A hybrid finite element model for spiral coil electromagnetic acoustic transducer (EMAT)

摘要

This paper discusses finite element modeling of spiral coil electromagnetic acoustic transducer (EMAT) to generate bulk waves. First, a 2D electromagnetic model is developed for calculating the Lorentz force density, which is the driving force for sound wave generation within the material. Second, the calculated force at each point in the material is used as the driving force for generating sound wave modes. This model is used to predict the ultrasonic A-scan signals of bulk (longitudinal and shear) waves in isotropic homogeneous material. Spiral coil EMATs of two different coil spacings are developed for experimental studies. The model predicted results are validated by experimental results and for this, the ratio of amplitude of shear wave to longitudinal wave is used.