Angle effects on bistability of a composite tape-spring

A bistable composite tape-spring (CTS) is designed with fibres oriented at ±45°, which is stable at both extended and coiled configurations, and able to be folded. It has been used within deployable structures and systems, and successfully launched in space. Its structural stability is dependent on angle layups, whilst the theoretical boundaries have not been released in detail. We have investigated the angle effects on structural stability of an antisymmetric CTS structure; a theoretical model was developed to evaluate the structural bistability of the CTS, where minimum strain energy paths were established to investigate the morphing mechanics. The bistability criteria of a CTS were then revealed by considering the fibre angle effects. Both the theoretical predictions and experimental observations show good agreement, and indicate further insight into the customised structural bistability design of the CTS for deep space explorations.