石墨烯力学性能的理论模型及模拟研究

发布时间：2018-07-07 15:47

本文选题：石墨烯材料 + 半连续体模型　；参考：《新疆大学》2017年硕士论文

【摘要】：随着石墨烯各种优异性能的深入研究,石墨烯在各个领域的应用潜能越来越大,因此对其基本性能的研究变得异常重要。本文基于半连续体模型分析方法研究了单层石墨烯的杨氏模量和在小应力下的挠度和谐振频率,并基于分子动力学方法模拟研究了石墨烯纳米带的尺度对其力学性能的影响。论文工作分为以下三个部分:(1)通过分析半连续体模型建立方法及AMBER势函数,构建了基于单层石墨烯纳米结构的形变位移关系,并运用该本构关系建立了单层石墨烯不同方向的杨氏模量的解析模型,分析了不同方向杨氏模量随石墨烯尺度的变化关系以及石墨烯的手性行为。结果表明,石墨烯两方向杨氏模量均随尺度的增加而增大,即两方向杨氏模量具有相同的尺寸效应且石墨烯表现出各向同性行为。(2)建立了单层石墨烯纳米带的挠度和谐振频率的解析模型,并分析了挠度和谐振频率随石墨烯纳米带长度、宽度的变化关系。结果表明,石墨烯纳米带的长度和宽度都会影响石墨烯纳米带的挠度和谐振频率的变化,但宽度对石墨烯纳米带力学特性的影响不大,长度是影响挠度和谐振频率的主要因素。(3)通过分子动力学方法模拟研究了锯齿型单层石墨烯纳米带在不同尺度探针作用下的谐振频率,并分析了石墨烯纳米带的长度、宽度及探针尺度对石墨烯纳米带谐振频率的影响。结果表明,石墨烯纳米带的长度、宽度和探针大小都会影响纳米带谐振频率的大小,但纳米带的宽度和探针的大小不是影响单层石墨烯纳米带谐振频率的主要因素,长度才是影响其谐振频率的主要因素。本论文主要是运用理论建模和分子动力学模拟的方法研究了石墨烯纳米材料的力学性能,并取得了一些成果。该研究结果对研究石墨烯的其它力学特性提供一定的参考价值,也对进一步研究单层石墨烯材料的其它力学性能提供一个新思路。
[Abstract]:With the in-depth study of various excellent properties of graphene, the application potential of graphene in various fields is increasing, so the study of its basic properties becomes extremely important. In this paper, the Young's modulus of graphene monolayer and the deflection and resonance frequency under small stress are studied based on semi-continuum model. The effects of the size of graphene nanobelts on the mechanical properties of graphene nanobelts are simulated based on the molecular dynamics method. The work of this paper is divided into three parts as follows: (1) the deformation displacement relationship of graphene nanostructures based on monolayer is constructed by analyzing the method of establishing semi-continuum model and the potential function of Amber. The analytical model of Young's modulus in different directions of graphene monolayer is established by using the constitutive relation. The variation of Young's modulus in different directions with the scale of graphene and the chiral behavior of graphene are analyzed. The results show that the Young's modulus in both directions of graphene increases with the increase of the scale. That is, the Young's modulus in two directions has the same size effect and graphene exhibits isotropic behavior. (2) the analytical model of deflection and resonance frequency of graphene nanoribbons is established, and the deflection and resonant frequency with the length of graphene nanoribbons are analyzed. The variation of width. The results show that the length and width of graphene nanobelts affect the deflection and resonant frequency of graphene nanobelts, but the width has little effect on the mechanical properties of graphene nanoribbons. Length is the main factor affecting deflection and resonant frequency. (3) Resonance frequency of zigzag monolayer graphene nanoribbons under different scale probe is simulated by molecular dynamics method, and the length of graphene nanoribbons is analyzed. Effects of width and probe size on resonance frequency of graphene nanobelts. The results show that the length, width and probe size of graphene nanobelts all affect the resonant frequency of nanobelts, but the width of nanobelts and the size of probes are not the main factors affecting the resonant frequency of graphene nanobelts. The length is the main factor affecting the resonant frequency. In this paper, the mechanical properties of graphene nanomaterials were studied by means of theoretical modeling and molecular dynamics simulation, and some achievements were obtained. The results provide some reference value for studying other mechanical properties of graphene and a new idea for further study of other mechanical properties of graphene monolayers.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71

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