Deployable Sandwich Surfaces with High Out-of-Plane Stiffness

This paper presents a set of deployable origami tube structures that can create smooth functional surfaces while simultaneously maintaining a high out-of-plane stiffness both during and after deployment. First, a generalized geometric definition for these tubes is presented such that they can globally have straight, curved, or segmented profiles, while the tubes can locally have skewed and reconfigurable cross sections. Multiple tubes can be stacked to form continuous and smooth assemblies in order to enable applications, including driving surfaces, roofs, walls, and structural hulls. Three-point bending analyses and physical prototypes were used to explore how the orthogonal stiffness of the tubular structures depends on the geometric design parameters. The coupled tube structures typically had their highest out-of-plane stiffness when near to a fully deployed state. Tubes with skewed cross sections and more longitudinal variation (i.e.,that had more zigzags) typically had a higher stiffness during deployment than tubes that were generally straight.