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Starved elastohydrodynamically lubricated contact is described as deviation from fully flooded contact due to insufficient lubricant supply. This insufficiency causes thinner lubricant film compared to fully flooded regime. Thinner lubricant film means that rolling surfaces are closer together. Each surface has its own roughness, which is created by machining of the surface and is composed by many individual asperities. These asperities are elastically deformed while passing through the contact area of the EHL contact as well as whole contact surface. It is important to know the magnitude of the deformation. Especially in the starved contact where is increased risk of surface wear due to mutual contact of asperities on the opposite surfaces. This paper presents experimental work on the topic of the surface roughness deformation, which is passing by contact. Analytical method called amplitude attenuation theory was used to predict deformation of the artificial asperity (ridge) under starved conditions. Deformations provided by predictions were compared with the experiments and from both method is clear that roughness deformation is increasing with the progressing starvation - thinning the lubricant film. Magnitude of the deformation however depends on the asperity profile.

This paper is an experimental study of grease lubrication in a starved elastohydrodynamic lubricated (EHL) contact. Lubricating film thickness is measured with tribological experimental device ball-on-disc using optical interferometry and high speed camera. The lubricants used were commercial greases with a various kinematic viscosities, additives and thickeners formulated for low and high-speed applications. The experiment is aimed at a comparison of results acquired by ball-ondisc device and full scale axial bearing. In addition, this paper also investigates the influence of number of the rolling elements (overrolling time) on the resulting film thickness. Experiments confirm the presence of replenishment mechanism caused by relative motion of the surfaces, which generates base oil flow into the inlet of the contact. [ABSTRACT FROM AUTHOR]