A statistical energy analysis subsystem formulation using finite element and periodic structure theory

In statistical energy analysis (SEA), a complex vibro-acoustic system is represented as an assembly of coupled subsystems. The parameters of an SEA model are typically derived by considering wave propagation within each subsystem. Analytical formulations exist for describing wave propagation in many commonly encountered subsystems (for example, flat plates, curved shells, ribbed panels, etc.). However, problematic subsystems are often encountered that are not well represented by existing analytical formulations. Examples include composite fuselages, isogrid fairings, complex ribbed panels and extruded train floors. This paper describes a SEA subsystem formulation based on a combination of finite elements (FEs), component mode synthesis (CMS) and periodic structure theory. The method enables the SEA parameters to be efficiently computed for very general structural panels. Expressions are derived for the modal density, damping loss factor and ‘engineering units’ response of the panel. By making use of an efficient Fourier transform approach, the resonant radiation efficiency, non-resonant transmission loss and acoustic input power are also obtained. The method is derived and a number of analytical and experimental validation cases are presented.