Wavenumber-Harmonic Analysis of a Periodically Supported Beam Under the Action of a Convected Loading

Abstract

The vibro-acoustic response of an infinite, fluid-loaded and periodically supported Timoshenko beam under a convected harmonic loading has been obtained in a mathematical form. Instead of considering the dynamics of a single substructure alone, an essentially different technique named as wavenumber-harmonic method for the analysis of periodic structures is presented. The method involves the use of Fourier transform, then the associated wavenumber response is expressed in a series form that represents wave components of the flexural motion. This approach differs from the space-harmonic analysis which describes the beam motion in spatial domain. With this approach the periodic boundary conditions and the phase relation between two substructures are not required. Furthermore, incorporating the heavy fluid loading effect is easy. This method can be used conveniently to calculate the sound power radiated from a fluid-loaded infinite beam, which is subject to either a moving point or distributed loading. The influence of periodic supports on the sound radiation has also been examined for different speeds of convected loading. [S0739-3717(00)01002-3]