Acoustical Scattering by Spherical Objects Containing Electrorheological Fluid Layers

Abstract

In an effort to explore the mechanism to exert control over the band gap in phononic structures or acoustic metamaterials, a layer of electrorheological (ER) fluid is introduced into a spherical scatterer. The ER fluids have the capability of changing the mechanical properties from fluid-like into a solid-like material in a matter of milliseconds. It is expected that such significant changes in the material properties would afford a range of significant opportunities for tuning the band gap. In this study, numerical analysis of acoustical scattering characteristics of such scatterers in a underwater environment is explored. The ER fluid layer is encased between a solid steel core and a steel shell, which provide electrodes to electrify the ER fluid. The ER fluid, both before and after the electrification is modeled as viscoelastic solid in order to account for its capability for sustaining the shear wave. Effects of externally applied electric field on the scattering characteristics are observed.