Viscosity Dependence of Static Friction in Lubricated Metallic Line Contacts

Abstract

The static friction of metallic line contacts is measured at a range of loads and under dry and lubricated conditions, where the effect of a lubricant is characterized using hydraulic fluids of different viscosities. Results indicate that viscosity does affect static friction but this dependence is a function of load such that static friction increases with viscosity at low loads and decreases with viscosity at high loads. These observations are interpreted in terms of the ability of highly pressurized fluid to limit the plastic deformation of surface asperities. Hypotheses are supported by measurements of statistical parameters that characterize the surfaces after testing.

Keywords:

• Static Friction
• Line Contact
• Viscosity

Acknowledgments

This work was funded through the National Science Foundation's Center for Compact and Efficient Fluid Power, grant EEC-0540834.

Review led by David Burris