扶手椅型单壁碳纳米管的扭转和弯曲变形

Torsional and bended deformation of armchair single-walled carbon nanotube

实验提出了一种针对单壁碳纳米管的原子尺度有限元模型。利用该模型对(5,5)型扶手椅型单壁碳纳米管的扭转和弯曲变形过程进行了模拟,发现其屈曲的临界扭转和纯弯曲角度分别约为40°和20,°与扭转屈曲相比,该碳管更容易发生弯曲屈曲。当弯扭复合变形时发生屈曲后,卸载时壁面褶皱的回复比较缓慢。在某些情况下,碳管的局部势能的变化与经典连续介质力学理论不一致,对此本文结合原子势理论给出了模拟结果的原子尺度的解释。

A finite element model for single - walled carbon nanotubes （SWCNT） is introduced. The model is applied to torsional and bended deformation simulations of a （ 5,5 ） armchair single - walled carbon nanotube. The critical bucking angles in twisting and pure bending are about 40° and 20°, respectively. Bucking deformation occurs more easily in bending than in twisting. When the nanotube is under combined torsion and bend load, it takes a long period for the wall to return back to cylinder shape once buckling occurs. In some cases, the change of local potential energy in the nanotube is inconsistent with classical continuum medium mechanics. Based on the atomic potential energy theory, this paper provides an explanation in atomic scale for these simulation results.