Sound transmission through cylindrical structures using a wave and finite element method

Abstract

This paper concerns the use of the Wave and Finite Element (WFE) method for predicting sound transmission through, and radiation from, an infinitely long cylindrical structure. The formulation is general and can be used to analyse acoustic radiation or transmission due to arbitrary internal or external excitation. The WFE method involves modelling a small segment of a structure using traditional Finite Element (FE) methods. The mass and stiffness matrices of the segment are then used to calculate the response of the structure to excitation. The WFE approach for calculating sound transmission is validated by comparison with analytic solutions for three example problems: (1) the internal sound field produced by an acoustic source exterior to a thin-walled cylinder, (2) the radiation from a thin-walled cylinder due to excitation from a point force acting on the inner surface and (3) sound transmission through an orthotropic cylinder. In order to demonstrate the usefulness of the approach, the WFE method is then used to predict sound transmission through, and radiation from, more complicated cylindrical structures, for which an analytical model would be difficult to develop.