Gradient Origami Metamaterials for Programming Out-of-Plane Curvatures

Origami structures are a traditional Japanese art that have recently found their way into engineering applications due to their powerful capability to transform flat 2D structures into complex 3D structures along their creases. This has given a rise to their application as designer materials with unprecedented mechanical characteristics, also known as metamaterials. Herein, gradient Miura-ori origami metamaterials are introduced as a method to preprogram out-of-plane curvatures. Several types of unit cell distributions in the origami lattice structure including checkered, linear gradient, concave radial gradient, convex radial gradient, and striped are considered. The results show that these distributions of Miura-ori origami can create single- or double curvatures including twisting, saddling, bending, local inflation, local twisting, local bending, and wavy shapes, when the origami metamaterial is loaded in compression. All the Gaussian curvatures (negative, positive, and zero) can be achieved using the proposed models. The approach helps tailoring complex preprogrammed surface geometries by employing linearly varying gradient distributions of Miura-ori origami.