Dynamic superelement modeling method for compound dynamic systems

A dynamic superelement modeling method for compound dynamic systems, which include springs, dampers, rigid and flexible substructures, and so on, is proposed. In this method, the finite element models of the flexible substructures in the system are first reduced in physical space to formulate their respective superelements. Then they are assembled to the global finite element model of the system directly, just like common elements. The reduced finite element model obtained from the proposed method is much smaller than the global model in dimension and can retain the dynamic characteristics in the low- and middle-frequency range of the global model. Because an iterative scheme is applied for the dynamic superelement modeling technique, its accuracy is much higher than for the static technique. Another advantage of this method is that the reduced model is still defined in the physical space. Numerical examples, including a floating raft isolation system and a tall building with one tuned mass damper are also included. The results show that the proposed dynamic superelement modeling method is efficient for compound systems and that its accuracy is much higher than the static method.