基于CGMD的半椭圆形截面自支撑石墨烯膜镜面屈曲研究  

Mirror Buckling Analysis of Freestanding Graphene Membranes with Semi⁃Elliptical Cross⁃Section Based on the CGMD Method

作　　者：续文龙 张锴[1] 郑百林[1] XU Wenlong;ZHANG Kai;ZHENG Bailin(School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学航空航天与力学学院,上海200092

出　　处：《力学季刊》2024年第2期493-505,共13页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(11872280)。

摘　　要：扫描隧道显微镜观测表明自支撑石墨烯膜在偏压和隧穿电流作用下发生镜面屈曲,针对该现象目前尚未开展系统性的研究.为此,本文使用基于粗粒化分子动力学结合实验结果构建半椭圆形截面石墨烯膜模型,着重研究截面几何形状对结构镜面屈曲行为的影响.计算结果表明,半椭圆形截面石墨烯膜能够发生曲率正负变化的变形,但是没有出现镜面屈曲现象,同时发现大高跨比情况下石墨烯膜的变形对温度的影响不敏感.将文献采用的扇形截面石墨烯膜镜面屈曲行为的计算结果与本文计算结果对比可知,扇形截面石墨烯膜更容易出现镜面屈曲现象,产生这种情况的原因与初始结构有关,半椭圆形截面由于其端部曲率更小,原子排布与二维石墨烯更接近,在温度变化过程中达到能量平衡时碳原子位置变化更小,所以表现出更小的变形.本文的研究可为基于石墨烯膜波动效应的能量收集装置的开发提供理论支持.Subjected to the bias voltage and the tunneling current in the scanning tunneling microscope,freestanding graphene membranes undergo a special mirror buckling phenomenon,which has not yet been systematically investigated.In order to investigate the effect of cross-section,semi-elliptical cross-section graphene membranes models based on coarse-grained molecular dynamics were used to analyze the mirror buckling behavior in combination with experiments.The results show that the semielliptic cross-section graphene membrane is capable of allowing deformation with positive and negative curvature changes,without mirror buckling.The deformation of the graphene membrane in the case of large depth-span ratio is found to be insensitive to the effect of temperature.Comparison of the calculated results in this paper with those of fan-shaped cross-section graphene membrane in the literature shows that the fan-shaped cross-section is more prone to mirror buckling.The reason is related to the initial structure.The semi-ellipsoidal cross-section shows smaller deformation due to the smaller curvature of its end,with the atomic arrangement closer to those of 2D graphene,and smaller position change of the carbon atoms during the process of energy equilibrium due to temperature change.This study on the mechanical characteristics of mirror buckling provides theoretical foundation for the development of energy harvesting devices.

关 键 词：石墨烯膜 镜面屈曲 半椭圆形截面 粗粒化分子动力学 

分 类 号：TB383[一般工业技术—材料科学与工程]