An unusual combination of ultralight weight and outstanding mechanical properties of graphene aerogel made it popular for a wide range of applications in the fields of material science, energy, and technology. In the present work, the mechanical properties and fracture behavior of graphene aerogels, which are highly brittle in nature, are investigated using molecular dynamics (MD) simulations. In tensile tests, elastic modulus and tensile strength exhibit a power law dependence on the density with their exponents predicted to be 2.95 ± 0.05 and 1.61 ± 0.04, respectively, which are in an excellent agreement with the reported works in the literature. In the compression simulations, Lennard-Jones contribution in the AIREBO potential is vital to predicting early densification. Moreover, in the compression loading–unloading simulations, as the density decreases, the dissipation energy increases. At the onset of the crack propagation, as the crack length to height ratio increases, the fracture strength decreased. However, for a considered range of the ratios, the fracture toughness values were nearly constant for all densities. Furthermore, the fracture toughness shows a power law dependence on the density, with the exponent estimated to be 1.41 ± 0.04. The outcome of this work is a vital step in the in-depth understanding of nanomechanics while designing advanced, highly porous materials.

中文翻译：

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石墨烯气凝胶的力学性能和断裂行为的分子研究。

石墨烯气凝胶的超轻重量和出色的机械性能的不寻常组合，使其在材料科学，能源和技术领域的广泛应用中广受欢迎。在当前的工作中，使用分子动力学（MD）模拟研究了性质非常脆的石墨烯气凝胶的机械性能和断裂行为。在拉伸试验中，弹性模量和拉伸强度表现出幂密度对密度的依赖性，其指数分别为2.95±0.05和1.61±0.04，这与文献报道的工作极为吻合。在压缩模拟中，Lennard-Jones对AIREBO潜力的贡献对于预测早期致密化至关重要。此外，在压缩装卸模拟中，随着密度降低，耗散能量增加。在裂纹扩展开始时，随着裂纹长高比的增加，断裂强度降低。但是，对于一定比例的比率，断裂韧性值对于所有密度几乎都是恒定的。此外，断裂韧性显示出幂律对密度的依赖性，其指数估计为1.41±0.04。这项工作的成果是在设计先进的高度多孔材料时深入了解纳米力学的重要一步。断裂韧性显示出幂律对密度的依赖性，指数估计为1.41±0.04。这项工作的成果是在设计先进的高度多孔材料时深入了解纳米力学的重要一步。断裂韧性显示出幂律对密度的依赖性，指数估计为1.41±0.04。这项工作的成果是在设计先进的高度多孔材料时深入了解纳米力学的重要一步。