Origami-inspired deployable auxetic metamaterials

Developing complex spatial objects from a fl at sheet of material using origami folding techniques has long attractedattention in science and engineering. Recent research has shown that in origami-based deployable folded sheetmaterials, such as Miura-ori, metamaterial properties of the patterns are basically because of their folding geom-etry [1, 2]. In this study, we employ tailored origami folding techniques as a means to create a class of metamate-rials. Simple stretching and bending experiments show that these materials exhibit a negative in-plane Poisson’sratio under extension (i.e., auxetic materials), and a positive Poisson’s ratio under bending. Therefore, similarly tothe Miura-ori pattern, the in-plane and out-of-plane Poisson’s ratios of these patterns are of opposite signs, whichis an unusual property of such material systems. In-plane Poisson’s ratio and planar stretching stiffness of suchclass of materials are also studied analytically. Eigenvalue analysis of the patterns and simple experiments showthat these patterns are rigid-foldable, fl at-foldable, and have only one kinematic degree of freedom. These proper-ties make them appropriate for applications such as deployable architectural ceiling and façades. In addition, theyhave the potential to be applied as light cellular folded core material among several other possible engineeringapplications. REFERENCES[1] Schenk, M. and Guest, S. Geometry of miura-folded metamaterials. Proc. Natl. Acad. Sci. U.S.A. 2013, 110, 3276.[2] Wei, Z., Guo, Z., Dudte, L., Liang, H., Mahadevan, L. Geometric mechanics of periodic pleated origami. Phys. Rev. Lett.2013, 110, 215501.