Year of Publication

2005

Document Type

Thesis

College

Engineering

Department

Mechanical Engineering

First Advisor

Lyndon Scott Stephens

Abstract

Theoretical and experimental results show that the performance of a load-bearing surface in hydrodynamic lubrication may be enhanced by engineering a definable surface texture onto the surface. These surface textures are in the form of protrusions (positive asperities) or cavities (negative asperities) of known size and geometry. The benefits of such surface textures include lower friction torque, higher load capacity and lower operating temperatures. This Thesis details a fabrication process to manufacture such surface textures/asperities on flat surfaces. The asperities are fabricated using a UV photolithography process followed by electroplating. A complete surface characterization is done to evaluate the effectiveness of the manufacturing process. From the characterization results, some errors in asperity geometry are identified and statistically quantified. These errors are found to be normally distributed and the random surface roughness is 1 to 3 orders of magnitude less than the deterministic feature size. The accuracy of the manufacturing process for fabricating the asperities was found to lie within 6.5 % of the desired value over all the errors studied. Finally, a sensitivity analysis is done to theoretically evaluate the effect of some of these errors in the hydrodynamic lubrication regime.

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