Dimple influence on load carrying capacity of parallel surfaces

Microdimples generated by laser surface texturing (LST) can be used to enhance performance in hydrostatic gas-lubricated tribological components with parallel surfaces. The pressure distribution and load carrying capacity for a single three-dimensional dimple, representing the LST, were obtained via two different methods of analysis: a numerical solution of the exact full Navier-Stokes equations, and an approximate solution of the much simpler Reynolds equation. Comparison between the two solution methods illustrates that, despite potential large differences in local pressures, the differences in load carrying capacity, for realistic geometrical and physical parameters, are small. Even at large clearances of 5% of the dimple diameter and pressure ratios of 2.5 the error in the load carrying capacity is only about 15%. Thus, for a wide range of practical clearances and pressures, the simpler, approximate Reynolds equation can safely be applied to yield reasonable predictions for the load carrying capacity of dimpled surfaces.

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Cross-hatched groove influence on the load carrying capacity of parallel surfaces with random roughness

Tribology International ◽

10.1016/j.triboint.2020.106610 ◽

2021 ◽

Vol 153 ◽

pp. 106610

Author(s):

W. Ma ◽

N. Biboulet ◽

A.A. Lubrecht

Keyword(s):

Carrying Capacity ◽

Load Carrying Capacity ◽

Random Roughness ◽

Load Carrying ◽

Parallel Surfaces

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Parallel Sliding Load Support in the Mixed Friction Regime. Part 2—Evaluation of the Mechanisms

Journal of Tribology ◽

10.1115/1.3261319 ◽

1987 ◽

Vol 109 (1) ◽

pp. 196-205 ◽

Cited By ~ 51

Author(s):

A. O. Lebeck

Keyword(s):

Carrying Capacity ◽

Friction Model ◽

Load Carrying Capacity ◽

Small Deviations ◽

Mixed Friction ◽

Friction Regime ◽

Load Carrying ◽

Parallel Surfaces ◽

Parallel Geometry ◽

Oil Type

When two parallel surfaces slide parallel to each other in the presence of a liquid, classical lubrication theory shows that no load carrying capacity should result. In Part 1 of this work the experimental data showing that such load support does occur are reviewed. In this paper several of the proposed mechanisms for parallel sliding load support are evaluated by combining the mechanism with a mixed friction model and comparing predictions to experimental results. Both water and oil type bearings are considered. While there are exceptions, it has been found that in general the thermal wedge, microasperity lubrication, microasperity collisions, and squeeze effects cannot account for the large apparent load support in the experimental cases studied. However, small deviations from parallel geometry have a strong effect and can easily account for the observed load support, but several questions remain. It is concluded that future investigations should be directed to developing a better understanding of how favorable macrogeometries might be developed and searching for other sources of pressure generation in parallel sliding.

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The Validity of the Reynolds Equation in Modeling Hydrostatic Effects in Gas Lubricated Textured Parallel Surfaces

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-63149 ◽

2005 ◽

Author(s):

Yuri Feldman ◽

Yuri Kligerman ◽

Izhak Etsion ◽

Shimon Haber

Keyword(s):

Carrying Capacity ◽

Reynolds Equation ◽

Stokes Equations ◽

Surface Texturing ◽

Laser Surface Texturing ◽

Navier Stokes ◽

Load Carrying Capacity ◽

Navier Stokes Equations ◽

Load Carrying ◽

Parallel Surfaces

The pressure distribution and load carrying capacity for a single 3D dimple, representing laser surface texturing (LST) of gas-lubricated tribological components with parallel surfaces, were obtained via two different methods of analysis: 1) a numerical solution of the exact full Navier-Stokes equations; 2) an approximate solution of the much simpler Reynolds equation. Comparison between the two solutions illustrated that the differences in load carrying capacity were negligible for clearances that are 3% or less of the dimple diameter. At larger realistic clearances the error in the load carrying capacity may reach a maximum of 10%.

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Numerical and experimental investigation on influence of compound dimple on tribological performances for rough parallel surfaces

Industrial Lubrication and Tribology ◽

10.1108/ilt-03-2016-0050 ◽

2017 ◽

Vol 69 (4) ◽

pp. 433-446 ◽

Cited By ~ 3

Author(s):

Fanming Meng ◽

Zhitao Cheng ◽

Tiangang Zou

Keyword(s):

Friction Coefficient ◽

Carrying Capacity ◽

Tribological Performance ◽

Textured Surface ◽

Load Carrying Capacity ◽

Friction Test ◽

Content Type ◽

Load Carrying ◽

Parallel Surfaces ◽

Simple Dimple

Purpose This study aims to explore the superiority of the compound dimple (e.g. the rectangular-rectangular dimple) and compare its tribological performance for rough parallel surfaces with those of the traditional one-layer dimple (simple dimple). Design/methodology/approach A mixed-lubrication model for a rough textured surface is established and solved using the finite difference method for film pressure and contact pressure. To accelerate the evaluation of surface deformation, the efficient Continuous convolution fast Fourier transform algorithm is applied. The effects of the compound dimple on the tribological performance for the rough parallel surfaces is numerically investigated. And these effects are compared with those of the simple dimple. Furthermore, a reciprocating friction test is conducted to verify the superiority of the compound dimple. Findings The compound dimple exhibits better tribological performances in comparison with the traditional simple dimple, that is, a larger load-carrying capacity and a smaller friction coefficient. To achieve the best tribological performances for the rough parallel surfaces, the depth ratio of the lower pore to the total pore of the compound dimple and the dimple interval should be reasonably chosen. For the surface with compound dimples, there exists an optimal surface roughness to simultaneously maximize the load-carrying capacity and minimize the friction coefficient. The smaller friction coefficient of the surface with compound dimples is verified by the reciprocating friction test. Originality/value The compound dimple is proposed and the superiority of this novel surface texture is confirmed. This study is expected to provide a new texturing method to improve the tribological performances of the traditional simple dimple.

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

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.2.15129 ◽

2005 ◽

Vol 10 (2) ◽

pp. 151-160 ◽

Cited By ~ 3

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.

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

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.1.15135 ◽

2005 ◽

Vol 10 (1) ◽

pp. 65-75 ◽

Cited By ~ 5

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.

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

Tire Science and Technology ◽

10.2346/1.2174344 ◽

2005 ◽

Vol 33 (4) ◽

pp. 210-226 ◽

Cited By ~ 6

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.

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