Experimental Investigation of Folding Damage for the Rigidizable Carbon-Epoxy Composites

This paper focused on the folding damage behavior of the space rigidizable materials in terms of 3-layer composite membranes. An experimental scheme was presented. The composite membranes were folded between the two plates for a short time, and then the unfolded composite membranes were compressively cured in an oven. By adjusting the displacement of one plate, the folding radius was changed. As expected, the strength and effective modulus of the cured composite membranes drop with decreasing the folding radius. When the strain controlled failure rule is applied to the composite membranes, a minimal folding radius can be reached, beyond which the membranes will keep intact. Furthermore, folding damage due to folding and unfolding processes was evaluated by a simplified model. Compared with the measured residual strength and effective modulus, calculated results have the same trend. A discrepancy is attributed to neglecting the effects of the transverse fibers and the matrix.