软三体颗粒润滑是利用大量松散的固体软颗粒在界面中的承载和剪切行为实现特殊环境下界面的减摩，因此研究软颗粒介质摩擦界面在剪切过程中的受力情况，对软三体颗粒润滑机理的分析以及润滑装置的设计都具有重要意义。研究中将第三体颗粒类比为流体，基于雷诺方程、黏度方程、Greenwood和Williamson接触模型（G-W模型）等建立了含大颗粒粗糙界面的混合润滑模型。该模型中摩擦副的总载荷及总摩擦力由流体、微凸体和大颗粒三部分共同构成。通过采用有限差分法对上述物理模型进行求解分析，探究膜厚比、第三体大颗粒的质量浓度、粒径以及试件的表面形貌、弹性模量对三体接触界面的承载和摩擦力的影响情况，进而分析大颗粒粒径和接触表面粗糙度耦合时软三体接触界面的力学性能。基于对所构建的软三体接触界面混合润滑模型的研究可知：合理选择大颗粒质量浓度、粒径以及试件的表面形貌、弹性模量有助于提高承载、减小摩擦力，使得软三体颗粒流具有更好的减摩润滑性能。
Soft three-body particle lubrication is the use of a large number of loose solid particles in the interface of the load and shear behavior to achieve low friction under special environment, so the study of the force of granular media friction interface in the shear process has great significance to the analysis of lubrication mechanism and the design of the lubrication device. In the study, the third-body granules are compared to fluid, a mixed lubrication model which contains large particles in rough interface is based on Reynolds equation, viscosity equation, Greenwood and Williamson contact model (G-W model) and so on. In this model, the total load and friction of the friction pair are composed of three parts:fluid, asperity and large granules. By using the finite difference method to solve the above physical model, the effects of the film thickness ratio, mass concentration, granular size, surface morphology and elastic modulus on the three-body contact interface of the load and friction are investigated, and the mechanical properties of the soft three-body contact interface are also analyzed by coupling the large granule size with the contact surface roughness. Based on the analysis of the mixed lubrication model, reasonable choices of large particle concentration, granular size, surface morphology of the specimen and elastic modulus helps to improve the load, reduce friction and make the soft three-body granular flow have better friction-reducing and lubrication performance.
[1] GODET M. The third-body approach:A mechanical view of wear[J]. Wear, 1984, 100(1):437-452.
[2] 韩晓明, 高飞, 符蓉. 三体摩擦体系中材料摩擦特性的研究进展[J]. 中国材料进展, 2009, 28(2):8-13. HAN Xiaoming, GAO Fei, FU Rong. Recent progress in tribological theories involving the behavior of the third body[J]. Materials China, 2009, 28(2):8-13.
[3] 温诗铸, 黄平. 摩擦学原理[M]. 北京:清华大学出版社, 2012. WEN Shizhu, HUANG Ping. Tribology theory[M]. Beijing:Qinghua University Press, 2012.
[4] HESHMAT H. The quasi-hydrodynamic mechanism of powder lubrication-part Ⅲ:On theory and rheology of triboparticulates[J]. Tribology Transactions, 1995, 38(2):269-276.
[5] 刘峰壁, 李续娥, 谢友柏. 粗糙表面三体接触理论研究[J]. 机械工程学报, 1997, 33(3):27-31. LIU Fengbi, LI Xue, XIE Youbai. Theoretical investigation on three body contact about rough surfaces[J]. Chinese Journal of Mechanical Engineering,1997, 33(3):27-31.
[6] WORNYOH E Y A, Ⅲ C F H. An asperity-based fractional coverage model for transfer films on a tribological surface[J]. Wear, 2011, 270(3-4):127-139.
[7] IORDANOFF I, KHONSARI M M. Granular lubrication:Toward an understanding of the transition between kinetic and quasi-fluid regime[J]. Journal of Tribology, 2004, 126(1):137-145.
[8] 王伟, 史超, 王智勇, 等. 多参数对三体摩擦界面剪切膨胀过程的影响[J]. 应用力学学报, 2015, 32(5):731-737. WANG Wei, SHI Chao, WANG Zhiyong, et al. Effects of several changing parameters on shear dilatancy process in three-body frictional interface[J]. Chinese Journal Of Applied Mechanics, 2015, 32(5):731-737.
[9] HESHMAT H, HESHMAF C A. On the rheodynamics of powder lubricated journal bearing:Theory and experiment[J]. Tribology & Interface Engineering, 1999, 36(99):537-549.
[10] 黄平, 孟永钢, 徐华. 摩擦学教程[M]. 北京:高等教育出版社, 2008. HUANG Ping, MENG Yonggang, XU Hua. Tribology course[M]. Beijing:Higher Education Press, 2008.
[11] GREENWOOD J A, WILLIAMSON J B P. Contact of nominally flat surfaces[J]. Proceedings of the Royal Society A Mathematical Physical & Engineering Sciences, 1966, 295(295):300-319.
[12] KHONSARI M M, WANG S H, QI Y L. A theory of liquid-solid lubrication in easley hydrodynamic regime[J]. ASME, Journal of Tribology, 1989, 111(3):440-444.
[13] TOMIMOTO M, MIZUHARA K. Effect of particles concentration on friction[J]. Tribology, 1999, 36(36):789-795.
[14] WANG W, LIU K, JIAO M. Thermal and non-newtonian analysis on mixed liquid-solid lubrication[J]. Tribology International, 2007, 40(7):1067-1074.
[15] HOU K, KALOUSEK J, MAGEL E. Rheological model of solid layer in rolling contact[J]. Wear, 1997, 211(1):134-140.
