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Many Tribology Group publications are Open Access thanks to funding from the EPSRC.

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  • Journal article
    Wong JSS, Sue HJ, Zeng KY, Li RKY, Mai YWet al., 2004,

    Scratch damage of polymers in nanoscale

    , Acta Materialia, Vol: 52, Pages: 431-443, ISSN: 1359-6454

    Recent advances in nanoscience and nanotechnology have led to the development of miniaturized devices and components based on polymeric materials. These polymeric components and devices are subject to surface damage in the nanoscale range. Since the surface properties of polymers may be different from those of the bulk, techniques that focus on nanoscale surface damage have been applied to correlate surface damage with material characteristics and surface roughness of epoxies, polycarbonate, and polymethylmethacrylate. Under a constant loading and constant scratch rate testing condition, the results suggest that surface damage encountered is mainly material specific. Surface roughness plays little or no role in surface damage formed during the course of this study. Material characteristics influence the damage occurred when varying the penetration depth. Such variations can be assessed in terms of elastic recovery, damage pattern and damage mechanism. The variations in scratch head geometry, which, in turn, lead to the variations in magnitude of stress and stress field distribution, give rise to various scratch features on the polymer. © 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
  • Conference paper
    Brajdic-Mitidieri P, Gosman AD, Ioannides S, Spikes HAet al., 2004,

    CFD analysis of a low friction pocketed PAD bearing

    , Pages: 737-747

    A commercial CFD code has been applied to model lubricant flow behaviour within 2D and 3D linear pad bearings having closed pockets or recesses. The study indicates that the presence of closed pockets can result in a significant reduction in bearing friction coefficient. At high convergence ratios, no cavitation is predicted within the pockets. This means that suitably-positioned pockets in the high-pressure region of the bearing result in a much greater reduction in local shear stress than in local pressure, so that there is an overall reduction in friction coefficient. At low convergence ratios, cavitation occurs in the inlet to the pockets so that each pocket acts an effectively-independent step bearing. This results in the overall bearing supporting a higher load and thus having lower friction coefficient than is the case without pockets. Copyright © 2004 by ASME.
  • Journal article
    Olver AV, Tiew LK, Medina S, Choo JWet al., 2004,

    Direct observations of a micropit in an elastohydrodynamic contact

    , WEAR, Vol: 256, Pages: 168-175, ISSN: 0043-1648
  • Journal article
    Damiens B, Venner CH, Cann PME, Lubrecht AAet al., 2004,

    Starved lubrication of elliptical EHD contacts

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 126, Pages: 105-111, ISSN: 0742-4787
  • Conference paper
    Dini D, Nowell D, Dyson IN, 2004,

    Experimental validation of a short crack approach for fretting fatigue threshold prediction (Article no.363)

    , 12th International Conference on Experimental Mechanics, 29 August - 2 September 2004, Bari, Italy, Publisher: McGraw-Hill, Pages: 1-6
  • Conference paper
    Rana A, Sayles RS, 2004,

    An experimental study on the friction behaviour of aircraft hydraulic actuator elastomeric reciprocating seals

    , 29th Leeds-Lyon symposium on tribology, Leeds, September 2004
  • Journal article
    Spikes HA, Olver AV, 2004,

    Basics of mixed lubrication

    , Lubrication Science, Vol: 16, Pages: 3-28, ISSN: 0954-0075
  • Report
    Benyajati C, Olver AV, 2004,

    The effect of a ZnDTP anti-wear additive on micropitting resistance of carburised steel rollers

    , AGMA Technical Paper, Alexandria, VA, Publisher: American Gear Manufacturers Association, 04FTM06
  • Conference paper
    Dini D, Hills DA, 2004,

    A new method for the quantification of nucleation of fretting fatigue cracks

    , 4th International Symposium on Fretting Fatigue (ISFF4), 26 - 28 May 2004, Lyon, France
  • Conference paper
    Sayles RS, Kondo S, 2004,

    A study of the compressibility and glass-transition behaviour of high-pressure oil and grease films trapped between a steel ball and a sapphire plate

    , NORDTRIB 2004
  • Conference paper
    Benyajati C, Olver AV, Hamer CJ, 2004,

    An experimental study of micropitting, using a new miniature test-rig

    , Amsterdam, 30th leeds-lyon symposium on tribology, Lyon, France, 2 - 5 September 2003, Publisher: Elsevier Science Bv, Pages: 601-610
  • Journal article
    Spikes HA, Olver AV, 2004,

    Basics of mixed lubrication

    , Lubrication Science, Vol: 16, Pages: 3-28, ISSN: 0954-0075
  • Conference paper
    Fujita H, Spikes HA, 2004,

    The influence of soot on lubricating films

    , Oxford, Transient processes in tribology, 43: proceedings of the 30th Leeds-Lyon symposium on tribiology, Lyon, France, 2 - 5 September 2003, Publisher: Elsevier, Pages: 37-43
  • Conference paper
    Dini D, Hills DA, 2004,

    The use of asymptotic solution in fretting fatigue (Article no.ECF15)

    , 15th European Conference of advanced Fracture mechanics for life and safety assessments (ECF15), 11 - 13 August 2004, Stockholm, Sweden, Publisher: ESIS, Pages: 1-8
  • Journal article
    Anghel V, Spikes HA, Glovnea RA, 2004,

    Friction and film forming behaviour of five traction fluids

    , Journal of Synthetic Lubrication, Vol: 21, Pages: 13-32, ISSN: 0265-6582
  • Conference paper
    Glovnea RP, Spikes HA, 2004,

    The influence of lubricant properties on EHD film thickness in variable speed conditions

    , Amsterdam, Transient processes in tribology, 43: proceedings of the 30th Leeds-Lyon symposium on tribiology, Lyon, France, 2 - 5 September 2003, Publisher: Elsevier Science Bv, Pages: 401-408
  • Journal article
    Damiens B, Lubrecht AA, Cann PM, 2004,

    Influence of cage clearance on bearing lubrication

    , Tribology Transactions, Vol: 47, Pages: 2-6, ISSN: 0569-8197
  • Conference paper
    Dini D, Nowell D, Dyson IN, 2004,

    The use of notch and short crack approaches to fretting fatigue threshold prediction: theory and experimental validation

    , 4th International Symposium on Fretting Fatigue (ISFF4), 26 - 28 May 2004, Lyon, France
  • Conference paper
    Choo J, Glovnea R, Forrest A, Spikes Het al., 2004,

    Friction in low load sliding contact

    , VARED 12, Succeava, 8 - 9 October 2004
  • Conference paper
    Medina S, Olver AV, Shollock B, 2004,

    Development of rolling contact damage in two bronze alloys

    , Amsterdam, 30th leeds-lyon symposium on tribology, Lyon, France, 2 - 5 September 2003, Publisher: Elsevier Science Bv, Pages: 619-627
  • Conference paper
    Dini D, Churchman CM, Hills DA, 2004,

    A re-evaluation of incomplete fretting fatigue experimental data using the concept of asymptotes (Article no.72)

    , 12th International Conference on Experimental Mechanics, 29 August - 2 September 2004, Bari, Italy, Publisher: McGraw-Hill, Pages: 1-6
  • Journal article
    Dwyer-Joyce RS, Reddyhoff T, Drinkwater BW, 2004,

    Operating limits for acoustic measurement of rolling bearing oil film thickness

    , Tribology Transactions, Vol: 47, Pages: 366-375, ISSN: 1040-2004

    An ultrasonic pulse striking a thin layer of liquid trapped between solid bodies will be partially reflected. The proportion reflected is a function of the layer stiffness, which in turn depends on the film thickness and its bulk modulus. In this work, measurements of reflection have been used to determine the thickness of oil films in elastohydrodynamic lubricated (EHL) contacts. A very thin liquid layer behaves like a spring when struck by an ultrasonic pulse. A simple quasi-static spring model can be used to determine the proportion of the ultrasonic waves reflected. Experiments have been performed on a model EHL contact between a ball and a flat surface. A transducer is mounted above the contact such that the ultrasonic wave is focused onto the oil film. The reflected signals are captured and passed to a PC for processing. Fourier analysis gives the reflection spectrum that is then used to determine the stiffness of the liquid layer and hence its thickness. In further testing, an ultrasonic transducer has been mounted in the housing of a deep-groove ball bearing to measure the film generated at the outer raceway as each ball passes. Results from both the ball-flat and ball bearing measurements agree well with steady-state theoretical EHL predictions. The limits of the measuring technique, in terms of the measurable rolling bearing size and operating parameters, have been investigated.
  • Conference paper
    Glovnea RP, Fujita H, Spikes HA, 2004,

    The behaviour of an anti-wear additive on different coatings in concentrated contacts

    , VAREHD12th international tribology conference, Suceava, Romania, 7 - 9 October 2004
  • Journal article
    Dwyer-Joyce R, Reddyhoff T, Drinkwater B, 2004,

    Operating limits for acoustic measurement of rolling bearing oil film thickness

    , Tribology Transactions, Vol: 47, Pages: 366-375, ISSN: 1040-2004

    An ultrasonic pulse striking a thin layer of liquid trapped between solid bodies will be partially reflected. The proportion reflected is a function of the layer stiffness, which in turn depends on the film thickness and its bulk modulus. In this work, measurements of reflection have been used to determine the thickness of oil films in elastohydrodynamic lubricated (EHL) contacts. A very thin liquid layer behaves like a spring when struck by an ultrasonic pulse. A simple quasi-static spring model can be used to determine the proportion of the ultrasonic waves reflected. Experiments have been performed on a model EHL contact between a ball and a flat surface. A transducer is mounted above the contact such that the ultrasonic wave is focused onto the oil film. The reflected signals are captured and passed to a PC for processing. Fourier analysis gives the reflection spectrum that is then used to determine the stiffness of the liquid layer and hence its thickness. In further testing, an ultrasonic transducer has been mounted in the housing of a deep-groove ball bearing to measure the film generated at the outer raceway as each ball passes. Results from both the ball-flat and ball bearing measurements agree well with steady-state theoretical EHL predictions. The limits of the measuring technique, in terms of the measurable rolling bearing size and operating parameters, have been investigated.
  • Patent
    Contaldi GF, Olver AV, 2003,

    Rotary pump

    , 6666671
  • Journal article
    Dini D, Hills DA, 2003,

    A method based on asymptotics for the refined solution of almost complete partial slip contact problems

    , EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, Vol: 22, Pages: 851-859, ISSN: 0997-7538
  • Journal article
    Müller M, Lee S, Spikes HA, Spencer NDet al., 2003,

    The influence of molecular architecture on the macroscopic lubrication properties of the brush-like co-polyelectrolyte poly(L-lysine)-<i>g</i>-poly(ethylene glycol) (PLL-<i>g</i>-PEG) adsorbed on oxide surfaces

    , TRIBOLOGY LETTERS, Vol: 15, Pages: 395-405, ISSN: 1023-8883
  • Patent
    Spikes H, 2003,

    Bearing

    , US 7,387.442 B2
  • Journal article
    Lee S, Müller M, Ratoi-Salagean M, Vörös J, Pasche S, De Paul SM, Spikes HA, Textor M, Spencer NDet al., 2003,

    Boundary lubrication of oxide surfaces by Poly(L-lysine)-<i>g-</i>poly(ethylene glycol) (PLL-<i>g</i>-PEG) in aqueous media

    , TRIBOLOGY LETTERS, Vol: 15, Pages: 231-239, ISSN: 1023-8883
  • Journal article
    Glovnea RP, Forrest AK, Olver AV, Spikes HAet al., 2003,

    Measurement of sub-nanometer lubricant films using ultra-thin film interferometry

    , TRIBOLOGY LETTERS, Vol: 15, Pages: 217-230, ISSN: 1023-8883
  • Journal article
    Kadiric A, Sayles RS, Zhou XB, Ioannides Eet al., 2003,

    A numerical study of the contact mechanics and sub-surface stress effects experienced over a range of machined surface coatings in rough surface contacts

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 125, Pages: 720-730, ISSN: 0742-4787
  • Journal article
    Wong JSS, Ferrer-Balas D, Li RKY, Mai YW, Maspoch ML, Sue HJet al., 2003,

    On tearing of ductile polymer films using the essential work of fracture (EWF) method

    , Acta Materialia, Vol: 51, Pages: 4929-4938, ISSN: 1359-6454

    The essential work of fracture (EWF) technique has been well established and accepted for the fracture characterization of ductile polymer films under in-plane (mode I) loading. In the present study, the technique has been further developed for the characterization of out-of-plane (mode III) tearing fracture of some ductile polymer films including PETG (polyethylene-terephthalate-glycol), PP homopolymer (H0) and a PP copolymer (C1). A two-zone model was proposed to describe the deformation and fracture behaviour of the tearing ligament. In the first zone, which is called zone A and is adjoining the initial crack-tip, the outer plastic zone height increases with the torn ligament length. At the end of zone A, the height of the plastic zone has saturated, and the deformation has entered zone B. The height of the outer plastic zone remains constant with further increase of torn ligament length. The zone B model is applicable to films with a large stabilized plastic zone (such as H0 and C1). It is observed that the tearing specific essential fracture work as measured from the zone A and zone B models are similar confirming the EWF concept can be applied to the mode III out-of-plane tearing of polymer films. © 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
  • Journal article
    Nowell D, Dini D, Duó P, 2003,

    Stress analysis of V-notches with and without cracks, with application to foreign object damage

    , JOURNAL OF STRAIN ANALYSIS FOR ENGINEERING DESIGN, Vol: 38, Pages: 429-441, ISSN: 0309-3247
  • Journal article
    Taylor LJ, Spikes HA, 2003,

    Friction-enhancing properties of ZDDP antiwear additive: Part II - Influence of ZDDP reaction films on EHD lubrication

    , TRIBOLOGY TRANSACTIONS, Vol: 46, Pages: 310-314, ISSN: 1040-2004
  • Journal article
    Taylor LJ, Spikes HA, 2003,

    Friction-enhancing properties of ZDDP antiwear additive: Part I - Friction and morphology of ZDDP reaction films

    , TRIBOLOGY TRANSACTIONS, Vol: 46, Pages: 303-309, ISSN: 1040-2004
  • Journal article
    Chiñas-Castillo F, Spikes HA, 2003,

    Mechanism of action of colloidal solid dispersions

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 125, Pages: 552-557, ISSN: 0742-4787
  • Journal article
    Choo JW, Glovnea RP, Olver AV, Spikes HAet al., 2003,

    The effects of three-dimensional model surface roughness features on lubricant film thickness in EHL contacts

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 125, Pages: 533-542, ISSN: 0742-4787
  • Journal article
    Spikes H, Granick S, 2003,

    Equation for slip of simple liquids at smooth solid surfaces

    , LANGMUIR, Vol: 19, Pages: 5065-5071, ISSN: 0743-7463
  • Journal article
    Olver AV, 2003,

    Discussion: "A new calculation method of Hertz elliptical contact pressure" ( Tanaka, N., 2001, ASME J. Tribology, 123(4), pp. 887-889)

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 125, Pages: 462-462, ISSN: 0742-4787
  • Journal article
    Glovnea RP, Choo JW, Olver AV, Spikes HAet al., 2003,

    Compression of a single transverse ridge in a circular elastohydrodynamic contact

    , JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 125, Pages: 275-282, ISSN: 0742-4787
  • Journal article
    Dini D, Nowell D, 2003,

    Prediction of the slip zone friction coefficient in flat and rounded contact

    , WEAR, Vol: 254, Pages: 364-369, ISSN: 0043-1648
  • Journal article
    Nowell D, Dini D, 2003,

    Stress gradient effects in fretting fatigue

    , TRIBOLOGY INTERNATIONAL, Vol: 36, Pages: 71-78, ISSN: 0301-679X
  • Journal article
    Spikes HA, 2003,

    The half-wetted bearing. Part 1: Extended Reynolds equation

    , Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, Vol: 217, Pages: 1-14, ISSN: 1350-6501

    <jats:p> Recent research has shown that, when a liquid is partially wetting or non-wetting against a very smooth solid surface, the conventional no-slip boundary condition can break down. Under such circumstances, the Reynolds equation is no longer applicable. In the current paper, the Reynolds equation is extended to consider the sliding, hydrodynamic lubrication condition where the lubricant has a no-slip boundary condition against the moving solid surface but can slip at a critical shear stress against the stationary surface. It is shown that such a ‘half-wetted’ bearing is able to combine good load support resulting from fluid entrainment with very low friction due to very low or zero Couette friction. </jats:p>
  • Journal article
    Ratoi M, Spikes HA, Bovington C, 2003,

    Langmuir-Blodgett films in high-pressure rolling contacts

    , TRIBOLOGY TRANSACTIONS, Vol: 46, Pages: 24-30, ISSN: 1040-2004
  • Journal article
    Ratoia M, Bovington C, Spikes H, 2003,

    <i>In situ</i> study of metal oleate friction modifier additives

    , TRIBOLOGY LETTERS, Vol: 14, Pages: 33-40, ISSN: 1023-8883
  • Conference paper
    Dini D, Nowell D, 2003,

    Application of short crack arrest concepts to the prediction of thresholds in fretting fatigue (Article no.139)

    , International Conference on Computational & Experimental Engineering and Sciences, 25 - 29 July 2003, Corfu, Greece, Publisher: Tech Science Press, Pages: 1-6
  • Conference paper
    Spikes HA, 2003,

    Slip at the wall - Evidence and tribological implications

    , Amsterdam, Leeds-Lyon symposium on tribology; tribological research and design for engineering systems, Publisher: Elsevier, Pages: 525-536
  • Conference paper
    Spikes HA, 2003,

    Slip at the wall - evidence and tribological implications

    , 29th Leeds-Lyon Symposium on Tribology, Publisher: ELSEVIER SCIENCE BV, Pages: 525-535
  • Conference paper
    Dini D, Hills DA, 2003,

    An asymptotic approach for the correlation of complete, incomplete and almost complete fretting contacts (Article no.242, Keynote)

    , International Conference on Computational & Experimental Engineering and Sciences, 25 - 29 July 2003, Corfu, Greece, Publisher: Tech Science Press, Pages: 1-6
  • Conference paper
    Olver AV, Medina S, 2003,

    Tribology of spline couplings

    , 29th Leeds-Lyon Symposium on Tribology, Publisher: ELSEVIER SCIENCE BV, Pages: 589-602

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