A novel actuated composite tape-spring for deployable structures

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