Transient modeling of Lamb waves generated in viscoelastic materials by surface bonded piezoelectric transducers
Résumé
In order to help optimize health monitoring systems based on Lamb wave propagation, a hybrid finite element–normal mode expansion modeling technique has been developed. This technique allows one to predict the Lamb waves generated in a structure as a function of the transducer parameters (size, location, material, etc.). The present paper shows how this hybrid modeling, initially valid for nonlossy materials and harmonic excitation, can be extended to lossy (viscoelastic) materials and transient excitation. For this purpose, simplifying assumptions have been proposed and validity conditions have been established and verified. Moreover, numerical results concerning Lamb wave generation have been successfully compared to experimental ones. As a result, the method has proved to be pertinent and practically unrestrictive.