Elastohydrodynamic Lubrication of Finite Line Contacts

1983 ◽  
Vol 105 (4) ◽  
pp. 598-604 ◽  
Author(s):  
A. Mostofi ◽  
R. Gohar
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Mineral Oil ◽  
Pressure Variation ◽  
Material Parameters ◽  
Line Contacts ◽  
Finite Line ◽  
Moderate Load ◽  
Infinite Line ◽  
Cylindrical Roller ◽  
Theoretical Results

In this paper, a numerical solution to the elastohydrodynamic lubrication (EHL) problem is presented for a cylindrical roller with axially profiled ends, rolling over a flat plane. Convergence was obtained for moderate load and material parameters (glass, steel, and a mineral oil). Isobars, contours, and section graphs, show pressure variation and film shape. Predictions of film thickness compare favorably with experiments which use the optical interference method, as well as with other theoretical results for an infinite line contact, or an ellipse having a long slender aspect ratio. The maximum EHL pressure occurs near the start of the profiling and can exceed pressure concentrations there predicted by elastostatic theory.

On the Negative Influence of Roller-End Axial Profiling on Friction in Thermal Elastohydrodynamic Lubricated Finite Line Contacts

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
W. Habchi
Keyword(s):  
Fatigue Life ◽  
Elastohydrodynamic Lubrication ◽  
Element Model ◽  
Negative Influence ◽  
Frictional Behavior ◽  
Minimum Film Thickness ◽  
Line Contacts ◽  
Negative Effect ◽  
Finite Line ◽  
Reducing Stress

Abstract This paper presents a finite element model for the solution of thermal elastohydrodynamic lubrication in finite line contacts, including edge effects. The model is used to investigate the influence of roller-end axial profiling on the frictional behavior of such contacts. Roller-end profiling in finite line contacts has always been used to enhance fatigue life by increasing lubricant minimum film thickness and reducing stress concentration at roller ends. The influence on friction on the other hand has often been overlooked in the literature. The current work reveals that roller-end profiling has a negative effect on friction. In fact, it turns out that the improvement in fatigue life comes at the expense of increased friction.

Numerical Running-In Method for Modifying Cylindrical Roller Profile Under Mixed Lubrication of Finite Line Contacts

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yazhao Zhang ◽  
Hui Cao ◽  
Alexander Kovalev ◽  
Yonggang Meng
Keyword(s):  
Contact Pressure ◽  
Hydrodynamic Pressure ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Pressure Distributions ◽  
Line Contacts ◽  
Finite Line ◽  
Roller Profile ◽  
Rough Surface Contact ◽  
Cylindrical Roller

A numerical method for modifying cylindrical roller profile was proposed to smooth axial pressure distributions of finite line contacts under the mixed lubrication regime. The mixed lubrication model, in which the Reynolds equation modified by Patir and Cheng has been solved with implementing the rough surface contact model of Kogut and Etsion for the stochastic solution of hydrodynamic pressure and asperity-contact pressure, was established and it is validated by the comparison between simulation results and experiments. Some common roller profiles were carried into the mixed lubrication model and obvious increment of pressure appears near the roller ends or at the central contact area. A numerical running-in method was developed to smooth pressure shapes and the crown drop of roller profile was modified gradually implementing Archard's wear law, where a higher asperity-contact pressure leads to a larger crown drop on a roller profile. The results of the numerical running-in method indicated that pressure distributions of finite line contacts are uniform if the optimized roller profile is employed.

Influence of Different Viscosity Lubricant to Finite Line Contacts on Elastohydrodynamic Lubrication (EHL) under Oscillating

2012 ◽  
Vol 538-541 ◽  
pp. 1939-1944
Author(s):  
Yan Fei Wang ◽  
Tong Shu Hua ◽  
Hao Yang Sun
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Oil Film ◽  
Entrainment Velocity ◽  
Finite Line Contact ◽  
Line Contacts ◽  
Finite Line ◽  
Contact Roller ◽  
Two Parameters ◽  
Experimental Rig

To make further researches into the elastohydrodynamic lubrication properties of a finite line contact roller, oscillating experiments were carried out on made overload experimental rig for oil film measurement using optical interference technique. Film thickness and shape were measured in two kinds of viscosity polyisobutylene. This study indicates that both lubricant viscosity and roller entrainment velocity play an important role on EHL of finite line contacts. On motion, the more increase in viscosity or speed, the thicker the oil film thickness, simultaneity edge effect is distinctly intensified and film thickness increases less on roller end, difference of the film thickness is increased between roller end and the central. Above two parameters are significant for logarithmic profile roller in crowning design.

Elastohydrodynamic Lubrication Analysis of Finite Line Contact Problem With Consideration of Two Free End Surfaces

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Haibo Zhang ◽  
Wenzhong Wang ◽  
Shengguang Zhang ◽  
Ziqiang Zhao
Keyword(s):  
Contact Problem ◽  
Finite Length ◽  
Elastohydrodynamic Lubrication ◽  
Line Contact ◽  
Free Boundaries ◽  
Finite Line Contact ◽  
Line Contacts ◽  
Speed Up ◽  
Finite Line ◽  
Overlapping Method

Elastohydrodynamic lubrication (EHL) analysis in finite line contacts is usually modeled by a finite-length roller contacting with a half-space, which ignores effect of the two free boundaries existing in many applications such as gears or roller bearings. This paper presents a semi-analytical method, involving the overlapping method and matrix formation, for EHL analysis in the finite line contact problem to consider the effect of two free end surfaces. Three half-spaces with mirrored loads to be solved are overlapped to cancel out the stresses at expected surfaces, and three matrices can be obtained and reused for the same finite-length space. The isothermal Reynolds equation is solved to obtain the pressure distribution and the fast Fourier transform (FFT) is used to speed up the elastic deformation and stress related calculation. Different line contact situations, including straight rollers, tapered rollers, and Lundberg profile rollers, are discussed to explore the effect of free end surfaces.

Influence of Lubricant Pressure Response on Subsurface Stress in Elastohydrodynamically Lubricated Finite Line Contacts

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Tobias Hultqvist ◽  
Aleks Vrcek ◽  
Braham Prakash ◽  
Pär Marklund ◽  
Roland Larsson
Keyword(s):  
Low Cost ◽  
Elastohydrodynamic Lubrication ◽  
Pressure Response ◽  
Stress Concentrations ◽  
Oil Viscosity ◽  
Lubricated Contacts ◽  
Low Viscosity ◽  
Line Contacts ◽  
Finite Line ◽  
Subsurface Stress

In order to adapt to increasingly stringent CO2 regulations, the automotive industry must develop and evaluate low cost, low emission solutions in the powertrain technology. This often implies increased power density and the use of low viscosity oils, leading to additional challenges related to the durability of various machine elements. Therefore, an increased understanding of lubricated contacts becomes important where oil viscosity–pressure and compressibility–pressure behavior have been shown to influence the film thickness and pressure distribution in elastohydrodynamic lubrication (EHL) contacts, further influencing the durability. In this work, a finite line EHL contact is analyzed with focus on the oil compressibility–pressure and viscosity–pressure response, comparing two oils with relatively different behavior and its influence on subsurface stress concentrations in the contacting bodies. Results indicate that increased pressure gradients and pressure spikes, and therefore increased localized stress concentrations, can be expected for stiffer, less compressible oils, which under transient loading conditions not only affect the outlet but also the edges of the roller.

Elastohydrodynamic lubrication of coated finite line contacts

2017 ◽  
Vol 232 (9) ◽  
pp. 1077-1092 ◽  
Author(s):  
Shivam S Alakhramsing ◽  
Matthijn B de Rooij ◽  
Dirk J Schipper ◽  
Mark van Drogen
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Surface Profile ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Lubrication Performance ◽  
Line Contacts ◽  
Finite Line ◽  
Axial Surface

In this work, a finite element-based model is presented that simulates elastohydrodynamic lubrication in coated finite line contacts. Using this model, the film thickness and pressure distributions, between a straight roller with rounded edges on a plate, were analyzed. The model was successfully validated against representative results reported in literature. Parameter studies were conducted to study the influence of varying operating conditions, axial surface profile parameters and coating mechanical properties on the overall elastohydrodynamic lubrication behavior of the contact. It was found that in contrast with typical elastohydrodynamic lubrication behavior, the maximum pressure and minimum film thickness, which are located at the rear of the contact, are largely influenced by variations in load. Results also reveal that axial surface profile parameters and coating mechanical properties may act as amplifiers to the effect of load on pressure and film thickness distribution and can thus, if smartly chosen, significantly enhance lubrication performance.

Bio–Based Lubricants for Numerical Solution of Elastohydrodynamic Lubrication

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
Dedi Rosa Putra Cupu ◽  
Jamaluddin Md Sheriff ◽  
Kahar Osman
Keyword(s):  
Numerical Solution ◽  
Vegetable Oils ◽  
Peak Pressure ◽  
Contact Region ◽  
Roller Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Infinite Cylinder ◽  
Line Contacts ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

This paper presents a numerical solution of elastohydrodynamic lubrication (EHL) problem in line contacts which is modeled through an infinite cylinder on a plane to represent the application of cylindrical roller bearing. In this work, the contact between roller element and raceway of outer ring of the cylindrical roller bearing is simulated using vegetable oils as bio-based lubricants. Temperature is assumed to be constant at 40oC. The results show that the EHL pressure for all vegetable oils was increasing from inlet flow until the center, then decrease a bit and rise to the peak pressure. The shapes of EHL film thickness for all tested vegetable oils are almost flat at contact region.

Non-Newtonian Starved Thermal-Elastohydrodynamic Lubrication of Finite Line Contacts

2013 ◽  
Vol 56 (1) ◽  
pp. 88-100 ◽  
Author(s):  
Athanassios Mihailidis ◽  
Konstantinos Agouridas ◽  
Konstantinos Panagiotidis
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Line Contacts ◽  
Finite Line
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