The mechanical characteristics of graded Miura-ori metamaterials

Origami structures have been widely used for impact energy absorption in lightweight structures. Recently, Miura-ori metamaterial structures have been attractively investigated due to their unique geometric properties, adjustable stiffness and excellent energy absorption performance. In this study, the quasi-static compression characteristics of a Miura-ori based 3D printed stainless steel metamaterial are investigated. It is a graded metamaterial composed of multiple Miura-ori layers with different acute angles. The effects of different gradients on structural deformation and energy absorption were investigated by experiment and numerical simulation. The results show that the graded metamaterials have higher specific energy absorption (SEA) than the uniform ones. In addition, the graded metamaterials effectively reduce the decreasing amplitude of the compression loading after the peak force and improve the SEA compared with the uniform metamaterials. When the volume of the metamaterials remains the same, the energy absorption increases with the gradient interval size. The metamaterial with a negative gradient from the top and bottom to the middle layer has better energy absorption capacity.