Antisymmetric Lamb Wave Simulation Study Based on Electromagnetic Acoustic Transducer with Periodic Permanent Magnets

Lianren Du; Ruizhen Gao; Xiaojuan Jia

doi:10.3390/s23167117

Antisymmetric Lamb Wave Simulation Study Based on Electromagnetic Acoustic Transducer with Periodic Permanent Magnets

Sensors (Basel). 2023 Aug 11;23(16):7117. doi: 10.3390/s23167117.

Authors

Lianren Du¹, Ruizhen Gao¹, Xiaojuan Jia¹

Affiliation

¹ College of Mechanical and Equipment Engineering, Hebei University of Engineering, Handan 056038, China.

Abstract

Due to its multi-mode and dispersion characteristics, Lamb waves cause interference to signal processing, which profoundly limits their application in nondestructive testing. To resolve this issue, firstly, based on the traditional EMAT, a horizontal polarization periodic permanent magnet electromagnetic acoustic transducer (HP-PPM-EMAT) was proposed. A 2-D finite element model was then developed to compare magnetic flux density, Lorentz force, and signal strength between the traditional EMAT and the HP-PPM-EMAT. The simulation results show that the HP-PPM-EMAT enhances the A0 mode Lamb wave (A0 wave) and suppresses the S0 mode Lamb wave (S0 wave). Finally, the influence of structural parameters of the HP-PPM-EMAT on the total displacement amplitude ratio of A0 and S0 was investigated using orthogonal test theory, and the width of magnet units was improved based on the orthogonal test. The results show that the total displacement amplitude ratio of A0 to S0 of the improved HP-PPM-EMAT can be improved by a factor of 7.74 compared with that of the traditional Lamb wave EMAT, which can produce higher-purity A0 mode Lamb waves.

Keywords: Lamb wave; electromagnetic acoustic transducer; mode; periodic permanent magnet; total displacement amplitude ratio.

Grants and funding

This work is supported by the National Natural Science Foundation of China (No. 12002115), the Natural Science Foundation of Hebei Province (Grant No. F2020402005), the Scientific and Technological Research Projects of Universities in Hebei Province (Grant No. QN2020181), and the Science and Technology Research and Development Project of Handan City (Grant No. 19422101008-8).