Analytical model for predicting folding stable state of bistable deployable composite boom

The bistable deployable composite boom (Bi-DCB) can achieve bistable function by storing and releasing strain energy, which has a good application prospect in space field. For example, it serves as the main support section of deployable structures (e.g., solar arrays and antennas). This paper investigates the folding stable state of the Bi-DCB through the analytical method. Based on the classical Archimedes' helix, the geometrical model of the Bi-DCB was established. Using energy principle, an analytical model for predicting the folding stable state of the Bi-DCB was presented. The failure indices of six Bi-DCBs in the folding stable state were calculated using the Tsai-Hill criterion and the maximum stress criterion. To validate the analytical model proposed in this paper, the prediction results were compared with the results of two Finite Element Models (FEMs) and experimental results, and the four were in good agreement. Finally, the effect of geometric parameters (i.e., radius of cross-section, thickness and length) on the folding stable state of the Bi-DCB was further investigated with the aid of the analytical model. It is shown that geometric parameters are one of the key factors affecting the folding stable state of the Bi-DCB.