Analysis of laser generated ultrasonic wave frequency characteristics induced by a partially closed surface-breaking crack
Analysis of laser generated ultrasonic wave frequency characteristics induced by a partially closed surface-breaking crack
复制标题
部分闭合表面破裂裂纹引起的激光产生超声波频率特性分析
DOI：
10.1364/ao.52.004179
复制
发表时间：
2013-06-20
期刊：
影响因子：
1.9
通讯作者：
Shen, Zhonghua
中科院分区：
文献类型：
--
作者：
Li, Jia;Zhang, Hongchao;Shen, Zhonghua
本研究主要分析部分闭合表面破裂裂纹所诱发之超音波频率特性。声波与裂纹相互作用时，发生透射、反射和模态转换，信号的频率特性发生明显变化。脉冲激光线源用于在具有部分闭合的表面断裂裂纹的样品中产生超声波，并且可以看到当脉冲激光束扫描样品表面时检测信号的频率特性如何变化。实验研究了光学偏转束法检测超声波信号的方法。利用快速傅里叶变换（FFT）对时域数据进行分析，并将FFT数据绘制成B扫描图。当激光束直接照射到裂纹上时，可以观察到B扫描中的明显中断，这是由于部分闭合的裂纹引起的频率特性的改变。给出了数值模拟结果的频域B扫描，也可以清晰地观察到明显的破裂。(C)2013年美国光学学会
This research focuses on analyzing the frequency characteristics of ultrasonic waves induced by a partially closed surface-breaking crack. When acoustic waves interact with the crack, transmission, reflection, and mode conversions occur and the frequency characteristics of signals perform obvious changes. A pulsed laser line source is used to generate ultrasonic waves in the sample with a partially closed surface-breaking crack, and one can see how the frequency characteristics of detected signals change as the pulsed laser beam scans across the sample surface. The optical deflection beam method is developed to detect the ultrasonic signals experimentally. The fast Fourier transform (FFT) is used to analyze the time-domain data, and the FFT data are visualized by a B-scan plot. A clear disruption in the B-scan can be observed when the laser beam illuminates directly onto the crack, which is due to the changes of frequency characteristics induced by the partially closed crack. A frequency-domain B-scan of numerical simulation results is presented, and the clear disruption can also be observed clearly. (C) 2013 Optical Society of America