利用激光超声技术研究表面微结构材料中瑞利波的传播特性

利用激光超声无损检测的实验方法,观察记录了瑞利波在具有不同表面微结构厚铝板中的传播过程,研究了表面微结构的声传输特性。对具有不同结构参数的微结构样品进行了分组对比实验,结果表明在一定深度范围内,表面微结构具有明显的分频效应。瑞利波中相对高频的部分被反射,反射信号通带带宽主要受制于微结构的深度,其能量主要受微结构宽度影响。相对低频部分沿表面继续传播,因此表面微结构同时具有一定的低通滤波效应。

Laser-ultrasonic investigation on Rayleigh wave propagation in surface micro-structures

The propagation of laser-generated Rayleigh wave on a thick aluminum plate with the surface micro-structure has been investigated by experiment. Experimental results have proved that the surface micro-structure act as a frequency divider for the Rayleigh wave within a certain depth range. The high-frequency part of the Rayleigh wave is reflected. Bandwidth of the reflected pass band is closely related to the depth of the surface micro-structure, and advanced by in-creasing the depth of the micro-structure. The amplitude of the reflected acoustic wave is suppressed by increasing the width of surface micro-structure. The low-frequency part propagates of the Rayleigh wave on the sample surface without disturbance, and the surface micro-structure works as a low-pass filter.