Sound transmission analysis using the hybrid finite element - wave based approach for coupled vibroacoustic problems

In this paper, a hybrid structural finite element (FE) acoustic wave based (WB) approach is formulated to avoid using extra acoustic FE in the case of a simple structural geometry but with complicated structural material properties. Following the formulation, the approach is implemented and validated. First, linear hexahedral solid elements with a selective reduced integration are implemented in an in-house code and are checked to be able to avoid the shear locking using a simple thin plate model. Then, in order to demonstrate the acoustic transmission through a curved structure, a simple fairing model is solved by using the hybrid approach. Finally, an acoustic transmission analysis through a flat honeycomb sandwich plate is analyzed. In this analysis, the honeycomb core layer is modeled as a homogeneous orthotropic material by using the numerical tensile and shear tests of a partial detailed model. In the hybrid analysis, two anechoic rooms are modeled as acoustic WB regions and the sandwich plate is modeled as FE region. It is observed that the acoustic point source excites the source room and that the receiving room is also excited due to the structural bending effects of the honeycomb sandwich plate.