Effect of Coil Configuration on Conversion Efficiency of EMAT on 7050 Aluminum Alloy

Compared to traditional ultrasonic detection methods, the electromagnetic acoustic transducer (EMAT) technique can be applied in many hostile environments such as elevated temperatures, on-line inspections, etc. However, the EMAT technique has a low conversion efficiency. This paper develops a numerical model to study the effects of the coil configurations on the conversion efficiency of shear-wave EMAT on 7050 aluminum alloy. The numerical model is fully validated by the experiment data. The effects of the configuration parameters, including the coil wires’ cross-sectional area, coil wires’ cross-sectional shape, and distance between coil wires, on the conversion efficiency are then discussed. The results indicate that after using the coil with a square cross-section, the conversion efficiency of EMAT is increased by 22.5%. In addition, the coil wires’ cross-sectional area and the distance between coil wires also have a significant effect on the conversion efficiency.