On the analysis of vibro-acoustic systems in the mid-frequency range using a hybrid deterministic-statistical approach

At present, several numerical prediction techniques are available for the steady-state dynamic analysis of vibro-acoustic problems. Most of these techniques can be classified as either deterministic or statistical approaches. The use of the deterministic methods, like the Finite Element Method (FEM), is limited to the so-called low-frequency range due to the decreasing wavelengths and subsequent increasing model sizes and computational loads for increasing frequency. The underlying assumptions for the statistical methods, like the Statistical Energy Analysis (SEA), limit their use to the so-called high-frequency range. In-between the low- and high-frequency ranges there is a relatively wide mid-frequency-range, in which some of the subsystems fulfill the requirements for the statistical approach and some others do not (yet). Therefore, Shorter and Langley developed a deterministic-statistical framework combining FEM and SEA models. However, this method is limited in use due to the computational load of the FEM models. This paper proposes a framework for coupling Trefftz-based deterministic models with statistical SEA models. Instead of the FEM, the recently developed and computationally more efficient Wave Based Method (WBM) is being used. The presented method is verified in a numerical example.