Showing papers in "Industrial Lubrication and Tribology in 2006"
TL;DR: In this paper, the performance of cutting fluids employed under two distinct machining operations involving aluminium alloys was investigated and the results indicated that an increase in the flow rate of the mist led to lower feed forces but higher torque, power consumption and specific cutting pressure in the drilling operation.
Abstract: Purpose – The knowledge over the performance of cutting fluids when applied under different machining conditions (such as distinct work material and cutting parameters) is critical in order to improve the efficiency of most machining operations. This paper is concerned with the performance of cutting fluids employed under two distinct machining operations involving aluminium alloys: drilling of AA 1050‐O aluminium applying cutting fluid as a mist and turning of AA 6262‐T6 aluminium alloy using cutting fluids (as a flood) with distinct extreme pressure additives (chlorine, sulphur and phosphor).Design/methodology/approach – This work reports on a experimental study of the performance of cutting fluids when machining aluminium alloys.Findings – The results indicated an increase in the flow rate of the mist led to lower feed forces but higher torque, power consumption and specific cutting pressure in the drilling operation (AA 1050‐O aluminium). The surface finish was not drastically affected by the cutting ...
36 citations
TL;DR: In this article, the authors developed a more realistic model for molecularly thin film hydrodynamic lubrication by incorporating fluid inhomogeneity and discontinuity effects across the fluid film thickness in this lubrication.
Abstract: Purpose – To develop a more realistic model for molecularly thin film hydrodynamic lubrication by incorporating the fluid inhomogeneity and discontinuity effects across the fluid film thickness in this lubrication.Design/methodology/approach – The total mass flow of the fluid through the contact in a basic one‐dimensional molecularly thin film hydrodynamic lubrication is studied by incorporating the fluid inhomogeneity and discontinuity effects across the fluid film thickness, based on a simplified momentum transfer model between neighboring fluid molecules across the fluid film thickness. This flow is calculated according to the present approach and the theory of viscous flow between two contact surfaces. The total mass flow of the fluid through the contact in this lubrication is also calculated from conventional hydrodynamic lubrication theory, which was based on continuum fluid assumption in the whole lubricated contact. The ratio of this flow calculated from the present approach to that calculated fro...
30 citations
TL;DR: In this paper, the effect of MoS2 content on composites' mechanical and tribological performances was investigated and worn morphologies, elements distribution and wear mechanisms under dry and water lubricant condition were also analyzed.
Abstract: Purpose – To provide some useful information on tribology performances of molybdenum disulfide (MoS2) reinforced thermoplastic polymide under dry and water lubrication conditions.Design/methodology/approach – The effect of MoS2 content on composites' mechanical and tribological performances was investigated and worn morphologies, elements distribution and wear mechanisms under dry and water lubricant condition were also analyzed.Findings – As a result, the composites' main mechanical performances decreased partly compared with pure PI and it became more stable with MoS2 content unceasingly increasing (up to 20 wt%). In the dry sliding condition, the friction coefficient decreased obviously by filling MoS2. The wear of composites which filled 10‐15 wt% MoS2 was less than other composites in which MoS2 content was below to 5 wt% or high than 20 wt%. It was found that materials wear happened mainly at initial stages of tribology test which the temperature was so high and the adhesive wear had a dominant plac...
26 citations
TL;DR: In this article, a feed forward neural network is designed to model bearing system and two results are compared for finding the exact model of the system; the results of the proposed neural network predictor gives superior performance for analysing the behaviour of ball bearing undergoing loading deformation.
Abstract: Purpose – To improve the application neural networks predictors on bearing systems and to investigate the exact neural model of the ball‐bearing system.Design/methodology/approach – A feed forward neural network is designed to model‐bearing system. Two results are compared for finding the exact model of the system.Findings – The results of the proposed neural network predictor gives superior performance for analysing the behaviour of ball bearing undergoing loading deformation.Research limitations/implications – The results of the proposed neural network exactly follows desired results of the system. Neural network predictor can be employed in practical applications.Practical implications – As theoretical and practical study is evaluated together, it is hoped that ball‐bearing designers and researchers will obtain significant results in this area.Originality/value – This paper fulfils an identified research results need and offers practical investigation for an academic career and research. Also, It shoul...
18 citations
TL;DR: In this paper, an analytical approximate formulation of the fluid film force of porous finite journal bearings is presented, based on an approximate mathematical model for the one-dimensional lubrication equation about the infinitely long porous journal bearing, while the Warner's method is adopted to describe the oil film pressure film in the finite bearing domain.
Abstract: Purpose – Aims to explore many aspects of the dynamic behaviour of a rotor on bearings, such as the fluid film force. In order to find in an analytical model an effective solution to provide a more readable description of the interaction between journal and bearing.Design/methodology/approach – The present theoretical analysis is carried out to determine the analytical approximate formulation of the fluid film force of porous finite journal bearings. This paper focuses on an approximate mathematical model for the one‐dimensional lubrication equation about the infinitely long porous journal bearing, while the Warner's method is adopted to describe the oil film pressure film in the finite bearing domain.Findings – The proposed model allows a quick analytical determination of the fluid film force for different values of the permeability coefficient, L/D ratio, eccentricity ratio. The results are in good agreement with those achieved by means of the FDM based solution.Originality/value – The results show good...
17 citations
TL;DR: In this article, the wear behavior of the various filler wires were tested and compared with each other in the light of microstructure, chemical, and mechanical properties, and the results showed that the wear rates were significantly increased with the increasing load, welding current, wear distance and poor mechanical properties.
Abstract: Purpose – To provide information about technical data; wear behaviour of worn rotor parts in mining industry and for the other application of ferrous alloys.Design/methodology/approach – Wear behaviour of the various filler wires were tested (tensile, hardness, and wear) and compared with each other in the light of microstructure, chemical, and mechanical properties.Findings – The results showed that the wear rates were significantly increased with the increasing load, welding current, wear distance and poor mechanical properties. A larger amount of C, Cr, and Mn specimen showed the best wear resistance since it contained a number of hard MC‐type carbides and coarse grains. Furthermore, for all materials the weight loss increases linearly with the increasing of welding arc current, load and wear distance.Research limitations/implications – It would be interesting to search about the toughness values and fatigue behaviour of these materials. It could be the good idea for future work could be concentrated f...
16 citations
TL;DR: The experimental and theoretical results of the contact-fluid interfacial shear strength and its caused contact fluid interfacial slippage in hydrodynamic lubrication and especially in EHL were reviewed in this paper.
Abstract: Purpose – To review, analyze and present the effects of the contact‐fluid interfacial shear strength and contact‐fluid interfacial slippage and the critical importance of these effects in elastohydrodynamic lubrication (EHL).Design/methodology/approach – The experimental and theoretical research results of the contact‐fluid interfacial shear strength and its caused contact‐fluid interfacial slippage in hydrodynamic lubrication and especially in EHL obtained in the past decades and progressed in recent years by the present author and by others are reviewed. Analysis and presentation are made on both the contact‐fluid interfacial shear strength versus fluid pressure curve for a given bulk fluid temperature in an isothermal EHL and the influence of the bulk fluid temperature on this curve.Findings – It is very clearly and well understood from the present paper that the value of the contact‐fluid interfacial shear strength in the inlet zone in an EHL contact, i.e. at low EHL fluid film pressures is usually lo...
14 citations
TL;DR: In this paper, the use of alternative oils for the lubrication of automobile engines has a potential of ecological and technical advantages, which requires the detailed knowledge of several thermophysical and viscosimetric properties in a large temperature range.
Abstract: Purpose – The use of alternative oils for the lubrication of automobile engines has a potential of ecological and technical advantages. It requires the detailed knowledge of several thermophysical and viscosimetric properties in a large temperature range.Design/methodology/approach – For 11 different oils, the density, the heat capacity, the thermal conductivity, the viscosity at ambient pressure and the pressure‐viscosity at maximal 1,000 bar have been measured. The latter has been measured with a newly developed apparatus which is described in detail. Two hydrocarbon‐based factory‐fill oils and nine alternative oils have been tested. Five of the alternative oils are based partly or completely on esters, the other four on polyglycols, one of them additionally on water.Findings – Data for thermophysical and viscosimetric properties are given in form of diagrams and tables. The consequences for the cooling capacity and the film forming behavior are discussed. The latter is only slightly better for the fact...
14 citations
TL;DR: In this paper, an analytical hierarchy process (AHP) is applied to assess the remaining useful life of lube oil. But, the suggested oil change period is conservative and results in non-efficient usage of oil.
Abstract: Purpose – The plant experience shows that the oil even after completion of a number of hours of recommended operation has some residual life. It is desirable to maximize its use to conserve this scarce resource but avoid failures. At present, continuation or change of the oil is decided, based on the manufacturer's recommendation and experience in the plant. The suggested oil change period is conservative and results in non‐efficient usage of oil. This practice needs refinement to include all possible properties/attributes of oil and use of appropriate procedure to assess its realistic performance degradation and determine the remaining useful life (RUL) of lube oil.Design/methodology/approach – Analytic hierarchy process (AHP), a multi criteria decision‐making method, in conjunction with vector projection approach is applied to assess the remaining useful life of lube oil.Findings – Physical and chemical properties related to degradation of the lube oil are considered as lubricant attributes and their we...
13 citations
TL;DR: In this article, the rheological effects of an isothermal incompressible non-Newtonian laminar lubricating film on the steady and dynamic characteristics of finite slider bearings are presented in the absence of fluid inertia and cavitation.
Abstract: Purpose – On the basis of the power‐law fluid model, the rheological effects of an isothermal incompressible non‐Newtonian laminar lubricating film on the steady and dynamic characteristics of finite slider bearings are presented in the absence of fluid inertia and cavitation.Design/methodology/approach – To account for the motion that the pad undergoes prescribed small‐amplitude oscillations in a direction perpendicular to itself, the non‐Newtonian dynamic Reynolds equation including the squeezing‐action effect is obtained. Both the steady pressure and the perturbed pressure are numerically solved and used to evaluate the steady‐state performance and dynamic characteristics.Findings – According to the results, higher steady load‐carrying capacity, dynamic stiffness and damping coefficients are predicted for the finite bearing with small wedge parameter and high viscosity‐shear rate index. In addition, the effects of non‐Newtonian power‐law lubricants on the bearing characteristics are more pronounced whe...
12 citations
TL;DR: In this paper, a general equation for finding out viscosity of lubricating oils at different temperatures and ages was provided, based on previous works and a case study on field.
Abstract: Purpose – To provide a general equation for finding out viscosity of lubricating oils at different temperatures and ages.Design/methodology/approach – Based on previous works and a case study on field, a general equation was formulated which relates viscosity‐temperature‐age of lubricant.Findings – The equation is very simple and a good consistency was found.Practical implications – This equation will help the designers/manufacturers to recommend the correct grade of lubricating oil.Originality/value – This type of relationship was never reported earlier.
TL;DR: In this article, the effects of metal matrix composite (MMC) journal structure on the pressure distribution and, consequently, on the load-carrying capacity of the bearing are predicted using feed forward architecture of neurons.
Abstract: Purpose – To discuss the effects of metal matrix composite (MMC) journal structure on the pressure distribution and, consequently, on the load‐carrying capacity of the bearing are predicted using feed forward architecture of neurons.Design/methodology/approach – The inputs to the networks are the collection of experimental data. These data are used to train the network using the Batch Back‐prop, Online Back‐prop and Quickprop algorithms.Findings – The neural network (NN) model outperforms the available experimental model in predicting the pressure as well as the load‐carrying capacity.Research limitations/implications – The experiment specimens used in this study have been made of MMC with aluminum based reinforced with SiC ceramic particles, using the stir casting technique. Various composite journal structures can be investigated.Practical implications – The simulation results suggest that the neural predictor would be used as a predictor for possible experimental applications on modelling journal beari...
TL;DR: In this paper, a novel thiadiazole complex of polyglycol (DMS2−GL) was synthesized as an ashless grease additive and the antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease.
Abstract: Purpose – Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex.Design/methodology/approach – The complex of thiadiazole dimmer and polyglycol (DMS2‐GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test.Findings – The additive DMS2‐GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does n...
TL;DR: In this paper, an up-to-date review and design guide for industry users and designers of hydrostatic fluid film journal bearings is provided, based on a detailed study and review of published works dating from 1965 to 2004.
Abstract: Purpose – To provide an up‐to‐date review and design guide for industry users and designers of hydrostatic fluid film journal bearingsDesign/methodology/approach – Detailed study and review of published works dating from 1965 to 2004 Comments and comparisons made on findings and ease of use for each Design guide study summarised in outline form showing relationships and interdependencies of dimensions and parametersFindings – Some previous design recommendations difficult to use owing to errors, ambiguous use of symbols and undefined terms Terms are frequently interchanged without definition, sometimes in the same paper Many works difficult and time‐consuming to retrieve and study without access to comprehensive technical library archivesResearch limitations/implications – Work indicated that more evaluation and practical study may be needed for full study Guideline approach useful for busy designers to help lead understanding through more detailed works availablePractical implications – A very u
TL;DR: In this paper, aqueous dispersions of collagen gelled media were reduced into micelles and gel liquid phase and the apparent viscosity of these systems was investigated as a function of the gap thickness, the shear rate and the collagen concentration.
Abstract: Purpose – To study the rheological behavior of aqueous dispersions of collagen gelled media and to bring it into relation with the gel stiffness and microstructure.Design/methodology/approach – Collagen gelled media were prepared at different concentrations and their stiffness was measured with dynamic elastic modulus (DEM) technique. The gelled media were reduced into dispersions of micelles and gel liquid phase and the apparent viscosity of these systems was investigated as a function of the gap thickness, the shear rate and the collagen concentration. The gap thickness was varied between 20 and 200 μm. The microstructure of the broken gelled media was finally explored with optical microscopy.Findings – DEM analysis has given values of the collagen gel stiffness ranging between 3 × 10−4 and 3.3 × 10−3 MPa. It has been shown that apparent viscosity grows with the increase of the gap thickness from 2 to 5 Pa s at constant collagen concentration and applied shear rate (4 percent, 100 s−1). A rise in the co...
TL;DR: In this paper, the results of single criteria approaches for minimum power, bearing coefficient and minimum temperature rise in circular hydrostatic axial journal bearings are not sufficient, there is a crucial need to consider multiple criteria optimisation cases and thirdly, thermodynamic effects must be taken into account for more efficient approach to compute the optimum values of bearing design parameters.
Abstract: Purpose – The results obtained from previous studies are not found to be sufficient for hydrostatic bearing design optimisation since thermodynamic effects are not considered. Therefore, this research is presented with considering parameter variations based on thermodynamic effects for more efficient optimisation of bearing parameters.Design/methodology/approach – Single and multi‐criteria approaches were carried out to determine the hydrostatic journal bearing design parameters so that the total performance of the system is optimal.Findings – It is seen that firstly, the results of single criteria approaches for minimum power, bearing coefficient and minimum temperature rise in circular hydrostatic axial journal bearings are not sufficient, secondly, there is a crucial need to consider multiple criteria optimisation cases and thirdly, thermodynamic effects must be taken into account for more efficient approach to compute the optimum values of bearing design parameters.Research limitations/implications – ...
TL;DR: In this article, the effect of surface roughness on the squeeze film characteristics of long porous partial journal bearings with couple stress fluids as lubricant was investigated, and the Stokes couple stress fluid model was included to account for the additives effects of lubricant.
Abstract: Purpose – The aim of this paper is to investigate the effect of surface roughness on the squeeze film characteristics of long porous partial journal bearings with couple stress fluids as lubricant.Design/methodology/approach – The Stokes couple stress fluid model is included to account for the additives effects of lubricant. The Christensen's stochastic method developed for the hydrodynamic lubrication of rough surfaces is used to derive the stochastic Reynolds type equation accounting for the surface roughness and couple stresses. In the context of Christensen's stochastic theory for the hydrodynamic lubrication of rough surfaces, two types of one‐dimensional surface roughness (longitudinal and transverse) patterns are considered. The non‐linear first order differential equation governing the journal center movement is solved numerically by using the fourth order R‐K method.Findings – From the numerical computations of the results, it is found that, the effect of couple stresses is to increase the load c...
TL;DR: In this article, the effects of commercial oil additives on the friction coefficient in the journal bearing under statically loaded have been studied experimentally at 25 and 100°C temperatures, and the results of the experimental coefficient of friction were graphically presented.
Abstract: Purpose – In this study, an attempt is made to show the linkage between the oil additive and journal bearing the running conditions such as temperature, load, speed, etc. in effecting lubricating. It is well known that one of the roles of additives is to form protective layer to reduce friction coefficient in lubricated contacts.Design/methodology/approach – The tests were performed at three different loads, and eight speeds. The tests were carried out for three different commercial additives that are concentration ratio of 3 per cent.Findings – The test results of the experimental coefficient of friction were graphically presented. The highest reduction in the friction coefficient was obtained at high temperature (100°C) in the tests than room temperature (25°C) tests.Research limitations/implications – In this study, effects of commercial oil additives on the friction coefficient in the journal bearing under statically loaded have been studied experimentally at 25 and 100°C temperatures.Practical implic...
TL;DR: In this article, the authors presented a theoretical analysis on the general behavior of a thrust bearing and used a neural network predictor to analyse the general behaviour of the bearing. But the results of the proposed n...
Abstract: Purpose – Seeks to present a theoretical analysis on the general behaviour of a thrust bearing.Design/methodology/approach – The model programme using a method adaptation of finite differences was developed to solve the Reynolds equation for lubrication. The model in the theoretical analysis uses a single one‐dimensional grid. The altering of total lubrication load obtained as a result of under‐cutting in the thrust bearing has been determined together with the parameters such as oil film thickness and pressure. Parameters such as the pressure and thickness of the oil film were determined. The hydrodynamic behaviour of thrust bearing was analysed by considering different dimensionless system pressure, speed and geometry of the bearing. The effect of the elastic load due to elastic deflection is taken into account as the load‐bearing characteristics are included. Also, a proposed neural network predictor is utilised to analyse the general behaviour of thrust bearing.Findings – The results of the proposed n...
TL;DR: In this paper, the dependence of the shear strength of a fluid on the fluid pressure and the bulk fluid temperature, respectively, was studied for given bulk fluid temperatures and fluid pressures in the whole ranges of fluid pressure.
Abstract: Purpose – Seeks to study the dependence of the shear strength of a fluid on the fluid pressure and the bulk fluid temperature, respectively, theoretically for given bulk fluid temperatures and fluid pressures in the whole ranges of fluid pressure and bulk fluid temperature.Design/methodology/approach – The analyses are, respectively, carried out with emphasis on the dependence of the shear strength of a fluid in liquid state, i.e. at low pressures on the fluid pressure and the bulk fluid temperature for given bulk fluid temperatures and fluid pressures based on the theory of the compression of the fluid by the pressurization of the fluid.Findings – The fluid shear strength versus fluid pressure curve in the whole range of fluid pressure and the fluid shear strength versus bulk fluid temperature curve in the whole range of bulk fluid temperature, respectively, for a given bulk fluid temperature and a given fluid pressure are obtained. It is shown by this fluid shear strength versus fluid pressure curve tha...
TL;DR: In this paper, a computer program is developed to determine and select all design parameters of the hydrostatic radial journal bearings with an optimisation algorithm which is used as a multi-criteria optimisation approach.
Abstract: Purpose – To characterise the optimal design parameters which are useful in hydrostatic radial journal bearings designDesign/methodology/approach – A computer program is developed With this program, designers can determine and select all design parameters of the hydrostatic radial journal bearings Design parameters are searched with an optimisation algorithm which is used as a multi‐criteria optimisation approachFindings – With this approach, the designer can use the time effectively This approach is faster and more precise than other approaches in the literatureResearch limitations/implications – This approach is valid only for a specific type of hydrostatic journal bearings and within limits of shaft velocity This approach should be improvedPractical implications – This approach can especially be used for the hydrostatic journal bearings which are used for shafts‐turned middle velocitiesOriginality/value – This paper fulfils the requests of the journal bearing designers exactly and quickly In
TL;DR: In this article, the authors provide an optimization methodology for the journal bearings of mass balancing systems, that consists in a sensibility analysis of the journal bearing design parameters in the journalbearing operating parameters, as well as the comparison and selection of journal bearing materials and the selection of the lubrication grooves suitable.
Abstract: Purpose – To provide an optimization methodology for the journal bearings of mass balancing systems, that consists in a sensibility analysis of the journal bearings design parameters in the journal bearing operating parameters, as well as the comparison and selection of the journal bearing materials and the selection of the lubrication grooves suitable.Design/methodology/approach – The methodology followed comprehends three steps. The first step is the one by one variation of the journal bearing design parameters (radial clearance, journal bearing diameter and journal bearing length) to analyse, independently, their influence on the journal bearing operating parameters (minimum film thickness, maximum pressure and power loss). The second step is the analysis and comparison of the metallic materials that can be used in the journal bearings. The third step is the selection of the lubrication groove.Findings – Applying this methodology it is shown that increasing the radial clearance the minimum film thickne...
TL;DR: In this article, a di(iso-butyl)polysulfide (DIBPS) additive was synthesized from some cheap materials at low temperature and under normal atmospheric pressure, as an additive in some mineral base oils compared with the traditional sulfurized olefin (SO) additive.
Abstract: Purpose – In order to develop novel high EP S‐containing additives and to meet the need of formulating GL‐5 gear oil or other high EP lubricating oils, aims to investigate the tribological behaviors and mechanism of a di(iso‐butyl)polysulfide (DIBPS), which was synthesized from some cheap materials at low temperature and under normal atmospheric pressure, as an additive in some mineral base oils compared with the traditional sulfurized olefin (SO) additive.Design/methodology/approach – The DIBPS additive was designed and synthesized, of which the main composition is the di(iso‐butyl)trisulfide. Its load‐carrying capacity, anti‐wear and friction reduction properties as additive in some mineral base oils, compared with the traditional SO additive, were investigated using a four‐ball machine and a Timken tester according to relative testing standards. The tribological mechanism was discussed according to the SEM and XPS analytical data.Findings – The results indicate that the four‐ball PD value and the Timke...
TL;DR: In this article, a Grubin-like EHL inlet zone analysis is derived with closed form of the analytical results of the EHL film thickness, the film pressure, the contact-lubricant interfacial shear stress and the contactlubricants interfacial slipping velocity in the inlet region.
Abstract: Purpose – To develop a fairly different EHL inlet zone analysis for investigating the contact‐lubricant interfacial limiting shear stress effect on line contact EHL film thickness in isothermal conditions. This analysis is purposed to give fast and qualitatively correct results.Design/methodology/approach – A Grubin‐like EHL inlet zone analysis is derived with closed form of the analytical results of the EHL film thickness, the EHL film pressure, the contact‐lubricant interfacial shear stress and the contact‐lubricant interfacial slipping velocity in the EHL inlet zone based on the assumption of the contact‐lubricant interfacial limiting shear stress in the EHL inlet zone. In this analysis, the lubricant is allowed to slip at the contact surface; The inlet contact surface shape is known from results referenced in this paper; The physical condition for the presence of the film slippage is incorporated; The lubricated area is divided into different kinds of film slippage zones where are, respectively, appli...
TL;DR: In this article, the anti-wear technology of piston rings with the application of ferrous oxides was investigated for two-stroke self-ignited diesel engines used for driving the diesel locomotives.
Abstract: Purpose – Ferric and ferrous oxides are used for coating of piston rings in order to obtain the layer, facilitating their wearing‐in at the beginning of work. This paper aims to present study and the implementation of the anti‐wear technology of piston rings production with the application of ferrous oxides. Those rings are intended for two‐stroke self‐ignited diesel engines used for driving the diesel locomotives.Design/methodology/approach – It was decided to use magnetite, Fe3O4, together with a binding agent, sodium metasilicate. Working out the adequate technology of filling the grooves of piston rings required performing a broad research range. It is possible to apply three different technologies. In order to find out which of the three methods of filling grooves gives the best results, the series of experiments were planned.Findings – Experimental results cover the variability intervals of input factors enabling the selection of their best combination by the analysis of the regression function. The...
TL;DR: In this article, the authors investigated the pressure distribution of journal bearings with aluminum shafts with varying surface porosity in varying revolutions using experimental and neural network approach, and found that neural network predictor has superior performance for modelling journal bearing systems with shafts of different surface porosities.
Abstract: Purpose – The purpose of this paper is to investigate pressure distribution of the journal bearings with aluminium shafts with varying surface porosity in varying revolutions using experimental and neural network approach.Design/methodology/approach – The collected experimental data such as pressure variations is employed as training and testing data for an artificial neural network (ANN). Back propagation algorithm is used to update the weight of the network during the training.Findings – Neural network predictor has superior performance for modelling journal bearing systems with shafts of different surface porosities.Research limitations/implications – Back propagation algorithm is used training algorithm for proposed neural networks. Various training algorithms can be used to train proposed network. The spectrum of the journal surface porosity can be enlarged.Practical implications – From the experimental and simulation results, neural network exactly follows the experimental results. Because of that, ...
TL;DR: In this article, a modified Reynolds equation was developed to investigate the effects of surface roughness and molecular rarefaction on ultra-thin compressible and isothermal gas lubrication.
Abstract: Purpose – According to the Christensen stochastic roughness model, the purpose of this study is to developing a modified Reynolds equation to investigate the effects of surface roughness and molecular rarefaction on ultra‐thin compressible and isothermal gas lubrication.Design/methodology/approach – Basing upon the average film thickness method with three adjustable coefficients, the higher order slip‐flow velocity distribution was accommodated.Findings – Compared to the smooth case, the longitudinal roughness improves the pressure distribution and load carrying capacity, while the effect of transverse roughness is opposite to that of longitudinal one. The molecular rarefaction effect may diminish the built‐up air bearing pressure and reduce the roughness effect on load carrying capacity. The squeeze number has evident effect in depression of maximum pressure of slider rail with transverse roughness.Originality/value – Combing the high‐order slip‐flow model and Christensen roughness model, this research p...
TL;DR: In this paper, the tensile properties of high velocity oxyfuel (HVOF) sprayed Inconel 625 coating of steel substrate before and after the aqueous corrosion were examined.
Abstract: Purpose – To examine the tensile properties of high velocity oxy‐fuel (HVOF) sprayed Inconel 625 coating of steel substrate before and after the aqueous corrosion.Design/methodology/approach – Workpieces were cut from steel sheets. After chemical and ultrasonic cleaning, workpiece surfaces were sand blasted and HVOF sprayed Inconel 625 coated. The coated and un‐coated surfaces were subjected to the aqueous corrosion tests for one and three weeks. After the completion of the corrosion tests, tensile properties of the workpieces were examined.Findings – The workpieces subjected to a three weeks static corrosion environment fail at a lower load than the untreated workpiece due to high stiffness. The defect sites in the coating and at the interface act as stress risers and contribute substantially crack initiation and propagation in the coating. Under increasing tensile load in the plastic region, the substrate material can no longer support the coating. This results in extended cracking and gradually spallin...
TL;DR: In this paper, an original criterion (in the form of limiting deformation power density) of wear resistance on the basis of structure energy theory of friction is proposed, which can be used for choosing suitable frictional materials and to compare and estimate the theoretical considerations with experime.
Abstract: Purpose – The purpose of this paper is to analyse the phenomenon of wear resistance of some metals and alloys with allowance for the stiffness of their stressed‐strained state of the surface.Design/methodology/approach – An original criterion (in the form of limiting deformation power density) of wear resistance on the basis of structure‐energy theory of friction is proposed. Experimental data on the wear resistance are generalized using the criterion for the conditions of hydroabrasive, impact‐abrasive and cavitational erosion.Findings – The dependence of the criterion on stiffness coefficient of the stressed‐strained state of the surface of materials is demonstrated. It has been found that an increase of the stiffness results in the reduction in the energy capacity and wear resistance of both metals and alloys investigated.Practical implications – The structure‐energy criterion can be used for choosing suitable frictional materials and to compare and estimate the theoretical considerations with experime...
TL;DR: In this paper, the effect of SiC particulate on the coating properties such as hardness, wear resistance and microstructure was investigated, and parallel work on microstructural examination by optical microscope were also conducted.
Abstract: Purpose – The aim of this study is to present an experimental research on a Al2O3 · TiO2 plasma coating on AISI 316 stainless steel substrate with and without SiC particulate reinforcement to show how SiC particulate effect on the hardness, wear resistance and microstructure of the coating.Design/methodology/approach – The main objective of the paper is to investigate the effect of SiC particulate on the coating properties such as hardness, wear resistance and microstructure. Achieving of this purpose, harness and sliding test, surface roughness measurements were carried out. In addition to that parallel work on microstructural examination by optical microscope were also conducted. Owing to SiC particulate is harder than Al2O3 · TiO2 plasma coating, it influence hardness and tribological behavior and result in increasing in hardness values and wear resistance of the coating reinforced with SiC particulate compare with unreinforced Al2O3 · TiO2 plasma coating.Findings – This study provides experimental res...