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Journal ArticleDOI

A Theory of Mixed Lubrication

H. Christensen1
01 Jun 1972-Vol. 186, Iss: 1, pp 421-430
TL;DR: In this paper, the phenomena observed when a lubricated contact or bearing is operating under mixed lubrication conditions are assumed to arise from an interaction of the surface asperities or roughness as well as a...
Abstract: The phenomena observed when a lubricated contact or bearing is operating under mixed lubrication conditions are assumed to arise from an interaction of the surface asperities or roughness as well a...
Citations
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Journal ArticleDOI
01 Apr 2010
TL;DR: A mixed lubrication model that permits real 3D surface topography as input is developed in this paper, and the theory of computing flow factors within the model is presented, and with a follow-up paper.
Abstract: A mixed lubrication model that permits real three-dimensional surface topography as input is developed. The theory of computing flow factors within the model is presented, and with a follow...

135 citations

Journal ArticleDOI
TL;DR: In this paper, optical interferometry measurements were made of artificially produced dents and grooves under rolling and sliding conditions to determine the local deformation associated with micro-EHD pressure generation.
Abstract: Elastohydrodynamic (EHD) film thickness measurements using optical interferometry have been made of artificially produced dents and grooves under rolling and sliding conditions. These measurements are compared to stylus traces of the dent and groove profiles to determine the local deformation associated with micro-EHD pressure generation. The surface geometry associated with the dents and grooves is seen to become intimately involved in the lubrication process itself, creating local pressure variations that substantially deform the local surface geometry, particularly under sliding conditions. The rolling results have implications concerning surface initiated fatigue and the sliding results show clearly the EHD surface interactions that must occur prior to scuffing failure. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Minneapolis, Minnesota, October 24–26, 1978

131 citations

OtherDOI
01 Jan 1998
TL;DR: In this article, the authors propose a 3.3-approximation algorithm for the 3.1-GHz bandit-16.3 GHz frequency bandit model, and
Abstract: 3

123 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view is presented, and the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multiscale textures are summarized, and future trends in this research direction are emphasized.
Abstract: Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.

119 citations

References
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Journal ArticleDOI
H. Christensen1
01 Jun 1969
TL;DR: In this article, two different forms of Reynolds-type equation corresponding to two different types of surface roughness are developed and the mathematical form of these equations is similar but not identical to the form of the Reynolds equation governing the behaviour of smooth, deterministic bearing surfaces.
Abstract: This paper deals with hydrodynamic aspects of rough bearing surfaces. On the basis of stochastic theory two different forms of Reynolds-type equation corresponding to two different types of surface roughnesses are developed.It is shown that the mathematical form of these equations is similar but not identical to the form of the Reynolds equation governing the behaviour of smooth, deterministic bearing surfaces.To illustrate the functional effects of surface roughness the influence on the operating characteristics of a plane pad, no side leakage slider bearing is analysed.It is shown that surface roughness may considerably influence the operating characteristics of bearings and that the direction of the influence depends upon the type of roughness assumed. The effects are not, however, critically dependent upon the detailed form of the distribution function of the roughness heights.

457 citations

Journal ArticleDOI
H. Christensen1
01 Feb 1971-Wear
TL;DR: In this article, a new theory of lubrication based upon probabilistic principles was proposed for sliding bearing analysis. But the results of the application of the theory to the analysis of a slider bearing are listed.

52 citations