微/纳米机电系统中的碳纳米管的机械性能研究

【作者】 何兰；

【导师】 沈允文；

【作者基本信息】 西北工业大学 ， 机械设计及理论， 2004， 硕士

【摘要】 本文采用分子动力学模拟方法对微／纳米机电系统中的碳纳米管的机械性能进行了研究。首先，简述了碳纳米管的研究现状和应用于纳米材料的各种数值模拟方法，同时介绍了碳纳米管的结构和特性以及碳纳米管在微／纳米机电系统中的应用前景。其次，对分子动力学模拟方法进行了评述，分析了应用于碳纳米管材料模拟中的各种势函数，得出了采用Tersoff-Brenner势函数对碳纳米管进行模拟将得到较好的结果。再次，深入研究了分子动力学模拟的基本算法，包括物理建模、势能截断、计算短程作用力的方法、时间求积算法和边界条件问题等，并详细讨论了分子动力学模拟前的数据准备工作、运行时的控制方法、影响系统达到平衡状态的各种因素和模拟后对原子结构的观测以及宏观特性的统计控制方法。进而，建立了碳纳米管的空间模型和物理模型，采用分子力学方法对初始模型进行了能量最优化计算，并探讨了应变能与碳纳米管的结构的关系。随后，对能量最优化后的碳纳米管进行了热稳定性分析，同时探讨了碳纳米管在低温和高温下的拉伸响应，估算了碳纳米管的杨氏模量，计算了其弹性应变。最后，总结全文并给出了今后的研究方向。更多还原

【Abstract】 In this thesis, the author studies the mechanical properties of carbon nanotubes in the micro/nano electrical and mechanical system (M/NEMS) by molecular dynamics simulation. Firstly, recent studies on carbon nanotubes and simulation methods of nano materials are introduced. The molecular structure and properties of carbon nanotubes are given. The potential applications of carbon nanotubes in M/NEMS are presented. Secondly, molecular dynamics simulation is reviewed. It is suggested that Tersoff-Brenner potential function is better than other potential functions in simulating carbon nanotubes. Thirdly, Basic approaches of molecular dynamics simulation, which include building the model potential, potential truncation, short-range interaction computations, integration methods, boundary conditions and so on, are studied in detail. They are discussed in detail which include preparations for data before simulating, control method during simulating, different factors related to equilibration of simulating systems, observation of atomic structure after simulating, statistic and control methods of macro characters. Fourthly, the mathematics model of single-wall carbon nanotube (SWCNT) is built. Molecular Mechanics Calculation is used to minimize the energy ofinitial model of SWCNT. The relationship of strain energy and structure of SWCNT is studied. Fifthly, thermal stability is analyzed based on optimized structure of SWCNT. Under low temperature and high temperature, tensile responses of SWCNT are probed. Young’s modulus and elastic strain are showed. Finally, the main points of the whole paper are sum up and researching approaches further are given.更多还原