碳纳米管轴向压缩行为的分子动力学模拟

用分子动力学方法对轴向压缩下的单壁和双壁碳纳米管的屈曲行为进行了模拟研究。在分子动力学模拟中,采用Tersoff-Brenner势结合6～12形式的Lennard-Jones势描述碳原子之间的相互作用。计算结果表明:单壁碳纳米管的屈曲临界力随着半径的增大而增大,但半径对其临界应力的影响只是在管径较小的情况下比较明显;在载荷下,双壁碳纳米管的外管首先失稳;双壁碳纳米管的屈曲临界应变高于外管对应的单壁碳纳米管的临界应变,而低于内管对应的单壁碳纳米管的临界应变。但是,双壁碳纳米管的屈曲临界力明显高于内、外管对应的单壁碳纳米管的临界力。

Molecular Dynamics Simulation on Buckling Behavior of Carbon Nanotubes Under Axial Compression

Buckling behavior of armchair sing-walled and double-walled carbon nanotubes under axial compression were presented by molecular dynamics simulation.The interaction force between atoms was modeled using the empirical bond-order Tersoff-Brenner potential coupled with the Lennard-Jones potential.The computational results show that the critical axial force of CNTs(carbon nanotubes)increased monotonically with increasing tube radius.But the dependence of the critical axial force of CNTs on the tube radius is remarkably only for small values of the tube radius.It is evident from simulation results that the outer tube of double-walled nanotubes strats to deform first.The results also indicate that the critical strain of DWCNTs is less than that of its isolated inter tube and bigger than that of its isolated outer tube.