On the Frictional Characteristics of Ball Bearings Coated With Solid Lubricants

1999 ◽  
Vol 121 (4) ◽  
pp. 761-767 ◽  
Author(s):  
M. R. Lovell ◽  
M. M. Khonsari
Keyword(s):  
Finite Element ◽  
Friction Force ◽  
Normal Load ◽  
Transversely Isotropic ◽  
Solid Lubricants ◽  
Operating Conditions ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Normal Contact ◽  
Low Speed

The problem of a ball bearing in normal contact between two transversely isotropic coated substrates is investigated using the finite element method (FEM). A three-dimensional finite element model is developed that accurately determines the steady friction force in low-speed bearing systems containing soft layered solid lubricant films. Extensive numerical results, which are verified using Hertzian contact theory and laboratory experiments, are obtained at 540 operating conditions by varying coating material, coating thickness, normal load, ball material, and ball radius. Friction force results generated from the FEM are normalized by introducing the dimensionless transversely isotropic coating parameter, ξ. A numerical expression for the normalized friction force in coated ball bearings is determined by curvefitting the results of the 540 simulations performed. The relevance of such an expression, as related to the durability of low-speed bearings, is subsequently ascertained and discussed.

Numerical Contact Analysis of Transversely Isotropic Coatings: A Cylinder Within a Circumferential Groove

2000 ◽  
Vol 123 (2) ◽  
pp. 436-440 ◽  
Author(s):  
Clint Morrow, ◽  
Michael Lovell, ◽  
Zhi Deng
Keyword(s):  
Finite Element ◽  
Normal Load ◽  
Transversely Isotropic ◽  
Element Model ◽  
Contact Length ◽  
Operating Conditions ◽  
Circumferential Groove ◽  
Approach Distance ◽  
Dimensional Finite Element ◽  
Coating Parameter

The contact characteristics of transversely isotropic coatings are investigated for a cylinder within a circumferential groove using a two-dimensional finite element model. With the model, contact behavior is evaluated at more than 400 operating conditions by varying coating material, coating thickness, normal load, and cylinder/groove radii. Based on the finite element results, numerical expressions are derived for the maximum surface pressure, contact length, and approach distance as a function of a transversely isotropic coating parameter, ζ. The importance of these expressions, as related to design and the selection of materials for reducing wear in contacting surfaces, is subsequently discussed.

Tribologisches Einsatzverhalten von PVD-Festschmierstoffsystemen im fluidfreien Wälzkontakt

2021 ◽  
Vol 68 (3-4) ◽  
pp. 71-78
Author(s):  
Sebastian Sklenak ◽  
Jens Brimmers ◽  
Christian Brecher ◽  
Bastian Lenz ◽  
Andreas Mehner
Keyword(s):  
Friction Force ◽  
Wear Behavior ◽  
Solid Lubricants ◽  
Load Level ◽  
Operating Conditions ◽  
Coating System ◽  
Tin Coating ◽  
Solid Lubricant Coating ◽  
Interval Operation ◽  
Coating Delamination

For special applications, the lubrication of gearboxes with liquid lubricants is not feasible. Liquid lubricants lose their positive lubricating properties when exposed to high contact stress and temperature fluctuations, for example. In the food industry and medical technology, liquid lubricants are often not permitted due to hygiene regulations. Solid lubricants offer an approach to implement dry tooth contacts. In this report, three different solid lubricant coating systems are investigated under different operating conditions. The focus of the experi mental investigation is the application behavior in terms of friction force and wear behavior. In a direct comparison, the MoS2:Ti-TiN coating system achieves the highest load level and exhibits a station ary frictional force behavior compared to the a-C:H:Ti-TiN coating system. In the wear investigation, continuous coating wear was found in addition to coating delamination. The layer wear correlates with an increasing friction force in interval operation.

scholarly journals Tribological Behaviour of Stellite Matrix Composites for High Temperatures Applications

2012 ◽  
Vol 498 ◽  
pp. 89-101 ◽  
Author(s):  
Karl Delbé ◽  
Solisabel Orozco Gomez ◽  
Juan Manuel Carrillo Mancuso ◽  
Jean Yves Paris ◽  
Jean Denape
Keyword(s):  
Normal Load ◽  
Solid Lubricants ◽  
Operating Conditions ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Plasma Sintering ◽  
Test Parameters ◽  
Pin On Disc ◽  
Spark Plasma ◽  
Innovative Materials

Extreme working conditions affect material used as friction components in transportation field: they rapidly reach their limits and critical parts require to be regularly replaced. Alternative solutions withstanding higher operating conditions imply to find innovative materials. Stellite matrix composites including various solid lubricants, WS2 and h-BN, able to admitextreme conditions were developed using a Spark Plasma Sintering technique, which makes possible the formation of new microstructures out of reach by conventional means. Sliding tests were conducted using a pin-on-disc tribometer in air at 450°C, with a velocity of 0,25 m/s and various normal load ranged from 2.5 to 40 N. Influence of solid lubricant content and sensitivity to test parameters were studied in terms of friction and wear responses of the contacting materials. Friction properties are equivalent to Stellite ones and sometimes lesseffective. A reduction of wear is quantified for many composites, and the best behavior is observed for those that contain WS2. In agreement with the third body approach, interpretations are proposed to describe the interphase dynamics within the contact.

Normal Vibrations and Friction Under Harmonic Loads: Part I—Hertzian Contacts

1991 ◽  
Vol 113 (1) ◽  
pp. 80-86 ◽  
Author(s):  
D. P. Hess ◽  
A. Soom
Keyword(s):  
Nonlinear Vibrations ◽  
Multiple Scales ◽  
Normal Load ◽  
Perturbation Technique ◽  
Friction Reduction ◽  
Hertzian Contact ◽  
Dynamic Component ◽  
Normal Contact ◽  
Normal Vibrations ◽  
Contact Parameters

Nonlinear vibrations at a Hertzian contact are studied by the perturbation technique known as the method of multiple scales. The vibrations are excited by the dynamic component of an externally applied normal load. Solutions are obtained for both the average and instantaneous contact deflections. As a result of the nonlinear Hertzian stiffness, the average normal contact deflection during oscillations is smaller than the static deflection under the same average load. It is shown that this can result in a reduction of the average area of contact and, by implication, the average friction force in the presence of even small dynamic loads. The parametric dependence of the normal motion on the various contact parameters is investigated. It is shown that the maximum average friction reduction without contact loss is approximately ten percent.

scholarly journals High Temperature Tribological Behaviour of Metal Matrix Composites Produced by SPS

2011 ◽  
Vol 482 ◽  
pp. 89-100 ◽  
Author(s):  
Solisabel Orozco Gomez ◽  
Karl Delbé ◽  
Alberto Benitez ◽  
Jean Yves Paris ◽  
Jean Denape
Keyword(s):  
Normal Load ◽  
Solid Lubricants ◽  
Operating Conditions ◽  
Steel Matrix ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Plasma Sintering ◽  
Pin On Disc ◽  
Spark Plasma ◽  
Materials Used

Materials used as friction components in transportation field are subjected to extreme working conditions: they rapidly reach their structural limits and critical parts require to be regularly replaced. Alternative solutions withstanding higher operating conditions imply to find innovative materials. Steel matrix composites including various solid lubricants, WS2 and h-BN, able to support high temperatures were developed using a Spark Plasma Sintering technique, which makes possible the formation of new microstructures out of reach by conventional means. Sliding tests were conducted using a pin-on-disc tribometer in air at 450°C, with a normal load of 15 N and various velocities ranged from 0.1 to 1.5 m/s. Influence of solid lubricant content and sensitivity to test parameters were studied in terms of friction and wear responses of the contacting materials. Test results reveal an improvement of friction properties for composites containing highest WS2contents. A reduction of wear is quantified for all composites, and the best behaviour is observed for those that contain WS2. In agreement with the third body approach, interpretations are proposed to describe the interphase dynamics within the contact.

Experimental and Numerical Studies on Nonlinear Dynamic Behavior of Rotor System Supported by Ball Bearings

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Changqing Bai ◽  
Hongyan Zhang ◽  
Qingyu Xu
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Ball Bearing ◽  
Rotor System ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Flexible Rotor ◽  
Nonlinear Dynamic Behavior

Ball bearings are important mechanical components in high-speed turbomachinery that is liable for severe vibration and noise due to the inherent nonlinearity of ball bearings. Using experiments and the numerical approach, the nonlinear dynamic behavior of a flexible rotor supported by ball bearings is investigated in this paper. An experimental ball bearing-rotor test rig is presented in order to investigate the nonlinear dynamic performance of the rotor systems, as the speed is beyond the first synchroresonance frequency. The finite element method and two-degree-of-freedom dynamic model of a ball bearing are employed for modeling the flexible rotor system. The discrete model of a shaft is built with the aid of the finite element technique, and the ball bearing model includes the nonlinear effects of the Hertzian contact force, bearing internal clearance, and so on. The nonlinear unbalance response is observed by experimental and numerical analysis. All of the predicted results are in good agreement with experimental data, thus validating the proposed model. Numerical and experimental results show that the resonance frequency is provoked when the speed is about twice the synchroresonance frequency, while the subharmonic resonance occurs due to the nonlinearity of ball bearings and causes severe vibration and strong noise. The results show that the effect of a ball bearing on the dynamic behavior is noticeable in optimum design and failure diagnosis of high-speed turbomachinery.

Numerical simulation and parameterisation of rail–wheel normal contact

2016 ◽  
Vol 231 (4) ◽  
pp. 419-430 ◽  
Author(s):  
Jacobus L Cuperus ◽  
Gerhard Venter
Keyword(s):  
Finite Element ◽  
Boundary Element ◽  
Maximum Error ◽  
Hertzian Contact ◽  
Test Case ◽  
Empirical Equations ◽  
Finite Element Analyses ◽  
Contact Parameter ◽  
Normal Contact ◽  
Power Law Equation

This investigation aims to find empirical equations that describe the rail–wheel normal (frictionless) contact characteristics. These equations can then be used to determine an equivalent Hertzian load to account for normal contact in the finite element analyses mandated by the Transnet RS/ME/SP/008 specification, without explicitly simulating the contact between two bodies. The standard is similar to UIC 510-5 and does not consider tangential contact. The normal contact problem is solved for the test case using nonlinear finite element methods as well as the boundary element method. Material plasticity was also investigated in finite element analyses with limited effect for contact away from the flange area. The data from boundary element analyses were fitted to a power law equation for each contact parameter. The equivalent Hertzian contact produced with the empirical equations is able to predict the normal contact parameters relatively accurately, producing a maximum error of 9.6% (excluding one area with a geometric anomaly).

Parameter Identification of Hysteresis Friction for Coated Ball Bearings Based on Three-Dimensional FEM Analysis

1997 ◽  
Vol 119 (3) ◽  
pp. 462-470 ◽  
Author(s):  
M. R. Lovell ◽  
M. M. Khonsari ◽  
R. D. Marangoni
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Steel Substrate ◽  
Three Dimensional ◽  
Element Model ◽  
Operating Conditions ◽  
Ball Bearings ◽  
Friction Behavior ◽  
Coating Materials ◽  
Hysteresis Friction

Using a three-dimensional finite element model, the hysteresis friction behavior of coated ball bearings is investigated. Ninety-six distinct operating conditions were examined by the finite element model that include normal loads of 81.6, 133.5, and 185.4 N per ball, ball diameters of .0127 m and .0191 m, ball materials of Si3N4 and steel, substrate materials of Si3N4 and steel, and coating materials of MoS2, NbSe2, Si3N4, and steel. From the finite element results, general trends for the two parameters of Dahl’s friction model, the rest slope, σ, and the steady friction torque, Ts, are established for coated surfaces. By performing a regression analysis of the data points, empirical expressions for σ and Ts are derived for coated bearing surfaces. These expressions are authenticated by comparisons to laboratory experimental results.

Performance enhancement of normal contact ratio gearing system through correction factor

2019 ◽  
Vol 13 (3) ◽  
pp. 5242-5258
Author(s):  
R. Ravivarman ◽  
K. Palaniradja ◽  
R. Prabhu Sekar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Correction Factor ◽  
Bending Strength ◽  
Performance Enhancement ◽  
Transmission Ratio ◽  
Contact Ratio ◽  
Element Analysis ◽  
Normal Contact ◽  
Root Region

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.

Tire Vibration Modes and Effects on Vehicle Ride Quality

1993 ◽  
Vol 21 (1) ◽  
pp. 23-39 ◽  
Author(s):  
R. W. Scavuzzo ◽  
T. R. Richards ◽  
L. T. Charek
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Operating Conditions ◽  
Modal Testing ◽  
Ride Quality ◽  
Vibration Modes ◽  
Inflation Pressure ◽  
Passenger Cars ◽  
Element Modeling ◽  
Road Surfaces

Abstract Tire vibration modes are known to play a key role in vehicle ride, for applications ranging from passenger cars to earthmover equipment. Inputs to the tire such as discrete impacts (harshness), rough road surfaces, tire nonuniformities, and tread patterns can potentially excite tire vibration modes. Many parameters affect the frequency of tire vibration modes: tire size, tire construction, inflation pressure, and operating conditions such as speed, load, and temperature. This paper discusses the influence of these parameters on tire vibration modes and describes how these tire modes influence vehicle ride quality. Results from both finite element modeling and modal testing are discussed.

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