Mixed-interface substructures for dynamic analysis of flexible multibody systems

This paper presents an efficient and accurate mixed-interface substructure formulation for dynamic analysis of multibody systems. The equation of motion is derived using the mixed-interface substructure approach, which is used to reduce the resulting number of elastic coordinates of multibody systems. The mixed-interface substructure procedure incorporates both the free- and fixed-interface boundary conditions that apply to different flexible and rigid bodies. The entire procedure requires a two-step transformation; first from one substructure to another substructure in the same body, and second from one body (or substructure) to another body (or substructure). This process is continued until it has been carried out for the entire multibody system. The applicability and accuracy of this formulation are illustrated on a two-link system with comparison made against the finite element method. It was found that the mixed-interface substructure procedure, although it uses fewer elements, provides numerical solutions comparable to the finite element method.