Topology and Shape Optimization of Ultrathin Composite Self-Deployable Shell Structures with Cutouts

This paper presents two methods to design cutouts that allow damage-free folding of the stiffest possible composite self-deployable thin shell structures of complex shapes. The first method uses level-set functions that define a general number of cutouts. The second method uses a spline representation of the contour of a single cutout and optimizes its shape. Material failure detection is implemented in the solution. Both methods are applied to the design of deployable thin shells forming 90° joints, and multiple viable solutions are obtained. Experiments on the best performing design, a thick shell made of Astroquartz with a cyanate ester matrix, with five cutouts on each side, are presented to illustrate and validate the proposed approach.