Compact structural-acoustic coupled models via model order reduction (MOR)

A reduced order model is developed for low frequency, fully coupled, undamped structural acoustic analysis of interior cavities, backed by flexible structural systems. The reduced order model is obtained by applying a projection of the coupled system matrices, from a higher dimensional subspace to a lower dimensional subspace, whilst preserving some essential properties of the coupled system. The basis vectors for projection are computed efficiently using the block Arnoldi algorithm, which generates an orthogonal basis for the Krylov subspace. Two computational test cases are analyzed, and the computational gains and the accuracy compared with the direct method in ANSYS. It is shown that reduced order model results in a very significant reduction in simulation time, while maintaining the desired accuracy of the state variables under investigation. The method could prove as a valuable tool in the analysis of complex coupled structural acoustic systems, and their subsequent optimization or sensitivity analysis, where, in addition to fast analysis, a fine frequency resolution is often required.