非连续阻抗粘接结构脱粘缺陷的稀布阵列超声成像  

Thinned array ultrasonic imaging of debonding defects in discontinuous impedance bonded structures

作　　者：张辉 朱文发[1] 范国鹏 张海燕[2] Zhang Hui;Zhu Wen-Fa;Fan Guo-Peng;Zhang Hai-Yan(School of Urban Rail Transportation,Shanghai University of Engineering Science,Shanghai 201620,China;School of Communication and Information Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海工程技术大学城市轨道交通学院,上海201620 [2]上海大学通信与信息工程学院,上海200444

出　　处：《物理学报》2023年第2期144-152,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12104290,11874255,12004240)资助的课题.

摘　　要：无砟轨道是典型的非连续阻抗粘接结构,在重载、环境恶化等因素的影响下,脱粘现象频发,严重危及列车运行安全.本文提出一种高精度阵列超声快速成像方法,建立考虑层间声速差异的非连续阻抗粘接结构声速理论模型,采用射线追踪方法获取声波在介质中的传播路径和时间.基于实数编码设计高自由度稀布阵列,构建稀布阵列合成孔径聚焦技术(synthetic aperture focusing technique,SAFT)成像,提高检测效率.在无砟轨道结构上的实验结果表明:射线追踪方法能够准确计算超声波的传播路径和传播时间,提高检测精度;优化设计的稀布阵列方向图主瓣宽度窄,旁瓣增益低,可提高检测效率和声场指向性;脱粘缺陷成像误差在±5%以内时,稀布阵列SAFT成像方法效率提高了30.9%,可为该类缺陷检测提供理论支撑.Ballastless track is a typical bonding structure with discontinuous impedance.Under the influence of heavy load,deteriorating environment and other situations,the circumstance of debonding occurs frequently and seriously affects the safety of train operation.In this work,a high-precision array ultrasound fast imaging method is proposed.Based on the propagation path and time of sound wave in the medium obtained by ray tracing method,a theoretical model of sound velocity of discontinuous impedance bonding structure is established when the difference in sound velocity among dielectric layers is taken into account.High degree of freedom sparse array based on real number coding as well as synthetic aperture focusing technology(SAFT)imaging method is used to improve detection efficiency.The results of the experiments carried out on ballast less track structure are shown below.The ray tracing method can accurately calculate the propagation path and propagation time of ultrasonic wave and improve the detection accuracy.The optimized thinned array pattern has narrowed the main lobe width and low side lobe gain,which improves the detection efficiency and sound field directivity.The efficiency of thinned array SAFT imaging method is improved by 30.9%when the imaging error of debonding defects is within±5%,which provides a theoretical support fordetecting such debonding defects.

关 键 词：超声成像 稀布阵列 非连续阻抗 脱粘 

分 类 号：TB553[理学—物理] U216.3[理学—声学] TP391.41[交通运输工程—道路与铁道工程]