Stowage and Deployment Strength of a Rollable Composite Shell Reflector

This paper presents the investigation of the stowage and deployment strength of a thin composite shell capable of being rolled and stowed in a tight dual-roll or single-roll configuration. This shell is square in shape and has a doubly-curved surface for use as a segment of a larger deployable reflective aperture. Carbon fiber reinforced polymer is the material chosen for this investigation due to its stiffness, conductive, and reflective characteristics. Analysis and coupon-level testing gave confidence that a [0,±45PW,0] laminate would be rollable and resistant to creep effects at the desired roll diameter. However full-scale prototype stowage testing proved the laminate to be too stiff to be hand rolled to the dual-roll configuration at 2.5 cm diameter. An alternative laminate [±45PW,0,±45PW] proved to roll much easier but exhibited severe creep effects. High speed video footage of deployment shows the presence of snap-through over-deployment behavior, but the shell quickly settled back into the desired doubly-curved shape. Relatively short-term, five-day, stowage testing proved both shell laminates to be susceptible to creep effects due to high stored elastic strain energy. Thinner laminas and additional cross-plies are expected to reduce creep effects and improve stowage manageability by reducing overall strain energy levels.