A Novel Actuated Composite Tape-Spring for Deployable Structures

Abstract

This paper presents a novel composite tape-spring that is suitable for use as a structural element of deployable space structures.The tape-spring uses a combination of material orthotropy and prestress to achieve the unique property known as neutral stability.A consequence of this property is that the tape-springs can be partially rolled and they neither want to unroll or rollup.Previously investigated composite tape-springs always proceed towards their manufactured geometry once the rolling process has been started.This paper documents a procedure to fabricate neutrally stable tape-springs.An analysis methodology is presented that predicts neutral stability in appropriately prestressed laminates.The analysis predictions are shown to agree with observations.Finally, the ability of neutrally stable tape-springs to undergo large elastic deformations with diminishingly small forces is exploited in the development of actuated tape-springs.Analytical and experimental results are presented.