点聚焦表面波EMAT声场特性及其试验

基金项目:

国家自然科学基金资助项目（51705231，51265044，51705232）；江西省优势科技创新基金资助项目（20171BCB24008）

详细信息

Sound Field Characteristics of a Focused Rayleigh Wave EMAT and Its Experimental Research

Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University, Nanchang 330063, China

摘要: 针对曲折线圈电磁超声换能器（EMAT）换能效率和信噪比低的问题，建立了点聚焦EMAT的三维声场有限元模型，通过瞬态和稳态分析，分析了激励频率、线圈匝数和导线长度对点聚焦EMAT的声场聚焦特性以及缺陷回波特征的影响规律。搭建了0.5 MHz点聚焦EMAT检测系统，用于铝板中不同直径的圆孔检测，并与传统的曲折线圈EMAT进行对比。结果表明：采用点聚焦表面波EMAT，可以极大程度地提高信噪比和缺陷检测能力。
- 点聚焦表面波 /
- 电磁超声 /
- 声场特性 /
- 信噪比
Abstract: The conversion efficiency of a meander coil EMAT is extremely low. In order to solve the problem, a three-dimensional finite element model for the sound field of a focused Rayleigh wave EMAT was established. Based on the transient and steady-state analysis, effects of excitation frequency, coil turns and length of the coil conductor on focusing characteristics and reflection echoes of defects were discussed. A 0.5 MHz point-focused surface wave EMAT was developed to detect holes of various diameters in aluminum, and it was also compared to a traditional meander coil EMAT. Result shows that signal-to-noise ratio (SNR) and flaw detectability can be greatly enhanced by a point-focused Rayleigh wave EMAT.
- point-focused Rayleigh wave /
- EMAT /
- sound field characteristics /
- signal-to-noise ratio

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