;52(4):530-5. doi: 10.1016/j.ultras.2011.11.005. Epub 2011 Dec 13.
This paper describes a novel approach to the simultaneous measurement of the phase and group velocities of Lamb waves based on images of their propagation. The laser-generation based imaging method was first introduced to obtain images of Lamb wave propagation. The time series of snapshot images is used to make a position-time diagram, and the velocities can be estimated based on the slopes of the position curves. Thus, the phase and group velocities can be obtained by measuring the phase advance and energy flow of the Lamb wave, respectively. Details of the principle of simultaneous measurement are presented herein. Experimental verification was also performed in the range of 0.2-3.0 MHz-mm using aluminum plates. The average errors between experiment and theory in the phase and group velocities were 3.31% and 5.68%, respectively.
本文提出了一种基于兰姆波传播图像的同时测量兰姆波相速度和群速度的新方法。首先介绍了基于激光激发的成像方法来获取兰姆波传播的图像。利用快照图像的时间序列制作位置-时间图，并根据位置曲线的斜率来估计速度。因此，可以通过测量兰姆波的相位超前和能量流来分别获得相速度和群速度。本文详细介绍了同时测量的原理。还在 0.2-3.0 MHz-mm 的范围内使用铝板进行了实验验证。相速度和群速度的实验值与理论值的平均误差分别为 3.31%和 5.68%。
