Shear waves in a Piezo-Fiber-Reinforced-Poroelastic composite structure with sandwiched Functionally Graded Buffer Layer: Power Series approach

Abstract

Love wave sensors are highly sensitive devices owing to the concentration of acoustic energy within a few wavelengths of the surface. The basic model of these high-performance devices is layered structures composed of highly sensitive composite and functionally graded materials. Thus the present work aims to establish an analytical framework to investigate the propagation characteristics of horizontally polarized shear waves (SH waves) in a composite structure comprised of a Functionally Graded (FG) buffer layer sandwiched between an overlying transversely isotropic Piezo-Fiber-Reinforced Composite (PFRC) material guiding layer and an underlying transversely isotropic Piezo-Poroelastic (PP) half-space. The motive considering the gradient materials, especially at the interface adjoining the layers, is to avoid the discontinuity of the inter-laminar stress and high local stress fields, which can arise around the edges of the laminates due to material mismatch across the interface. The functional gradient of the buffer layer is configured in terms of volume fractions of the guiding layer and the half-space material. The power series technique is employed to solve the governing equations of the FG-buffer layer. For the propagating SH wave, the dispersion relation relating the wave number with phase velocity through the mechanical and electrical parameters of the PFRC and PP materials, the gradient parameter, and the widths of the guiding and buffer layer is presented for the electrically open (EO) as well as electrically shorted (ES) conditions. Furthermore, mass loading sensitivity is analyzed by coating a fine layer on the free surface of the structure. The obtained results on the dispersion relations are compared and found to be in well-agreement with some of the outcomes available in the extant literature, thus validating the present study. To graphically delineate the impact of all influencing parameters, a layered structure of ZnO-Epoxy (PFRC)/ FG-buffer Layer/PZT-1 (PP) is considered. Also, the mass loading sensitivity is graphically illustrated for the coating of a fine layer of SiO2 on the free surface. The present study may be applied for a myriad of engineering applications like manufacturing and optimizing sensors, actuators, transducers, etc. The obtained results are specifically useful for developing and enhancing the performance of surface acoustic wave (SAW) devices/Love wave sensors.