Effect of topography parameter, load, and surface roughness on friction coefficient in mixed lubrication regime

2019 ◽  
Vol 31 (5) ◽  
pp. 218-228 ◽  
Author(s):  
Deepak K. Prajapati ◽  
Mayank Tiwari
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Mixed Lubrication ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime

A Friction Model for Cold Strip Rolling With Two-Wavelength Surface Roughness in the “Mixed” Lubrication Regime

2003 ◽  
Vol 125 (3) ◽  
pp. 670-677 ◽  
Author(s):  
H. R. Le ◽  
M. P. F. Sutcliffe
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Rolling Direction ◽  
Hydrodynamic Pressure ◽  
Friction Model ◽  
Mixed Lubrication ◽  
Strip Rolling ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Cold Metal

A two-dimensional friction model has been developed for cold metal rolling in the “mixed” lubrication regime. Roughness is modelled using superimposed short and long wavelength asperities with a lay orientated along the rolling direction. The hydrodynamic pressure in the lubricant is solved using Reynolds’ equation, coupled with the crushing process of the two-wavelength roughness. This allows for the solution of film thickness and contact area ratio and hence friction coefficient through the roll-bite. The model extends the authors’ earlier model [15] by allowing for a variation in hydrodynamic pressure across the width of the contact. Predictions for both the surface roughness and the friction coefficient are in reasonable agreement with published measurements.

scholarly journals Friction coefficient in mixed lubrication: A simplified analytical approach for highly loaded non-conformal contacts

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770626 ◽  
Author(s):  
Javier Echávarri Otero ◽  
Eduardo de la Guerra Ochoa ◽  
Enrique Chacón Tanarro ◽  
Benito del Río López
Keyword(s):  
Friction Coefficient ◽  
Thermal Effects ◽  
Mixed Lubrication ◽  
Good Precision ◽  
Experimental Conditions ◽  
Lubrication Regime ◽  
Line Contacts ◽  
Mixed Lubrication Regime ◽  
Lubrication Conditions ◽  
Highly Loaded

This article presents an analytical model for predicting friction in mixed lubrication regime. The calculations consider load shared between roughness asperities and the lubricant film, as well as the appearance of thermal effects in the contact and the influence of the lubricant rheology. Tests using tribometers have been performed to measure the friction coefficient in non-conformal surfaces for both point and line contacts. This allows verifying the results of the model under a broad range of experimental conditions with an influence on the lubrication conditions. Reasonably good precision has been found in the results obtained, which combined with a simplicity of use confers the model a high practical utility for rough estimates of the friction coefficient under mixed lubrication.

Parametric Study of the Behavior of a Mechanical Face Seal Operating in Mixed and TEHD Lubrication Regimes

2012 ◽  
Author(s):  
André Parfait Nyemeck ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Fluid Viscosity ◽  
Face Seal ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mechanical Face Seal ◽  
Mixed Lubrication Regime

In this paper, the behavior of a mechanical face seal is analyzed for different operating conditions and designs. For that, a theoretical model including a multiscale approach of the mixed lubrication regime, heat transfer and deformation of the seal rings is used. It has been possible to clearly identify the three different lubrication regimes of a mechanical seal: the mixed lubrication where the friction coefficient decreases, the rough hydrodynamic regime corresponding to an increasing friction and then the thermo-elasto-hydrodynamic (TEHD) regime for which the coefficient of friction is approximately constant. In this work, the influence of the fluid pressure, the seal roughness height, the balance ratio, the rings materials, the dry friction coefficient and viscosity are respectively examined. Generally speaking, the variation of these parameters affects the location of the optimum value of the friction coefficient in the mixed lubrication regime. In the TEHD regime, the temperature is mainly influenced by the materials and the fluid viscosity, which control the amplitude of deformation and heat transfer. A dimensionless parametric analysis has been carried out in order to perform an overall discussion of the results. It is shown that the mixed and rough hydrodynamic lubrication regimes are controlled by the modified duty parameter, while the TEHD regime is controlled by the sealing parameter.

The Collapse of Sliding Micro-EHL Films by Plastic Extrusion

1991 ◽  
Vol 113 (4) ◽  
pp. 805-810 ◽  
Author(s):  
J. C. Hamer ◽  
R. S. Sayles ◽  
E. Ioannides
Keyword(s):  
Surface Roughness ◽  
Velocity Profile ◽  
Film Thickness ◽  
Mixed Lubrication ◽  
Lubrication Regime ◽  
Elastohydrodynamic Film Thickness ◽  
Mixed Lubrication Regime

In the mixed lubrication regime, where surface roughness may exceed the elastohydrodynamic film thickness, sliding micro-ehl films appear to collapse during their passage through the contact. A possible explanation for this can be found if the film is treated as a plastic solid. In this work, the collapse velocity is found by simultaneously solving the plastic extrusion equations and the elastic pressure equations for the film trapped between approaching asperities. The velocity of collapse is shown to be very sensitive to the asperity wavelength, slide-roll ratio, and the velocity profile between the sliding asperities.

scholarly journals Modelling tribochemistry in the mixed lubrication regime

2019 ◽  
Vol 132 ◽  
pp. 265-274 ◽  
Author(s):  
Abdullah Azam ◽  
Ali Ghanbarzadeh ◽  
Anne Neville ◽  
Ardian Morina ◽  
Mark C.T. Wilson
Keyword(s):  
Mixed Lubrication ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime

Lubrication efficiency of crankpin bearing using square-cylindrical textures of partial textures optimized by genetic algorithm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shaoyong Xu ◽  
Vanliem Nguyen ◽  
Xiaoyan Guo ◽  
Huan Yuan
Keyword(s):  
Genetic Algorithm ◽  
Mixed Lubrication ◽  
Bearing Surface ◽  
Machining Time ◽  
Obvious Effect ◽  
Content Type ◽  
Density Distributions ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Geometrical Dimensions

Purpose This paper aims to propose an optimal design of the partial textures in the mixed lubrication regime of the crankpin bearing (CB) to maximize the CB's lubrication efficiency. Design/methodology/approach Based on a hybrid model between the slider-crank-mechanism dynamic and CB lubrication, the square-cylindrical textures (SCT) of partial textures designed on the CB’s mixed lubrication regime are researched. The effect of the density distributions of partial textures on CB’s lubrication efficiency is then evaluated via two indices of increasing the oil film pressure (p) and decreasing the frictional force (Ff) of the CB. The SCT’s geometrical dimensions are then optimized by the genetic algorithm to further improve the CB’s lubrication efficiency. Findings The results show that the SCT of partial textures optimized by the genetic algorithm has an obvious effect on enhancing CB’s lubrication efficiency. Especially, with the CB using the optimal SCT of partial textures (4 × 6), the maximum p is significantly increased by 3.7% and 8.2%, concurrently, the maximum Ff is evidently reduced by 9.5% and 21.6% in comparison with the SCT of partial textures (4 × 6) without optimization and the SCT of full textures (12 × 6) designed throughout the CB’s bearing surface, respectively. Originality/value The application of the optimal SCT of partial textures on the bearing surface not only is simple for the design-manufacturing process and maximizes CB’s lubrication efficiency but also can reduce the machining time, save cost and ensure the durability of the bearing compared to use the full textures designed throughout the CB’s bearing surface.

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