中国机械工程 ›› 2023, Vol. 34 ›› Issue (10): 1140-1156.DOI: 10.3969/j.issn.1004-132X.2023.10.002

• 机械基础工程 • 上一篇    下一篇

分子动力学模拟纳米颗粒添加剂对边界润滑的影响

潘伶;林国斌;韩雨晴;余辉   

  1. 1.福州大学机械工程及自动化学院,福州,350108
    2.福州市摩擦与润滑行业技术创新中心,福州,350108
  • 出版日期:2023-05-25 发布日期:2023-06-06
  • 作者简介:潘伶,女,1969年生,博士、教授。研究方向为摩擦学和机械设计。E-mail:panling@fzu.edu.cn。
  • 基金资助:
    国家自然科学基金(51875105, 51975123);福建省产学合作项目(2020H6025)

Molecular Dynamics Simulation for Effect of Nanoparticle Additives on Boundary Lubrication

PAN Ling;LIN Guobin;HAN Yuqing;YU Hui   

  1. 1.School of Mechanical Engineering and Automation,Fuzhou University,Fuzhou,350108
    2.Fuzhou Friction and Lubrication Industry Technology Innovation Center,Fuzhou,350108
  • Online:2023-05-25 Published:2023-06-06

摘要: 通过试验和模拟的方法研究了不同压力条件下纳米铜颗粒添加剂在正十六烷基础油中的边界润滑行为。建立具有正弦曲面粗糙峰的边界润滑模型,采用分子动力学分别模拟了在25,50,100,200 MPa 4种压力下,含纳米铜颗粒与不含纳米铜颗粒时润滑油沿膜厚方向的密度分布。在润滑体系的上下固体壁面施加方向相反的剪切速度,计算出壁面原子与铜颗粒原子的应力、固液界面摩擦力、正压力和摩擦因数。采用微纳米划痕仪测量了含铜颗粒润滑剂的摩擦因数。结果表明:不同压力下两种润滑体系中的十六烷基础油均出现分层现象;纳米粗糙峰直接接触时,接触界面仍存在少量的正十六烷分子,且分子主链的排列方向与剪切方向相同;在200 MPa时铜颗粒使固体壁面的最大应力减小35.3%,提高了润滑体系的承载能力;不含铜颗粒润滑体系润滑油膜在50 MPa时破裂,含铜颗粒润滑体系润滑油膜在200 MPa时破裂;模拟计算的边界润滑状态下两种润滑体系的摩擦因数符合试验测量值。

关键词: 边界润滑, 分子动力学, 纳米颗粒, 添加剂, 粗糙面接触

Abstract: The boundary lubrication behavior of Cu nanoparticles in n-hexadecane was investigated under different loads by experiments and simulations herein. Boundary lubrication model with sinusoidal rough peaks was established. The density distribution of the lubricant along the film thickness with and without Cu nanoparticles were simulated at different loads using MD respectively. The shear velocity in the opposite direction was applied to the upper and lower solid walls of the system, and the stress between the wall atoms and the copper particle atoms, the friction force of the solid-liquid interface, the normal pressure and the friction coefficient were calculated. The friction coefficient of the lubricant containing nano-copper particles was measured with a micro-nano scratch meter. The results show that the base oil n-hexadecane in the two lubrication systems is stratified under different pressures. There are still a small amount of n-hexadecane molecules at the contact interface when the nano-rough peaks are directly contacted, and the arrangement direction of the molecular main chain is the same as the shear direction. Cu nanoparticles may reduce the maximum stress of solid wall by 35.3% and improve the bearing capacity of lubrication system at 200 MPa. The lubricating oil film of lubrication system without Cu nanoparticles breaks at 50 MPa, while that of lubrication system with Cu nanoparticles breaks at 200 MPa. The friction coefficient of two lubrication system under boundary lubrication is simulated, which is in accordance with the experimental measurement. 

Key words:  , boundary lubrication, molecular dynamics(MD), nanoparticle, additives, rough interface contact

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