Closed-cell metal foams are cellular solids that show unique properties such as high strength to weight ratio, high energy absorption capacity, and low thermal conductivity. Due to being computation and cost effective, modeling the behavior of closed-cell foams using regular unit cells has attracted a lot of attention in this regard. Recent developments in additive manufacturing techniques which have made the production of rationally designed porous structures feasible has also contributed to recent increasing interest in studying the mechanical behavior of regular lattice structures. In this study, five different topologies namely Kelvin, Weaire–Phelan, rhombicuboctahedron, octahedral, and truncated cube are considered for constructing lattice structures. The effects of foam density and impact velocity on the stress–strain curves, first peak stress, and energy absorption capacity are investigated. The results showed that unit cell topology has a very significant effect on the stiffness, first peak stress, failure mode, and energy absorption capacity. Among all the unit cell types, the Kelvin unit cell demonstrated the most similar behavior to experimental test results. The Weaire–Phelan unit cell, while showing promising results in low and medium densities, demonstrated unstable behavior at high impact velocity. The lattice structures with high fractions of vertical walls (truncated cube and rhombicuboctahedron) showed higher stiffness and first peak stress values as compared to lattice structures with high ratio of oblique walls (Weaire–Phelan and Kelvin). However, as for the energy absorption capacity, other factors were important. The lattice structures with high cell wall surface area had higher energy absorption capacities as compared to lattice structures with low surface area. The results of this study are not only beneficial in determining the proper unit cell type in numerical modeling of dynamic behavior of closed-cell foams, but they are also advantageous in studying the dynamic behavior of additively manufactured lattice structures with different topologies.

闭孔金属泡沫是多孔固体，具有独特的特性，例如高强度重量比、高能量吸收能力和低导热性。由于计算和成本效益，使用常规晶胞对闭孔泡沫的行为进行建模在这方面引起了很多关注。增材制造技术的最新发展使合理设计的多孔结构的生产变得可行，这也促使人们对研究规则晶格结构的机械行为的兴趣日益浓厚。在这项研究中，考虑了五种不同的拓扑结构，即 Kelvin、Weaire-Phelan、菱形八面体、八面体和截头立方体来构建晶格结构。泡沫密度和冲击速度对应力-应变曲线的影响，研究了第一峰值应力和能量吸收能力。结果表明，晶胞拓扑结构对刚度、第一峰值应力、失效模式和能量吸收能力有非常显着的影响。在所有晶胞类型中，开尔文晶胞表现出与实验测试结果最相似的行为。Weaire-Phelan 晶胞虽然在中低密度下显示出有希望的结果，但在高冲击速度下表现出不稳定的行为。与具有高斜壁比例的晶格结构（Weaire-Phelan 和 Kelvin）相比，具有高比例垂直壁的晶格结构（截断立方体和菱形八面体）显示出更高的刚度和第一峰值应力值。然而，至于能量吸收能力，其他因素也很重要。与具有低表面积的晶格结构相比，具有高细胞壁表面积的晶格结构具有更高的能量吸收能力。这项研究的结果不仅有利于确定闭孔泡沫动态行为数值建模中合适的晶胞类型，而且有利于研究具有不同拓扑结构的增材制造晶格结构的动态行为。