光热调制的基础温度对光声非线性声信号特性的影响  

Influence of the base temperature of photothermal modulation on the characteristics of optoacoustic nonlinear acoustic signal

作　　者：黄婷婷 张宏超[1] 袁玲[1] 倪辰荫[2] 沈中华[1] HUANG Tingting;ZHANG Hongchao;YUAN Ling;NI Chenyin;SHEN Zhonghua(School of Science,Nanjing University of Science&.Technology,Nanjing 210094,China;School of Electronic and Optical Engineering,Nanjing University of Science&Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学理学院,南京210094 [2]南京理工大学电子工程与光电技术学院,南京210094

出　　处：《无损检测》2022年第8期1-8,共8页Nondestructive Testing

基　　金：国家自然科学基金项目(61975080)。

摘　　要：传统的激光超声无损检测技术已能够实现对宽度为亚毫米量级裂纹的非接触式无损检测,但其对更小的裂纹并不敏感。而非线性激光超声检测技术可实现对微裂纹的无损检测。其中,基于热调制的光声非线性混频技术一直广受学者关注。通过搭建光声非线性混频试验平台,研究光声非线性信号特征与激发源和泵浦源功率之间的关系,讨论了基础温度对非线性现象的影响,研究了基础位移对裂纹非线性机制转变的影响,可为进一步研究光声非线性混频中微裂纹的接触机制提供参考,也为利用光声非线性方法半定量、定量表征裂纹提供了理论依据。The traditional laser ultrasonic non-destructive testing technology has been able to achieve non-contact nondestructive testing of cracks with a width of submillimeter, but it is not sensitive to smaller cracks. However, the nonlinear laser ultrasonic testing technology can realize the nondestructive testing of microcracks. Among them, the nonlinear optoacoustic frequency-mixing technology based on thermal modulation has been widely concerned by scholars. In this paper, an optoacoustic nonlinear frequency-mixing experiment platform was built. On the one hand, the relationship between the characteristics of the nonlinear optoacoustic signal and the power of the excitation source and the pump source was studied. On the other hand, the nonlinear phenomenon affected by base temperature was discussed. Besides, the influences of the base displacement generated by the base temperature on the transformation of the nonlinear mechanism in micro cracks was studied, which will be considered to provide a reference for further research on the contact mechanism of microcracks in nonlinear optoacoustic frequency-mixing technology, and also provide a theoretical basis for the semi-quantitative and quantitative characterization of cracks by using nonlinear optoacoustic methods.

关 键 词：激光超声 非线性混频 微裂纹检测 

分 类 号：TG115.28[金属学及工艺—物理冶金]