A Time-Domain Impedance Element for FEA of Axisymmetric Exterior Structural Acoustics

Abstract

A finite element (FE)-based procedure is presented for the solution directly in the time-domain of transient problems involving axisymmetric three-dimensional structures submerged in an infinite acoustic fluid. The central component of the procedure is a novel impedance element that is used to render the computational domain finite. The element is local in both time and space, and is completely defined by a pair of stiffness and damping matrices. It is shown that the exterior structural acoustics problem can be solved accurately and efficiently by using the same tools as those used for interior problems. The method is illustrated with numerical results for a submerged shell.