Features of SH-Wave Propagation in a Bimorphic Piezoelectric/Piezomagnetic Plate Made of Functionally Graded Materials

Propagation of shear horizontally polarized surface acoustic waves (SH-SAW) in a composite magnetoelectroelastic plate of inhomogeneous piezoelectric and piezomagnetic layers are studied in a quasi-static approximation. To simulate inhomogeneity of the layers, a two-component model of functionally gradient materials with properties depending on thickness is used (ranging from parameters of the base material to the parameters of the inclusion material). PZT-5H and CoFe2O4 materials are used as a base of the piezoelectric and piezomagnetic layers of the plate. The inclusions of the piezoelectric layer are PZT-based ceramics with different elastic, piezoelectric, and dielectric properties. The inhomogeneity of the piezomagnetic layer models a solid solution of the layer materials in a narrow transition region at the interface. The propagation of SH-SAW in the plate is initiated by the action of a remote source of harmonic oscillations, the mode of which is assumed to be steady. The adhesion conditions are met at the interface of the inhomogeneous layers. On external surfaces freely contacting with vacuum, in the absence of mechanical stresses, four types of electrical and magnetic conditions are considered, depending on which four problems are studied. The solution is constructed in the space of Fourier images by reducing to a system of initial-boundary value Cauchy problems. Matrix representations of the dispersion equations of the problems convenient for the numerical implementation are obtained. By using an example of the problem with electrically short-circuited and magnetically open surface conditions, we investigated how inhomogeneity of the piezoelectric and piezomagnetic layers of the plate influences the behavior of SH-SAW velocities in a wide frequency range. We determined the influence of localization of various types of inclusions of the piezoelectric layer on their behavior. Features of the behavior of SH-SAW velocities in a magnetoelectroelastic plate are described for different characteristics of inhomogeneity at the interface. The obtained results are given in dimensionless parameters and can be of particular interest in the development, design and optimization of new materials for modern micro- and nanosized devices and devices using SH SAW.