Deformation and instability of three-dimensional graphene honeycombs under in-plane compression: Atomistic simulations
Deformation and instability of three-dimensional graphene honeycombs under in-plane compression: Atomistic simulations
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DOI：
10.1016/j.eml.2020.100861
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发表时间：
2020-09-01
影响因子：
4.7
通讯作者：
Fan, Feifei
中科院分区：
文献类型：
--
作者：
Cao, Luoxia;Fan, Feifei
虽然单层石墨烯坚固且易碎，但其三维 (3D) 放大到石墨烯气凝胶等架构组件可带来卓越的压缩性和弹性。 3D 石墨烯组件具有纳米级特征尺寸，其本构机械行为源自复杂的变形模式。然而，3D 石墨烯组件是否表现出在传统泡沫中广泛观察到的变形机制尚不清楚。通过分子动力学模拟，我们探索了 3D 石墨烯蜂窝体在单轴面内压缩下的变形和不稳定机制。我们的模拟捕获了应力应变响应和变形模式的方向依赖性。沿扶手椅方向的压缩会导致逐渐屈曲并导致结构转变。相反，沿锯齿形方向的压缩会导致局部剪切。这些发现表明，无论是实验还是理论上，3D 石墨烯蜂窝中的变形和不稳定机制与宏观尺度上六角形蜂窝中确定的变形和不稳定机制非常相似。 (C) 2020 Elsevier Ltd. 保留所有权利。
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. (C) 2020 Elsevier Ltd. All rights reserved.