Defects including topological and vacancy defects have been observed in graphene during fabrication. Defects are also introduced to break the lattice symmetry of graphene and thereby obtain enhanced optoelectronic and other properties. It is important that gains in certain properties due to the presence defects are not at the expense of mechanical strength which is important in handling graphene and device fabrication. This paper presents a comprehensive study of the tensile strength and fracture strain of monolayer graphene with commonly observed topological defects and nanopores. Both molecular dynamics and the atomic-scale finite element method (AFEM) are used in this study, and the accuracy of AFEM in simulating complex topological and vacancy defects including line defects is established. It is found that the tensile strength properties have a complex dependency on the defect shape, size, and chirality. Certain defect geometries are found to be mechanically superior to other defect geometries thereby supporting the concept of topological design of graphene to optimize properties. The study also establishes AFEM as an efficient and potential tool for topological optimization of the mechanical behaviour of graphene.

中文翻译：

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具有复杂空位和拓扑缺陷的石墨烯拉伸强度性能的原子模拟

在制造过程中在石墨烯中观察到包括拓扑和空位缺陷在内的缺陷。还引入了缺陷来破坏石墨烯的晶格对称性，从而获得增强的光电和其他性能。重要的是，由于存在缺陷而获得的某些性能的提高不会以机械强度为代价，而机械强度在处理石墨烯和器件制造中很重要。本文综合研究了具有常见拓扑缺陷和纳米孔的单层石墨烯的拉伸强度和断裂应变。本研究同时使用分子动力学和原子尺度有限元方法（AFEM），建立了AFEM在模拟复杂拓扑和空位缺陷（包括线缺陷）中的准确性。发现拉伸强度特性与缺陷形状、尺寸和手性具有复杂的依赖性。发现某些缺陷几何形状在机械上优于其他缺陷几何形状，从而支持石墨烯拓扑设计以优化性能的概念。该研究还将 AFEM 确立为石墨烯力学行为拓扑优化的有效和潜在工具。