ABSTRACT In recent years, the porous bearings are being increasingly used in various industrial applications because they are less noisy, have good precision, and are relatively maintenance free. In this article, the numerical analysis of conical porous hybrid journal bearing system (CPHJBS) has been carried out. The interactive effects of permeability parameter, semi cone angle and pseudoplastic (shear

Abstract To study the dynamic support characteristics of an auto-eliminating clearance auxiliary bearing (ACAB) after a rotor fall, this paper proposes a parameter identification method based on the finite element method (FEM). First, a dynamic model of the magnetic suspension bearing–rotor system was established. Next, the support-stiffness and damping matrices of the ACAB were deduced, and the feasibility

Abstract An extended Reynolds equation is presented to evaluate the effects of the fluid inertia and cavitation on the performance of a spiral-grooved mechanical face seals at the high-speed conditions. The segregated finite element procedures are employed to solve the fluid inertia terms and the fluid film pressure distribution with the artificial viscosity stabilization strategy and Streamline-U

ABSTRACT The present work aims to investigate the synergetic effect of Titanium Dioxide (TiO2) and graphene (GnP) nanoparticle additives on rheological and machining characteristics of biodegradable vegetable oil (Rice bran). The rice bran oil has been used in turning of M2 steel using Minimum Quantity Lubrication (MQL) technique. The effect of varying concentrations by weight (0.5 wt.% and 1 wt.%)

Abstract In this study, a rough surface thermal elastohydrodynamic lubrication (TEHL) model tailored for the simulation of high-speed and high-temperature contacts of relatively smooth surfaces is introduced. The model uses a modified Carreau-Yasuda constitutive function to capture the non-Newtonian effects and a limiting shear formulation to consider any lubricant–solid slippage. It is employed to

Abstract High-temperature tribology of steel components is typically characterized by high friction and excessive wear, which need to be addressed. In the present study, the tribological properties of an alkali borate were evaluated in a steel contact by ball-on-disc testing over a wide range of temperatures (600–800 °C) and loads. The compound exhibits good lubrication performance consistently throughout

ABSTRACT Oxygenated fuel is recognized as an effective alternative fuel for the petrochemical industry. Studies have shown that using a mixture of dimethyl carbonate (DMC) and diesel fuel can help reduce soot emissions. Due to incomplete combustion of some diesel fuel, a small amount of fuel will inevitably enter into the engine oil and cause engine oil dilution. Herein, the tribological properties

Abstract In gas foil bearings, frictional contacts are one of the main factors that affect the bearing performance, which are highly nonlinear as well. Using finite element method, this paper presents a nonlinear model for static performance analysis of the foil bearings based on frictional contacts. The model incorporates the top foil and the interactions between bumps by modeling the foil structure

ABSTRACT The tribological performances of polymer stabilized TiO2 particles dispersed in mineral base oil were investigated. Two polymer/TiO2 mass ratios were investigated, with a constant polymer concentration of 0.3 wt% and two nanoparticles concentrations of 0.1 and 1 wt%. Friction tests were carried out with a pin on a reciprocating flat test configuration under boundary lubricated sliding conditions

Abstract To explore the mechanisms of squeak generation in automotive interior, the stick-slip experiments of polypropylene verse leather were conducted under various conditions. The friction properties were researched with the normal force, velocity and temperature changing, then the static friction coefficients were generally smaller at low temperature, larger at room temperature, and intermediate

ABSTRACT Epoxy is a polymeric material that is widely used in various fields as an adhesive, coating, and bulk material due to its outstanding properties. Many researches about reinforced polymers have been conducted by adding micro/nano particles or fibers to attain better tribological properties. However, the tribological properties of patterning on epoxy surface are relatively obscure. In this study

Abstract A test apparatus is described which evaluates the performance of static aviation seals under an environment similar to the lubrication system in gas turbine engines. The seals can be tested at operating temperatures as high as 400 °C in the static seal rig (SSR). Incorporating an air/oil mist generating system, the test facility exposes the seals to degraded oil, which can deteriorate the

ABSTRACT In this paper, the synergistic effect of the addition V and Nb on CoCrFeMnNi high-entropy alloy (HEA) coating prepared by plasma cladding was studied. The results shown that the additions of V and Nb promoted the precipitation of intermetallics in the HEA coating and had no effect on the FCC structure of the matrix. The CoCrFeMnNiVNb composite coating presented complex phases structure including

ABSTRACT The difference in wear behaviour of superelastic NiTi and conventional Ti6Al4V alloys with similar elastic limits was investigated. Reciprocating dry-sliding wear tests were performed with a ball-on-plate tribometer machine at different normal loads and sliding times. Mechanical properties were also examined using different microindentation tests, and wear track morphologies and chemical compositions

ABSTRACT Friction and wear are the primary factors for the failure of liner, which affects the lifting capacity and the milling cost in ball mills. But there are not effective methods to measure and evaluate the friction and wear behaviour of liner. Therefore, it is vital to understand the friction and wear mechanisms of liner in ball mills. In this paper, the multi-body friction and wear properties

Abstract Disc brakes are widely used in various kinds of light vehicles. Currently, it has become a tendency to reduce mass and volume of the brake systems because of the increasing lightweight requirement for vehicles, especially for passenger vehicles in the populated cities and outdoor sport. However, there is often conflict between lightweight and reliability. In this paper, braking characteristics

Abstract The wear characteristics and related mechanisms of the ring chain of a scraper chain were investigated. Multiple sets of wear tests were performed in order to simulate the working environment of the heavy-load scraper conveyor. The wear characteristics of the ring chain in different environmental media (acid, alkaline, neutral electrolyte solution, deionized water and pulverized coal mixture)

Most magnetic fluid seals are multi-teeth structures for the high sealing capacity. However, the pressure transfer mechanism in the multi-teeth magnetic fluid seal is only carried out through experimental methods. In this paper, a simulation method is presented to solve the two-phase flow of magnetic fluid and air in the sealing clearance. The boundary of magnetic fluid is obtained by Volume of Fraction

A solid contact model with high accuracy is required for mixed lubrication calculation to predict friction loss and wear in sliding parts by computer aided engineering; however, existing models have numerous limitations. A new asperity contact model was constructed to determine contact states using the roughness parameters of pairs of surfaces. Although the contact states differed greatly depending

The objectives of this investigation were to experimentally and analytically investigate the dynamics of a medium sized, relatively high speed ball bearing supported turbocharger (TC). In order to achieve the objectives a TC test rig was designed, developed and instrumented with a combination of strain gauge based load sensors and proximity probes. The sensors were used to measure the axial and frictional

A mixture model suitable for thermal effect on EHL of emulsions is proposed. The maximum temperature rise occurs at the emulsion layer because sliding occurs mainly in the emulsion layer to generate shear heating, and it increases with increasing oil concentration, slide-to-roll ratio, mean speed and load. The rise in surface temperature of the rollers decreases with the increase in the adsorbed layer’s

The failure of moving mechanical components is often accompanied by hydrogen embrittlement caused by hydrogen diffusion in steel. One considerable mechanism for hydrogen diffusion is its ingress from lubricant decomposition. We investigated quantitatively the ingress of hydrogen generated by lubricant decomposition into bearing steels using time-of-flight secondary ion mass spectrometry (ToF-SIMS)

A grooved texture surface was fabricated to enhance the wear resistance of the guide rail surface of molding machine. The effects of sand concentration in the oil and the groove width on the tribological properties were studied using a pin-on-disk tribometer. Surfaces with groove widths of 1000 μm (S1) and 1500 μm (S2) had lower friction coefficient and better anti-wear properties than a non-grooved

The CoCrMo alloys are commonly used in artificial joints. However, tribocorrosion phenomena have led to the search for improvements to diminish wear debris and ion release. The engineering of surfaces has been an alternative to achieve this purpose. In the present study it was investigated the tribological effect of AlCrN, AlTiN, AlTiON and AlCrON coatings deposited on cast CoCr alloy. The coatings

This work presents a study on tribological behavior of surfaces obtained by turning in sintered self-lubricating composites. Turned surfaces were obtained at constant cutting speed (vc = 100 m/min), feed (f = 0.2 mm), and depth of cut (ap = 1 mm). The tested composites have solid lubricants (graphite and hexagonal Boron Nitride - hBN) mixed in a Fe-C-Ni-Si matrix manufactured by single (SP) and double

The elastohydrodynamic (EHD) lubrication straight contact line conjunction is studied to evaluate the mixed lubrication heat generation experimentally over bordering operational conditions in a disc-on-disc machine. An experimental investigation is carried out using an accessory device that collects and measures the outlet lubricant temperature. The experimental results show the typical transition

This article proposes a new thermohydrodynamic (THD) bearing design method based on an improved version of a precedent method. The precedent method used two charts prepared in advance to easily and quickly find two crucial predicted data of the maximum bearing temperature and the effective temperature of the bearing oil film to be used later in an isoviscous Reynolds equation. Three sets of charts

The different fretting wear behaviors of alloy 690TT in air and in a flowing nitrogen environment were revealed. Moreover, the grain refinement to nanoscale caused by fretting wear in nitrogen was investigated. The results showed that when compared with the air environment, the coefficient of friction in nitrogen was slightly higher due to direct contact between the metals with strong adhesion which

Abstract Magnetron-sputtered physical vapor deposited (PVD) thin-film TiB2 coatings were investigated as a wear-resistant cam tappet coating that runs under the boundary lubrication regime in internal combustion engines (ICEs). AISI 52100 samples with a high negative bias were coated at RF powers of 150, 170, and 190 W. Coatings were characterized via nanoindentation, scanning electron microscopy/energy-dispersive

Abstract This article proposes a new thermohydrodynamic (THD) bearing design method based on an improved version of a precedent method. The precedent method used two charts prepared in advance to easily and quickly find two crucial predicted data of the maximum bearing temperature and the effective temperature of the bearing oil film to be used later in an isoviscous Reynolds equation. Three sets of

Abstract An innovative vanadium carbonitride coating with C element doped in a vanadium nitride (VN) matrix was developed on Inconel 718 and Si (100) substrates using a multi-arc ion plating technique. The micromorphology and microstructure of the as-deposited VCN coating were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy

Abstract Electroplated bolts have been widely used in the automotive industry for many decades. In the present work, for the first time, the role of each layer of the bolt coating (i.e., electroplating, passivation layer, and topcoat layer) on the coefficient of friction of a bolted joint were experimentally and systematically investigated. The coefficient of total friction (μ tot), coefficient of

Abstract A simple and inexpensive corrosion sensor was manufactured to study the corrosion rate of new and water-contaminated lubricating grease using a galvanic cell. A galvanic charge was developed between electroless nickel immersion gold (ENIG) and zinc, manufactured by selectively plating on a custom manufactured interdigitated printed circuit board. This article shows the methodology in using

Abstract To reduce the irregular “typewriter” noise in main engine bearings, a comprehensive experimental study on the effect of carbon black particles (CBPs) with different particle sizes, concentrations, and standing times on noise in an oscillatory parallel-plate oil squeeze film test apparatus was carried out. The results show that the presence of CBPs can significantly reduce the generation of

Abstract This article presents a numerical analysis of elastohydrodynamic lubrication (EHL) with grease in point contacts to predict the grease film thickness at low speeds, which can increase with decreasing speed and exceed the base oil film thickness by orders of magnitude. The grease film thickness is obtained by solving the EHL problem, taking grease flow as a single-phase flow with a non-Newtonian

In this work, a systematic investigation was carried out to study the electrochemical and tribocorrosion behavior of LY12 aluminum alloy sliding against Al2O3 pin in artificial seawater, using a pin-on-disk tribometer combined with an in-situ electrochemical workstation. The results revealed that the cathodic shift of open circuit potential and two order of magnitude increase in current density caused

This paper makes the first attempt to present the experimental investigation on fretting wear behavior of piezoceramics P51, PSnN5 and PLiS51 against Si3N4 ceramic ball under air condition. The sphere-on-flat contact pattern is used as the contact model. The influences of the displacement amplitude, frequency and normal force are taken into account. After each test, friction logs are used to determine

Abstract Copper and graphite are the main components of copper-based brake materials commonly used in high-speed trains. Their interaction influences the tribological performance of copper-based brake materials. In this article, with copper and graphite as the materials, three kinds of layered samples were prepared as pins and tested against a disc made of H13 steel. Friction tests were conducted under

The effect of the annealing treatment on wear performance of hot-rolled wear-resistant steel/carbon steel cladded plate was investigated. The novel cladding that can provide high wear resistance, strong structure and low cost is typically employed for the metallurgical mining equipment, agricultural machinery, coal mining and other industries, which could provide equipment with high wear resistance

Abstract One of the urgent problems that has yet to be addressed in the field of drilling engineering is how to further improve the working performance of rock bit journal bearings (RBJBs) and prolong their service life under complicated conditions of low speed, heavy load, and high temperature. Generally, reasonable surface texture parameters serve as an effective means for enhancing the lubrication

Abstract The commonly used quasi-static model for angular contact bearings is enhanced by coupling contact mechanics and bearing kinematic analyses with traction or friction behavior in ball–race contacts. The points of pure rolling in the contacts, which constitute the primary inputs in the kinematic equations, are determined by minimizing the frictional dissipation based on a prescribed elastohydrodynamic

Abstract The relatively high toughness, high adhesion to steel, and low internal stress of hydrogenated amorphous carbon (a-C:H) films containing Ag make them good candidate materials for various applications in sensors, tribology, and biomaterials; however, the relatively low hardness and poor tribological properties in oxidizing environments hinder their broad use. Incorporating a small amount of

Abstract Reliable lubrication is essential to the life of gear transmission systems. An approach to predict the reliability of gear elastohydrodynamic lubrication (EHL) under a random input torque is proposed in this article. Firstly, a single-degree-of-freedom nonlinear stochastic dynamic model that considers backlash, a time-varying mesh stiffness, and random loads is established to obtain the probability

AISI D2 steels are an interesting family of tool steels that generally found applications in knife blades, shaper blades as well as forging and punching dies owing to its optimum toughness, lower wear rate and relatively high hardness. The present research work aims at designing a new heat treatment cycle consisting of single tempering followed by cryogenic treatment and soft tempering with the intention

The texture of die surface plays an important role in the tribology of metal forming processes. The surface texture is defined by surface roughness and its orientation, which is influenced by the manufacturing processes. In this research, the effects of various die machining operations on the frictional condition in the forming process of CK45 steel are investigated by means of ring compression test

Carbon fibre reinforced polymers (CFRP) are often exposed to solid particle erosion wear due to small particles moving freely in the atmosphere or in the environment and their impact on aircraft bodies. In this study, fibre weaves of CFRP composite materials of the following types were produced; uni-directional (U), plain weave multidirectional (P) and twill 2 × 2 weave multidirectional (T). Tests

The frictional vibration, generated at water-lubricated rubber bearings operating under low-speed, heavy-load, start-up and shutdown conditions, can severely degrade the reliability and the sheltered performance of underwater vehicles. The rubber layer of the ship stern tube water-lubricated rubber bearings is easily elastically deformed under certain loads, which affect the damping performance of

Ni-Ti-C metal matrix composites (MMC) with in situ formed, homogeneously distributed titanium carbide (TiC), as well as graphite (C) reinforcement in nickel metal matrix, were synthesized using Mechanical Alloying (MA) followed by Spark Plasma Sintering (SPS). The main objective of this research is to consolidate Ni-Ti-C MMCs with varying the C/Ti ratio and characterize the MMCs to investigate the

During their lifetime, gears may undergo starved lubrication operating conditions. Starvation condition has an impact on friction between gears that leads to modify gearbox efficiency. In this paper, lubricant starvation tests on an FZG test rig adapted to this condition are presented. Gears were equipped with embedded thermocouple sensor to measure their operating bulk temperature. An experimental

Abstract Hybrid pump-controlled asymmetric cylinder drive systems are implemented for energy saving purposes in applications that do not require fast responses. Under low-velocity and low-pressure conditions, the friction influence in the hybrid pump-controlled system is evident. Researchers have developed various models to describe friction. These friction models are implemented based on the relative

Abstract High-performance coatings with self-lubrication, superior wear, and corrosion resistance are sought after in modern industry. Here we reported a cobalt–nickel/tungsten disulfide (Co-Ni/WS2) composite coating fabricated by a pulse electrodeposition approach. The codeposition of WS2 significantly affects the microstructure, hardness, and tribological and electrochemical behaviors of the Co-Ni/WS2

Abstract The premature failure of cutting tools during machining of titanium alloys is primarily attributed to their low thermal conductivity and strain hardening. The coefficient of friction (CoF) at the tool –chip contact depends on the high stress–strain values, interface temperatures, and the velocity of the chip. In this work, a new tribometer is developed to overcome the drawbacks of the existing

Ethylene–vinyl acetate (EVA) foam is sometimes used in the outer soles of sport shoes. To improve the slip resistance of EVA foam, this study investigated the effects of porosity and the fraction of styrene–ethylene–butadiene–styrene (SEBS) on the dry sliding friction behavior of EVA foams. Sliding friction tests were performed against a pin specimen with a semicylindrical tip, which was covered with

The purpose of this study was to design a tribo-tester that can evaluate the lubrication performance of ferrofluids under the effect of the magnetic field. A novel bronze-based tribopair was fabricated with the potential to employ a controllable magnetic field in such a way that it accurately mimics the friction of thrust pad bearing. The designed experimental scheme enables direct measurement of the

During acceleration and deceleration processes of a bearing, the kinetic relationship of collision and friction between the cage and the rolling element is complex, which has an important influence on the dynamic characteristics and stability of the rolling bearing. In this study, experimental investigation of dynamic motions of a cage under various external radial loads was performed during acceleration

The tribological and vibrational behaviours of conventional and textured spur gear pairs have been experimentally explored under fully flooded and starved lubricating conditions at different operating parameters. Three different textures on gears’ teeth profiles were created by placing the dimples of vertically oriented ellipsoid, horizontally oriented ellipsoid and hemisphere in the zigzag patterns

To increase the efficiency of a gearbox, research on gear mesh loss is of importance. Britton at al. concluded that the surface finishing method affects the gear mesh efficiency. The efficiency benefits of super finishing a surface and reducing the surface roughness have been reported by Kahraman. A novel method for calculating the bearing loss-torque was proposed by Tu et al. Andersson found that

Effects of thermo physical properties of crambe, linseed, and jojoba oils, a typical petroleum-based lubricant (PBL), and blends of crambe oil and PBL on their tribological performance were investigated. Biolubricants showed better lubricity (i,e., lower coefficient of friction). At 55 N load, linseed and jojoba oils had the lowest and PBL had the highest wear. At 90 N and 160 N normal loads crambe

A recent interest on emergency shoe braking in high speed trains stimulated the research on the damage due to sliding contact between brake blocks and wheel tread. Bi-disc tests, with rolling/sliding contact between specimens extracted from wheels and brake blocks, were previously performed in constant working conditions to reproduce the temperature of the wheel during stop braking. However, stop braking

The commonly used quasi-static model for angular contact bearings is enhanced by coupling the contact mechanics and bearing kinematic analyses with traction or friction behavior in ball-to-race contacts. The points of pure rolling in the contacts, which constitute the primary inputs in the kinematic equations, are determined by minimizing the frictional dissipations based on a prescribed elastohydrodynamic