The Influence of Lubricants on Static Friction Characteristics Under Boundary Lubrication

1985 ◽  
Vol 107 (2) ◽  
pp. 188-194 ◽  
Author(s):  
S. Kato ◽  
E. Marui ◽  
A. Kobayashi ◽  
S. Senda
Keyword(s):  
Machine Tool ◽  
Surface Topography ◽  
Contact Pressure ◽  
Boundary Lubrication ◽  
Carrying Capacity ◽  
Static Friction ◽  
Load Carrying Capacity ◽  
Sliding Speed ◽  
Friction Characteristics ◽  
Load Carrying

Based on a new boundary lubrication model, the characteristics of lubricants under boundary lubrication at low sliding speed and low contact pressure such as in machine tool slideways are investigated in relation to surface topography. It is clarified theoretically and ascertained experimentally that the property of lubricants under boundary lubrication can be estimated by the newly defined appraisal coefficient of boundary lubrication property determined by the thickness and load carrying capacity of adsorbed lubricant film and the surface topography.

scholarly journals Two-scale homogenization of hydrodynamic lubrication in a mechanical seal with isotropic roughness based on the Elrod cavitation algorithm

2021 ◽  
pp. 135065012110176
Author(s):  
Yanxiang Han ◽  
Qingen Meng ◽  
Gregory de Boer
Keyword(s):  
Surface Topography ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Polar Coordinate System ◽  
Load Carrying Capacity ◽  
Mechanical Seal ◽  
Macro Scale ◽  
Load Carrying

A two-scale homogenization method for modelling the hydrodynamic lubrication of mechanical seals with isotropic roughness was developed and presented the influence of surface topography coupled into the lubricating domain. A linearization approach was derived to link the effects of surface topography across disparate scales. Solutions were calculated in a polar coordinate system derived based on the Elrod cavitation algorithm and were determined using homogenization of periodic simulations describing the lubrication of a series of surface topographical features. Solutions obtained for the hydrodynamic lubrication regime showed that the two-scale homogenization approach agreed well with lubrication theory in the case without topography. Varying topography amplitude demonstrated that the presence of surface topography improved tribological performance for a mechanical seal in terms of increasing load-carrying capacity and reducing friction coefficient in the radial direction. A Stribeck curve analysis was conducted, which indicated that including surface topography led to an increase in load-carrying capacity and a reduction in friction. A study of macro-scale surface waviness showed that the micro-scale variations observed were smaller in magnitude but cannot be obtained without the two-scale method and cause significant changes in the tribological performance.

Tribological Properties of the Surface Bonded Self-Lubricating Coating

2010 ◽  
Vol 154-155 ◽  
pp. 583-587 ◽  
Author(s):  
Yan Guo Yin ◽  
Fu Dong Lin ◽  
Wei Yao ◽  
Ting Xie ◽  
Jian Wei Yu
Keyword(s):  
Carrying Capacity ◽  
Dry Friction ◽  
Tribological Performance ◽  
Transfer Film ◽  
Metallic Surface ◽  
Load Carrying Capacity ◽  
Sliding Speed ◽  
Lubricating Film ◽  
Load Carrying ◽  
Wear Tests

In order to investigate the effect of load and sliding speed on the tribological performance of epoxy bonded self-lubricating coatings on the metallic surface, a series of wear tests of the coatings containing MoS2 and graphite under dry friction conditions were carried out with different loads and speeds. The results showed that the appropriate load and speed are favorable to the formation of the solid lubricating film on the coating surface and the transfer film on the counterface, which make the coatings have better self-lubricating performance and the friction counterparts run steadily. The load carrying capacity of the surface adhesive self-lubricating coatings decreases as the sliding speed increases.

Characteristics of Surface Topography and Static Friction on Scraped Surface Slideway—Part 1

1980 ◽  
Vol 102 (2) ◽  
pp. 97-103 ◽  
Author(s):  
S. Kato ◽  
E. Marui ◽  
A. Kobayashi ◽  
T. Matsubayashi
Keyword(s):  
Surface Topography ◽  
Boundary Lubrication ◽  
Complex Surface ◽  
Static Friction ◽  
Friction Characteristics ◽  
Depth Direction ◽  
Ellipsoidal Shape

The complex surface topography of a scraped surface is studied quantitatively. The scraped surfaces are composed of the surface elements which are formed by each scraping operation, distribute in the depth direction, and have many asperities. Based on this model, the microscopic contacting problem between two scraped surfaces and static frictional characteristics are investigated under boundary lubrication. As a result, it is clarified that the ellipsoidal shape of the asperity tip of scraping surface may be regarded as optimal from the point of static friction, and the static friction characteristics are considerably influenced by the scraping directions.

Characteristics of Surface Topography and Static Friction on Scraped Surface Slideway—Part 2

1980 ◽  
Vol 102 (2) ◽  
pp. 104-108
Author(s):  
S. Kato ◽  
E. Marui ◽  
A. Kobayashi ◽  
T. Matsubayashi
Keyword(s):  
Surface Topography ◽  
Boundary Lubrication ◽  
Static Friction ◽  
Topographic Effects ◽  
Friction Characteristics ◽  
Nondimensional Parameter ◽  
Large Coefficient ◽  
Parameter Coefficient

The relation between static friction characteristics and surface topography of contacting scraped surfaces are theoretically examined under boundary lubrication. As a result, it is clarified that the topographic effects on static friction of a scraped surface can be evaluated quantitatively by a nondimensional parameter (coefficient of surface topography). The sliding characteristics of scraped surface slideway can be improved by using surfaces having a large coefficient of surface topography.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala
Keyword(s):  
Fuzzy Sets ◽  
Carrying Capacity ◽  
Stochastic Methods ◽  
Nonlinear Behaviour ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Input Parameters ◽  
Stochastic Solution ◽  
Fuzzy Solution ◽  
Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Load carrying capacity of cylindrical shells

2020 ◽  
Vol 2020 (21) ◽  
pp. 146-153
Author(s):  
Anatolii Dekhtyar ◽  
◽  
Oleksandr Babkov ◽  
Keyword(s):  
Carrying Capacity ◽  
Cylindrical Shells ◽  
Load Carrying Capacity ◽  
Load Carrying
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