A novel type of transverse surface wave propagating in a layered structure consisting of a piezoelectric layer attached to an elastic half-space

The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is assumed. Dispersion equations relating phase velocity to material constants for the existence of various modes are obtained in a simple mathematical form for a piezoelectric material of class 6 mm. It is discovered and proved by numerical examples in this paper that a novel Bleustein-Gulyaev (B-G) type of transverse surface wave can exist in such piezoelectric coupled solid media when the bulk-shear-wave velocity in the substrate is less than that in the piezoelectric layer but greater than the corresponding B-G wave velocity in the same piezoelectric material with an electroded surface. Such a wave does not exist in such layered structures in the absence of piezoelectricity. The mode shapes for displacement and electric potential in the piezoelectric layer are obtained and discussed theoretically. The study extends the regime of transverse surface waves and may lead to potential applications to surface acoustic wave devices.