Structural acoustics and vibration behavior of complex panels

Abstract

Among the many mechanical parameters that influence structure-borne sound are the effects of stiffeners, added mass and complex support conditions along the structure boundaries. In the present paper, these effects are incorporated into a model of sound radiation in air from a complex, baffled, rectangular panel under harmonic point force or point moment excitation. A complex panel is thus defined as a panel which is stiffened lengthwise and widthwise by flexural-torsional beams, which carries point masses and which is elastically restrained against transverse displacement and rotation along the edges. The vibration of the panel assumes no fluid loading and is solved using the Rayleigh-Ritz method with simple polynomial trial functions. The expressions of the kinetic and strain energies associated with stiffeners, added mass and elastic boundary conditions, are detailed. A simple computation scheme is used to derive the farfield sound pressure from the transverse displacement of the panel. Numerical results are shown in terms of the mean quadratic velocity of the panel, radiated sound power and radiation efficiency for a variety of situations including force or moment excitation, simply-supported, clamped or free edges, addition of stiffeners and addition of a point mass, and are used to draw some useful guidelines in practice.