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激光阵列用于改善声表面波信噪比的数值研究
引用本文:刘津升,徐振华,顾国庆.激光阵列用于改善声表面波信噪比的数值研究[J].激光技术,2011,35(3):403-406.
作者姓名:刘津升  徐振华  顾国庆
作者单位:1.南京航空航天大学 金城学院, 南京 211156;
摘    要:为了改善激光超声检测中声表面波的信噪比,利用对激光线源进行时间和空间上的调制获得激光阵列作为激励源辐照铝板表面,采用有限元法分别模拟了大位移幅值声表面波(巨声表面波)的激发以及巨声表面波与铝板表面矩形缺陷相互作用的过程。结果表明,激光阵列经过时间调制后辐照铝材料上激发出的声表面波,其垂直于表面方向的位移幅值与阵列中线源个数成线性比例;且巨声表面波与表面缺陷作用后所产生的反射回波的位移幅值也随着线源个数的增多得到明显增大。模拟结果对在激光超声检测中应用激光阵列提高声表面波的信噪比提供了理论依据。

关 键 词:激光技术    无损检测    有限元法    激光阵列    声表面波    信噪比
收稿时间:2010-10-16

Numerical study on improvement of signal-to-noise ratio of surface acoustic waves based on laser array
LIU Jin-sheng,XU Zhen-hua,GU Guo-qing.Numerical study on improvement of signal-to-noise ratio of surface acoustic waves based on laser array[J].Laser Technology,2011,35(3):403-406.
Authors:LIU Jin-sheng  XU Zhen-hua  GU Guo-qing
Abstract:In order to improve the signal-to-noise ratio (SNR) of surface acoustic waves (SAWs) in laser ultrasonic test, laser array, obtained by the temporal and spatial modulation of the line sources, was used to irradiate on the aluminum plate, and the physical processes, including the generation of SAWs (giant SAWs) with huge displacement amplitude and the interactions between the giant SAWs and the surface breaking crack were simulated by means of the finite element method. The numerical results demonstrate that the displacement amplitude of the giant SAWs generated by the laser array increases in proportion with the number of laser array elements. Besides, the amplitude of the reflected SAWs, generated by the interactions between the giant SAWs and the surface breaking crack, is also increased as the numbers of the line sources increased. The results can provide some hints for the utilization of the thermoelastic laser array to improve SNR of the SAWs.
Keywords:
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