AN EXACT MODEL-REDUCTION TECHNIQUE FOR BEAM STRUCTURES - COMBINATION OF TRANSFER AND DYNAMIC STIFFNESS MATRICES

An exact and direct modelling technique is presented in this paper for modelling beam structures. This technique is based on the combination of transfer and dynamic stiffness matrices. In this technique, the wh ole structure is first divided into substructures based on the require d master degrees-of-freedom. For each substructure, the global dynamic stiffness matrix (DSM) is obtained directly by rearranging the corres ponding global transfer matrix. In this way, the internal degrees-of-f reedom of each substructure are not used in the model. Therefore, the order of the model is greatly reduced. The efficiency and simplicity o f the method is demonstrated by two numerical examples. The results ar e compared with those obtained by other model reduction methods such a s static and dynamic reduction methods and with experimental results. It is shown that the method presented in this paper can predict accura tely all the eigensolutions in a large frequency range in terms of a l ow dimension dynamic stiffness matrix. (C) 1995 Academic Press Limited