摘要
采用有限元法研究了脉冲激光激励表面波在表面缺陷近场不同归一化深度的反射系数,验证表面波在缺陷近场处的信号增强现象。同时,通过对反射系数随距离变化的分析,建立反射信号增强区域半径的概念,并发现信号增强区域半径与表面缺陷的深度有关,拟合得到表面缺陷深度测量公式并分析矩形缺陷宽度对深度测量的影响,修正了测量表面缺陷深度的公式。此外,根据反射系数随缺陷深度变化的现象,分析归一化深度与表面波波长的关系。研究结果表明,利用反射系数测量缺陷深度时存在短波限制,也就是当表面波波长小于缺陷深度一半时,反射系数为与缺陷深度无关,此时反射系数为0.4。
The reflection coefficients of surface waves excited by pulsed laser at different normalized depths in the near field of surface defects were studied using finite element method,and the signal enhancement phenomenon of surface waves at the near field of defects was verified.At the same time,by analyzing the variation of reflection coefficient with distance,the concept of the radius of the reflection signal enhancement region was established,and it was found that the radius of the signal enhancement region is related to the depth of surface defects.A formula for measuring the depth of surface defects was fitted;We also analyzed the influence of rectangular defect width on depth measurement and corrected the formula for measuring surface defect depth.In addition,based on the phenomenon of reflection coefficient changing with defect depth,the relationship between normalized depth and surface wave length was analyzed.The research results indicate that there is a shortwave limitation when using reflection coefficient to measure defect depth,which means that when the surface wave length is less than half of the defect depth,the reflection coefficient is independent of the defect depth,and at this point,the reflection coefficient is 0.4.
作者
李海洋
许家玮
邓江
潘强华
李喆
Li Haiyang;Xu Jiawei;Deng Jiang;Pan Qianghua;Li Zhes(Shanghai Acoustics Laboratory,Chinese Academy of Science,Shanghai 201815,China;Shanri Provincial Key Laboratory of Advanced Manufacturing Technology,North University of China,Taiyuan 030051,Shani,China;Jiaring Hengtai Special Equipment Testing Co.,Ltd.,Jiaxing 31420l,Zhejiang,China;China Special Equipment Testing and Research Institute,Beijing 100029,China;Shenyang Liming Aero Engine(Group)Co.,Ltd.,Shenyang 1100o0,Liaoning,China)
出处
《应用激光》
CSCD
北大核心
2023年第10期170-178,共9页
Applied Laser
基金
国家自然科学基金国家重大科学仪器研制项目(61927807)、国家自然科学基金项目(11604304,11874386)
山西省基础研究计划面上项目(202203021221099)
“生物医学成像与影像大数据”山西省重点实验室开放研究基金资助项目(KF2020-04)
先进制造技术山西省重点实验室开放基金(XJZZ202006)
无损检测技术教育部重点实验室开放基金项目(EW202180221)
中国特种设备检测研究院内部科研项目(2022青年11)。
关键词
激光超声
表面波
近场分析
深度检测
laser ultrasound
surface wave
n
ear field analysis
depth detection
