In this paper, a temperature and size-dependent molecular model is proposed to calculate the mechanical properties of carbon nanotubes. The cross section of carbon nanotubes is regarded as a hexagonal ring structure, and the covalent bond between carbon atoms is regarded as a beam of nonlinear spring structure, that is, the molecular structure system is regarded as a "beam-helical spring" structure. For considering the wall thickness of carbon nanotube, the influence of force constant on the molecular structure model is analyzed. On this basis, according to the principle of molecular mechanics, the expressions of calculating surface Young's modulus, Poisson's ratio, shear modulus and bulk modulus are obtained. It is found that due to the wall thickness, the Young's modulus, shear modulus, and bulk modulus of carbon nanotubes decrease with the increase of radius size.

在本文中，提出了一个温度和尺寸相关的分子模型来计算碳纳米管的机械性能。碳纳米管的横截面被视为六边形环结构，碳原子之间的共价键被视为非线性弹簧结构的梁，即分子结构体系被视为“梁-螺旋弹簧”结构。考虑到碳纳米管的壁厚，分析了力常数对分子结构模型的影响。在此基础上，根据分子力学原理，得到了表面杨氏模量、泊松比、剪切模量和体积模量的计算表达式。发现由于壁厚、杨氏模量、剪切模量、