The behavior of a functionally graded origami structure subjected to quasi-static compression

Abstract Origami-inspired metamaterials are receiving increasing attention because they can provide unusual and favorable mechanical properties that are determined by their unique patterned geometry. In this paper, a novel design based on Miura-ori pattern, with varying geometries throughout its volume, is proposed and analyzed under quasi-static compression. Both experiments and numerical simulations indicate that the new design, both two-dimensional graded (2DG) and three-dimensional graded (3DG), can generate periodically graded stiffness as well as superior energy absorption. The sensitivity of the graded behavior to various parameters of the problem is studied. It appears that both in-plane and out-of-plane graded stiffness can be accomplished with an appropriate introduction of the geometric gradients. As to the coupling effect, when the 3DG model is compressed in the z-direction, the existence of the x-directional gradient tends to reduce the stress level and specific energy absorption (SEA), whereas when compressed in the x-direction, the opposite trend is observed regarding the z-directional gradient. Comparing with the conventional design, the proposed design can achieve an increase of 129.68% in SEA in the optimal case. In general, the proposed origami metamaterial, whose behavior can be customized and programmed, shows great potential in engineering applications where a non-uniform response is needed.