Structural effects of ply-level imperfections and extreme temperatures on bistable ultra-thin composite booms

Bistable ultra-thin composite booms capable of self-deploying from coiled stable configuration to extended shape offer significant potential for lightweight deployable space structures. This paper explores the effects of ply-level thickness and angle defects on the bistable behavior of ultra-thin composite booms with circular cross-sections made from carbon fiber-reinforced epoxy (CF-Epoxy) and glass fiber-reinforced polypropylene (GF-PP) laminates. The results show that the curvatures and coiling angles are more sensitive to ply angle defects than to ply thickness imperfections. This work investigates the influence of uniform temperature variations on the bistability of the booms and the shapes of stable equilibrium states. The results suggest that the CF-Epoxy boom can maintain bistability with a wide range of temperatures, but the GF-PP boom would lose bistability in typical temperatures in space. The temperature variations have stronger effects on the coiled stable state than the extended stable shape. Furthermore, the paper investigates the combined effects of imperfections and temperature variations on the CF-Epoxy boom. Ply-level imperfections generally intensify the effects of temperature variations on the curvatures and angles of the stable states. Combined with temperature variations, ply angle imperfections still have greater effect on the curvatures than ply thickness imperfections.