Multiport models for dynamics of flexible multibody systems

The paper presents a multiport model of flexible multibody systems by analogy with a connection multiport in electrical circuit theory. First we introduce a concept of a fundamental pair, that is, a pair of a mechanical joint and its adjacent body to recognize the flexible multibody system as an interconnected system of such fundamental pairs. Second we employ a finite element model to describe flexible deformations associated with large overall motions using moving frames and we also model various kinematical and dynamical relations of the fundamental pair such as geometric nonlinear effects associated with the flexible deformations and kinematical constraints due to the mechanical joint by nonenergic multiports together with dual connection matrices. Finally it is shown that the interconnection of the nonenergic multiports with physical elements provides a multiport model of the fundamental pair and also that the equations of motion of the flexible multibody system can be systematically formulated by the present approach.