IMPLEMENTATION AND RESULTS OF A MASS INERTIA COUPLING AS AN EXTENSION OF THE BEM FOR THIN SHELLS

摘要

The conventional 3D boundary element method for the determination of sound radiation from thin shell-like layered structures requires a high computational cost, since a corresponding customized model must be used for discretization, which needs different shell layer areas and leads to a large number of unknowns. For example, the calculation of a coupled problem for one elastic shell requires four discretized boundary element areas. In many cases, the approximate approach outlined in this paper may be used, which gives acceptable results using a mass inertia coupling for thin structures. The number of required boundary element regions in the example above is reduced to only two, leading to a much smaller order of the system matrix and an accordingly greatly reduced solution time. At this time, the method is suitable primarily within the middle frequency range because it is not able to take into account shear waves. In this paper the basics of this coupling method are outlined and some results for general coupled structures are given and compared with results obtained from FEM calculations.