Changes in Surface Topography with Running-In

1968 ◽  
Vol 183 (16) ◽  
pp. 57-65 ◽  
Author(s):  
R. Østvik ◽  
H. Christensen
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Surface Topography ◽  
Mixed Lubrication ◽  
Contact Conditions ◽  
Line Contacts

The paper will describe the results of an experimental study of changes in surface roughness and contact conditions as running-in and wear take place. Line contacts under conditions of mixed lubrication in both sliding and sliding with rolling have been studied.

Modeling of Surface Topography for Reduced Friction

2008 ◽  
Author(s):  
Marko Sedlacˇek ◽  
Bojan Podgornik ◽  
Jozˇe Vizˇintin
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Surface Texturing ◽  
Test Results ◽  
Textured Surfaces ◽  
Roughness Parameters ◽  
Contact Conditions ◽  
Surface Roughness Parameters ◽  
Pin On Disc ◽  
Texture Size

The aim of the present research was to investigate surface topography in terms of different surface roughness parameters and to correlate surface topography change to friction of contact surfaces. For this purpose, different 100Cr6 plate samples with different surface topography were prepared. Using different grades and combinations of grinding and polishing samples with similar Ra values, but different Rku and Rsk values were obtained. To evaluate influence of roughness parameters on friction and wear, dry and lubricated pin-on-disc tests were carried out under different contact conditions. Test results indicate that high Rku and negative Rsk values lead to decrease in friction. To investigate the effect of surface texturing on surface roughness parameters, real roughness profiles were virtually altered to achieve virtually textured surfaces. Using NIST SMATS softgauge for calculation of surface roughness parameters, virtually altered roughness profiles were investigated in terms of texture size, shape and spacing, and their influence on surface roughness parameters, especially on skewness and kurtosis. Lower diameter, higher spacing and wedge-shaped dimples reflect in higher Rku and more negative Rsk parameters.

Experimental study on the surface roughness of micromilled Elgiloy™

2011 ◽  
Vol 225 (11) ◽  
pp. 2138-2143 ◽  
Author(s):  
P Zhang ◽  
B Wang ◽  
Y Liang ◽  
M J Jackson
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Surface Topography ◽  
Industrial Applications ◽  
Depth Of Cut ◽  
Mean Deviation ◽  
Machining Accuracy ◽  
Feed Speed ◽  
3D Surface ◽  
Axial Depth

Elgiloy™ is a cobalt-based alloy with excellent physical and chemical performance, and is used widely in medical and industrial applications. The machining accuracy, surface topography, and surface damaged layer play an important role in the use of the alloy for specific applications. In this paper, an experimental study on the surface roughness of precision micromilling of Elgiloy is accomplished by using a super-fine-grained tungsten carbide milling cutter. The surface topography of the surface of the slots milled is achieved with different values of feed speed and axial depth of cut. Three-dimensional (3D) measurement results are considered to reflect the surface topography based on a comparison of the difference between two-dimensional (2D) and 3D surface roughness measurements. The arithmetic mean deviation of the slots’ 3D surface is achieved by using a white light interferometric profilometer. By using analysis of variance (ANOVA), the factors of feed speed, axial depth of cut, and their interaction are proven to be the most important factors relating to the magnitude of surface roughness.

An Experimental Study of Some of the Factors Affecting the Contact Conditions and the Slip between a Rolling Ball and Its Track

1967 ◽  
Vol 182 (1) ◽  
pp. 757-768 ◽  
Author(s):  
J. Hailing ◽  
M. A. Al-Qishtaini
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Wear Debris ◽  
Normal Load ◽  
Operating Conditions ◽  
Hydrodynamic Effect ◽  
Contact Conditions ◽  
Factors Affecting ◽  
Rolling Ball ◽  
Theoretical Considerations

The problem of a rolling ball subjected to combined normal load and tangential tractions has been studied for a variety of operating conditions. It is shown that for dry steady state loading the resultant slip may be explained in terms of a microslip theory based on the differential elastic straining of the ball and the track. Such results necessitate a careful experimental technique in which the surfaces must be free from contamination and loose wear debris. It is also shown that the preceding arguments are not significantly affected by dynamically varying loads or by speed variations in the range 0-150 in/min. The slip behaviour is found to be markedly affected by the presence of a lubricant. The behaviour with load and speed now indicates a definite hydrodynamic effect, although the theoretical film thickness is considerably less than the surface roughness. These results agree well with the results of other investigations for similar conditions. Using these experimental results and theoretical considerations a tentative power law formulation for the slip under such conditions is proposed.

Precision Honing of Stainless Steel Valve Core

2011 ◽  
Vol 487 ◽  
pp. 438-442
Author(s):  
Zhi Gang Dong ◽  
C.W. Kang ◽  
L. Xu
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Topography ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Grit Size ◽  
Steel Cylinder

The paper reports an experimental study on the effect of honing parameters on the honing surface roughness, material removal rate and surface topography. A cylindrical honing machine was developed, on which the honing experiments for stainless steel cylinder parts were performed with different honing parameters including the abrasives and its grit size of honing stones, honing pressure and honing time. The results can provide helpful instruction to the determination of the honing process and parameters.

Influence of surface functional parameters on friction behavior and elastic–plastic deformation of grinding surface in mixed lubrication state

2018 ◽  
Vol 233 (6) ◽  
pp. 870-883 ◽  
Author(s):  
Bin Zhao ◽  
Song Zhang ◽  
Jianfeng Li
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Mixed Lubrication ◽  
Surface Model ◽  
Roughness Parameters ◽  
Solid Contact ◽  
Friction Behavior ◽  
Surface Roughness Parameters ◽  
Simulation And Experiment ◽  
Friction Performance

Mixed lubrication is a common lubrication regime in sliding contact and has received much attention in recent research. The influences of surface topography on friction performance in this lubrication state are significant owing to the coexistence of fluid–solid contact and solid–solid contact conditions. First, an accuracy surface model is built based on wavelet transform results. Then, the average Reynolds equation is revised for a grinding surface to be used in simulation. Third, four surface roughness parameters ( Sa, Sbi, S ci, and Svi) are selected to characterize surface topography. Additionally, the impacts on the solid–solid contact area, friction coefficient, and surface flattening are investigated. Finally, optimizations of surface roughness parameters directed toward energy saving and sliding stability are conducted and verified. Simulation and experiment methods are jointly applied to guarantee the accuracy of this research. The result of this study can provide theoretical support for machining contact surfaces.

Surface roughness and substrate induced symmetry-breaking: influence on the plasmonic properties of aluminum nanostructure arrays

Nanoscale ◽  
2020 ◽  
Author(s):  
Feifei ZHANG ◽  
Jérôme Plain ◽  
Davy Gerard ◽  
Jérôme Martin
Keyword(s):  
Surface Roughness ◽  
Optical Properties ◽  
Symmetry Breaking ◽  
Surface Topography ◽  
Metallic Nanoparticles ◽  
Far Field ◽  
Al Nanoparticles ◽  
Nanostructure Arrays

The surface topography is known to play an important role on the near- and far- field optical properties of metallic nanoparticles. In particular, aluminum (Al) nanoparticles are commonly fabricated through...

The behaviour of heavily loaded line contacts with transverse roughness

1999 ◽  
Vol 213 (4) ◽  
pp. 309-320 ◽  
Author(s):  
C. J. Hooke
Keyword(s):  
Surface Roughness ◽  
Full Range ◽  
Numerical Results ◽  
Operating Conditions ◽  
Entrainment Velocity ◽  
Original Surface ◽  
Line Contacts ◽  
Transverse Roughness ◽  
Inlet Length

In heavily loaded, piezoviscous contacts the surface roughness tends to be flattened inside the conjunction by any relative sliding of the surfaces. However, before it is flattened, the roughness affects the inlet to the contact, producing clearance variations there. These variations are then convected through the contact, at the entrainment velocity, producing a clearance distribution that differs from the original surface. The present paper explores this behaviour and establishes how the amplitude of the convected clearance varies with wavelength and operating conditions. It is shown that the primary influence is the ratio of the wavelength to the inlet length of the conjunction. Where this ratio is large, the roughness is smoothed and there is little variation in clearance under the conjunction. Where the ratio is small, significant variations in clearance may occur but the precise amplitude and phasing depend on the ratio of slide to roll velocities and on the value of a piezoviscous parameter, c. The numerical results agree closely with existing solutions but extend these to cover the full range of operating conditions.

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.

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