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4 edition of Experimental study of load carrying capacity of point contacts at zero entrainment velocity found in the catalog.

Experimental study of load carrying capacity of point contacts at zero entrainment velocity

Experimental study of load carrying capacity of point contacts at zero entrainment velocity

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Published by National Aeronautics and Space Administration, Lewis Research Center, National Technical Information Service, distributor in [Cleveland, Ohio], Springfield, VA .
Written in English


Edition Notes

StatementB.A. Shogrin ... [et al.].
Series[NASA technical memorandum] -- NASA/TM-1998-208650., NASA technical memorandum -- 208650.
ContributionsShogrin, Bradley A., Lewis Research Center.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL17593143M
OCLC/WorldCa41501887

  This paper describes an experimental study on dimple formation under elastohydrodynamic lubrication (EHL) conditions. Kigusbury, E. P., and Prahl, J. M., , “Experimental Determination of Load Carrying Capacity of Point Contact at Zero Entrainment Velocity,” NASA/TM— (). Cited by: 1. Introduction. According to the early EHL experiments, and theories, the typical EHL film shape or thickness of point contact is characterized by flat thickness in contact region and a decrease in the oil film at the exit the contour map of film thickness looks like a horseshoe. However, the point contact EHL film demonstrates a dimple instead of the parallel film thickness under Cited by: 8.

Li X.M, Guo F. and Wong P.L., “Study of boundary slippage using movement of a post-impact EHL dimple under conditions of pure sliding and zero entrainment velocity”, Tribology International, Vol, 2, pp, Nov.   The success of any satellite mission largely depends upon the performance of the attitude control systems such as gyroscopes and momentum/reaction wheels. The required life and performance quality of these rotating mechanisms are ensured by the selection of bearings and its lubrication. The design and development of lubrication system to meet the long-term uninterrupted performance is a Cited by: 9.

Fig. 3: Temperature field in a zero entrainment velocity EHL contact, showing the gradients in film thickness at the origin of the load-bearing capacity. From the experimental point of view, major advances were made in order to measure in situ pressure and temperature fields inside the contact and to be able to validate the model predictions.   The research onto the transient effect of geometry upon the behaviour of EHD films has been driven by studies on mixed lubrication, where roughness plays an important role [e.g. 14–16] and those on surface featured lubrication seen as a way to improve load carrying capacity and reduce friction drag [17,18,19].Cited by: 1.


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Experimental study of load carrying capacity of point contacts at zero entrainment velocity Download PDF EPUB FB2

Entrapment is discussed as an explanation of the load carrying capacity at zero entrainment velocity conditions, relevant to the ball-ball contacts occurring in retainerless ball hearings. 1 INTRODUCTION Spacecraft use momentum and reaction wheels for attitude control.

Three wheels are adequate, but redundant wheels are often by: Since the entrainment velocity is zero at this point, the pressure gradient along the direction of motion is equal to zero, and therefore, the load carrying capacity is zero. The formation of an immobile film formed by lubricant entrapment is discussed as an explanation of the load carrying capacity at these zero entrainment velocity conditions, relevant to the ball.

Shogin BA, Jones WR, Kingsbury EP, et al. Experimental study of load carrying capacity of point contacts at zero entrainment velocity.

NASA TM, Google ScholarAuthor: Shanshan Wang, Jing Wang, Yiming Han, Weimin Li. The formation of an immobile surface film formed by lubricant entrapment is discussed as an explanation of the load carrying capacity at zero entrainment velocity conditions, relevant to the ball-ball contacts occurring in retainerless ball bearings.

Experiments were conducted on wide point contacts in Zero Entrainment Velocity conditions. A numerical model of thermal elastohydrodynamic contacts was also developed and used to provide useful information on local quantities such as the pressure, the temperature or the viscosity : Bilel Meziane, Philippe Vergne, Nicolas Devaux, Lionel Lafarge, Guillermo E.

Morales-Espejel, Nicola. Experimental and numerical EHL analyses at zero-entrainment-velocity conditions were conducted. Full EHL films could be generated at ZEV contacts with oleophobic and oleophilic surfaces.

ZEV EHL is attributed to boundary slip at the oleophobic surfaces of the oleophobic and oleophilic contacts. A method to approximate slip velocity is by: 1. Reference: Film thickness build-up in zero entrainment velocity wide point contacts Experimental Determination of Load Carrying Capacity of Point Contacts at Zero Entrainment Velocity.

Motohiro Kaneta's 18 research works with 77 citations and reads, including: Numerical Study on Effect of Dimples on Tribo-characteristics in Non-Newtonian Thermal EHL Point Contacts with. Study of boundary slippage using movement of a post-impact EHL dimple under conditions of pure sliding and zero entrainment velocity Li, X.

M., Guo, F. & Wong, P. L., NovIn: Tribology Letters. 44, 2, p. Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal. Scopus citations: 6.

The experimental evidence of lubricant entrapment under reciprocation was given by direct observation in Ref. The entrapped lubricant ensured the load-carrying capacity of contact at the ends of stroke despite the zero entrainment speed at which the EHL film failure is by: 4.

The role of cavitation in tribological contacts has been discussed by many authors with regard to load capacity, lubricant thickness, frictional losses and wear in sliding or rolling contact bearings [].

The pioneering work of Osborne Reynolds in showed that the lubricant pressure distribution. Pure rolling experiments were performed under maximum contact stresses and entrainment velocities of GPa and m/s to m/s, respectively. All data from these baseline tests conformed to theory.

ZEV tests were initiated after calibration of the tribometer and verification of film thickness approximation accuracy. attractive choice because of its zero wear, negligible friction, and low cost, but it suffers from low load capacity, low radial stiffness, lack of damping and high axial instability.

To enhance the radial load and radial stiffness and reduce the axial thrust, a theoretical and experimental study of various radial. A Numerical Analysis for TEHL of Eccentric-Tappet Pair Subjected to Transient Load J to the Steady-State and Transient EHL Line Contacts and the Arbitrary Entrainment EHL Point Contacts,” P., Jansen, M.

J., and Prahl, J. M.,“Experimental Study of Load Carrying Capacity of Point Contacts at Zero Entrainment Velocity,” NASA Cited by:   1. Introduction. A review by Mackenzie et al. [] in of backpack loads carried by school students during a school day identified that children were carrying as much as 30% to 40% of their body review, while acknowledging that no critical maximal load had been established (to address back pain), recommended around 10% of the child’s bodyweight as a maximum by: 5.

Experimental Study Of Load Carrying Capacity Of Point Contacts At Zero Entrainment Velocity (OCoLC) Online version: Shogrin, Bradley A. Experimental study of load carrying capacity of point contacts at zero entrainment velocity (OCoLC) Material Type: Government publication, National government publication: Document Type: Book.

Experimental Study Of Load Carrying Capacity Of Point Contacts At Zero Entrainment Velocity (OCoLC) Microfiche version: Experimental study of load carrying capacity of point contacts at zero entrainment velocity (OCoLC) Material Type: Document, Government publication, National government publication, Internet resource: Document.

A capacitance technique was used to monitor the film thickness separating two steel balls of a unique tribometer while subjecting the ball-ball contact to. Get this from a library. Experimental determination of load carrying capacity of point contacts at zero entrainment velocity.

[Bradley A Shogrin; Lewis Research Center.;]. Theoretical and experimental investigations on EHL point contacts with different entrainment velocity directions Conference Paper September with 27 Reads How we measure 'reads'.Variation of surface dimple in point contact thermal EHL under ZEV condition.

Experimental Study of Load Carrying Capacity of Point Contacts at Zero Entrainment Velocity of the load. Experiments were carried out to examine the load-carrying capacity of a series of three-layer compound shells of revolution of the cone-cylinder type.

The structure is symmetric through its thickness. The load-carrying layers were made of a glass-reinforced plastic, a filler was a foam plastic. The shells were subjected to axial and hydrostatic : A. O. Rasskazov, N. P. Semenyuk, V.

M. Trach, A. P. Primak.