Design and Analysis of a Foldable/Unfoldable Corrugated Architectural Curved Envelop

Origami and paperfolding techniques may inspire the design of structures that have the ability to be folded and unfolded: their geometry can be changed from an extended, servicing state to a compact one, and back-forth. In traditional origami, folds are introduced in a sheet of paper (a developable surface) for transforming its shape, with artistic, or decorative intent; in recent times the ideas behind origami techniques were transferred in various design disciplines to build developable foldable/unfoldable structures, mostly in aerospace industry (Miura, 1985, “Method of Packaging and Deployment of Large Membranes in Space,” Inst. Space Astronaut. Sci. Rep., 618, pp. 1–9; Ikema et al., 2009, “Deformation Analysis of a Joint Structure Designed for Space Suit With the Aid of an Origami Technology,” 27th International Symposium on Space Technology and Science (ISTS)). The geometrical arrangement of folds allows a folding mechanism of great efficiency and is often derived from the buckling patterns of simple geometries, like a plane or a cylinder (e.g., Miura-ori and Yoshimura folding pattern) (Wu et al., 2007, “Optimization of Crush Characteristics of the Cylindrical Origami Structure,” Int. J. Veh. Des., 43, pp. 66–81; Hunt and Ario, 2005, “Twist Buckling and the Foldable Cylinder: An Exercise in Origami,” Int. J. Non-Linear Mech., 40(6), pp. 833–843). Here, we interest ourselves to the conception of foldable/unfoldable structures for civil engineering and architecture. In those disciplines, the need for folding efficiency comes along with the need for structural efficiency (stiffness); for this purpose, we will explore nondevelopable foldable/unfoldable structures: those structures exhibit potential stiffness because, when unfolded, they cannot be flattened to a plane (nondevelopability). In this paper, we propose a classification for foldable/unfoldable surfaces that comprehend non fully developable (and also non fully foldable) surfaces and a method for the description of folding motion. Then, we propose innovative geometrical configurations for those structures by generalizing the Miura-ori folding pattern to nondevelopable surfaces that, once unfolded, exhibit curvature.