论文部分内容阅读
小变形情况下,碳纳米管C-C共价键间的相互作用可以用基于分子力学的宏观力学模型进行模拟.其中,基于分子结构力学的等价结构力学模型是最为有效的碳纳米管弹性参数的预测模型.现有的碳纳米管的等价结构力学模型是用具有刚性节点的空间框架结构模拟碳纳米管的原子晶格受力和变形的关系.根据碳纳米管的原子晶格的变形特点,本文首次提出了一个用柔性节点空间框架模拟碳纳米管原子晶格键角变化的分析模型,再通过应变能等价推导了柔性节点的等价抗弯刚度与分子力学中力常数的关系,从而给出了一个更精确的计算碳纳米管等价弹性参数的分子结构力学模型.文中用ANSYS计算了不同尺寸的锯齿型(zigzag)和扶手型(armchair)单壁碳纳米管的轴向杨氏模量、泊松比、剪切模量及径向杨氏模量,分析了碳纳米管的尺寸效应,并且与其它各种模型所得结果进行了比较.计算结果表明,本文所给碳纳米管的等价柔性节点空间框架模型不仅计算简单、高效,而且准确;并可以直接推广到多壁碳纳米管等价弹性模量的计算及碳纳米管的稳定和动力分析.
In the case of small deformation, the interaction between the CC covalent bonds in carbon nanotubes can be modeled by a macroscopic mechanical model based on molecular mechanics, in which the equivalent structural mechanics model based on molecular mechanics is the most effective parameter for the elastic properties of carbon nanotubes Prediction model.The existing equivalent mechanical model of carbon nanotubes is to simulate the relationship between the deformation and the lattice deformation of carbon nanotubes by using the space frame structure with rigid nodes.According to the deformation characteristics of the atomic lattice of carbon nanotubes , This paper presents for the first time an analytical model for simulating the lattice angle variation of carbon nanotubes using a flexible node space frame and deduces the relationship between the equivalent flexural stiffness of flexible nodes and the force constant in molecular mechanics through the equivalent strain energy. A more accurate molecular structural mechanics model for calculating the equivalent elastic parameters of carbon nanotubes is given.The axial yangs of zigzag and armchair single-walled carbon nanotubes of different sizes are calculated by ANSYS Modulus, Poisson’s ratio, shear modulus and radial Young’s modulus, the size effect of carbon nanotubes was analyzed, and the results obtained with other models The results show that the equivalent flexible node space frame model of carbon nanotubes given in this paper is not only simple, efficient and accurate, but also can be directly extended to the calculation of equivalent elastic modulus of multi-walled carbon nanotubes and carbon nanotubes Stability and dynamics analysis.