基于分子动力学方法，采用 Tersoff 势函数，研究了含中心裂纹扶手椅型单层石墨烯薄膜的破坏过程．得到了相应的应力- 应变曲线及破坏形态，分析了裂纹尺寸、应变率以及温度变化对含中心裂纹石墨烯薄膜拉伸力学性能的影响．研究结果表明: 随着裂纹尺寸的增大及温度的升高，石墨烯薄膜的破坏强度和破坏应变均减小，裂纹开始扩展时对应的应力减小; 随着应变率增大，石墨烯薄膜的破坏强度和破坏应变均增加，裂纹的起裂应力及扩展过程中的平均速度均增加; 薄膜的破坏均是从中心裂纹附近开始，随着裂纹尺寸、应变率及温度的变化，石墨烯薄膜表现出不同的破坏机制; 较高应变率作用下，薄膜中心和边缘处均出现 C—C 键断裂．

The destruction process of armchair single- layered graphene sheets with central crack was investigatedvia the molecular dynamics simulation based on Tersoff potential function,and the corresponding stress- straincurves as well as the failure mode were obtained.Then,the effects of crack length,strain rate and temperature onthe tensile mechanical properties of armchair graphene sheets with central crack were explored.It is found that (1)the fracture strength,the fracture strain and the crack initiation stress all decrease with the increase of crack lengthand temperature; (2) with the increase of strain rate,the fracture strength and strain,the crack initiation stressand the average cracking speed increase accordingly; (3) the fracture begins around the central crack and exhibitsdifferent deformation mechanisms with the variation of crack length,strain rate and temperature; and (4) C-Cbonds break in both the center and the edge of graphene sheets at higher strain rates.