Abstract
The fundamental shear horizontal(SH0) wave has several unique features that are attractive for long-range nondestructive testing(NDT). By a careful design of the geometric configuration, electromagnetic acoustic transducers(EMATs) have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal(SH) waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet(PPM) EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SH0-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern of PPM EMATs, and can be used for their parameter optimization.
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This project is supported by National Natural Science Foundation of China(Grant Nos. 51075012, 10772008), and Beijing Municipal Natural Science Foundation of China(Grant No. 1122005)
MA Qingzeng, born in 1971, is currently an engineer at Electric Power Research Institute of Guangdong Power Grid Corporation, China. He received his master’s degree on thermal power engineering at Wuhan University of Hydraulic and Electricity, China, in 1996.
JIAO Jingpin, born in 1973, is currently a professor at Beijing University of Technology, China. He received his PhD degree in mechanical engineering in Beijing University of Technology, China, in 2005. Her research interests include transducers and measurements, and nondestructive testing techniques, such as guided wave, phased array, and nonlinear ultrasonic.
HU Ping, born in 1973, is currently an engineer at Electric Power Research Institute of Guangdong Power Grid Corporation, China. She received her PhD degree in materials processing engineering in South China University of Technology, China, in 2001.
ZHONG Xi, born in 1988, is currently a master’s candidate at Beijing University of Technology, China.
WU Bin, born in 1962, is currently a professor at Beijing University of Technology. He received his PhD degree from Beihang University, China, in 1997. His research interests include mechanical engineering, and ultrasonic nondestructive testing techniques.
HE Cunfu, born in 1958, is currently a professor at Beijing University of Technology. He received his PhD degree from Tsinghua University, China, in 1996. His research interests include mechanical engineering, and ultrasonic nondestructive testing techniques.
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Ma, Q., Jiao, J., Hu, P. et al. Excitation and detection of shear horizontal waves with electromagnetic acoustic transducers for nondestructive testing of plates. Chin. J. Mech. Eng. 27, 428–436 (2014). https://doi.org/10.3901/CJME.2014.02.428
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DOI: https://doi.org/10.3901/CJME.2014.02.428