基于超声导波波束成形的缺陷反演方法研究  

Defect Inversion Method Based on Ultrasonic Guided Wave Beamforming

作　　者：武靖昌 张应红[1] 钱智 马智勇[1,2] 李鹏 李翔宇[3] 钱征华 WU Jingchang;ZHANG Yinghong;QIAN Zhi;MA Zhiyong;LI Peng;LI Xiangyu;QIAN Zhenghua(National Key Laboratory of Aerospace Structural Mechanics and Control,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China;The Fourth Military Representative Office of the Naval Armament Department Stationed in Nanjing,Nanjing 211100,China;Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]南京航空航天大学航空航天结构力学及控制全国重点实验室,南京210016 [2]海装驻南京地区第四军事代表室,南京211100 [3]西南交通大学应用力学与结构安全四川省重点实验室,成都610031

出　　处：《南京航空航天大学学报》2023年第3期497-506,共10页Journal of Nanjing University of Aeronautics & Astronautics

基　　金：南京航空航天大学研究生创新基地(实验室)开放基金(kfjj20200105);国家自然科学基金(11972276,12061131013,12172171);航空航天结构力学及控制全国重点实验室自主课题(MCMS-I-0520G01);广西制造系统与先进制造技术重点实验室项目(17-259-05-005Z);应用力学与结构安全四川省重点实验室开放课题(SZDKF-202002)。

摘　　要：利用超声导波对板结构中的缺陷进行反演可以确定缺陷的位置和形状信息,针对走时成像方法在低频范围内效果不佳的问题,提出一种基于波动场的超声导波缺陷反演成像方法。根据波动方程推导出波束成形成像原理,利用Born近似下的散射场数据对成像区域像素点的值进行相干叠加,得到缺陷的位置和形状。再通过波束成形与傅里叶衍射定理在频域的映射关系,将波束成形的结果转化为衍射层析成像图像,得到了更为清晰的反演图像。针对衍射层析成像中存在伪影和噪声的问题,利用二维变分模态分解(Two-dimensional variational mode decomposition,2D-VMD)方法对图像进行降噪处理,有效去除了伪影和缺陷轮廓边缘的毛刺,进一步提高了成像分辨率。反演结果表明该方法可以较为准确地重构出铝板上减薄缺陷的位置、大小和形状,具有较高的分辨率。The position and shape information of defects can be determined by using ultrasonic guided wave to invert the defects in the plate structures.Aiming at the problem that the travel time imaging method is not effective in the low frequency range,an ultrasonic guided wave defect inversion imaging method based on wave field is proposed.According to the wave equation,the imaging principle of beamforming is derived,and the scattering field data in Born approximation are used to coherently stack the values of pixels in the imaging area to obtain the position and shape of defects.Through the mapping relationship between beamforming and Fourier diffraction theorem in frequency domain,the results of beamforming are transformed into diffraction tomography images,and some clearer inversion images are obtained.Aiming at the problems of artifact and noise in diffraction tomography,the two⁃dimensional variational mode decomposition(2D⁃VMD)method is used to denoise the images,which can effectively remove the artifact and the burr of defect contour edge,and further improve the imaging resolution.The inversion results show that the proposed method can accurately reconstruct the location,size and shape of the thinning defects on the aluminum plate with high resolution.

关 键 词：固体力学 超声导波 缺陷反演 波束成形 衍射层析成像 二维变分模态分解 

分 类 号：TB559[理学—物理]