Affiliations: [a] School of Civil and Transportation Engineering, Ningbo University of Technology, Ningbo, Zhejiang, China | [b] School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China
Correspondence:
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Corresponding author: Jiang Xu, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, Hubei, China. Tel.: +86 15872419550; E-mail: [email protected]
Abstract: The flexural mode guided waves of pipes which are sensitive the axial crack and suitable for wave focused gain more attention recently. In this paper, a non-contact flexural mode guided wave transducer based on magnetostrictive effect is provided for pipes. Based on the magnetostrictive transduction principle and the wave structure of the flexural mode guided wave, the sensing method for generating and receiving the flexural mode guided waves based on magnetostrictive effect is obtained. According to the theoretical analysis, a non-contact magnetostrictive transducer for F (3, m) mode guided waves is given. Six permanent magnets which are evenly distributed in the circumferential direction of the pipe and arranged in opposite polarities are employed to provide the bias magnetic field in the circumferential direction. A solenoid coil is employed to induce the axial alternating magnetic field. The bias magnetic field distribution of the flexural mode guided wave in the pipeline is analyzed by the finite element simulation. The mode of the transduction guided wave in the pipe is verified by experiments based on the dispersion curves.
