Acoustic surface wave dispersion with strain gradient elasticity and micro-inertia effect in lossy polymer-coated piezoelectric structure

Abstract

This research paper utilizes second-order gradient electroelasticity theory to develop a theoretical model of Love-type surface wave transference considering strain and inertia gradient effects in a Kelvin–Voigt type viscoelastic lossy polymer-coated piezoelectric substrate. Non-classical constitutive equations derived from variational principles are used to obtain electromechanically coupled field equations. Using proper analytical techniques and non-classical boundary conditions, dispersion relations for electrically open and short cases are derived. Numerical example has been provided and graphs have been plotted to visualize the dependency of velocity and attenuation traits of Love-type waves on considered strain gradient, inertia gradient, and other relevant parameters like viscosity and layer width. It has been observed that the phase velocity of the fundamental mode of surface wave is highly affected by strain gradient elasticity and micro-inertia and high gradient elasticity helps to achieve high phase velocity. The investigation can provide proper guidelines to optimize biological or chemical surface acoustic wave (SAW) sensors with nanocoating. Highlights Nanoscale strain gradient elasticity and micro-inertia effect are considered in the shear wave propagation model. Non-conductive Kelvin–Voigt model-based viscoelasticity is assumed for coating polymer. Attenuation is also characterized along with phase velocity on a logarithmic scale. Dispersion characteristics are investigated for electrically open and short boundary types.