• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2020, Vol. 56 ›› Issue (1): 110-118.doi: 10.3901/JME.2020.01.110

• 摩擦学 • 上一篇    下一篇

分子动力学模拟环烷烃含碳量对边界润滑的影响

潘伶, 鲁石平, 陈有宏, 余辉   

  1. 福州大学机械工程及自动化学院 福州 350108
  • 收稿日期:2019-03-23 修回日期:2019-06-18 出版日期:2020-01-05 发布日期:2020-03-09
  • 通讯作者: 潘伶(通信作者),女,1969年出生,博士,教授。主要研究方向为机械设计及理论、摩擦学。E-mail:panling@fzu.edu.cn
  • 作者简介:鲁石平,男,1994年出生。主要研究方向为摩擦学。E-mail:n160220050@fzu.edu.cn;陈有宏,男,1992年出生。主要研究方向为摩擦学。E-mail:949976847@qq.com;余辉,男,1994年出生。主要研究方向为摩擦学。E-mail:15659125105@163.com
  • 基金资助:
    国家自然科学基金(51875105,51875106)和福建省自然科学基金(2016J01226)资助项目。

Molecular Dynamics Simulation on Boundary Lubrication: The Effect of Cycloalkane Carbon Content

PAN Ling, LU Shiping, CHEN Youhong, YU Hui   

  1. School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108
  • Received:2019-03-23 Revised:2019-06-18 Online:2020-01-05 Published:2020-03-09

摘要: 研究了四种不同含碳量的环烷烃润滑膜在不同负载下的边界润滑行为。建立具有正弦曲面凸峰的粗糙面边界润滑系统模型,采用分子动力学模拟了四种润滑膜分别在25~500 MPa的四种负载下沿膜厚方向的密度分布。在系统的上、下固体壁面施加方向相反的剪切速度,计算出壁面原子的应力、固液界面摩擦力、正压力和摩擦因数。试验测量了环己烷油膜的摩擦因数。结果表明,分子含碳量不同的四种环烷烃润滑剂均出现分层现象,随着润滑剂分子含碳量的增加,密度分布曲线中间区域的波谷值越高,层间的原子数越多,分层越不明显;润滑剂分子含碳量越大,承载能力越高;环己烷和环十二烷润滑膜在50 MPa时相继破裂,环二十四烷润滑膜在100 MPa时破裂,环四十八烷润滑油膜承载能力超过500 MPa;模拟计算边界润滑状态下环己烷油膜的摩擦因数,符合试验测量值。

关键词: 边界润滑, 粗糙面接触, 分子动力学, 环烷烃, 剪切流动

Abstract: Molecular dynamics (MD) simulation is adopt to investigate the boundary lubrication behaviors of cycloalkane lubricants on nanoscale. The effects of lubricant molecular carbon content and loads on boundary lubrication are studied. The boundary lubrication model with single asperity for friction analysis is set up. The distributions of density are illustrated in the direction of the film thickness when the pressure changes from 25 to 500 MPa. The converse shear velocity is enforced on each wall. The friction, the normal pressure and the stress of the system are calculated. The results show that all the four cycloalkane lubricants are stratified. With the increase of carbon content in lubricant molecule, the trough value in the middle of density distribution curve get higher, the number of the atoms between layers get larger, and the stratification become less obvious. The bearing capacity of the lubricating film increases with the carbon content of the lubricant molecules. The cyclohexane and cyclododecane lubricating films are successively broken at 50 MPa, the cyclotetracosane lubricating film is broken at 100 MPa, while the bearing capacity of the cyclotetradecane exceeds 500 MPa. The friction coefficient of cyclohexane oil film under boundary lubrication is simulated, which is in accordance with the experimental measurement.

Key words: boundary lubrication, rough interface contact, molecular dynamics, cycloalkane, shear flow

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