Jin Y, Yuan F G
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7921, USA.
J Nanosci Nanotechnol. 2005 Apr;5(4):601-8. doi: 10.1166/jnn.2005.071.
Macroscopic fracture parameters are investigated on 2D graphene systems containing atomic-scale cracks. In the discrete atomistic simulations the interatomic forces are described by the Tersoff-Brenner potential. Two methods to calculate the elastic energy release rates in atomic systems, the global energy method and the local force method, are developed. The values of energy release rates of several graphene systems in symmetric (mode I) and antisymmetric (mode II) small deformation are obtained from atomistic simulations and then compared with the results obtained through homogenized material properties based on linear elastic fracture mechanics. The results show good agreement between discrete atomistic and continuum mechanics modeling for fracture. Meanwhile, atomic stress fields in front of crack tips are investigated through molecular mechanics simulation by applying remote K-field deformation. The atomic stress distributions match very well with those of linear elastic solutions. These establish connections of fracture parameters between microscopic and macroscopic description of fracture in covalently bonded solids.
在含有原子尺度裂纹的二维石墨烯系统上研究了宏观断裂参数。在离散原子模拟中，原子间力由Tersoff-Brenner势描述。开发了两种计算原子系统中弹性能量释放率的方法，即全局能量法和局部力法。通过原子模拟获得了几个石墨烯系统在对称（I型）和反对称（II型）小变形下的能量释放率值，然后将其与基于线弹性断裂力学的均匀材料特性所得到的结果进行比较。结果表明，离散原子模型和连续介质力学模型在断裂方面具有良好的一致性。同时，通过施加远程K场变形，利用分子力学模拟研究了裂纹尖端前方的原子应力场。原子应力分布与线弹性解的分布非常吻合。这些建立了共价键合固体中断裂微观和宏观描述之间的断裂参数联系。
