Analysis of Love waves propagation in a functionally graded porous piezoelectric composite structure

Propagation of Love waves in a composite structure, containing a functionally graded porous piezoelectric material layer over a dielectric elastic half space, is studied. The material properties gradually vary with the layer thickness. Constitutive equations for a functionally graded porous piezoelectric material layer are laid down and then their analytical solutions are derived by using the Wentzel-Kramers-Brillouin method. Variations in the mechanical properties and electrical properties are considered and dispersion equations are derived for both electrically short and open boundaries. The effects of porosity and grade coefficients on the phase velocity of the Love waves and on electro-mechanical coupling are discussed. Numerical computation of the phase velocity and electromechanical coupling factor is done for different levels of thickness of the layer and results, obtained, are validated by deriving earlier results as a special case of this study. This study finds application in making high-performance surface acoustic wave devices.