Jacobian Free Newton-GMRES Method for Analysing Combined Effects of Surface Roughness and Couple Stress Character of Lubricant on EHL Line Contact

2016 ◽  
Vol 82 (4) ◽  
Author(s):  
M. H. Kantlia ◽  
B. M. Shettarb ◽  
N. M. Bujurkea
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Gmres Method ◽  
Combined Effects ◽  
Line Contact

A Study of Combined Effects of Surface Roughness and Lubricant Rheology on the Hydrodynamic Contact Behavior Using the Homogenized Method

2010 ◽  
Author(s):  
Ahcene Mouassa ◽  
Mustapha Lahmar ◽  
Benyebka Bou-Said
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Fluid Model ◽  
Lower Surface ◽  
Homogenization Method ◽  
Performance Characteristics ◽  
Hydrodynamic Performance ◽  
Combined Effects ◽  
Slider Bearing ◽  
Lubricant Rheology

The combined effects of surface roughness and lubricant rheology on the performance characteristics of a hydrodynamic inclined slider bearing are investigated by means of the homogenized method. The pad surface is rough and stationary while the lower surface is assumed to be smooth and moving. The V. K. Stokes couple stress fluid model is adopted to describe the rheological behavior of the lubricant flowing between the two surfaces. The numerical simulations are performed by considering three roughness patterns (transverse, longitudinal and anisotropic), and various values of the couple stress parameter. It is found that the homogenization method is rigorous and efficient for the three roughness patterns considered. It is also found that the combined effects of the surface roughness as well as the couple stress due to the presence of polymer additives on the hydrodynamic performance characteristics such as load carrying capacity, friction factor are significant.

Combined effects of piezo – viscous coupled stress lubricant and rotational inertia upon squeeze film performance of rough circular discs

2015 ◽  
Vol 67 (6) ◽  
pp. 564-571 ◽  
Author(s):  
M. Daliri ◽  
D. Jalali-Vahid
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Squeeze Film ◽  
Rotational Inertia ◽  
Combined Effects ◽  
Film Performance ◽  
Content Type ◽  
Couple Stresses ◽  
Pressure Dependency ◽  
Film Characteristics

Purpose – The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by piezo – viscous couple stress lubricant with pressure-dependent viscosity variation. Design/methodology/approach – Based upon the Stokes couple stress theory, Barus viscosity-pressure dependency relation and Christensen rough surfaces model, squeeze film characteristics between two rough parallel circular discs are obtained. Findings – According to the results, it is found that, the combined effects of couple stresses and viscosity-pressure dependency increases squeeze film performance with respect to the classical Newtonian iso-viscous (constant viscosity) lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it. Originality/value – This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with viscosity-pressure dependency, rotational inertia, couple stresses and surface roughness effects.

Effect of surface roughness on couple stress squeeze film lubrication of long porous partial journal bearings

2006 ◽  
Vol 58 (4) ◽  
pp. 176-186 ◽  
Author(s):  
N.M. Bujurke ◽  
N.B. Naduvinamani ◽  
Syeda Tasneem Fathima ◽  
S.S. Benchalli
Keyword(s):  
Surface Roughness ◽  
Couple Stress ◽  
Journal Bearings ◽  
Squeeze Film ◽  
Film Lubrication ◽  
Effect Of Surface

Effect of Rolling Velocity and Maximum Hertzian Pressure on Fluid Film in Steady State EHL Line Contact with Rough Surface and Linear Piezoviscosity

2014 ◽  
Vol 592-594 ◽  
pp. 1371-1375
Author(s):  
Nitesh Talekar ◽  
Punit Kumar
Keyword(s):  
Surface Roughness ◽  
Steady State ◽  
Film Thickness ◽  
Rough Surface ◽  
Computer Code ◽  
Fluid Film ◽  
Line Contact ◽  
Rolling Velocity ◽  
Load Carrying ◽  
Lubricated Contact

Consideration of surface roughness in steady state EHL line contact is the first step towards understanding the lubrication of rough surface problem. Current paper investigates the use of sinusoidal waviness in the contact; more precisely it gives performance of real fluid in EHL line contact. The effect of various parameters like rolling velocity (U) and maximum Hertzian pressure (ph) on surface roughness by using properties of linear and exponential piezo-viscosity is taken into consideration to evaluate behavior of pressure distribution of load carrying fluid film and film thickness. Full isothermal, Newtonian simulation of EHL problem gives described effects. Spiking or fluctuation of pressure and film thickness curves is expected to show presence of irregularities on the surface chosen and amount of fluctuation depends on certain parameters and intensity of irregularities present. Rolling side domain of-4.5 ≤ X ≤ 1.5 with grid size ∆X=0.01375 is selected. A computer code is developed to solve Reynolds equation, which governs the generation of pressure in the lubricated contact zone is discritized and solved along with load balance equation using Newton-Raphson technique.

Simulation of Plasto-Elastohydrodynamic Lubrication in Line Contacts of Infinite and Finite Length

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Tao He ◽  
Jiaxu Wang ◽  
Zhanjiang Wang ◽  
Dong Zhu
Keyword(s):  
Surface Roughness ◽  
Finite Length ◽  
3D Model ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Axial Direction ◽  
Contact Length ◽  
Line Contact ◽  
Line Contacts ◽  
3D Surface Topography

Line contact is common in many machine components, such as various gears, roller and needle bearings, and cams and followers. Traditionally, line contact is modeled as a two-dimensional (2D) problem when the surfaces are assumed to be smooth or treated stochastically. In reality, however, surface roughness is usually three-dimensional (3D) in nature, so that a 3D model is needed when analyzing contact and lubrication deterministically. Moreover, contact length is often finite, and realistic geometry may possibly include a crowning in the axial direction and round corners or chamfers at two ends. In the present study, plasto-elastohydrodynamic lubrication (PEHL) simulations for line contacts of both infinite and finite length have been conducted, taking into account the effects of surface roughness and possible plastic deformation, with a 3D model that is needed when taking into account the realistic contact geometry and the 3D surface topography. With this newly developed PEHL model, numerical cases are analyzed in order to reveal the PEHL characteristics in different types of line contact.

A Comparison of Porous Structures on the Performance of a Slider Bearing with Surface Roughness in Couple Stress Fluid Film Lubrication

2015 ◽  
Vol 813-814 ◽  
pp. 921-937
Author(s):  
P.S. Rao ◽  
Santosh Agarwal
Keyword(s):  
Surface Roughness ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Type Equation ◽  
Random Variable ◽  
Couple Stress Fluid ◽  
Load Carrying Capacity ◽  
Porous Structures ◽  
Slider Bearing ◽  
Load Carrying

This paper presents the theoretical study and analyzes the comparison of porous structures on the performance of a couple stress fluid based on rough slider bearing. The globular sphere model of Kozeny-Carman and Irmay’s capillary fissures model have been subjected to investigations. A more general form of surface roughness is mathematically modeled by a stochastic random variable with non-zero mean, variance and skewness. The stochastically averaged Reynolds type equation has been solved under suitable boundary conditions to obtain the pressure distribution in turn which gives the expression for the load carrying capacity, frictional force and coefficient of friction. The results are illustrated by graphical representations which show that the introduction of combined porous structure with couple stress fluid results in an enhanced load carrying capacity more in the case of Kozeny-Carman model as compared to Irmay’s model.

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