Deployment Dynamics of Thin-Shell Space Structures

This study was motivated by the desire to develop accurate simulation models for the deployment dynamics of future, ultralight deployable structures consisting of multiple thin shells packaged elastically, through a combination of folding and coiling. The specific problem studied is the packaging and unconstrained deployment of a rectangular space frame formed by two thin-shell longerons connected by multiple transverse rods, and called a strip. The study included experiments on high-quality test articles, using a suspension system with low inertia and friction. The elastic folds in the strips were tracked with high-speed three-dimensional digital image correlation for deployment in both air and near-vacuum. The study also developed a high-fidelity finite element model of the strips that captures the elastic, localized deformation that occurs during the initial folding, the self-contact between different parts of the structure as the folding develops, and the strain energy stored during the folding process. This model accurately captured the deployment dynamics and self-latching of the strips, as well as the effects of air on deployment.