Radiation pattern of lamb waves generated by electromagnetic acoustic transducers

Radiation pattern is an important characteristic of Lamb waves when applied to nondestructive testing and evaluation. However, this character cannot be analyzed by 2-D analytical or numerical models. In this paper, a 3-D finite element (FE) model is presented and frequency domain analysis is used to study the acoustic field of Lamb waves generated by electromagnetic acoustic transducers (EMATs). Based on the FE model, the divergence angle of S0 Lamb wave is calculated to be 6.6°. Experiments are carried out to measure the in-plane displacements of Lamb waves and experiment results agree well with the simulation results.