Quasi-static and dynamic mechanical properties of Miura-ori metamaterials

In this study, the compression behaviours of Miura-ori nylon metamaterials were experimentally and numerically investigated under quasi-static loading and impact loading. The Miura-ori sheets had four acute angles, 50 degrees, 55 degrees, 60 degrees, and 65 degrees, which produced four uniform specimens and nine graded specimens with different stacking orders. All specimens were manufactured by polymer 3D printing. The results showed that for the uniform structures, the specific energy absorption first increased with the acute angle alpha and then decreased when the angle alpha continued to increase. All the investigated graded structures considerably enhanced the energy absorption capacity and avoided the force drop after the initial peak force due to their different deformation modes compared with that of the uniform structures. For the impact loading tests, the initial peak force increased as the acute angle increased for the uniform specimens. Comparison experiments were carried out for specimens 50-55-60-65 with positive and negative gradients, and the results showed that the specimen with a negative gradient had a better energy absorption capacity.