Abstract Cellular materials are attractive for applications in structural protection and impact energy absorption. Progressive buckling of cell walls during compression delivers good specific strength and energy absorption. In a cellular solid, the arrangement of the cell wall material with respect to the direction of loading has a key influence on its mechanical response. This is especially true for cellular materials loaded in dynamic compression, where dynamic buckling and inertial stabilisation effects can also be sensitive to the alignment of cell walls with the loading direction. Origami-based geometries provide one route to designing cellular materials to achieve controllable collapse modes and, in some cases, auxeticity. The stacked Miura-ori geometry has been proposed recently as a strategy for constructing a volume of periodic cellular solid from an origami-inspired unit cell. However, these have been previously difficult to manufacture. Using selective laser melting, an additive manufacturing process, stainless steel stacked origami materials were produced in a periodic cellular arrangement for the first impact tests on such a cellular material. The origami specimens were tested with a gas gun and direct impact Hopkinson bar apparatus, at impact speeds of 50 m/s and 100 m/s. The auxetic behaviour of the origami fold was observed to diminish at the higher impact speeds, due to the localisation of deformation to individual fold layers. Different fold configurations were studied through simulations, with clear trends observed between fold angle and specific energy absorption and strength. Lastly, the influence of material strain rate sensitivity was investigated numerically.

中文翻译：

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金属叠层折纸蜂窝材料的冲击响应

摘要 蜂窝材料在结构保护和冲击能量吸收方面的应用很有吸引力。压缩过程中单元壁的逐渐屈曲提供了良好的比强度和能量吸收。在多孔固体中，细胞壁材料相对于加载方向的排列对其机械响应具有关键影响。对于以动态压缩加载的蜂窝材料尤其如此，其中动态屈曲和惯性稳定效应也可能对蜂窝壁与加载方向的对齐很敏感。基于折纸的几何形状提供了一种设计蜂窝材料的途径，以实现可控的坍塌模式，在某些情况下，还可以实现拉胀。堆叠的 Miura-ori 几何最近被提出作为一种策略，用于从受折纸启发的单元格中构建一定体积的周期性单元格固体。然而，这些以前难以制造。使用选择性激光熔化（一种增材制造工艺），不锈钢堆叠折纸材料以周期性蜂窝状排列生产，用于对此类蜂窝状材料的首次冲击测试。折纸样品用气枪和直接冲击霍普金森棒装置进行测试，冲击速度为 50 m/s 和 100 m/s。由于变形局部化到单个折叠层，观察到折纸折叠的拉胀行为在较高的冲击速度下减弱。通过模拟研究了不同的折叠配置，在折叠角与比能量吸收和强度之间观察到明显的趋势。最后，数值研究了材料应变率敏感性的影响。