Excitation and propagation of shear horizontal waves in a piezoelectric layer imperfectly bonded to a metal or elastic substrate

The performance of shear horizontal waves excited by an external voltage imposed on the surface of a transversely isotropic piezoelectric sensitive layer imperfectly bonded to a metal or elastic substrate is investigated. The phase velocity, electromechanical coupling factor, temperature coefficient of delay, mass loading sensitivity, and displacement distribution along the thickness direction for the propagation of free waves, resonance frequency, and displacement signal and input admittance for the forced vibration are considered. Numerically, the SH wave speed smaller than Bleustein-Gulyaev wave velocity of a piezoelectric layer can be achieved for electrically open and shorted conditions when the interface is imperfect, which is totally different from the case of perfect interface. The imperfect interface evidently improves the energy transformation ratio, temperature stability, and mass sensitivity of the composite structure. The viscoelastic damping parameter has no relationship with resonance frequencies, and it only decreases the amplitudes of displacement signal and input admittance. The outcome is widely applicable and can be used to design high-performance surface acoustic wave devices.