Finite element determination of the absolute magnitude of an ultrasonic pulse produced by an EMAT

Electromagnetic acoustic transducers or EMATs for short, are investigated in transmitting mode for nonferromagnetic conducting materials. Two different finite element (FE) formulations, derived from different definitions of source current density, are compared. A differential equation based on an incomplete equation for the source current density is solved analytically for the magnetic vector potential (MVP). To validate the FE results, one-dimensional (1D) analytical solutions are used. An EMAT example containing six source conductors is also modeled. The FE results are compared with results obtained from existing methods for two EMAT meander coil conductor sizes. The results show the importance of using the complete equation for the source current density in the modeling of EMATs, in order to properly account for skin and proximity effects.