单层石墨烯温度效应的分子动力学模拟

在不同温度条件（0 K-3000K）下,采用AIREBO势函数对单层石墨烯薄膜的弛豫性能和拉伸性能进行分子动力学模拟,研究单层石墨烯在弛豫过程中温度效应对其原子结构的影响以及单层石墨烯在拉伸过程中力学性能与温度效应的关系.研究结果表明：单层石墨烯的弛豫性能和拉伸性能均对温度具有很强的依赖性.理想状态下,单层石墨烯的弛豫是一个原子结构的动态平衡过程,随着温度升高,石墨烯稳定性降低,弛豫过程中原子的波动起伏变得不规则和剧烈起来.在温度从0K上升到3000K的过程中,单层石墨烯的拉伸强度、拉伸极限应变和弹性模量值均呈现下降趋势,且锯齿型石墨烯的弹性模量对温度的依赖程度比扶手椅型大,薄膜的拉伸随温度变化表现出不同的破坏形态.

Molecular dynamics simulation of temperature effect on mono-layer graphene sheets

The tensile and relaxation properties of mono-layer graphene sheets at different temperatures （0 K-3000 K） were investigated based on Molecular Dynamics（MD） simulation with AIREBO potential. The temperature effect on atomic structure of mono-layer graphene sheets during relaxation was analyzed as well as the relationship between temperature and mechanical properties of mono-layer graphene sheets under tensile stress/strain/load. The simulation results showed that the tensile properties and relaxation properties of mono-layer graphene sheets were all highly dependent on the temperature. When T=0 K, the relaxation of mono-layer graphene sheets was a dynamic equilibrium process with a complete atomic structure. The stability of mono-layer graphene sheets reduced when the temperature increased, the fluctuations of atoms during relaxation became somewhat irregular and violent with the increasing temperature. The tensile strength, ultimate tensile strain and Young＇s modulus of mono-layer graphene sheets all decreased when the temperature rose from 0 K to 3000 K. The Young＇s modulus of zigzag graphene sheets had a more temperature dependence than armchair graphene sheets, and the failure modes of mono-layer graphene sheets were different when the temperature changed.