Abstract The traditional electromagnetic acoustic longitudinal wave transducers possess low energy conversion efficiency as well as weak horizontal bias magnetic field which cannot be fully utilized, resulting in a modest echo signal and affecting the accuracy of the detection. In this paper, a new type of longitudinal wave transducer is applied, whose permanent magnet poles are arranged according to the Halbach array, which can significantly intensify the horizontal magnetic field. Aiming to improve the echo signal, the finite element software was used, and the orthogonal test and uniform test methods were operated respectively. The parameters of the transducer were optimized with considering the number of coil turns. The simulation results illustrate that reducing the spacing, width, and height of the wire can enhance the echo signal, maintaining the lift-off distance of the permanent magnet within a proper range can also be so. Make the sound attenuation and voltage amplitude at a appropriate level is conducive to detection by setting a proper excitation frequency. The experimental results demonstrate that the echo amplitude of the optimized transducer is 83 % higher than that of the previous transducer.
Cai Zhichao,Li Yibo. Optimum Design of Electromagnetic Acoustic Longitudinal Wave Transducer Based on Halbach Array[J]. Transactions of China Electrotechnical Society, 2021, 36(21): 4408-4417.
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2021, Vol. 36 
