With optical interferometry technique, an interesting multi-dimple phenomenon has been discovered under pure-sliding conditions in the point contact between a glass disk and a 3-inch diameter steel ball. At low sliding speeds, two or three stable dimples can be generated in the contact, but at higher sliding speeds, such multi-dimples become unstable. At even higher sliding speeds, however, dimples become stable again, but two dimples become single dimple, or three become two. Numerical solutions of the steady-state thermal elastohydrodynamic lubrication (EHL) theory based on the Newtonian flow model can simulate the stable multi-dimples very well. By changing the slide-roll conditions from pure-rolling to pure-sliding, the theoretical analysis shows clearly that the stable multi-dimples are produced by the thermal effect through the familiar EHL pressure spike.

Issue Section:
Technical Papers
Keywords:
mechanical contact, sliding friction, lubrication, liquid films, rolling friction, film flow, elasticity, thermal properties
Topics:
Disks, Pressure, Steel, Temperature, Viscosity, Lubricants, Glass, Flow (Dynamics), Film thickness, Stress, Kinematics, Temperature effects
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 by ASME
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