Space Frames with Multiple Stable Configurations
This paper is concerned with beamlike spaceframes that include a large number of bistable elements, and exploit the bistability of the elements to obtain structures with multiple stable configurations. By increasing the number of bistable elements, structures with a large number of different configurations can be designed. A particular attraction of this approach is that it produces structures able to maintain their shape without any power being supplied. The first part of this paper focuses on the design and realization of a low-cost snap-through strut, whose two different lengths provide the required bistable feature. A parametric study of the length-change of the strut in relation to the peak force that needs to be applied by the driving actuators is carried out. Bistable struts based on this concept have been made by injection molding nylon. Next, beamlike structures based on different architectures are considered. It is shown that different structural architectures produce structures with workspaces of different size and resolution, when made from an identical number of bistable struts. One particular architecture, with 30 bistable struts and hence over 1 billion different configurations, has been demonstrated.
Copyright © 2006 by S. Pellegrino and T. Schioler. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Presented as Paper 1529 at the 45th SDM Conference, Palm Springs, CA, 19–22 April 2004; received 25 March 2005; revision received 18 July 2006; accepted for publication 17 September 2006. Financial support from the Cambridge-MIT Institute (CMI) is gratefully acknowledged. T.S. thanks the Engineering and Physical Sciences Research Council for the award of a studentship and the Cambridge Newton Trust for additional support. We thank Stephen Dubowsky for inspiring our work on bistable structures, and for advice on the present research. An earlier version of this paper was presented at the 38th AIAA SDM Conference.
Published - SCHIaiaaj07.pdf