An approach for modal coupling based on experimental and computed modes using non-conforming grids

The combination of experimental and numerical data is a typical challenge in complex vibro-acoustic problems. Rather than employing model-updating techniques, we combine the modal substructuring technique with non-conforming grids in order to be able to directly employ experimental and numerical modes for the description of weakly coupled vibro-acoustic systems. By incorporating Delaunay triangulation in the process, mechanical modes of any origin and discretized in terms of point clouds can be coupled with computational acoustic modes. The method is validated using a two-sided vibro-acoustic box. It is demonstrated that, by employing suitable interpolation techniques, systems based on coarsely discretized experimental modes can be used analogously to computational modes. The approach makes it straightforward to take into account modal damping and to fit numerical modes via experimental modal parameters, such as eigenfrequency, modal mass and damping.