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Deformation and instability of three-dimensional graphene honeycombs under in-plane compression: Atomistic simulations
Extreme Mechanics Letters ( IF 4.3 ) Pub Date : 2020-06-26 , DOI: 10.1016/j.eml.2020.100861
Luoxia Cao , Feifei Fan

While monolayer graphene is known strong and brittle, its three-dimensional (3D) scaleup to architected assemblies, such as graphene aerogels, leads to superior compressibility and resilience. 3D graphene assemblies feature nanoscale characteristic dimensions, and their constitutive mechanical behaviors arise from complex deformation modes. However, whether 3D graphene assemblies exhibit deformation mechanisms widely observed in conventional foams is unclear. Using molecular dynamics simulations, we explore the deformation and instability mechanisms in a 3D graphene honeycomb subjected to uniaxial in-plane compression. Our simulations capture the orientation-dependence of stress–strain response and deformation mode. Compression along the armchair direction causes progressive buckling and results in a structural transformation. In contrast, compression along the zigzag direction results in localized shearing. These findings demonstrate that deformation and instability mechanisms in 3D graphene honeycombs are very similar to those identified in hexagonal honeycombs at the macro-scale level, both experimentally and theoretically.



中文翻译:

平面压缩下三维石墨烯蜂窝的变形和不稳定性:原子模拟

尽管已知单层石墨烯坚固且易碎,但其三维(3D)放大到已构造组件(例如石墨烯气凝胶)的尺寸可带来出色的可压缩性和回弹力。3D石墨烯组件具有纳米级特征尺寸,其本构力学行为源自复杂的变形模式。然而,尚不清楚3D石墨烯组件是否表现出在常规泡沫中广泛观察到的变形机制。使用分子动力学模拟,我们探索了经受单轴平面压缩的3D石墨烯蜂窝的变形和不稳定性机制。我们的仿真捕获了应力应变响应和变形模式的方向依赖性。沿着扶手椅方向的压缩会导致逐渐屈曲并导致结构变形。相反,沿之字形方向的压缩会导致局部剪切。这些发现表明,无论是在实验上还是在理论上,3D石墨烯蜂窝的变形和不稳定性机理都与宏观上在六角形蜂窝中鉴定出的那些非常相似。

更新日期:2020-06-26
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