范德华力对多壁纳米碳管力学性质的影响

INFLUENCE OF VAN DER WAALS FORCE ON MECHANICAL PROPERTIES OF MULTI-WALL CARBON NANOTUBES

用分子动力学方法模拟了多壁纳米碳管在压缩、弯曲变形下力与变形的关系 .通过与组成多壁碳管的各单壁碳管的比较分析 ,揭示了多壁纳米碳管层间范德华力对碳管力学性质的影响 .采用Tersoff Brenner势描述每一单壁纳米碳管内原子间作用 ,采用Lennard Jones势描述碳管壁间范德华力 .计算结果表明 :多壁纳米碳管的比强度明显高于单壁纳米碳管 .纳米碳管的半径虽然对杨氏模量影响不大 ,但对纳米碳管的曲屈行为影响却相当显著 .

Linear and nonlinear mechanical properties of carbon nanotubes are studied by using molecular dynamics. Both single-wall and multi-wall nanotubes subjected to different external loading are simulated to examine the influence of van der Waals force on the property of multi-wall carbon nanotubes. The Tersoff-Brenner potential is used to describe the interaction of atoms in each wall and the van der Waals force between the walls is approximated through the use of the Lennard-Jones potential. Although the diameter has no remarkable effect on the Young's modulus, its influence on the buckling behavior of a nanotube is significant. The nonlinear property of multi-walled carbon nanotubes is discussed in detail.