Peculiarities of SH wave propagation in a two-layer structure of inhomogeneous piezoelectric and dielectric layers

An approach to modeling dynamic processes in a semi-infinite composite plate of inhomogeneous piezoelectric and dielectric layers is proposed. When modeling the inhomogeneity of the layers, a two-component model with a functionally gradient change in properties was used, in which the physical parameters of the base material continuously change along the thickness up to the inclusion parameters. The material of the piezoelectric layer is a combination of PZT-based piezoceramics with a significant difference in speed characteristics. The possibility of localizing the inhomogeneity both at the outer surface of the plate, and in the middle of the layer or at the interface has been implemented. The dielectric layer is made of SiO2, the inhomogeneity of the dielectric layer models the interpenetration of the piezoelectric and the dielectric in a narrow transition region near the interface. The elastic and dielectric moduli of the piezoelectric material located near the interface were considered as parameters of the inclusion material. The outer surfaces of the composite plate are stress-free and electrically short-circuited. The problem of the propagation of surface SH-waves in a composite structure of functionally gradient piezo- and dielectric layers initiated by the action of an infinitely distant source of harmonic oscillations is considered. The solution is constructed in the space of Fourier images by reducing to the solution of a system of ordinary differential equations with variable coefficients, which in turn is constructed using the Runge - Kutta - Merson method. The dispersion equation of the problem is presented, the analysis of which made it possible to investigate the influence of the nature, size of the transition region of materials and localization of structural inhomogeneity on the behavior of SAW phase velocities for a wide frequency range. The results obtained are given in dimensionless parameters and may be of particular interest in the development, design and optimization of new materials for micro- and nanoscale devices and devices based on SH SAW with high performance characteristics.