Model reduction methodology for articulated, multiflexible body structures

Abstract

Multibody dynamics simulation packages such as DISCOS are commonly used to simulate and analyze systems of interconnecte d rigid or flexible bodies. In many applications using these codes, the flexible components must be described in a way that when they are assembled, important system-level modes are accurately captured. The projection and assembly model reduction method, developed at the Jet Propulsion Laboratory, serves this purpose very well. However, early application of the method on the Galileo spacecraft model indicated mismatches in transfer function zeros between the full-order model and a reduced-order model constructed using the projection and assembly method. In this paper, an enhanced projection and assembly method, employing static correction modes to augment either the selected mode set of the system or the projected mode sets of the components is presented. The effectiveness of the proposed methodology in generating reduced-order system models, accurate at multiple system configurations and over a frequency range of interest, has been successfully demonstrated on a high-order finite element model of the Galileo spacecraft.