Simulation of ultrasonic and EMAT arrays using FEM and FDTD

• We combine an EM model with an ultrasonic model for EMAT simulation.
• Frequency domain simulation (FEM) and time domain simulation (FDTD) linked together.
• Radiation pattern obtained with Hilbert transform on time domain waveforms.
• Various wave modes observed with the proposed method.

This paper presents a method which combines electromagnetic simulation and ultrasonic simulation to build EMAT array models. For a specific sensor configuration, Lorentz forces are calculated using the finite element method (FEM), which then can feed through to ultrasonic simulations. The propagation of ultrasound waves is numerically simulated using finite-difference time-domain (FDTD) method to describe their propagation within homogenous medium and their scattering phenomenon by cracks. Radiation pattern obtained with Hilbert transform on time domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle.