Hydrodynamic Lubrication of Surfaces with Asymmetric Microdimple

Abstract

Surface texturing has been recognized as a feasible method of surface engineering to improve the lubrication properties of mechanical components. This work focuses on the hydrodynamic lubrication properties of the textured surface with asymmetric microdimples. The validity of the Reynolds equation in asymmetric microdimples is discussed based on theoretical analysis and numerical simulation. The effects of modified Reynolds number, motion directions, and parameters of the microdimple profile are investigated. The following results were obtained: Firstly, the Reynolds equation is invalid under almost all of the general conditions used in experiments and industries. Secondly, the ultimate load-carrying capacity can be taken as a new characteristic parameter to assess the lubrication property of a textured surface. Thirdly, the motion directions have a great effect on the lubrication properties. The positive motion can generate more stable load capacity under all of the modified Reynolds numbers employed, even though the load-carrying capacity is smaller than the negative motion’under larger modified Reynolds numbers. Additionally, the asymmetric microdimple can obtain larger load-carrying capacity than a symmetric rectangular microdimple and will become a potential microdimple candidate.

KEY WORDS:

• Asymmetric Microdimple
• Hydrodynamic Lubrication
• Surface Texture

ACKNOWLEDGEMENT

The authors gratefully acknowledge the financial support of this research by the National Basic Research Program of China (Issue 2007CB607605), the National Natural Science Foundation of China (50975276), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (200802900513).

Review led by Dong Zhu