Dynamic substructuring in the medium-frequency range

Abstract

International audienceThere are several methods in dynamic substructuring for numerical simulation of complex structures in the low-frequency range, that is to say in the modal range. For instance, the Craig-Bampton method is a very efficient and popular method in linear structural dynamics. Such a method is based on the use of the first structural modes of each substructure with fixed coupling interface. In the medium-frequency range, i.e. in the non-modal range, and for complex structures, a large number of structural modes should be computed with finite element models having a very large number of degrees of freedom. Such an approach would not be efficient at all and generally, cannot be carried out. In this paper, we present a new approach in dynamic substructuring for numerical calculation of complex structures in the medium-frequency range. This approach is still based on the use of the Craig-Bampton decomposition of the admissible displacement field but the reduced matrix model of each substructure with fixed coupling interface, which is not constructed using the structural modes, is constructed using the first eigenfunctions of the mechanical energy operator of the substructure with fixed coupling interface related to the medium-frequency band. The method and a numerical example is presented