Publications

Expansion of Coupled Structural-Acoustic Systems

Schultz, Ryan S.; Beale, Dagny; Romeo, Ryan

Expansion is useful for predicting response of un-instrumented locations and has traditionally been applied to structures alone. However, there are a range of hollow structures where the influence of the acoustic cavity affects the structural response, and the structural response affects the acoustic response. This structural-acoustic coupling results in a gyroscopically coupled system with complex modes. Though more complicated than modes of a structure alone, the modes of the coupled structural-acoustic system can be used as the basis vectors in an expansion process. In this work, complex modes of a model of a coupled structural-acoustic system are used to expand from a sparse set of structural and acoustic response degrees of freedom to a larger set of both structural and acoustic degrees of freedom. The expansion technique is demonstrated with a finite element model of a hollow cylinder with simulated displacement and pressure measurements, and expansion is studied for both modal and transient responses. Though more nuanced than traditional structure-only expansion problems, the displacement and pressure response of a coupled structural-acoustic system can be expanded using the coupled-system modes.