Design and analysis of load relieving trusses for large space structure applications.

摘要

In the absence of a gravitational field, the major design considerations for large space structures are stiffness, to provide controllability, and transient dynamic loadings, rather than the traditional static load associated with earth based structures. As a result, space structures can be designed significantly lighter than their counterparts on earth. They are designed using brittle composites and high slenderness ratio struts to reduce weight and decrease packaging requirements. The resulting lightweight structures tend to be fragile and unforgiving due to high transient dynamic loadings. These higher than expected loadings can occur during the construction process or the operation life of the structure. The current research proposes a new design methodology to eliminate the possibility of structural overload and failure from rare or unexpected high transient loadings on large space structures. This methodology introduces a structural "fuse" into a structure, altering the behavior of the structure to meet specific high transient loading requirements. A load absorbing strut serves as a restorable fuse in the structure. The design of the strut is presented and the strut is characterized analytically and experimentally. An analytical testbed of a flexible truss beam with the load absorbing strut installed is presented. The modifications of the characteristics created by the fuse are investigated, including reduction of stiffness and dissipation of energy in the system.