bluuebunny/crossref_metadata_2025_split huggingface dataset:
The importance of static friction characteristics of brake friction couple, and methods of testing
Authors: Ścieszka S. F. , Jankowski A. 
Published: July 2006

AbstractDetailed knowledge about static friction materials is required for the accurate calculation of the braking torque needed to hold a load at rest. This is particularly important for brakes in cranes, elevators, hoists and mining winding machines, which must meet specifications such as the definite value of the static safe braking factor. The study of static friction is also a useful supplement to the dynamic testing of brake friction materials. In such a study, precise control of the temperature on the surfaces is possible, as well as surface roughness, and existence of the third‐body can be accurately identified. It is an important fact that the coefficient of static friction, μs, is not an invariant, and it cannot be adequately represented in many engineering applications as a single number. The study of static friction dependence upon factors such as stationary contact time, rate of tangential loading, and surface temperature, contributes to a better understanding of friction phenomena.In this paper, a test apparatus is presented, and a series of experiments is described. The experiments reveal the static friction characteristics of some brake friction materials.
The effect of slip amplitude and test time on fretting wear in metal‐metal contact
Authors: Vižintin J. , Kalin M. , Podgornik B. , Vodopivec F. 
Published: July 2006

AbstractA study was conducted to determine the effect of amplitude and test time on surface damage in metal‐to‐metal contact under lubricated conditions. The test set up consisted of a ball loaded against a flat disc, with an external drive imparting a linear oscillatory motion to the ball on the flat. The materials were steel AISI 52100/AISI 52100, and the lubricant was ISO VG 220. Damage characteristics were defined for amplitudes in the range of 5 to 50 microns and for test times of 10 to 360 min.
An approach to tribosystem simulation and tribotesting
Authors: Kuzmin N. N. , Shuvalova E. A. , Checkina O. G. 
Published: July 2006

AbstractThis paper proposes an approach to the problems of simulation and description of tribosystems, based on an investigation of various fundamental aspects of tribosystem operation. A complex of parameters to be measured in testing, and characteristics analysed after the tests, are selected, using the authors' experience in tribotesting. Methods of processing experimental data and their interpretation are discussed. The approach described here has been successfully used for solution of various practical problems.
Predictability of high‐performance spindles using a complete thermo‐elastohydrodynamic lubrication (TEHD) solution
Authors: Pahud Pierre , Rüstenberg Ines 
Published: July 2006

AbstractSpindles experience problems related to increased power and velocity, and can have very high power consumption. The work reported here is aimed at improving design methods for high‐performance spindles and machine‐tool bearings, and is aimed at determining the influence, of the oil quantity supplying the contact, on power consumption and on contact temperature. A finite element program, TACT, can efficiently predict power loss and the thermal state of machine‐tool bearings, and the remaining unknown in these thermo‐piezo‐viscous‐elastic (TPVE) calculations is inlet oil film height. The authors address this problem and, within the context of this work, develop a high‐speed ISO 50 spindle which has a thin‐wall bearing housing, and is ‚thermally tuned‚, so avoiding thermal instability, while the preload stays constant. Its experimentally determined power consumption values agree well with the TPVE prediction for an assumed inlet film height of 0.5 μm.
A new approach to wear testing of case‐hardened steels
Authors: Senatorski Jan , Tacikowski Jan 
Published: July 2006

AbstractThis paper reports a three‐cylinder‐cone test configuration, which is claimed to be more appropriate to testing the tribological properties of surface hardened steels. Tests are run, for comparative purposes, against a Falex (pin and vee‐block) and Amsler (disc on disc) machines, and the results compared. For various plain carbon, low and medium‐alloy structural steels, nitrided and heat treated under various conditions, and for various test conditions, results are given for the three test methods and apparatus. An example is also given of laboratory simulation of a rubbing part in a hydraulic motor. © Leaf Coppin 1997.
Advanced lubricants for diesel engine particulate control
Authors: Gates Richard S. , Hsu Stephen M. 
Published: July 2006

AbstractDiesel exhaust particulates contain an organic fraction than can be attributed to the engine lubricant. This lubricant fraction varies from a mass fraction of 15% to over 50%, depending on the engine and the operating conditions. This paper addresses the issue of developing novel lubricants that have a lower contribution to diesel particulate. In this work, an analytical technique (TGA/DTA) was developed to measure rapidly the lubricant contribution to diesel particulate. Two apparatus were constructed to simulate the interactions between carbonaceous soot and lubricant products under a variety of test conditions. The combination of simulation apparatus and analytical technique guided the development of lubricants with reduced contribution to particulate. Several formulated lubricants were developed, based on concepts of lower volatility and better oxidative and thermal stability. Initial testing of these lubricants in the simulation apparatus indicated several candidates with reduced interaction with diesel particulate soot.
Diesel lubricant monitoring with new‐concept shipboard test equipment
Authors: Gorin N. , Shay G. 
Published: July 2006

AbstractAccurate diesel lubricating oil testing, formerly relegated only to oil laboratories, can now be performed routinely aboard ship using a series of first‐generation, new‐concept, oil analysis meters. The modern design equipment yields reliable oil test data whose quality approaches that derived from traditional, but often difficult to perform, oil laboratory testing. This equipment contains operating concepts that were jointly codeveloped for fleet use by contractors with direct technical input from NSWCCD‐SSES engineering personnel. The oil testers available are compact, affordable, streamlined, microprocessor‐based devices, containing simplified hardware and menu‐driven software. Further, these devices were designed with extensive onboard oil‐test data storage capabilities. Engine test data obtained is stored so that it can be offloaded to a printer or a computer for operational trending, characteristics that are useful for long‐term tracking of engine conditions, commensurate with condition‐based machinery maintenance concepts. Design ideas employed in the equipment were aimed at making it essentially equivalent to laboratory testing, yet operator‐friendly and easy to use.Evaluation of the testers was completed in about three years from initial conception until commercial products were realised. Included in the evaluaton studies were statistical data comparisons with established testing procedures, along with long‐term fleet testing. The equipment includes kinematic viscosity, fuel dilution (FD), and total base number (TBN) meters.Additional work is continuing on the development of similar equipment for assessing moisture, solids contamination, wear/particle analysis, and total acid number (TAN) evaluations in other oils, so that the US fleet may increase real‐time analysis and diagnostics capabilities.
On the influence of surface finish of SSiC on the results of tribological laboratory tests in the case of water lubricated oscillating sliding
Authors: Klaffke D. , Hartelt M. , Spur G. , Weigmann U.‐P. 
Published: July 2006

AbstractThe development of materials for tribological applications requires characterisation of their friction and wear behaviour. This characterisation is often based on tribological model testing, working with simple shaped specimens, running under well‐defined conditions. Discrepancies in test results may arise from the fact that non‐standard tests with different sets of operational parameters are used.An essential starting point for the development of tribological standards is knowledge of the main parameters that influence the tribological properties. One aspect that is not often adequately taken into account is the surface finish of the test specimens. Results are presented of friction and wear tests with self‐mated SSiC couples (ball on disc), running in water in an oscillating sliding mode. The surfaces of the disc were ground, lapped, or polished, respectively, running against a polished ball.For certain test conditions, the influence of the surface finish on wear is found to be negligible, while for other conditions, the wear rate can differ by one order of magnitude or even more.The consequences for the standardisation of wear tests of ceramic materials are discussed.
Rerefining of used oils — a review of commercial processes
Authors: Dang G. S. 
Published: July 2006

AbstractThe total demand for lubricants in India is in the region of 855,000 tonnes a year. This constitutes 1.5% of total petroleum products consumption. Presently, there are three lubricant refineries in the country with a total installed capacity of 535,000 tonnes. The shortfall, of about 370,000 tonnes (approximately 45% of demand), is met through imports. In addition, there are generated 60,000–65,000 tonnes a year of base oil through rerefining of used oils. The three refineries are being expanded in order to raise base oil production to 810,000 tonnes per annum. Some other refinery projects are also under consideration and approval by the government. The current expansion programmes, together with the projected new refineries, are expected to make India self‐sufficient in terms of base stock production lubricant.Overall, lubricant production in India is entirely dependent on imported lubricant‐bearing crudes, and not on the indigenous crudes, which are non‐lube bearing. With recent advances in engine design, together with improved lubricant quality through high‐performance lubricants, the consumption, or demand rate, has been in decline or unchanging in most countries. In India, a gap still exists between production and demand of lubricants, necessitating import. Since they are a high‐value, non‐energy product, lubricant conservation measures are therefore essential.Interest in rerefining of used oil is increasing, with more and more emphasis on making the processes environmentally friendly. The conventional acid‐clay rerefining process is environmentally unfriendly, and hence needs modification. An attempt is made in this paper to highlight various rerefining processes available. The relative merits and demerits of each process are discussed, and among the various processes, that based on molecular/high vacuum distillation is covered in detail.
Anti‐shudder durability of automatic transmission fluids: Mechanism of the loss of shudder control
Authors: Watts R. F. , Nibert R. K. , Tandon M. 
Published: July 2006

AbstractField samples of automatic transmission fluid (ATF) from vehicles fitted with controlled‐slip torque converter clutches have been analysed to determine the cause of the onset of vehicle shudder. A laboratory anti‐shudder test has been developed using the SAE No. 2 machine. This test includes several degradation mechanisms: thermal degradation in engaging clutches, oxidative degradation in the presence of catalytic metals, and degradation produced by a continuously sliding clutch. At least in the case of one specific fluid, the mode of failure produced in the laboratory test was very similar to the mode of failure in the vehicle. Fluids with improved anti‐shudder durability have been evaluated by this test method and fail by different mechanisms. Test matrices have been conducted to separate the contribution of fluid and hardware to the loss of shudder control in these systems.
Efficiency determination of cylindrical gear units in a back‐to‐back gear test rig
Authors: Miloiu G. 
Published: July 2006

AbstractA method is presented for determining the efficiency of gear units in test rigs with a mechanically closed energy flow, based on measuring the losses in the rig, that is, the torsion torque at the driving motor and the stabilised thermic level. The energy losses between the two gear units would be separated according to the direction of power flow within the stressed framework of the rig.Experimental results are given for gear units including three types of gears, i.e.: involute gears with hobbed toothing, involute gears with ground toothing, and Wildhaber/Novikov (W/N) non‐involute circular arc gears with two meshing lines, achieved by hobbing.
A new methodology to estimate starvation in ball bearings
Authors: Olaru D. N. , Gafitanu M. D. 
Published: July 2006

AbstractIn agreement with isothermal EHD theory, increases in speed and lubricant viscosity determine the increase in film thickness. Beyond certain limits, both speed and viscosity lead to a decrease in film thickness, as a result of thermal effects and starvation. To estimate starvation limits and film thickness in high‐speed, mist‐lubricated ball bearings, a new analytical methodology has been developed. This methodology is based both on the oil flow rate in ball‐race contacts and Hamrock and Dowson's starvation theory. This new methodology has been used to estimate minimum film thickness in a 7206C angular contact ball bearing, axially‐loaded, and rotated between 0 and 35,000 r/min−1. Good correlation between computed and experimental values of the minimum film thickness have been obtained.
A comparative study of different wear measurement techniques applied to fretting wear of a spherical against a flat steel specimen
Authors: de Baets P. , Strijckmans K. , van Peteghem A. P. 
Published: July 2006

AbstractOne of the main problems in fretting wear research is accurate measurement of the very small wear volumes (in microgams) produced. Different techniques, with their own advantages and disadvantages, can be used. Classic wear techniques lack sensitivity and often fail to measure the fretting wear volumes at all, or are not accurate enough. The authors have developed a Thin Layer Activation (TLA) method for quantification of the fretting wear of steel surfaces. The same method can also be used to determine material transfer between wear specimens. In this paper, the different methods are reviewed, and their accuracy in terms of the fretting wear measurement of steel surfaces is discussed. It is concluded that TLA has relatively good reproducibility and accuracy in comparison with classic fretting wear measurement techniques, such as normal approach measurement and spherical cap modelling. Modern threedimensional profilometry has better reproducibility than TLA, but is afflicted by systematic errors because of the oxidation of the metal surface. The different methods emphasise different features of the fretting process, and it is advisable to use them together for measuring fretting wear; their combined use provides a better understanding of the fundamentals of the fretting wear process.
A disc‐on‐flat wear test under starved lubrication
Authors: Levitin M. , Shamshidov B. 
Published: July 2006

AbstractThe ‘disc‐on‐flat’ system has been used for testing wear under starved lubrication conditions. The rotating discs were made of a carbon steel, the surface finish of the discs being ground. Some of the discs were treated by ‘vibrogrooving’, to form regular microrelief. The flat counterface was made of a ground copper alloy. An industrial oil was used as a lubricant in a one‐drop test procedure. Microreliefs of a non‐touching design with a relative groove area of 34% caused less wear than microreliefs of a touching type with a relative groove area of 50%, whereas the wear caused by the ground disc was high, with seizure after 200–250 m of sliding distance. A one‐drop disc‐on‐cylinder test also showed that the wear caused by discs with regular microrelief was considerably less than that caused by discs treated by conventional finishing (grinding, polishing).
Three‐dimensional description of sheet‐metal surfaces
Authors: Wagner Stefan 
Published: July 2006

AbstractDuring sheet‐metal forming processes, the friction conditions have a decisive influence on forming limits, the robustness of the production process, and the quality of the parts produced, with significant forces required to overcome friction between the sheet and the tools. If batch‐to‐batch reproducibility is to be guaranteed, an appropriate method of characterising the sheet surface topography is needed to monitor the sheetmetal fabrication process. Newly developed optical measurement techniques and computer workstation technology are presented, which enable the topography of sheet surfaces to be described in three dimensions. New parameters for describing sheet surface topography are developed. This may correlate more closely with frictional behaviour in sheet stamping than the previously used two‐dimensional parameters, with the size, shape, and distribution of the peaks and valleys of the topography defined. Results generated on a special drawing friction test machine indicate that numerous narrow peaks and large, separate, uniformly distributed valleys yield a desirable resistance to adhesion.
Severity of wear: A new index
Authors: Jones M. H. , Alberich J. 
Published: July 2006

AbstractA Time Dependent Particle Quantifier (TDPQ) system can measure the concentration of ferrous wear debris suspended in a lubricant, and the severity of wear associated with the particle size of this suspended debris. A coding system is proposed covering: PQ index (total wear); initial TDPQ slope (large particles); and final TDPQ slope (small particles). Correlation with existing measurement systems is also given.
Functional behaviour of PVD coatings under sliding and rolling stress conditions
Authors: zu Köcker G. Meier , Santner E. , Löffelbein B. 
Published: July 2006

AbstractWhereas wear‐resistant PVD coatings are well established in the field of metalcutting, and the functional and tribological behaviour of these coatings is well known under such conditions, PVD coatings are used only occasionally in mechanical engineering. The reason for this seems to be the lack of information concerning the functional behaviour of these coatings in closed tribosystems.To evaluate new areas of application together with optimised coating compounds, model wear tests were performed under sliding, rolling and slip‐rolling stress conditions. In addition, the test parameters, such as sliding speed, load, ambient temperature, and number of revolutions were varied, as were the coating compounds and their thicknesses.The results obtained show that friction and wear of PVD coatings are both strongly influenced by the kind of stress and the test parameters themselves. Coatings that perform well under certain test conditions can break down quickly under some other stress conditions. TiN coatings, for example, which display low friction and wear under sliding friction, fail under rolling conditions very shortly afterwards.
Evaluation of various methods to detect metallic wear particles in lube‐oil filter debris
Authors: Fisher Gary C. 
Published: July 2006

AbstractStudies were conducted to evaluate methods of detecting metallic wear particles in lube‐oil filter debris. The methods studied were: low‐temperature oxidation of the organic constituents in the debris, separation of ferromagnetic particles by passage through a magnetic field, and counting/sizing of metallic particles in a fluid stream using a commercially available detector. Laboratory‐prepared simulations of wear debris and actual filter debris samples from operational military aircraft systems were used in the evaluation. The relative ability of each method to detect metallic wear particles is discussed, along with the effects of each method on subsequent debris examination.
Development of a combined AFM‐tribometer test rig
Authors: Sch Jörg , Schneider Thomas , Santner Erich 
Published: July 2006

AbstractA test rig has been developed that combines an atomic force microscope with a tribometer built for testing sliding electrical contacts. This instrument is able to visualise the onset and development of topographical changes in surfaces due to tribological stress, quasi in situ, at ambient air conditions. The spatial resolution reaches atomic levels, and exact quantitative topographical information is available in all three dimensions. Using a so‐called ‘stand‐alone AFM’, commercial components can be tested without the need for extended sample preparation.Some first measurements on the conductive plastic film of a commercial potentiometer tribologically stressed by a precious metal wiper are presented. The results demonstrate that all surface modifications in a selected area occurring within the first few stress cycles can be visualised and prepared for quantitative analysis. Topographical changes can be identified as a combination of adhesive and abrasive wear leading to the formation of small plateaux that are partly built up from wiper material, and have widths in the region of 5 μm to 10 μm.
Tribology and tribodiagnostics in Russia: An overview
Authors: Bronovets M. A. , Zaritsky S. P. , Lopatin A. S. 
Published: July 2006

AbstractThis paper offers a brief look at the development of the theory and practice of tribology and tribodiagnostics in Russia. It covers the main directions in tribology, and looks at magnetofluid (ferrofluid) tribosystems, classification of triboelements, tribomonitoring systems, thin‐layer activation, renovation of tribosystems without disassembly, tribosystems with automatic wear compensation, and controlled tribochemical regimes.
Development of an experimental rig with hydrostatic bearings for testing the EHD traction force of high‐speed lubricants
Authors: Yang  , Bo‐Yuan  , Zheng  , Pei‐Bin  , Yang  , Ru‐Ping  , Shen  , Ming‐Wu  , Wang  , Teng‐Fang  
Published: July 2006

AbstractA test rig for the EHD traction force of lubricants is essential equipment for the study of the non‐Newtonian properties of lubricants operating at high pressure. In this paper is described the development of test equipment with hydrostatic bearings, on the basis of analysis of EHD traction and other test rigs. Hydrostatic bearings allow the rig to pick up the signals of the EHD traction force more precisely. Thus, good test results for an aviation lubricant have been obtained.
Filtration characteristics of magnetic fibrous polymer as a new oil filter material for lubrication systems
Authors: Ahn Byeng‐Gil , Choi Ung‐Su , Shim Hyun‐Hae , Kwon Oh‐Kwan , Moon Tak‐Jin 
Published: July 2006

AbstractMagnetic fibrous polymeric filter (MFPF) elements for lubrication systems were obtained by pneumoextrusion of a thermoplastic polymer (polyamide) containing a magnetic particulate filler (barium ferrite), and treating it subsequently in magnetic fields. Using a standard laboratory oil filtration test rig, metallic particle quantifier, and an image analyser system, the dependence of the filtration characteristics of the magnetic filter medium on the magnetic parameters was investigated. The variation of pressure drop and filtration efficiency with the packing density of the lubricating filter elements was measured. A conventional lubricant filter for an internal combustion engine was also tested for comparison with the filtration performance of the magnetised filter medium. Increasing the magnetic force of the filter medium made the MFPF material more effective in filtering fine ferrous particles, without changing the pressure drop. It was concluded that MFPF can be used as an effective filter in lubrication systems.