EMAT Phased Array System for Plate Inspection

摘要

An eight-channel electromagnetic acoustic transducer (EMAT) phased array detection system is designed and a scanning imaging for a defect in an aluminum plate is obtained using this system. Hand-wound racetrack coils with many turns instead of PCB coils with single turn is applied to design the coil structure of the phased array EMATs, and two coil structures are designed. According to simulation results, the sound pressure of the final EMATs is doubled. A transmitting circuit with high power and high delay precision and a receiving circuit with high gain and low noise are designed. Experiments are completed to verify the simulated field directivity of the phased array EMATs and to obtain a sector scanning imaging of a slot defect on the bottom surface of an aluminum plate.