Receiving performance analysis and optimal design of surface wave electromagnetic acoustic transducers in nonferromagnetic materials

The receiving signals of electromagnetic acoustic transducers (EMATs) are extremely weak, which confines their application in nondestructive testing. A multi-physical finite element model was presented to study the ultrasonic generation and reception processes of surface wave EMATs. Simulation analysis revealed that the receiving performance of EMAT was greatly affected by EMAT parameters. As a consequence, based on the established model and by using orthogonal test method, the EMAT's key parameters that significantly influence the receiving performance were extracted and the geometrical parameters were optimized. After optimization, the peak-to-peak amplitude of induced voltage in EMAT increased to 1.41 times of that in the original EMAT. A meander-line coil with six wires in series was designed, which increased the induced voltage to 3.83 times of the optimized one and the receiving performance of EMAT was greatly improved. The validity of the model and the optimal design method were verified by the experiments.