%A Pan HE, Chao LU, Wenze SHI, Ying ZHU, Guo CHEN, Liping ZHAO %T Comparation of reception performance of EMATs in laser ultrasonic surface detection of aluminum alloys %0 Journal Article %D 2023 %J Acta Aeronautica et Astronautica Sinica %R 10.7527/S1000-6893.2022.28085 %P 428085-428085 %V 44 %N 16 %U {https://hkxb.buaa.edu.cn/CN/abstract/article_19441.shtml} %8 2023-08-25 %X

Meander-line coil Electromagnetic Acoustic Transducer (EMAT), linear coil in-plane EMAT, and linear coil out-of-plane EMAT are often used to receive ultrasonic waves in the laser-EMAT Rayleigh Wave (RW) detection of aluminum alloy plate. However, the reception performance and applications of these three types of EMATs remain unclear. Therefore, a finite element model of the laser-EMAT RW detection process for aluminum alloys was first established, and the effects of three types of EMAT configurations on the energy of RW, shear wave, and longitudinal wave modes of ultrasonic were analyzed. Secondly, the effects of the surface constraint mechanism on the RW amplitude and its purity were studied, and the surface defect detection capability of the three types of EMATs was explored. Finally, three types of EMAT probes were made, and RW detection experiments were carried out with laser-EMAT on aluminum alloy plates. The influence of the surface constraint mechanism on the amplitude of each mode of ultrasonic waves received by the three types of EMATs and the ability of surface defect detection was analyzed. The results show that compared to the linear coil in-plane EMAT, the meander-line coil EMAT and linear coil out-of-plane EMAT receive a higher purity RW and are more suitable for surface defect detection. The multi-mode ultrasonic wave received by the linear coil in-plane EMAT is obvious, which is shown to be more suitable for simultaneous detection of surface/internal defects. Compared to the non-surface constraint mechanism, the RW amplitude of three kinds of EMATs can be enhanced more than two times by using the surface constraint mechanism, with the enhancement of the RW amplitude of the meander-line coil EMAT being the most significant. Compared to the laser-linear coil in-plane EMAT without a surface constraint mechanism, the laser-linear coil out-of-plane EMAT with a surface constraint mechanism can increase the received DW amplitude by more than 6 times.