FINITE ELEMENT METHODS FOR STRUCTURAL ACOUSTICS ON MISMATCHED MESHES

In this paper, a new technique is presented for structural acoustic analysis in the case of nonconforming acoustic-solid interface meshes. We first describe a simple method for coupling nonconforming acoustic-acoustic meshes, and then show that a similar approach, together with the coupling operators from conforming analysis, can also be applied to nonconforming structural acoustics. In the case of acoustic-acoustic interfaces, the continuity of acoustic pressure is enforced with a set of linear constraint equations. For structural acoustic interfaces, the same set of linear constraints is used, in conjunction with the weak formulation and the coupling operators that are commonly used in conforming structural acoustics. The constraint equations are subsequently eliminated using a static condensation procedure. We show that our method is equally applicable to time domain, frequency domain, and coupled eigenvalue analysis for structural acoustics. Numerical examples in both the time and frequency domains are presented to verify the methods.