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Sunday, July 26, 2020 | History

2 edition of Statistical model for asperity contact time fraction in elastohydrodynamic lubrication found in the catalog.

Statistical model for asperity contact time fraction in elastohydrodynamic lubrication

Steven M. Sidik

Statistical model for asperity contact time fraction in elastohydrodynamic lubrication

by Steven M. Sidik

  • 190 Want to read
  • 23 Currently reading

Published by National Aeronautics and Space Administration, Scientific and Technical Information Office, for sale by the National Technical Information Service in [Washington], Springfield, Va .
Written in English

    Subjects:
  • Lubrication and lubricants -- Mathematical models.

  • Edition Notes

    StatementSteven M. Sidik and John J. Coy.
    SeriesNASA technical paper ; 1130, NASA technical paper -- 1130.
    ContributionsCoy, John J., United States. National Aeronautics and Space Administration. Scientific and Technical Information Office.
    The Physical Object
    Pagination39 p. :
    Number of Pages39
    ID Numbers
    Open LibraryOL17647155M

    In mixed lubricated contact, the asperity contact regions may be separated by a thin layer of lubricant film. Simulations of mixed lubrication often use empirical formulae to describe the change of density with pressure in the lubricated areas. However, these models may not be applicable to molecularly thin films at asperity contact regions. We.   The modern theoretical proof of elastohydrodynamic lubrication (EHL or EHD) as an explanation for incongruities in hydrodynamic theory was first published in the Before this time only hydrodynamic theory, developed in the late s, was known. Under high loads it was observed that less wear and friction occurred than would be expected in a.

    EHL - Elastohydrodynamic Lubrication. Looking for abbreviations of EHL? It is Elastohydrodynamic Lubrication. Theoretical Analysis of the Influence of Asperity's Dimensions Affected by a Scale Factor on the Mixed Lubrication between Parallel Surfaces. "Analytical solution to a mode of mixed elastohydrodynamic lubrication with mixed. An Elastohydrodynamic Lubrication Model Considering Surface Roughness and Mixed Friction Jakob Moder1, Florian Grün1 1Chair of Mechanical Engineering, Montanuniversität, Leoben, Austria Abstract In mechanical engineering machine elements such as gears or .

      Finite Element Modeling of Elastohydrodynamic Lubrication Problems is an ideal book for researchers and graduate students in the field of Tribology. About the Author WASSIM HABCHI, P H D, is an Associate Professor of Mechanical Engineering in the Department of Industrial and Mechanical Engineering at the Lebanese American University, : Wassim Habchi. Ball Bearing Lubrication constant contact angle contact ellipse continuity equation curvature defined developed diameter dimensionless film thickness dimensionless inlet distance dimensionless pressure dimensionless speed disc Dowson and Higginson effects elastic deformation elastohydrodynamic film elastohydrodynamic lubrication ellipsoidal.


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Statistical model for asperity contact time fraction in elastohydrodynamic lubrication by Steven M. Sidik Download PDF EPUB FB2

An individual asperity in contact is compressed by a distance w = z d, which gives rise to a contact spot of area A, = nw (2) and a force Wear, 79() ASPERITY CONTACT IN ELASTOHYDRODYNAMIC LUBRICATION 95 (3) where the effective elastic modulus E' is defined by +1^1 i i.

1 Jl-v, l-vf E' 'L J Hence the expected total load per unit area Cited by: Relations for the asperity contact time fraction during elastohydrodynamic lubrication of a ball bearing are presented. The analysis is based on a two Cited by: 6. A simple theory of asperity contact in elastohydro-dynamic lubrication Article (PDF Available) in Wear 19(1) January with 2, Reads How we measure 'reads'.

A statistical model of elasto-plastic asperity contact between rough surfaces Article in Tribology International 39(9) September with Reads How we measure 'reads'.

Lubrication and lubricants: A treatise on the theory and practice of lubrication, Statistical model for asperity contact time fraction in elasthydrodynamic lubrication / Microasperity model for elastohydrodynamic lubrication of a spinning ball on a flat surface [electronic resource] /. 5=2 Statistical function for asperity load carrying capacity F 2 Statistical function for asperity contact area h Separation or film thickness h 0 Initial gap between surfaces h ini Height of the highest peak relative to the mean centre-line of the surface m Mass of floating plate L Length of sliding strip p Hydrodynamic pressure p atm Cited by: Using an asperity based model including five families of asperities (2 for full fluid lubrication and 3 for local boundary lubrication), we simulate mixed lubricated behavior.

Our theoretical results confirm the relation between the mixed regime and the by: 1. the pressure and film deformation become time-dependent as the asperity enters the contact region. To determine the change in pressure and de-formation caused by the asperity, it is required to solve the coupled elastohydrodynamic equation at successive time intervals taking into account the effect of the squeeze film term.

For each time interval,Cited by: 7. Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubricants can be solids (such as Molybdenum disulfide MoS 2), solid/liquid dispersions (such as grease), liquids (such as oil or water), liquid-liquid dispersions [citation needed] or gases.

Elasto-hydrodynamic lubrication. Dowson, G. Higginson. Archard Battelle Memorial Institute calculated capacitance cavitated Chapter coefficient of friction constant viscosity contact zone Crook deformation dielectric constant dimensionless disk machine displacement dry contact effect elastic elastic modulus elasto All Book Search.

This review of elastohydrodynamic lubrication (EHL) was derived from many excellent sources (Refs. 1–5). The review of Blok’s flash temperature theory was derived from his publications (Refs. 6–9). An excellent general reference on all aspects of tribology is the Encyclopedia of Tribology (Ref.

10). usually referred to elastohydrodynamic lubrication (EHL) regimes. At the same time, in the zones close to contact boundaries the contribution of the lubricant flow and contact solid elasticity are comparable [Kudish and Covitch, ].

The conditions when the lubrication film thickness is comparable to the height of surface asperities are usuallyFile Size: KB. Elastohydrodynamic lubrication is the condition that occurs when a lubricant is introduced between surfaces that are in rolling contact, such as ball and rolling element bearings.

In this lubrication regime, the load is sufficiently high enough for the surfaces to elastically deform during the hydrodynamic Size: 7KB. asperity lubrication through use of the statistical distribution for height and radius. Mechanical behaviour of asperity Each asperity can act through several way and as an example, let us consider a particular situation of the contact of a rough deformable surface on a smooth rigid one (Figure 2).

The general case of two rough surfaces. Elastohydrodynamic lubrication (EHL) is a mode of fluid-film lubrication in which hydrodynamic action is significantly enhanced by surface elastic deformation and lubricant viscosity increases due to. "Elastohydrodynamic lubrication (EHL) is a relatively new area in the development of lubrication theory and practice.

This monograph is devoted to selected performances of liquid lubricants, particularly mineral oils and synthetic fluids. combines asymptotic and numerical techniques to solve EHL problems for line and point : Hardcover. Tribology International 39 () – A statistical model of elasto-plastic asperity contact between rough surfaces Robert L.

Jacksona, Itzhak Greenb aDepartment of Mechanical Engineering, Auburn University, Auburn, ALUSA bGeorge W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GAUSA. Elastohydrodynamic Lubrication (EHL) is commonly known as a mode of fluid-film lubrication in which the mechanism of hydrodynamic film formation is enhanced by surface elastic deformation and lubricant viscosity increase due to high pressure.

It has been an active Cited by: The isothermal elastohydrodynamic lubrication (EHL) of apoint contact wasanalyzednumerically bysimultaneously solving the elasticity andReynolds equations. In the elasticity analysis the contact zone was divided into equal rectangular areas, andit wasassumedthat a uniformpres File Size: KB.

Summary. Elastohydrodynamic Lubrication for Line and Point Contacts: Asymptotic and Numerical Approaches describes a coherent asymptotic approach to the analysis of lubrication problems for heavily loaded line and point contacts.

This approach leads to unified asymptotic equations for line and point contacts as well as stable numerical algorithms for the solution of these elastohydrodynamic. Finite Element Modeling of Elastohydrodynamic Lubrication Problems is an ideal book for researchers and graduate students in the field of Tribology.

About the Author WASSIM HABCHI, P H D, is an Associate Professor of Mechanical Engineering in the Department of Industrial and Mechanical Engineering at the Lebanese American University, : Wiley.the asperity and the wafer; the dynamics of this fluid layer can be described by low Reynolds number lubrication theory [2, 9].

We will make use of elastohydrodynamic lubrication theory (EHL) to describe the interaction between the slurry fluid and the deformation of the asperities.Lubrication Knowledge Menu. Elastohydrodynamic (EHD) Lubrication. Definition of EHD lubrication. The lubrication principles applied to rolling bodies, such as ball or roller bearings, is known as elastohydrodynamic (EHD) lubrication.

Rolling body lubrication.