基于激光超声绕射波能量的微裂纹角度检测  

Detection of Microcrack Angle Based on Laser Ultrasonic Diffraction Wave Energy

作　　者：张晓彤 潘强华[2] 邓进[2] 徐光明[2] 李喆 李海洋 Zhang Xiaotong;Pan Qianghua;Deng Jin;Xu Guangming;Li Zhe;Li Haiyang(School of Information and Communication Engineering,North University of China,Taiyuan,Shanxi 030051,China;China Special Equipment and Research Institute,Beijing 100029,China;AECC Shenyang Liming Aero Engine Co.Ltd.,Shenyang,Liaoning 110000,China)

机构地区：[1]中北大学信息与通信工程学院,山西太原030051 [2]中国特种设备检测研究院,北京100029 [3]中国航发沈阳黎明航空发动机有限责任公司,辽宁沈阳110000

出　　处：《应用激光》2022年第6期69-78,共10页Applied Laser

基　　金：国家自然科学基金项目(11604304,11874386);国家自然科学基金国家重大科研仪器研制项目(61927807);“生物医学成像与影像大数据”山西省重点实验室开放基金项目(KF2020-04);先进制造技术山西省重点实验室开放基金项目(XJZZ202006);无损检测技术教育部重点实验室开放基金项目(EW202180221);中国特检院青年科技基金项目(2018青年08)。

摘　　要：为对工件表面产生的倾斜微裂纹进行检测,从理论上和试验上分析激光产生的宽带瑞利波与矩形铝板上的倾斜角缺陷之间的相互作用。使用瑞利波与倾斜裂纹相互作用产生的透射波、反射波以及在裂纹尖端产生的绕射波来对裂纹角度进行定量检测。通过观察有限元仿真的应力云图,发现瑞利波沿缺陷传播,在缺陷尖端处发生模态转换,有一部分波沿着裂纹绕射到金属表面,部分波反射,还有部分转换成纵波和横波。通过对绕射波信号进行傅里叶变换,得到频谱图并观察绕射波在频域的变化趋势,对绕射波能量进行计算,最终得到绕射波能量随缺陷角度增大而减小,呈e指数衰减分布。将有限元仿真与试验相结合,结果表明,当表面缺陷与表面呈一定倾角时,绕射波能量提取是检测表面裂纹倾斜角的一种有效的方法。In order to detect the inclined microcracks on the surface of the workpiece,this paper analyzes the interaction between the broadband Rayleigh wave generated by the laser and the inclined angle defect on the rectangular aluminum plate theoretically and experimentally.The angle of the defect is measured quantitatively by the transmitted wave,reflected wave and the diffraction wave generated at the crack tip by the Rayleigh wave interacting with the inclined defect.By observing the stress nephogram of the finite element simulation,it is found that Rayleigh waves propagate along the defect,and modal conversion occurs at the tip of the defect.Some waves are diffracted along the crack to the metal surface,and some of the waves are reflected while some are converted into longitudinal and transverse waves.In this paper,through the Fourier transform of the diffracted wave,the frequency spectrum of the diffracted wave is obtained,the trend of the diffracted wave in the frequency domain is observed,and the energy of the diffracted wave is calculated.The energy of the diffracted wave decreases with the increase of defect angle,and it is e exponential decay distribution.Combining finite element simulation with experiments,the results show that when the surface defect and the surface are inclined at a certain angle,the energy extraction of the diffraction wave may be an effective method to detect the inclination angle of the surface defect.

关 键 词：激光超声 无损检测 有限元仿真 斜裂纹 

分 类 号：TB551[理学—物理]