用于测厚和裂纹检测的正交横波电磁超声换能器仿真分析及实验研究  

Simulation and Experiment of Orthogonal Shear Waves with Electromagnetic Acoustic Transducer for Thickness Measurement and Crack Detection

作　　者：刘继伦[1,2] 刘素贞[1,2] 金亮[1,2] 张闯[1,2] 杨庆新[1] Liu Jilun;Liu Suzhen;Jin Liang;Zhang Chuang;Yang Qingxin(State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology,Tianjin,300130,China;Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province Hebei University of Technology,Tianjin,300130,China)

机构地区：[1]省部共建电工装备可靠性与智能化国家重点实验室(河北工业大学),天津300130 [2]河北省电磁场与电器可靠性重点实验室(河北工业大学),天津300130

出　　处：《电工技术学报》2022年第11期2686-2697,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51777052,51977058)。

摘　　要：垂直入射的横波在测厚时具有较高的灵敏度,但检测裂纹常需采用斜入射方式,单个换能器无法同时进行这两种检测。该文设计了一种正交横波电磁超声换能器(EMAT),通过两个蝶形线圈在铝板中激发正交偏振的横波,提出在脉冲回波模式下利用两个线圈接收信号的声时信息和幅值差,同时进行测厚、检测裂纹并确定裂纹方向的方法。建立正交偏振EMAT三维有限元模型,对横波声场与裂纹缺陷的相互作用进行仿真,研究线圈间距、裂纹尺寸对正交声场和信号幅值差的影响。仿真和实验结果表明:正交横波EMAT通过一次检测可以同时实现测厚、裂纹检出及裂纹方向定位,为腐蚀减薄和裂纹等缺陷的在线检测提供了新方法。Shear waves have high sensitivity when measuring thickness in vertical incident direction,but oblique incidence probes are required in crack detection.The two tasks can not be finished with a single transducer at the same time.In this paper,firstly,an electromagnetic acoustic transducer(EMAT)of orthogonal shear waves is designed.It permits the excitation of two orthogonal polarized shear waves in an aluminum plate using two butterfly coils.Then a methodology for simultaneously measuring thickness,detecting cracks and determining the direction of cracks using the time of flight and amplitude difference of the back-wall reflection recorded with the two coils in the pulse echo mode is proposed.A 3-D FE model of the orthogonal EMAT is established,and the wave field generated by the EMAT and its interaction with a crack in the plate are simulated.The effect of coil spacing on the symmetry of the wave field is studied and the influence of crack size on the amplitude difference of received signals is analyzed.Finally,the experimental results showed that good performance of thickness measurement,crack detection and determination of crack direction simultaneously using the orthogonal EMAT,which make the technique a potential new method for online inspection of corrosion thinning and crack defects.

关 键 词：偏振横波 厚度测量 裂纹检测 正交电磁超声换能器 

分 类 号：TB552[理学—物理]