Finite element modelling of the interaction of ultrasonic guided waves with coupled piezoelectric transducers

摘要

Finite element analysis (FEA) has been used to investigate the reflections and mode conversions arising from a coupled piezoelectric transducer. By including the geometry of the transducer in the FEA procedure for excitation, closer agreement between theoretical predictions and experimental results was observed. The approach used in this investigation was to model a 3D geometric feature representing the transducer coupled to an aluminium rod and to perform a controlled experiment using the same input parameters. The time domain responses for single-point excitation, transducer excitation and experiment were compared to assess their similarity. The results show that a mode conversion between the first-order non-axisymmetric flexural mode F(1,1) and axisymmetric longitudinal mode L(0,1) occurs due to the presence of the coupled transducer. It is therefore demonstrated that the use of single-point excitation is not necessarily adequate for a reliable FEA correlation with corresponding experimental results. Moreover, the work illustrates the importance of considering the effect of the presence of transducers themselves in FEA and the design of ultrasonic arrays for inspection purposes.