Lightweight materials that are simultaneously strong and stiff are desirable for a range of applications from transportation to energy storage to defense. Micro- and nanolattices represent some of the lightest fabricated materials to date, but studies of their mechanical properties have produced inconsistent results that are not well captured by existing lattice models. We performed systematic nanomechanical experiments on four distinct geometries of solid polymer and hollow ceramic (Al_2O_3) nanolattices. All samples tested had a nearly identical scaling of strength (σy) and Young's modulus (E) with relative density (ρ¯), ranging from σy∝ρ¯1.45 to ρ¯1.92 and E∝ρ¯1.41 to ρ¯1.83, revealing that changing topology alone does not necessarily have a significant impact on nanolattice mechanical properties. Finite element analysis was performed on solid and hollow lattices with structural parameters beyond those realized experimentally, enabling the identification of transition regimes where solid-beam lattices diverge from existing analytical theories and revealing the complex parameter space of hollow-beam lattices. We propose a simplified analytical model for solid-beam lattices that provides insight into the mechanisms behind their observed stiffness, and we investigate different hollow-beam lattice parameters that give rise to their aberrant properties. These experimental, computational and theoretical results uncover how architecture can be used to access unique lattice mechanical property spaces while demonstrating the practical limits of existing beam-based models in characterizing their behavior.

中文翻译：

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重新审视三维晶格结构的力学性能空间

从运输到能量存储再到国防的一系列应用都需要同时具有强度和刚度的轻质材料。微米和纳米晶格代表了迄今为止最轻的一些制造材料，但对其机械性能的研究产生了不一致的结果，现有晶格模型无法很好地捕捉到这些结果。我们对固体聚合物和空心陶瓷 (Al_2O_3) 纳米晶格的四种不同几何形状进行了系统的纳米力学实验。所有测试样品的强度 (σy) 和杨氏模量 (E) 与相对密度 (ρ¯) 的比例几乎相同，范围从 σy∝ρ¯1.45 到 ρ¯1.92 和 E∝ρ¯1.41 到 ρ¯1.83，揭示了仅改变拓扑结构并不一定会对纳米晶格机械性能产生重大影响。对实心和空心晶格进行了有限元分析，其结构参数超出了实验实现的范围，从而能够识别实心梁格子与现有分析理论不同的过渡区，并揭示空心梁格子的复杂参数空间。我们为实心梁晶格提出了一个简化的分析模型，该模型可以深入了解其观察到的刚度背后的机制，并且我们研究了导致其异常特性的不同空心梁晶格参数。这些实验、计算和理论结果揭示了如何使用架构来访问独特的晶格机械特性空间，同时展示了现有基于梁的模型在表征其行为方面的实际局限性。