The Influence of Longitudinal and Transverse Roughness on the Elastohydrodynamic Lubrication of Circular Contacts

1988 ◽  
Vol 110 (3) ◽  
pp. 421-426 ◽  
Author(s):  
A. A. Lubrecht ◽  
W. E. Ten Napel ◽  
R. Bosma
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Factor Method ◽  
Flow Factor ◽  
Transverse Roughness

The effect of longitudinal and transverse roughness on the elastohydrodynamic lubrication of circular contacts was investigated numerically for two different lubricating conditions. The influence of the amplitude and the wavelength of the roughness texture was also studied. The results are compared with predictions from the flow factor method.

Similarities and Differences Between the Flow Factor Method by Patir and Cheng and Homogenization

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Andreas Almqvist ◽  
John Fabricius ◽  
Andrew Spencer ◽  
Peter Wall
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Homogenization Method ◽  
Correct Solution ◽  
Factor Method ◽  
Flow Factor ◽  
Similarities And Differences ◽  
Averaging Techniques

Different averaging techniques have proved to be useful for analyzing the effects of surface roughness in hydrodynamic lubrication. This paper compares two of these averaging techniques, namely the flow factor method by Patir and Cheng (P&C) and homogenization. It has been rigorously proved by many authors that the homogenization method provides a correct solution for arbitrary roughness. In this work it is shown that the two methods coincide if and only if the roughness exhibits certain symmetries. Hence, homogenization is always the preferred method.

The Behaviour of Transverse Roughness in EHL Contacts

1994 ◽  
Vol 208 (2) ◽  
pp. 121-132 ◽  
Author(s):  
J A Greenwood ◽  
G E Morales-Espejel
Keyword(s):  
Reynolds Equation ◽  
Complete Solution ◽  
Elastohydrodynamic Lubrication ◽  
Steady State Solution ◽  
Two Dimensional ◽  
Viscosity Effects ◽  
Complementary Function ◽  
Mean Pressure ◽  
Transverse Roughness ◽  
Transient Case

By assuming the contact geometry in elastohydrodynamic lubrication (EHL) to be that of an infinitely long contact with given nominal film thickness and mean pressure and considering the elastic displacements of the separate components of the initial roughness, it is possible to extend the Greenwood and Johnson analysis for sinusoidal pressure to any two-dimensional roughness. For typical EHL pressures the viscosity effects are negligible, so the Reynolds equation can be linearized and solved analytically; the solution provides a criterion to relate the amplitudes of the undeformed and deformed roughness to the wavelength, and shows that roughness with a short wavelength is likely to persist after deformation. The linearization of the Reynolds equation is extended to the transient case and it is found that the complete solution is made of two separate parts: the particular integral (steady state solution) and the complementary function (which depends on the entry of the partly deformed roughness into the Hertzian zone).

Numerical Study on the Interaction of Transverse and Longitudinal Roughness on Elastohydrodynamic Lubrication Contact Surfaces With Different Thermal Conductivities and Elastic Moduli

2020 ◽  
Vol 143 (9) ◽  
Author(s):  
Motohiro Kaneta ◽  
Kenji Matsuda ◽  
Jing Wang ◽  
Jinlei Cui ◽  
Peiran Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Finite Length ◽  
Elastic Moduli ◽  
Elastohydrodynamic Lubrication ◽  
High Thermal Conductivity ◽  
Low Thermal Conductivity ◽  
Longitudinal Roughness ◽  
Transverse Roughness ◽  
Contact Surfaces ◽  
Thermal Conductivities

Abstract The interaction and surface features between point contact surfaces composed of longitudinal roughness with infinite or finite length and transverse roughness were discussed based on a transient non-Newtonian thermal elastohydrodynamic lubrication (EHL) model. Each surface shape is greatly affected by the difference in elastic moduli, thermal conductivities, and velocities of both contact surfaces. There is a large difference in pressure behavior when the transverse roughness is in contact with the longitudinal roughness with finite length and when it is in contact with the longitudinal roughness with infinite length. In the contact between surfaces with infinitely long longitudinal and transverse roughness, the friction coefficient is lower when the surface with longitudinal roughness has a low thermal conductivity than when it has a high thermal conductivity. Furthermore, the pressure fluctuation is larger when the transverse roughness surface has a high thermal conductivity than when it has a low thermal conductivity.

scholarly journals Performance evaluation of rough thrust pad bearing under thermo-elastohydrodynamic lubrication using an improved iterative method

2019 ◽  
Vol 20 (1) ◽  
pp. 110
Author(s):  
Rahul Kumar ◽  
Mohammad Sikandar Azam ◽  
Subrata Kumar Ghosh ◽  
Hasim Khan
Keyword(s):  
Film Thickness ◽  
Load Capacity ◽  
Frictional Coefficient ◽  
Elastohydrodynamic Lubrication ◽  
Simple Algorithm ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Transverse Orientation ◽  
Practical Applications ◽  
Transverse Roughness

The asperities present on interacting surfaces of a bearing influence the film formation when the oil film becomes thinner and thinner. The aim of this article is to study the effect of stochastic roughness on bearing performance under thermo-piezoviscous and elastic condition using an average flow model. To investigate the present operating conditions, progressive mesh densification method as a fast and simple algorithm has been applied. The results obtained indicate that transverse roughness generates higher pressure compared to other orientational roughness at various film thicknesses. Maximum pressure, mass flow rate and load capacity are larger in transverse roughness compared to other orientational roughness for all values of hydrodynamic roughness parameters. A large sensitivity in load capacity for transverse orientation compared to longitudinal at higher film thickness and small film thickness ratios are witnessed. The frictional coefficient in longitudinal orientation is large compared to transverse orientation at all values of film thickness ratio and step ratios. Materials with low elastic modulus undergo large deformation, resulting in generation of two sharp pressure peaks. These results may possess good acceptability to practical applications for studying the effect of surface roughness under thermo-elastohydrodynamic lubrication condition.

The influence of transverse roughness in thin film, mixed elastohydrodynamic lubrication

2007 ◽  
Vol 40 (2) ◽  
pp. 220-232 ◽  
Author(s):  
Jian Wen Choo ◽  
Andrew V. Olver ◽  
Hugh A. Spikes
Keyword(s):  
Thin Film ◽  
Elastohydrodynamic Lubrication ◽  
Transverse Roughness
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