Stress-strain in large composite shell cured in temperature gradient in Earth orbit

A large hermetic hull of the epoxy/carbon fibres composite materials is proposed for the next-generation habitable space construction. The hull shell made of prepreg with uncured binder of long shelf life is prepared on Earth, folded, delivered to Earth orbit and inflated. The binder of the prepreg is cured directly in free space in Earth orbit under Sun irradiation. Then the cured composite shell is filled with atmospheric pressure and used for a crew. In this paper, we study the stresses and deformation of the 100 m length and 10 diameter cylindrical shell cured in a temperature gradient caused by non-uniform illumination from the Sun, Earth and a mirror. We analyse the material properties under simultaneous change of heating/cooling conditions and the chemical curing reaction during orbital flight. It is shown that the resulting stresses have a variable sign and a complex profile over the shell. This causes stresses and deformation of the shape of the cured shell. However, the absolute values of the stresses are much less than the critical stresses for rupture of the cured shell. The maximum amplitude of the deformation of the shell shape is comparable to the error in the shape during shell inflating. The results show that the temperature gradient caused by the non-uniform illumination during the curing process will not lead to a decrease in the strength of the shell.