Publications
170 results found
Hurley S, Cann PME, Spikes HA, 1998, Thermal degradation of greases and the effect on lubrication performance, Tribology for energy conservation, Editors: Dowson, Dowson, Amsterdam, Publisher: Elsevier, Pages: 75-83, ISBN: 9780444500335
Cann P, 1997, Grease lubricant film distribution in rolling contacts, NLGI Spokesman (National Lubricating Grease Institute), Vol: 61, Pages: 22-29, ISSN: 0027-6782
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- Citations: 28
Cann PME, Chevalier F, Lubrecht AA, 1997, Track depletion and replenishment in a grease lubricated point contract: A quantitative analysis, 23rd Leeds-Lyon Symposium on Tribology:Elstohydrodynamics - '96: Fundamentals and applications in lubrication and traction, Pages: 405-414, ISSN: 0167-8922
Anghel V, Cann PME, Spikes HA, 1997, Direct measurement of boundary lubricating films, Elastohydrodynamics '96 Proceedings of the Leeds-Lyons Symposium on Elastohydrodynamics '96 Leeds September 1996, Editors: Dowson, Amsterdam, Publisher: Elsevier, Pages: 459-466, ISBN: 9780444416773
Cann PME, 1997, Film distribution in grease lubricated rolling contact, NLGI Spokesman (National Lubricating Grease Institute), Vol: 61, Pages: 22-29, ISSN: 0027-6782
Anghel V, Cann PME, Spikes HA, 1997, Direct measurement of boundary lubricating films, Elastohydrodynamics '96 Proceedings of the Leeds-Lyons Symposium on Elastohydrodynamics '96 Leeds September 1996, Editors: Dowson, Amsterdam, Publisher: Elsevier, Pages: 459-466, ISBN: 9780444416773
Olver AV, Cann PM, Loric JC, 1996, An investigation into the properties of a thin solid coating using an optical method, Tribology Series, Vol: 31, Pages: 471-478, ISSN: 0167-8922
The elastic modulus of a thin (3 μm) solid coating has been determined by pressing a coated wire against a diamond flat and measuring the contact width optically. The technique neither involves the use of ultra-low loads, nor of costly equipment, and provides results which are accurate enough to be useful in contact stress analysis. © 1996 Elsevier Science E.V. All rights reserved.
Cann PME, 1996, Understanding grease lubrication, Tribology Series, Vol: 31, Pages: 573-581, ISSN: 0167-8922
Grease lubrication remains a scientifically neglected area of tribology as, in contrast, to fluid film lubrication there has been little progress hi our understanding hi recent years. At present we know little of the mechanisms of film formation, and loss, and the nature of the separating film formed. There is no satisfactory model for greases and thus it is impossible to predict performance, or service life, from simple bulk Theological properties. The aim of this paper is to clarify the mechanisms of film formation by greases in rolling elastohydrodynamic (EHD) contacts. Thus existing lubrication models are reviewed and compared to experimental findings and, hi the light of this, more recent work being carried out hi the Tribology Section is reported. These studies have concentrated on fundamental aspects of grease behaviour in a model bearing contact and have sought to explain the lubrication mechanisms and nature of the film formed. The different film formation mechanisms observed in this work are discussed. Evidence of both hydrodynamic and boundary layer formation is presented and the implications of the different mechanisms of load carrying considered. © 1996 Eisevier Science E.V. All rights reserved.
Palios S, Cann PME, Spikes HA, 1996, Behaviour of PTFE suspensions in rolling/sliding contacts, The Third Body Concepts: Interpretation of Tribological Phenomena Proceedings of the 22nd Leeds/Lyon Symposium on Tribology, Lyon France September 5th-8th 1995, Publisher: Elsevier, ISBN: 9780444825025
Cann PME, Hamer JC, Sayles RS, et al., 1996, Direct observation of particle entry and deformation in rolling EHD contact, The third body concept: interpretation of tribological phenomena, proceedings of the 22nd Leeds-Lyon symposium on tribology, Lyon, France September 5-8th, 1995, Publisher: Elsevier, Pages: 127-134
Cann PME, Hutchinson J, Spikes HA, 1996, Development of a space layer imaging method (SLIM) for mapping elastohydrodynamic contacts, Tribology Transactions, Vol: 39, Pages: 915-921, ISSN: 0569-8197
Cann PME, 1996, Starvation and reflow in grease-lubricated elastohydrodynamic contact, Tribology Transactions, Vol: 39, Pages: 698-704, ISSN: 0569-8197
Guangteng G, Smeeth M, Cann PME, et al., 1996, Measurement and modelling of the boundary film properties of polymeric lubricant additives, Proceedings of the Institution of Mechanical Engineers Part J-Journal of Engineering Tribology, Vol: 210, Pages: 1-15, ISSN: 1350-6501
Spikes HA, Cann PME, 1996, The thickness and rheology of boundary lubricating layers, Proceedings of the International Tribology Conference Yokohama October 1995, Publisher: JST, Pages: 1089-1094
Guangteng G, Smeeth M, Cann PME, et al., 1996, Measurement and modelling of the boundary film properties of polymeric lubricant additives, Proceedings of the Institution of Mechanical Engineers Part J-Journal of Engineering Tribology, Vol: 210, Pages: 1-15, ISSN: 1350-6501
Caporiccio G, Cann PME, Spikes HA, 1996, Additives for fluorosilicone oils at high temperature, Wear, Vol: 193, Pages: 261-268, ISSN: 0043-1648
Chevalier F, Lubrecht AA, Cann PME, et al., 1995, Starved Film Thickness: A Qualitative Explanation, Tribology Series, Vol: 30, Pages: 249-257, ISSN: 0167-8922
Numerically calculated film thickness can accurately predict measured film thicknesses under fully flooded conditions. However, as more detailed information concerning real life applications becomes available, the validity of the “fully flooded” assumption becomes less tenable. Starved films are much thinner than those formed under fully flooded conditions and it is of great practical importance therefore to be able to predict the ensuing lubrication level. Previous researchers have investigated the relation between the position of the inlet meniscus and starved film thickness. This paper combines a hydrodynamic lubrication approach with a physical boundary condition: the oil inlet film thickness distribution on the surface. Three different cases are investigated; a constant and a harmonic oil inlet film thickness distribution, and the effect of repeated passes. The results are compared qualitatively with experimental observations of starved EHL. © 1995 Elsevier Science B.V.
Smeeth M, Cann PM, Spikes HA, 1995, Measurement of Elastohydrodynamic Film Formation in Rolling Contacts at Very High Pressures, Tribology Series, Vol: 30, Pages: 497-502, ISSN: 0167-8922
A modified optical interferometry technique was used to measure the EHD central film thickness of two oils up to pressures of 3.6 GPa. In order to generate such pressures a tungsten carbide ball was loaded against a hardened steel disc with a sapphire window insert. The results showed that the film thickness generated was slightly lower than that predicted by the Dowson-Hamrock equation and the load exponent lay between that predicted by Dowson-Hamrock and recent high pressure computed solutions. © 1995 Elsevier Science B.V.
Cann PM, Spikes HA, 1995, Visualisation of starved grease and fluid lubricant films, Tribology Series, Vol: 30, Pages: 161-166, ISSN: 0167-8922
Most grease lubricated applications operate under starved conditions as there is usually no mechanism to continually resupply the contact with bulk grease. Consequently the grease is rapidly pushed to the side of the track where it is thought to act as a reservoir supplying oil to the contact (3). Recent work (5) has shown that grease lubricant films measured under such conditions in a rolling contact have two Theologically distinct components; a solid surface film of deposited thickener particles, which is augmented by a hydrodynamically generated film from base oil either in the track or supplied from the grease reservoir. The resulting film thickness represents a balance between increasing bulk starvation, deposition of shear degraded grease thickener within the track and oil replenishment from the grease reservoir. All these effects are time, speed and temperature dependent. It is impossible therefore to predict film thickness from simple rheological properties or from classical elastohydrodynamic theory using the base oil viscosity. These effects have been studied in a series of papers in which grease film thickness has been measured with time and rolling speed for the fully starved condition in a model rolling contact (4)(5)(6). The current paper provides visual evidence for some of the proposed mechanisms by direct observation of the changes in the grease track using spacer layer imaging. © 1995 Elsevier Science B.V.
CANN PM, SPIKES HA, 1994, THE BEHAVIOR OF POLYMER-SOLUTIONS IN CONCENTRATED CONTACTS - IMMOBILE SURFACE-LAYER FORMATION, TRIBOLOGY TRANSACTIONS, Vol: 37, Pages: 580-586, ISSN: 0569-8197
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- Citations: 36
CANN P, IOANNIDES E, JACOBSON B, et al., 1994, THE LAMBDA RATIO - A CRITICAL REEXAMINATION, WEAR, Vol: 175, Pages: 177-188, ISSN: 0043-1648
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- Citations: 40
Cann PM, Spikes HA, 1994, The Influence of Base Oil Rheology on the Behaviour of VI Polymers in Concentrated Contacts, Tribology Series, Vol: 27, Pages: 65-72, ISSN: 0167-8922
Whereas elastohydrodynamic (EHD) film thicknesses for simple base stocks can be predicted with some confidence from their bulk properties this is not so for polymer-containing fluids. The behaviour of such fluids in an EHD contact is extremely complex and can include elements of shear thinning, viscoelasticity and boundary properties. In this paper polymer solution behaviour in a concentrated contact has been investigated through detailed EHD film thickness measurements. A series of model polymers; polyisoprenes in the molecular weight range 27-86,000, have been studied in two different basestocks, the intention being to examine the effect of base stock rheology and solvation properties on polymer behaviour. © 1994, Elsevier Science B.V.
ENTHOVEN JC, CANN PM, SPIKES HA, 1993, TEMPERATURE AND SCUFFING, TRIBOLOGY TRANSACTIONS, Vol: 36, Pages: 258-266, ISSN: 0569-8197
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- Citations: 29
CANN PM, SPIKES HA, 1992, FOURIER-TRANSFORM INFRARED STUDY OF THE BEHAVIOR OF GREASE IN LUBRICATED CONTACTS, LUBRICATION ENGINEERING, Vol: 48, Pages: 335-343, ISSN: 0024-7154
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- Citations: 16
GUANGTENG G, CANN PM, SPIKES HA, 1992, A STUDY OF PARCHED LUBRICATION, WEAR, Vol: 153, Pages: 91-105, ISSN: 0043-1648
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- Citations: 45
CANN PM, WILLIAMSON BP, COY RC, et al., 1992, THE BEHAVIOR OF GREASES IN ELASTOHYDRODYNAMIC CONTACTS, INTERNATIONAL CONF ON FRONTIERS OF TRIBOLOGY, CELEBRATING THE 10TH ANNIVERSARY OF THE TRIBOLOGY GROUP OF THE INST OF PHYSICS, Publisher: IOP PUBLISHING LTD, Pages: A124-A132, ISSN: 0022-3727
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- Citations: 40
Cann PM, Williamson BP, Coy RC, et al., 1992, The behaviour of greases in elastohydrodynamic contacts, Journal of Physics D: Applied Physics, Vol: 25, Pages: A124-A132, ISSN: 0022-3727
The ability of grease to generate elastohydrodynamic (ehd) films has been studied and interpreted in terms of the response of grease structure to contact conditions. For most liquid lubricants, ehd film thickness depends upon the rheological properties of the fluid in the contact inlet. This mechanism is reasonably well understood for fluids that are Newtonian in behaviour. However, greases have complex bulk structures, the scale of which is larger than the dimensions of a contact inlet. The ehd performance of grease must therefore depend upon the response of grease structure to the high-shear inlet conditions. In this study, ehd film thickness has been measured for a range ol greases using optical interierometry. In parallel work, grease structural changes have been monitored directly in the inlet of ehd contacts using reflection-absorption infrared speciruswjpy. By using these two approaches in combination, changes in composition and loss of bulk grease structure have been observed and correlated with the ability of greases to form films under EHD conditions. © 1992 IOP Publishing Ltd.
Cann PM, Aderin M, Johnston GJ, et al., 1992, An Investigation into the Orientation of Lubricant Molecules in EHD Contacts, Tribology Series, Vol: 21, Pages: 209-218, ISSN: 0167-8922
There is growing evidence from infrared and from computer simulation work that the very high shear stresses associated with elastohydrodynamic (EHD) contacts result in the partial alignment of lubricant molecules. Such an effect has important implications with respect to the lubricant's EHD film forming and traction behaviour. In this Paper, the film formation and alignment of thermotropic liquid crystals are studied in an EHD point contact. Two complementary experimental techniques are employed, in-contact, infrared reflection absorption spectroscopy and polarised, thin film optical interferometry. The work shows the extent and direction of orientation of liquid crystal molecules in EHD contacts and indicates how similar effects can be studied in more conventional lubricants. © 1992, Elsevier B.V. All rights reserved.
Cann PM, Spikes HA, 1992, Film thickness measurements of lubricating greases under normally starved conditions, NLGI SPOKESMAN, Vol: 56, Pages: 61-67, ISSN: 0027-6782
A thin film optical technique developed to study starved grease lubrication is described. Film thickness measurements were taken from a rolling elastohydrodynamic contact operating under both fully-flooded and starved conditions for two lithium hydroxystearate greases. Evidence of residual lubricant films, capable of maintaining contact separation for extended running times is presented. The implications of these results in the context of existing theories of grease lubrication are discussed. (P.M.T.)
CANN PM, SPIKES HA, 1991, IN LUBRO STUDIES OF LUBRICANTS IN EHD CONTACTS USING FTIR ABSORPTION-SPECTROSCOPY, Tribology Transactions, Vol: 34, Pages: 248-256
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