Prediction of substructure properties using decoupling procedures

In this paper the decoupling problem, i.e. the identification of the modal properties of a substructure that is part of a larger structure, is considered. The dynamic behaviour of the whole structure, in terms of Frequency Response Functions (FRFs) at the joints, is assumed to be known, together with the physical (finite element) model of the second substructure. The decoupling procedure recalls the FRFs based structural modification procedure. If the coupling conditions include rotational DoFs, an expansion of the experimental degrees of freedom is necessary to match theoretical and experimental data. The procedure is applied to a simply connected structure using both simulated and experimental test data.