Research Progress of Electromagnetic Acoustic Transducers for Ultrasonic Guided Waves Inspection

Ultrasonic guided waves have been widely applied to the defect inspection of typical waveguide structures including plates and pipes because of their large area inspection capability and high efficiency. As one type of the transducer for ultrasonic guided waves inspection, electromagnetic acoustic transducers (EMAT) attracted wide attention and got rapid development. In this paper, the research progress of EMAT for ultrasonic guided waves inspection in the past twenty years was reviewed. Main contents include the following aspects: the structural design of the single-mode EMAT used in the ultrasonic guided waves inspection of plate-like and pipe structures; the configuration parameters optimization design of coil and magnet for improving the energy and the purity of guided wave modes, the configuration design of new type patch EMAT for non-metallic materials; and the application of array technique on the EMAT performance optimization and defect localization and imaging.