单壁碳纳米管力学性能研究

发布时间：2018-07-06 15:37

本文选题：碳纳米管 + 分子动力学　；参考：《燕山大学》2015年硕士论文

【摘要】：作为一种新型纳米材料,碳纳米管具有许多独特的性能,有望在纳米机械及材料增强体等领域获得广泛的应用。碳纳米管的力学性能参数是其主要参数,对其研究具有重要意义。分子动力学是目前纳米力学计算机模拟中应用最广泛的一种方法,此方法通过模拟原子运动并结合统计力学原理得到系统热学和力学等材料特性。本文采用分子动力学软件LAMMPS编程和REBO势函数模拟了单壁碳纳米管在拉伸与压缩时的力学性能。通过单壁碳纳米管在不同温度下弛豫,得到了温度对原子热运动和碳纳米管结构的影响,并由此绘制出径向分布函数。通过不同温度下碳纳米管的拉伸模拟,给出温度、碳纳米管尺寸及手性角对其力学性能的影响。通过对比锯齿型碳纳米管的拉伸和压缩模拟,给出碳纳米管在拉伸与压缩过程中的不同性能表现。人工制备的碳纳米管一般包含多种缺陷。通过对含单点缺陷、典型两点缺陷及Stone-Wall缺陷锯齿型碳纳米管的模拟并与无缺陷碳纳米管进行对比,给出缺陷对碳纳米管力学性能的影响。分子结构力学是研究碳纳米管力学性能的另一种方法,该方法用微梁等效碳-碳键,然后整个体系采用结构力学方法求解。采用分子结构力学方法模拟了锯齿型和扶手椅型碳纳米管的拉伸过程,给出不同直径对两种碳纳米管弹性模量及泊松比的影响。通过引入热膨胀系数体现温度对碳-碳键和结构力学常数的影响,探讨了温度对碳纳米管的力学性能影响。
[Abstract]:As a new type of nano-materials, carbon nanotubes (CNTs) have many unique properties and are expected to be widely used in nano-mechanical and material reinforcements. The mechanical properties of carbon nanotubes (CNTs) are the main parameters, which is of great significance to the study of CNTs. Molecular dynamics is one of the most widely used methods in computer simulation of nanomechanics at present. By simulating atomic motion and combining with the principle of statistical mechanics, the properties of materials such as system heat and mechanics are obtained. In this paper, the mechanical properties of single-walled carbon nanotubes during tensile and compression have been simulated by using molecular dynamics software LAMMPS and REBO potential function. The effects of temperature on atomic thermal motion and carbon nanotube structure were obtained by relaxation of single-walled carbon nanotubes at different temperatures, and the radial distribution function was derived. The effects of temperature, size and chiral angle on the mechanical properties of carbon nanotubes (CNTs) were studied by the tensile simulation of CNTs at different temperatures. By comparing the tensile and compression simulation of sawtooth carbon nanotubes, the different properties of carbon nanotubes in the process of drawing and compression are presented. Artificial carbon nanotubes (CNTs) generally contain many defects. The effects of defects on mechanical properties of carbon nanotubes (CNTs) with single point defects, typical two-point defects and Stone-Wall defects were simulated and compared with those of non-defect CNTs. Molecular structural mechanics is another method to study the mechanical properties of carbon nanotubes. The tensile process of sawtooth and armchair carbon nanotubes was simulated by molecular structural mechanics. The effects of different diameters on elastic modulus and Poisson's ratio of two carbon nanotubes were given. The influence of temperature on the mechanical properties of carbon nanotubes was investigated by introducing the thermal expansion coefficient to reflect the effect of temperature on the carbon bond and structural mechanical constants.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O613.71

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