The decoupling problem, i.e. the identification of the dynamic behaviour of a structural subsystem, starting from the known dynamic behaviour of the complete system, and from information about a second component subsystem, is revisited in the general framework of Frequency Based Substructuring. Several approaches have been proposed in the literature to tackle the decoupling problem. However, all of them present some pitfalls that have been also highlighted, such as modal truncation, lack of information on coupling DoFs (rotational DoFs), ill-conditioning in the neighbourhood of particular frequencies. It has been shown that the last problem can be circumvented by including internal DoFs in the measured dataset, of course together with coupling (or interface) DoFs. In previous papers, two frequency based approaches were considered: an impedance based approach and a mobility based approach. In both approaches, the FRF matrix of the coupled system is assumed to be known at the coupling DoFs, and eventually at some internal DoFs of one subsystem. In this paper, an approach derived through the dual formulation, within the general framework of frequency based substructuring, is developed and discussed. Possible difficulties in the use of additional internal DoFs are envisaged and investigated.

Decoupling procedures in the general framework of Frequency Based Substructuring

D'AMBROGIO, WALTER;
2009-01-01

Abstract

The decoupling problem, i.e. the identification of the dynamic behaviour of a structural subsystem, starting from the known dynamic behaviour of the complete system, and from information about a second component subsystem, is revisited in the general framework of Frequency Based Substructuring. Several approaches have been proposed in the literature to tackle the decoupling problem. However, all of them present some pitfalls that have been also highlighted, such as modal truncation, lack of information on coupling DoFs (rotational DoFs), ill-conditioning in the neighbourhood of particular frequencies. It has been shown that the last problem can be circumvented by including internal DoFs in the measured dataset, of course together with coupling (or interface) DoFs. In previous papers, two frequency based approaches were considered: an impedance based approach and a mobility based approach. In both approaches, the FRF matrix of the coupled system is assumed to be known at the coupling DoFs, and eventually at some internal DoFs of one subsystem. In this paper, an approach derived through the dual formulation, within the general framework of frequency based substructuring, is developed and discussed. Possible difficulties in the use of additional internal DoFs are envisaged and investigated.
978-1-935116-02-8
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/38925
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