Enhancement of ultrasonic signal using a new design of Rayleigh-wave electromagnetic acoustic transducer

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• 作者：Lei Kang^a ; ^b ; ^{victorkang11@126.com} ; Chao Zhang^a ; Steve Dixon^a ; ^b ; Hui Zhao^a ; Samuel Hill^b ; Menghan Liu^a
• 关键词：Electromagnetic acoustic transducer ; EMAT ; Rayleigh wave ; Meander-line coil ; Finite element simulation
• 刊名：NDT & E International
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：86
• 期：Complete
• 页码：36-43
• 全文大小：1200 K
• 卷排序：86

文摘

The main disadvantage of electromagnetic acoustic transducers (EMATs) is their inefficiency in generating ultrasound. A new design of Rayleigh-wave EMAT is proposed with improved ultrasonic generation efficiency on non-ferromagnetic materials. The new EMAT's magnet is narrower than the meander-line coil used in the transducer and the coil itself has an uneven distribution of conductors. The principle of the new design is informed by finite element simulations, which show that the EMAT generates Rayleigh waves more efficiently by taking advantage of both horizontal and vertical magnetic fields of the magnet simultaneously. Experimental measurements verify that the maximum amplitude of the ultrasonic signal generated by the new design of EMAT working under a pulse-echo configuration has been enhanced by 90%, when compared to conventional designs.