scholarly journals A solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation

2012 ◽  
Vol 2 (3) ◽  
pp. 032004
Author(s):  
Hans B. Löfgren
Keyword(s):  
Flat Surface ◽  
Hydrodynamic Lubrication ◽  
Point Contact ◽  
Circular Point

Effect of Crack on Elasto-hydrodynamic Lubrication in Point Contact

2021 ◽  
Author(s):  
Yujuan Li ◽  
Wen Wang ◽  
Mingfei Ma ◽  
Yongqiang Wang
Keyword(s):  
Hydrodynamic Lubrication ◽  
Point Contact

scholarly journals Theoretical model of the effect of dimple on friction behavior in hydrodynamic lubrication regime

2021 ◽  
Vol 264 ◽  
pp. 04076
Author(s):  
Auezhan Amanov ◽  
Xasan Turkmenov
Keyword(s):  
Theoretical Model ◽  
Hydrodynamic Lubrication ◽  
Renewable Energy Sources ◽  
Point Contact ◽  
Friction Behavior ◽  
Mechanical Parts ◽  
Research Areas ◽  
Lubrication Regime ◽  
Rigid Smooth ◽  
Film Lubrication

In this paper, full-film lubrication between the rigid smooth and dimpled surfaces was addressed. A theoretical model is developed to study the effect of a dimple on friction where the smooth surface is rotating while the dimpled surface is at rest. To simplify the problem, the magnified dimple cell is investigated along with some assumptions. Because dimples deploy periodically along with the x and y directions, the lubricant pressure also deploys periodically. A theoretical model can be developed for one cell and then extended to the whole surface. The main goal of this study is to understand the dimple effect on friction in a hydrodynamic lubrication regime. The main applications of this model are several types of bearings (point contact, line contact etc.) and mechanical parts where two surfaces interact in relative motion. Findings the optimum dimensions for the dimples also seem to be one of the interesting research areas in mechanization of agricultural and renewable energy sources.

Measurement of Boundary Lubricant Viscosity at Metal-Deformation Pressures (3000 Atmospheres, 20 Tons/Sq In.)

1967 ◽  
Vol 89 (3) ◽  
pp. 272-281 ◽  
Author(s):  
G. W. Rowe
Keyword(s):  
Boundary Lubrication ◽  
Flat Surface ◽  
Hydrodynamic Lubrication ◽  
Elastohydrodynamic Lubrication ◽  
Wire Drawing ◽  
Average Pressure ◽  
Boundary Lubricant ◽  
Metal Deformation ◽  
Local Pressures ◽  
Lubricant Viscosity

In many metalworking operations, such as rolling and wire drawing, the average pressure acting between the workpiece and the tool will be of the order of the yield stress of the metal, usually 20–50 tons/sq in. The lubricant temperature may also rise by 60 deg C or more. Any consideration of hydrodynamic lubrication in these operations should thus take account of the large viscosity changes which may occur under such pressures and temperatures. In addition, it is probable that the rate of shear will be important [1], but this will not be considered in this paper. Local pressures of the same order are developed in typical boundary-lubrication apparatus using a hemispherical slider on a flat surface under kilogram loads [2]. Information on the pressure and temperature coefficients of viscosity for lubricants is therefore important also in studies of boundary lubrication and elastohydrodynamic lubrication [3], especially in the presence of boundary additives [4]. This paper describes a simple apparatus for viscosity measurement at temperatures up to 70 deg C and pressures up to 20 tons/sq in. (3000 atmospheres) or with future modifications up to 45 tons/sq in., together with some results for fluids with and without boundary additives.

Elastohydrodynamic lubrication of a circular point contact for a compliant layered surface bonded to a rigid substrate Part 1: Theoretical formulation and numerical method

2000 ◽  
Vol 214 (3) ◽  
pp. 267-279 ◽  
Author(s):  
Z. M. Jin
Keyword(s):  
Numerical Method ◽  
Reynolds Equation ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Contact Radius ◽  
Rigid Substrate ◽  
Theoretical Formulation ◽  
Circular Point ◽  
Present Solution ◽  
Raphson Method

A full numerical analysis of the elastohydrodynamic lubrication problem of a circular point contact involving a compliant layered surface firmly bonded to a rigid substrate is reported in the present study. The Reynolds equation has been solved simultaneously with the full elasticity equation for the layered bearing surface under entraining motion, using the Newton-Raphson method. The theoretical formulation and the numerical method are presented in the present paper (Part 1), together with the comparison of the predicted minimum and central film thickness between the present solution when the contact radius is much smaller than the layer thickness and the results for a semi-infinite solid reported in the literature.

Analysis of a Low Speed Flexible Flat Land Thrust Bearing

1990 ◽  
Vol 112 (4) ◽  
pp. 678-683
Author(s):  
M. Carpino
Keyword(s):  
Circular Plate ◽  
Thrust Bearing ◽  
Flat Surface ◽  
Hydrodynamic Lubrication ◽  
Fluid Film ◽  
Surface Point ◽  
Low Speed ◽  
Flexible Circular Plate

The problem of a flexible flat land thrust bearing is studied here. The bearing consists of a flexible circular plate running against a rigid flat surface. Point loads are applied to the plate at equally spaced locations causing deflection of the plate. The deflection of the plate creates the converging clearances necessary for hydrodynamic lubrication. The fluid film between the disk and the plate is treated as incompressible. Results are presented in terms of normalized variables enabling the design of a broad range of bearings based on this mechanism.

scholarly journals Effect of Oil Temperature on Load Capacity and Friction Power Loss in Point Contact Elasto-hydrodynamic Lubrication

2019 ◽  
Vol 22 (3) ◽  
pp. 180-186
Author(s):  
Hassan S Fatehallah ◽  
Zaid S. Hammoudi ◽  
Lutfy Y. Zidane
Keyword(s):  
Film Thickness ◽  
Friction Force ◽  
Coefficient Of Friction ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Point Contact ◽  
Fortran Program ◽  
Maximum Pressure ◽  
Force Coefficient ◽  
Friction Power

This study presents a numerical analysis for point contact Elasto-hydrodynamic lubrication EHL. The oils used are (0W-30 and 10W-40) as lubricants. The pressure and film-thickness profiles for point contact EHL are evaluated. The aims of this study are to estimate the effect of oil’s temperature on friction force, coefficient of friction and load carrying capacity. By using FORTRAN program, the Forward-iterative method is used, to solve two dimensional (2D) EHL problem. The viscosity is updating in the solution by using Roeland’s model. After the convergence of pressure is done, the friction force, friction power losses, and friction coefficient are calculated. The temperature used ranges from (-20 to 120 oC). The results showed the film-thickness decreases with the increasing of temperature. Though the maximum pressure is not affected, only the pressure distribution and profile are changed, inlet pressure decreases and the pressure profile tends towards a hertzian (dry contact) one. The friction force and the coefficient of friction decrease with the increasing of temperature.

scholarly journals Transient analysis of isothermal elastohydrodynamic circular point contacts

2001 ◽  
Vol 215 (10) ◽  
pp. 1159-1172 ◽  
Author(s):  
D Jalali Vahid ◽  
H Rahnejat ◽  
Z M Jin ◽  
D Downson
Keyword(s):  
Transient Analysis ◽  
Solution Method ◽  
Numerical Solutions ◽  
Flat Glass ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Point Contacts ◽  
Good Qualitative Agreement ◽  
Circular Point ◽  
Good Agreement

In this paper a solution method is presented for the transient isothermal elastohydrodynamic lubrication of point contact conjunctions, based upon the Newton-Raphson scheme and low iteration relaxation. The numerical results are compared with the numerical and experimental observations of others for the circular point contact of a ball against a flat glass disc under oscillating conditions. Good agreement has been found with other numerical solutions. The comparison with the experimental results shows good qualitative agreement.

scholarly journals Analysis of Starvation Effects on Hydrodynamic Lubrication in Nonconforming Contacts

1982 ◽  
Vol 104 (3) ◽  
pp. 410-417 ◽  
Author(s):  
D. E. Brewe ◽  
B. J. Hamrock
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Three Dimensional ◽  
Point Contact ◽  
Sharp Decrease ◽  
Reduction Factor ◽  
Wide Range ◽  
Minimum Film Thickness ◽  
Contour Plots ◽  
Starvation Effects

Numerical methods were used to determine the effects of lubricant starvation on the minimum film thickness under conditions of a hydrodynamic point contact. Starvation was effected by varying the fluid inlet level. The Reynolds boundary conditions were applied at the cavitation boundary and zero pressure was stipulated at the meniscus or inlet boundary. The analysis is considered valid for a range of speeds and loads for which thermal, piezoviscous, and deformation effects are negligible. It is applied to a wide range of geometries (i.e., from a ball-on-plate configuration to a ball in a conforming groove). Seventy-four cases were used to numerically determine a minimum-film-thickness equation as a function of the ratio of dimensionless load to dimensionless speed for varying degrees of starvation. From this, a film reduction factor was determined as a function of the fluid inlet level. Further, a starved fully flooded boundary was defined and an expression determining the onset of starvation was derived. As the degree of starvation was increased, the minimum film thickness decreased gradually until the fluid inlet level became critical. Reducing the fluid inlet level still further led to a sharp decrease in the minimum film thickness. An expression determining the critically starved fluid inlet level was derived. The changes in the inlet pressure buildup due to changing the available lubricant supply are presented in the form of three-dimensional isometric plots and also in the form of contour plots.

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