Graphene assembly, e.g. graphene aerogel, is an open-cell porous material with randomly distributed graphene sheets and voids. In this study, we propose a method to generate the 3D graphene assembly models which can reasonably display the structural properties of graphene aerogel. Our 3D graphene assembly models are firstly established by a Voronoi construction method that is usually used to build the polycrystalline materials. The optimization and relaxation are then conducted to obtain 3D graphene assembly with proper structures by using molecular dynamics (MD) simulations. In order to explore the mechanical properties of graphene assembly, the tensile and compressive tests are carried out by MD simulations. The results show that the 3D graphene assembly reveals auxetic behavior under compression while it has positive Poisson’s ratio under tension. We also find that the Poisson’s ratios are specifically related to the grain sizes and mass densities. Furthermore, from our simulation the stress–strain relations for the compressive tests and tensile tests are also obtained. The compressive Young’s modulus, tensile Young’s modulus, compressive strength and tensile strength are found to follow the power law relation to the mass density with the exponential factors of 2.31756, 2.33005, 2.6243 and 1.5084, respectively.

石墨烯组件，例如石墨烯气凝胶，是一种具有随机分布的石墨烯片和空隙的开孔多孔材料。在这项研究中，我们提出了一种生成3D石墨烯组装模型的方法，该模型可以合理地显示石墨烯气凝胶的结构特性。我们的3D石墨烯装配模型首先是通过Voronoi构造方法建立的，该方法通常用于构造多晶材料。然后，通过使用分子动力学（MD）模拟，进行优化和松弛，以获得具有适当结构的3D石墨烯组件。为了探索石墨烯组件的机械性能，通过MD模拟进行了拉伸和压缩测试。结果表明，3D石墨烯组件在受压时显示出拉张行为，而在拉伸下却具有正泊松比。我们还发现，泊松比与晶粒尺寸和质量密度特别相关。此外，从我们的仿真中，还获得了压缩测试和拉伸测试的应力-应变关系。发现压缩杨氏模量，拉伸杨氏模量，抗压强度和抗张强度遵循幂律与质量密度的关系，其指数因子分别为2.31756、2.33005、2.6243和1.5084。