A SEA based FEM-BEM approach for acoustical FSI-problems in the mid-frequency range

The prediction of structure borne sound in vehicles or buildings and the related sound fields in the acoustic volume typically is carried out either with Finite Element-, Boundary Element and hybrid FEM/BEM-approaches or with the help of energy methods like the Statistical Energy Analysis (SEA). Whereas the first method is limited to lower frequencies the SEA is appropriate for higher frequency ranges, where the structures have a high modal density and the system´s behaviour is dominated by resonant vibrations. In the mid-frequency range, which is between 200 Hz and 800 Hz for structures in the automotive industry for example, neither the FEM/BEM approach nor the SEA are able to provide realistic results. In this paper an energy flow analysis based on a "SEA-like" averaging is carried out, in which the structure is modelled with the help of finite elements and the acoustic fluid is built up with boundary elements. The requirements in the scope of the SEA as for example weakly coupled subsystems, which are excited at resonance, and typical simplifications like a "rain on the roof excitation" are not necessary. The system is split up into subsystems, which are excited with harmonically oscillating loads. Out of the input power, applied to each subsystem, as well as from the resulting kinetic and potential energy of the subsystems, the Energy Influence Coefficients (EICs) are derived. The application of the method is presented using a simplified vehicle model to outline the advantages compared to classic FEM/BEM models.     «

The prediction of structure borne sound in vehicles or buildings and the related sound fields in the acoustic volume typically is carried out either with Finite Element-, Boundary Element and hybrid FEM/BEM-approaches or with the help of energy methods like the Statistical Energy Analysis (SEA). Whereas the first method is limited to lower frequencies the SEA is appropriate for higher frequency ranges, where the structures have a high modal density and the system´s behaviour is dominated by res...     »