单壁碳纳米管弯曲屈曲行为的原子模拟

Atomistic Simulation for the Buckling of Single-walled Carbon Nanotubes upon Bending

借助一个原子尺度的数值计算方法模拟单壁碳纳米管在弯曲载荷作用下的机械反应。碳原子之间的影响用Tersoff-Brenner势函数描述,计算了每个迭代步系统总势能对原子位置的一阶和二阶导数,系统的平衡位置通过New-ton’s方法来确定。不同类型的纳米管被模拟,当弯曲曲率达到一定值时,纳米管将发生屈曲变形。讨论了纳米管的长度和直径对屈曲变形以及关键屈曲曲率的影响。测试了2种弯曲加载方式,并对结果进行了比较和讨论。

An atomistic scale numerical method was provided to model the buckling of single-walled carbon nanotubes upon bending. Tersoff-Brenner potential was employed to describe the C-C atomistic interaction, and the stable state was determined using the Norton＇s method with the calculated first-and second-order derivatives of the total energy with respect to the atomistic coordinates. The buckling occured when the bending curvature reached to the critical value. Several types of nanotubes swere tested to investigate the effect of the tube type, and tube length and diameter on the bending buckling behavior. Two loading manners were tested, and the differences between these two manners were compared.