摘要
利用分子动力学方法研究了单壁碳纳米管拉伸变形行为,发现(8,8)～(22,22)单臂型碳纳米管和(9,0)～(29,0)锯齿型碳纳米管能在拉伸应变分别达到35%～38%和20%～27%的情况下仍处于弹性变形阶段,并从能量的角度解释了这一现象.分析了单壁碳纳米管管径和结构螺旋性对碳纳米管力学性质的影响.结果表明,碳纳米管的微观结构特征对其基本力学性质有着重要的影响.碳纳米管的杨氏模量在750～960GPa之间,并随着其半径的增加而减少;微观结构的影响使得锯齿形碳纳米管的模量高于单臂型碳纳米管.模拟结果显示,碳纳米管在拉伸过程中的结构变化特征不同于连续介质力学所描述的弹塑性断裂或脆性断裂.
The tension deformation behavior of single-walled carbon nanotubes （SWCNTs） was numerically studied with the molecular dynamics method. The simulations show that armchair SWCNTs （8,8）-（12,12） can be stretched by 35%-38% with no sign of plas- ticity or atomic rearrangement, while zigzag SWCNTs （9,0） - （29,0） by 20% - 27%. This peculiar behavior was explained from the viewpoints of the energy change. The effects of the chirality and the tube radius on the mechanical behavior of SWCNTs were further investigated. The results show that the micro structural characteristic of the configuration of a SWCNT has a great influence on its mechanical properties. The range of the Young＇s modulus is about 750-960 GPa, decreasing as the radius increases. The Young＇s modulus of the zigzag SWCNTs is higher than that of the armchair SWCNTs.
基金
国家自然科学基金(10172081)资助项目.
关键词
碳纳米管
分子动力学
螺旋性
拉伸
结构相关
single-walled carbon nanotube （SWCNT）, molecular dynamics, chirality, tension, structure-dependent
