5K-4 Pseudo-3d Modeling Of The Lamb Wave Field Generated By A Surface-Bonded, Finite-Sized Piezoelectric Transducer

The aim of this work is to predict the acoustic field radiated in an isotropic plate by an integrated piezoelectric transducer. A "pseudo-3D" formulation has been developed in order to take into account the 3D aspects of the problem in a simple way. The basic principles of this model have been published recently. An adaptation of the model to an actual piezoelectric source bonded to the plate surface is presented here. First, a 2D finite element-normal mode expansion hybrid model is applied to account for the behavior of the piezoelectric transducer. Then the 3D effects are predicted by applying a corrective term to the 2D result. Theoretically speaking, this corrective term is rigorously applicable in particular situations only (low directivity angle, small transducer compared to the wavelength). However, looser validity conditions are precisely discussed, for which a very satisfying approximation is still obtained. Finally, the predicted results are compared to 3D numerical data. Though approximate, the model thus appears to provide a very satisfying estimate of the acoustic field generated in the whole plate