Imperial College London
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ProfessorHughSpikes

Faculty of Engineering, Department of Mechanical Engineering

Professor
 
 
 
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Contact

 

+44 (0)20 7594 7063h.spikes

 
 
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Assistant

 

Mrs Chrissy Stevens +44 (0)20 7594 7064

 
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Location

 

673City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

472 results found

Reddyhoff T, Spikes HA, Olver AV, 2009, Improved temperature mapping of ehl contacts, Miami, FL, United states, 2008 STLE/ASME International Joint Tribology Conference, IJTC 2008, October 20, 2008 - October 22, 2008, Publisher: ASME, Pages: 265-267

An effective means of studying lubricant film rheology within EHL contacts is by detailed mapping of the temperature of the fluid and the bounding surfaces within the lubricated contact area. This provides a way of directly measuring the rheology of lubricant films under true EHL conditions. Furthermore, temperature measurement itself provides a very effective means of testing and validating computer simulations. In the current work, the experimental approach initially developed by Sanborn and Winer [11 and then by Spikes and co-workers [2], has been advanced to include a high specification infrared (IR) camera and microscope. This is a similar approach to that taken by Yagi and Kyogoku [3]. As well as the instantaneous capture of full field measurements, this has the advantage of increased sensitivity and higher spatial resolution than previous systems used. The increased sensitivity enables a much larger range of testable operating conditions; namely lower loads, speeds and reduced sliding. In addition, the range of test lubricants can be extended beyond high shearing traction fluids. One additional advantage of instantaneous full field measurements is that the weak infrared optical interference caused by the film can be observed and can used to exactly locate the centre of the contact in the resulting temperature maps. These new possibilities have been used to investigate and compare the rheological properties and compression cooling effects exhibited by a PAO, a group II mineral oil, and a traction fluid. Copyright 2008 by ASME.

Conference paper

Fowell MT, Olver A, Spikes HA, Pegg IGet al., 2009, MODELLING OF MICRO TEXTURED BEARINGS WITH MASS-CONSERVING CAVITATION: A TWO DIMENSIONAL PROBLEM, STLE/ASME 2008 International Joint Tribology Conference, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 343-+

Conference paper

Benedet J, Green JH, Lamb GD, Spikes HAet al., 2009, Spurious Mild Wear Measurement Using White Light Interference Microscopy in the Presence of Antiwear Films, TRIBOLOGY TRANSACTIONS, Vol: 52, Pages: 841-846, ISSN: 1040-2004

Journal article

Topolovec-Miklozic K, Lockwood F, Spikes H, 2008, Behaviour of boundary lubricating additives on DLC coatings, WEAR, Vol: 265, Pages: 1893-1901, ISSN: 0043-1648

Journal article

Spikes H, 2008, Low saps antiwear additives

Modern engine lubricant specifications impose limits on permissible sulfur and phosphorus and ash levels. This necessitates a reduction in the concentration of the additive ZDDP which, in future, may require the latter's partial or complete replacement by other chemistries which have less or zero phosphorus, sulfur, and/or ash. The main types of low SAPS additive that have been suggested to have antiwear performance includes MDDP, thiophosphates and thiophosphonates, metal dialkylphosphates phosphates, metal dithiocarbamates, and organosulfides. These classes of additives were presented. This is an abstract of a paper presented at the 16th International Colloquium Tribology Lubricants Materials and Lubrication Engineering (Stuttgart/Ostfildern, Germany 1/15-17/2008).

Conference paper

Hartinger M, Dumont M-L, Ioannides S, Gosman D, Spikes Het al., 2008, CFD modeling of a thermal and shear-thinning elastohydrodynamic line contact, JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 130, ISSN: 0742-4787

Journal article

Smeeth M, Hamer C, Spikes HA, 2008, A study of antiwear additive film build up using the MTM (mini-traction machine), Pages: 101-103

The measurement of lubricant film thickness under elastohydrodynamic (EHL) contact conditions is well established and a variety of experimental techniques have been used, the most accurate and widely used of which is optical interferometry. This lends itself particularly well to the study of the all-important mixed and boundary regimes, since the films are of the same order of magnitude as the wavelength of light. The vast majority of these studies have been made under pure rolling conditions, since the necessary optical coatings preclude the use of high sliding speeds within the critical thin fluid film regime. These conditions are however precisely those required to activate ZDDPs and other antiwear additives, making accurate 'in situ' optical studies of additive film build-up difficult. A modification to the existing MTM (mini-traction machine) has allowed steel on steel contacts to be run under high sliding speed conditions, thereby allowing antiwear additive reactions to occur. By optically measuring the film thickness of these reaction films as they form, in tandem with friction measurements, a full picture of both friction and reaction film build-up can be made. Using a novel LED (light emitting diode) light source and accurate calibration procedures, the film thickness of the whole contact area can be measured down to a few nanometres. This paper presents a study of the behaviour of standard additive combinations under realistic operating conditions and describes the rig in detail. Copyright © 2007 by ASME.

Conference paper

Choo JW, Olver AV, Spikes HA, Dumont M-L, Ioannides Eet al., 2008, Interaction of asperities on opposing surfaces in thin film, mixed elastohydrodynamic lubrication, JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 130, ISSN: 0742-4787

Journal article

Miklozic KT, Forbus TR, Spikes HA, 2008, Performance of friction modifiers on ZDDP-Generated surfaces, TRIBOLOGY TRANSACTIONS, Vol: 50, Pages: 328-335, ISSN: 1040-2004

Journal article

Spikes HA, 2008, Beyond ZDDP, LUBRICATION SCIENCE, Vol: 20, Pages: 77-78, ISSN: 0954-0075

Journal article

Spikes H, 2008, Low- and zero-sulphated ash, phosphorus and sulphur anti-wear additives for engine oils, LUBRICATION SCIENCE, Vol: 20, Pages: 103-136, ISSN: 0954-0075

Journal article

Topolovec-Miklozic K, Forbus TR, Spikes H, 2008, Film forming and friction properties of overbased calcium sulphonate detergents, TRIBOLOGY LETTERS, Vol: 29, Pages: 33-44, ISSN: 1023-8883

Journal article

Topolovec-Miklozic K, Forbus TR, Lockwood F, Spikes Het al., 2008, Behaviour of boundary lubricating additives on DLC coatings, ASME/STLE International Joint Tribology Conference, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 141-143

Conference paper

Mueller M, Fan J, Spikes H, 2008, Design of functionalized PAMA viscosity modifiers to reduce friction and wear in lubricating oils, Symposium on Automotive Lubricant Testing and Advanced Additive Development, Publisher: AMER SOCIETY TESTING AND MATERIALS, Pages: 116-+, ISSN: 0066-0558

Conference paper

Hartinger M, Gosman D, Ioannides S, Spikes Het al., 2008, Thermal effects in an elastohydrodynamic line contact using a CFD approach, ASME/STLE International Joint Tribology Conference, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 179-180

Conference paper

Fan J, Mueller M, Stoehr T, Spikes HAet al., 2007, Reduction of friction by functionalised viscosity index improvers, TRIBOLOGY LETTERS, Vol: 28, Pages: 287-298, ISSN: 1023-8883

Journal article

Müller M, Fan J, Spikes H, 2007, Design of functionalized PAMA viscosity modifiers to reduce friction and wear in lubricating oils, Journal of ASTM International, Vol: 4, Pages: 116-125, ISSN: 0066-0558

Polyalkylmethacrylates (PAMAs) are widely used as both viscosity index improvers and dispersant boosters in engine, hydraulic, and transmission oils. Since they are employed in a relatively high concentration in these roles, it is desirable that they be able to enhance other characteristics of a lubricant and, in particular, its boundary lubricating properties. A series of functionalized PAMAs have been synthesized that can adsorb from oil solution onto rubbing surfaces to produce thick boundary films. These films enhance lubricant film formation in slow speed and high temperature conditions and thus make a significant contribution to their lubricating ability. The current paper describes a systematic study of the influence of functionallzed PAMAs on boundary lubrication performance. The high frequency reciprocating test rig (HFRR) was applied to investigate friction and wear under pure sliding. A new test method has been developed which allows wear to be monitored in a rolling and sliding contact based on the mini traction machine (MTM). This, in combination with other tests, is employed to investigate the influence of polymer architecture, functionality, concentration and molecular weight on friction and wear in a range of lubricant formulations. This enables the tailored design of polymers which offer low friction and wear properties. Copyright © 2007 by ASTM International.

Journal article

Müller M, Bartels T, Hedrich K, Wincierz C, Spikes Het al., 2007, Tailor-made polyalkylmethacrylate additives to meet the stringent requirements of current and future generations of engine, transmission, gear and hydraulic oils

A discussion covers an introduction into polyalkylmethacrylates (PAMA) and their chemistry; viscometric and tribological effects of PAMA in lubricant formulations; recent findings from a scientific study of EHD film formation, friction and wear reduction through specifically designed PAMA; results of various performance and application tests demonstrating the effect of PAMA on different performance aspects of modern lubricants; wear reduction and fuel economy engine oils, including pitting performance, operating temperature control, and energy efficiency in transmission and gear oils; and the effect of PAMA on hydraulic pump efficiency and delivered hydraulic work in different performance and field tests. This is an abstract of a paper presented at the 13th Annual Fuels and Lubes Asia Conference (Bangkok, Thailand 3/7-9/2007).

Conference paper

Choo J-H, Forrest AK, Spikes HA, 2007, Influence of organic friction modifier on liquid slip: A new mechanism of organic friction modifier action, TRIBOLOGY LETTERS, Vol: 27, Pages: 239-244, ISSN: 1023-8883

Journal article

Choo JH, Glovnea RP, Forrest AK, Spikes HAet al., 2007, A low friction bearing based on liquid slip at the wall, JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 129, Pages: 611-620, ISSN: 0742-4787

Journal article

Fan J, Spikes H, 2007, New test for mild lubricated wear in rolling-sliding contacts, TRIBOLOGY & LUBRICATION TECHNOLOGY, Vol: 63, Pages: 36-45, ISSN: 1545-858X

Journal article

Topolovec-Miklozic K, Forbus TR, Spikes HA, 2007, Film thickness and roughness of ZDDP antiwear films, TRIBOLOGY LETTERS, Vol: 26, Pages: 161-171, ISSN: 1023-8883

Journal article

Fan J, Spikes H, 2007, New test for mild lubricated wear in rolling-sliding contacts, TRIBOLOGY TRANSACTIONS, Vol: 50, Pages: 145-153, ISSN: 1040-2004

Journal article

Fowell M, Olver AV, Gosman AD, Spikes HA, Pegg Iet al., 2007, Entrainment and inlet suction: Two mechanisms of hydrodynamic lubrication in textured bearings, JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 129, Pages: 336-347, ISSN: 0742-4787

Journal article

Choo JH, Spikes HA, Ratoi M, Glovnea R, Forrest Aet al., 2007, Friction reduction in low-load hydrodynamic lubrication with a hydrophobic surface, TRIBOLOGY INTERNATIONAL, Vol: 40, Pages: 154-159, ISSN: 0301-679X

Journal article

Xu X, Spikes H, 2007, Study of zinc dialkyldithiophosphate in di-ethylhexyl sebacate using electrochemical techniques, TRIBOLOGY LETTERS, Vol: 25, Pages: 141-148, ISSN: 1023-8883

Journal article

Choo JW, Olver AV, Spikes HA, 2007, The influence of transverse roughness in thin film, mixed elastohydrodynamic lubrication, TRIBOLOGY INTERNATIONAL, Vol: 40, Pages: 220-232, ISSN: 0301-679X

Journal article

Müller M, Fan J, Spikes H, 2007, Influence of polymethacrylate viscosity index improvers on friction and wear of lubricant formulations, SAE Technical Papers, ISSN: 0148-7191

Polyalkylmethacrylates (PAMAs) are widely used as viscosity index improvers and dispersant boosters in engine, transmission and hydraulic oils. They have been shown to be able to adsorb from oil solution on to metal surfaces, to produce thick, viscous boundary films. These films enhance lubricant film formation in slow speed and high temperature conditions and thus produce a significant reduction of friction and wear. In a recent systematic study a range of dispersant and non-dispersant PAMAs has been synthesized. The influence of different functionalities, molecular weights and architectures on both boundary film formation and friction has been explored using optical interferometry and friction-speed charting. From the results, guidelines have been developed for designing PAMAs having optimal boundary lubricating properties. In the current paper the film forming, friction and wear properties of solutions of two functionalised PAMAs is first described. Then the impact of different lubricant additives on these friction and wear properties is explored. A number of components from all major classes of additives commonly used in commercial DI packages have been investigated. The results help the performance of PAMAs in fully formulated oils to be predicted and thus their design to be optimized.

Journal article

Spikes HA, 2006, Sixty years of EHL, Lubrication Science, Vol: 18, Pages: 265-291, ISSN: 0954-0075

It is now 60 years since Ertel produced the first solution to the elastohydrodynamic lubrication (EHL) problem. There has been enormous progress since then, both in numerical modelling and in experimental research on EHL. The moving, rough surface EHL problem can now be solved on laptop-level computers, while maps of film thickness, pressure and temperature can be obtained experimentally from within rolling/sliding contacts. However, there remain some important questions that have not been fully resolved. One of the most contentious is how to describe the Rheological properties of lubricants under the very severe conditions present in thin film EHL contacts. A second is how to model mixed lubricated contact, where the fluid film can break down at asperity conjunctions. But perhaps the greatest challenge to researchers in EHL is to produce useful design equations for predicting the performance of machine components operating in EHL and thereby ensure that EHL theory becomes an integral part of the design process. Copyright © 2006 John Wiley & Sons, Ltd.

Journal article

de Vicente J, Spikes HA, Stokes JR, 2006, Viscosity ratio effect in the emulsion lubrication of soft EHL contact, JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME, Vol: 128, Pages: 795-800, ISSN: 0742-4787

Journal article

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