摘要
基于分子动力学方法对含预制裂纹石墨烯进行扶手椅向拉伸断裂模拟.使用连续介质理论结合分子动力学计算石墨烯能量释放率,确定石墨烯能量释放率GIC为10.25J/m^2;应力强度因子KIC为3.33 MPa√m.进一步对影响石墨烯裂纹扩展速率的因素-初始裂纹长度与加载速率进行讨论.结果表明：裂纹初始长度与加载率会在一定程度上影响石墨烯中裂纹扩展速率.裂纹扩展速率会随着初始裂纹长度的增加而降低;但随着初始裂纹长度的增加,裂纹扩展速率对其敏感度降低.裂纹扩展速率会随着加载率的升高而增大.初始裂纹长度与加载率对裂纹扩展速率的影响有一定的关联性,加载率的升高会降低裂纹扩展速率对初始裂纹长度变化的敏感度.在此基础上确定了石墨烯中裂纹扩展极限速率为8350m/s.
The fracture parameters of graphene are very important to graphene devices,but the relevant research is still in the primary stage.In this paper,the tensile fracture process of pre-cracked armchair graphene is simulated using the molecular dynamics software-LAMMPS.Firstly,the energy release rate and the stress intensity factor of graphene are obtained using the continuum theory and the molecular dynamics calculation.It is found that the energy release rate of graphene GICis 10.11 J/m2 and the stress intensity factor KICis 3.33 MPa m（1/2）.Furthermore,a new model based on the continuum theory and molecular dynamics is proposed to accurately compute the crack propagation rate of graphene.The factors that affect the crack propagation rate of graphene are discussed,including the initial crack length and the strain loading rate.The results show that the initial crack length and the strain loading rate affect the crack propagation rate to a certain degree.Before reaching the limit crack propagation rate,the shorter the initial crack length is,the higher the crack propagation rate is.But with the increase of the initial crack length,the crack propagation rate becomes insensitive to the initial crack length;and it shows that the higher the strain loading rate is,the higher the crack propagation rate is.Besides,the relationship between the influences of initial crack length and strain loading rate on crack propagation rate is preliminarily discussed.The results show that the influences of initial crack length and strain loading rate on crack propagation rate are related to some extent.With the increase of strain loading rate,the sensitivity of crack propagation rate to the initial crack length decreases.Based on the previous findings and discussion,an objective analysis of the limit of crack propagation rate is conducted.The limit crack propagation rate is 8350 m/s.The conclusions are expected to provide some reference for the practical design and application of graphene devices.
作者
刘秦龙
华军
李东波
段志荣
肖攀
陈垣欣
Qinlong Liu;Dongbo Li;Zhirong Duan;Pan Xiao;Yuanxin Chen(Mechanics Experiment Center,Department of Mechanics,College of Science,Xi＇an University of Architecture and Technology,Xi＇an,710055;Department of Mechanics,School of Science,Xi＇an University of Architecture and Technology,Xi＇an,710055)
出处
《固体力学学报》
CAS
CSCD
北大核心
2018年第4期412-418,共7页
Chinese Journal of Solid Mechanics
基金
西安建筑科技大学青年科技基金项目(QN1634)
国家自然科学基金项目(51641809)
中国博士后基金项目(2018M633478)资助
关键词
石墨烯
分子动力学
断裂性能
裂纹扩展速率
graphene
molecular dynamics
fracture property
crack propagation rate
作者简介
通讯作者：刘秦龙,Tel：13519154131，E-mail：460084001@qq．com．
