Simulations of ultrasonic guided waves with use of combined Finite Element and Finite Difference Methods

This paper presents an approach to simulate Lamb wave propagation with use of both Finite Element (FE) and Finite Difference (FD) methods. In the work selected modes of Lamb waves were generated in a model of a plate with bonded Interdigital Transducer (IDT). A multiphysics coupled field FE modelling was used to reproduce the piezoelectric effect present in the IDT. The FE model comprised only the transducer and its close vicinity, while the whole structure was modelled with the FD method. The displacement fields obtained from the multiphysics FE analyses where transferred to the FD model in order to predict the wave propagation in the considered object. The results from the combined method were compared with the outcomes from a referential FE analysis and experiments. The beam patterns and time history plots were subjected to analysis. The main advantage of the two-step method is a time-efficient simulation of the ultrasonic field produced by complex shape transducers.