弹流润滑条件下织构表面亚表层特性研究

Study on Subsurface Properties of Textured Surfaces Under Elastohydrodynamic Lubrication

为研究在弹流润滑状态下表面形貌对亚表层特性的影响,利用激光加工方法获得2种微凹坑型织构表面形貌,通过将实测的表面形貌坐标输入弹流润滑数值计算程序得到油膜压力和膜厚分布;以对应工况的油膜压力作为表面法向压应力,利用Rabinowicz经验公式算出剪切应力;将表面法向压应力和切向剪应力叠加后对弹流润滑界面亚表层特性进行仿真研究。结果表明:表面织构使亚表层应力分布发生显著改变;微凹坑直径、卷吸速度对亚表层应力的大小与分布有不同的影响;亚表层变形在摩擦过程中呈现随深度增加先缓慢减小后快速下降的规律,研究结果将为通过表面形貌设计改善轴承等零件受力状况提供理论支持。

In order to study the influence of surface topography on subsurface characteristics under the condition of elastohydrodynamic lubrication,two kinds of micro-pitted texturing surface topography were obtained by laser machining method.The oil film pressure and film thickness distribution were gained by substituting the measured surface topography data into numerical calculation procedure of elastohydrodynamic lubrication.The oil film pressure of corresponding operating condition was treated as the surface normal compressive stress,and the shear stress was calculated by using Rabinowicz empirical formula.The subsurface characteristics of the elastohydrodynamic lubrication interface were simulated by superimposing the surface normal compressive stress and tangential shear stress.The results show that the surface texture obviously changes the stress distribution of subsurface layer.The influences of micro-pit diameter and entrainment velocity on the magnitude and distribution of subsurface stress are different.In the process of friction,the deformation of subsurface decreases slowly at first and then rapidly with the increase of depth.The research results will provide a theoretical support for the design of surface topography to improve the stress conditions of bearing and other mechanical parts.