Structural Vibration Of Space Power Station Systems

In this paper the vibration research being conducted at Auburn in regard to both the vibration prediction and the vibration control of large flexible structures is discussed. This research work has been carried out in the following areas each of which is reviewed briefly. A finite element model of the vibratory response of large flexible spacecraft truss structures to systems of applied forces representing machinery forces and maneuvers has been developed. Predictions on the pointing accuracy and tip displacement of such structures to assumed maneuvering and machinery force inputs is presented. A study of the response of structures to traveling loads is also underway. An analytical model using spatial/temporal Finite Element method is di cussed. The motivation of this study is the determination and minimization of the response of a structure such as an electromagnetic launcher system to the traveling loads imposed by the projectiles. Another area of study has been the optimization of space structures to minimize dynamic response. The goal of this study is to optimize the location of the masses (such as power generating equipment and other systems that would be positioned on the space structure) in order to obtain minimum dynamic response. The vibration response of structures can be minimized by the use of passive damping techniques. One area of study is the modeling of interfacial passive damping in composite materials. Because of lack of passive energy dissipation mechanisms in space, even small disturbances can lead to motions sufficiently large to be detrimental to the performance requirements (of the structures) such as precision pointing in a micro-gravity environment. In such cases an active vibration control system can be added to the passive damping devices to enhance system performance. Hence work in the area of active vibration control is in progress. A new approach to active vibration control based on wave cancellation techniques is also presented.