Fig. 5.

Cellular origami metamaterial consisting of 36 tubes with $\alpha =75°$, $N=3$ arranged as zipper in the horizontal Y direction and as aligned in the vertical Z direction. (A) Kinematic folding sequence of the assemblage (Movie S3). (B) Compression stiffness of the metamaterial in the three Cartesian directions vs. extension. (C–E) Initial (red line) and deformed geometry of the assemblage at 90% extension for uniform compression tests in the X, Y, and Z directions, respectively. The deformed shapes are scaled so the mean displacement of the loaded surfaces is equal to the panel height ($a=1$) and do not represent stiffness. (F and G) Metamaterial prototypes constructed with additive manufacturing cannot undergo the full folding motion in A, but inherit the anisotropic mechanical properties of the cellular zipper assemblages. In F a soft metamaterial from resin with a wall thickness of 0.09 mm can be deformed by hand, whereas the polyamide assemblage in G with a wall thickness of 0.8 mm is substantially stiffer (Materials and Methods).