Vibroacoustic Response of an Annular Sandwich Electrorheological Disc

Abstract

The steady-state sound radiation characteristics of a rigidly-baffled clamped-free sandwich annular disc with a tunable electrorheological fluid (ERF) core is studied. Hamilton's principle is employed to derive the governing equations of motion for the composite plate along with the associated boundary conditions in general form. The classical Galerkin procedure is subsequently utilized to reduce the structural problem into a linear system of algebraic equations for the unknown displacement coefficients. A modal summation approach based on Rayleigh integral formula along with the proper integral representation of the cylindrical Bessel functions are used to arrive at a useful single integral relation for the far-field modal radiated sound pressure and subsequently determine the radiation power and efficiency. Numerical results reveal the imperative influence of the applied electric field strength (0–3.5kV/mm) on controlling acoustic radiation from the adaptive panel in a wide frequency range. In particular, an effort is made to find the optimal electric field which yields improved sound radiation characteristics for each excitation frequency. Limiting cases are considered and good agreements with the calculations made by using a commercial finite element package as well as with the solutions available in the literature are obtained.