Partial Elastomer Texturing in Soft Elasto Hydrodynamic Lubrication

2008 ◽  
Author(s):  
Alexey Shinkarenko ◽  
Yuri Kligerman ◽  
Izhak Etsion
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Leading Edge ◽  
Friction Reduction ◽  
Fluid Film ◽  
Laser Surface Texturing ◽  
Pressure Fields ◽  
Load Carrying ◽  
Micro Dimples ◽  
Viscous Fluid Film

A dimensionless theoretical model of Soft Elasto Hydrodynamic Lubrication (SEHL) between partially textured elastomer and rigid counterpart is developed. The model consists of a soft elastomer with partial Laser Surface Texturing (LST) and an absolutely rigid and smooth counterpart moving relatively to each other in the presence of viscous lubricant. The elastomer surface is partially textured at its leading edge in the form of spherical micro-dimples. The pressure distribution in the fluid film and the elastic deformations of the elastomer are obtained from a simultaneous solution of the Reynolds equation and the equation of linear elasticity, respectively. Friction force and load carrying capacity are evaluated by integration of the shear stress and pressure fields in the viscous fluid film, respectively. The main goal of the present work is to study the potential of the elastomer partial LST in SEHL to friction reduction.

Influence of Laser Surface Texturing Distribution Patterns on the Hydrodynamic Lubrication

2010 ◽  
Vol 97-101 ◽  
pp. 1429-1432 ◽  
Author(s):  
Hong Bin Liu ◽  
Hong Biao Han ◽  
Yu Jun Xue ◽  
Ji Shun Li
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Distribution Patterns ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Laser Texturing ◽  
Coverage Ratio ◽  
Lubricating Film ◽  
Load Carrying ◽  
Film Lubrication

Laser Surface Texturing (LST) is an advanced method of surface micro-texturing technology. The aim of this paper is to investigate the influence of laser surface texturing distribution patterns on lubricant characteristics for laser texturing surfaces against cylindrical under conditions of film lubrication. The laser texturing surfaces are processed with power levels under YAG laser. Under conditions of constant depth and area coverage ratio of LST,patterns of the texture distribution and the sliding orientation relative to the texture were systematically varied. The experimental results suggested that 20° circumferential interval can increase the load-carrying ability of lubricating film.

Feasibility of Laser Surface Texturing for Friction Reduction in Surgical Blades

2013 ◽  
Author(s):  
Tim Velasquez ◽  
Peidong Han ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Substantial Reduction ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Stress Concentrations ◽  
Tissue Samples ◽  
Friction Forces ◽  
Edge Surface ◽  
Phantom Tissue ◽  
Micro Dimples

Trauma resulting from surgical blade friction can cause several complications and delay the recovery time of a patient. In order to attain optimal tribological properties, an 8 ps pulsed 532 nm Nd:YVO4 laser was used to ablate the cutting edge surface of surgical blades to create micro dimples of ∼110 μm in diameter and ∼30 μm in depth. Additionally, certain arrays of dimples endured an extra laser ablation operation to add a fillet to the dimple rims with the hope of reducing stress concentrations during tissue cutting and reducing friction even further. These surface textures were experimentally investigated through cutting experiments on phantom tissue material. Ultimately, the blades with the cutting surface texture that employed blended dimple rims showed a substantial reduction in friction forces when cutting phantom tissue samples.

scholarly journals Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts

Friction ◽  
2021 ◽  
Author(s):  
G. Boidi ◽  
P. G. Grützmacher ◽  
A. Kadiric ◽  
F. J. Profito ◽  
I. F. Machado ◽  
...  
Keyword(s):  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Textured Surfaces ◽  
Engineering Applications ◽  
Lubricated Contacts ◽  
Fluid Uptake ◽  
Direct Laser ◽  
Frictional Performance

AbstractTextured surfaces offer the potential to promote friction and wear reduction by increasing the hydrodynamic pressure, fluid uptake, or acting as oil or debris reservoirs. However, texturing techniques often require additional manufacturing steps and costs, thus frequently being not economically feasible for real engineering applications. This experimental study aims at applying a fast laser texturing technique on curved surfaces for obtaining superior tribological performances. A femtosecond pulsed laser (Ti:Sapphire) and direct laser interference patterning (with a solid-state Nd:YAG laser) were used for manufacturing dimple and groove patterns on curved steel surfaces (ball samples). Tribological tests were carried out under elasto-hydrodynamic lubricated contact conditions varying slide-roll ratio using a ball-on-disk configuration. Furthermore, a specific interferometry technique for rough surfaces was used to measure the film thickness of smooth and textured surfaces. Smooth steel samples were used to obtain data for the reference surface. The results showed that dimples promoted friction reduction (up to 20%) compared to the reference smooth specimens, whereas grooves generally caused less beneficial or detrimental effects. In addition, dimples promoted the formation of full film lubrication conditions at lower speeds. This study demonstrates how fast texturing techniques could potentially be used for improving the tribological performance of bearings as well as other mechanical components utilised in several engineering applications.

Tribological effects of laser surface texturing and residual stress

2018 ◽  
Vol 70 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Shuwen Wang ◽  
Feiyan Yan ◽  
Ao Chen
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Friction And Wear ◽  
Surface Texturing ◽  
Laser Surface ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Wear Testing ◽  
Content Type ◽  
Surface Textures

Purpose The purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces. Design/methodology/approach Three different surface textures (circular dimple, elliptical dimple and groove) with two different textured area ratios (10 and 20 per cent) are designed and fabricated by a Picosecond Nd YAG Laser machine. The friction and wear performance of textured specimens is tested using a UMT-2 friction and wear testing machine in mixed lubrication. Findings Test results show that elliptical dimples exhibit the best performance in wear resistance, circular dimples in friction reduction and grooves in stabilization of friction. The surfaces with larger textured area density exhibit better performance in both friction reduction and wear resistance. The improved performance of LST is the coupled effect of surface texture and residual stress. Originality/value The findings of this study may provide guidance for optimal design of functional surface textures in reciprocating sliding contacts under mixed or hydrodynamic lubrication, which can be used in automotive and other industrial applications.

Effectiveness of multi-shape laser surface texturing in the reduction of friction under lubrication regime

2016 ◽  
Vol 68 (1) ◽  
pp. 116-124 ◽  
Author(s):  
Dawit Zenebe Segu ◽  
Pyung Hwang
Keyword(s):  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Content Type ◽  
Laser Ablation Process ◽  
Specific Formula ◽  
Steel Surfaces ◽  
Lubrication Conditions

Purpose – The purpose of this paper is to investigate and discuss the effect of multi-shape laser surface texturing (LST) steel surfaces on tribological performance. Design/methodology/approach – The textured surface with some specific formula arrays was fabricated by laser ablation process by combining patterns of circles and triangles, circles and squares and circles and ellipses. The tribological test was performed by a flat-on-flat tribometer under dry and lubrication conditions, and results were compared with that of untextured surface. Findings – The results showed that the textured surface had better friction coefficient performance than the untextured surface due to hydrodynamic lubrication effect. Through an increase in sliding speed, the beneficial effect of LST performance was achieved under dry and lubrication conditions. Originality/value – This paper develops multi-shape LST steel surfaces for improving the friction and wear performance under dry and lubrication conditions.

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

2005 ◽  
Vol 128 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Y. Feldman ◽  
Y. Kligerman ◽  
I. Etsion ◽  
S. Haber
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Physical Parameters ◽  
Load Carrying Capacity ◽  
Wide Range ◽  
Load Carrying ◽  
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.

Simulation and Experimental Investigation on Friction Reduction by Partial Laser Surface Texturing on Piston Ring

2020 ◽  
Vol 63 (2) ◽  
pp. 371-381
Author(s):  
Xingyu Liang ◽  
Xiaohui Wang ◽  
Yin Liu ◽  
Xu Wang ◽  
Gequn Shu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Piston Ring ◽  
Surface Texturing ◽  
Laser Surface ◽  
Friction Reduction ◽  
Laser Surface Texturing

scholarly journals Possibilities of Dry and Lubricated Friction Modification Enabled by Different Ultrashort Laser-Based Surface Structuring Methods

Lubricants ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 43 ◽  
Author(s):  
Stefan Rung ◽  
Kevin Bokan ◽  
Frederick Kleinwort ◽  
Simon Schwarz ◽  
Peter Simon ◽  
...  
Keyword(s):  
Laser Beam ◽  
Surface Engineering ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Surface Structures ◽  
Laser Surface Texturing ◽  
Periodic Surface ◽  
The Coefficient Of Friction ◽  
Disc Configuration ◽  
Micro Structures

In this contribution we report on the possibilities of dry and lubricated friction modification introduced by different laser surface texturing methods. We compare the potential of Laser-Induced Periodic Surface Structures and Laser Beam Interference Ablation on 100Cr6 steel in a linear reciprocating ball-on-disc configuration using 100Cr6 steel and tungsten carbide balls with load forces between 50 mN and 1000 mN. For dry friction, we find a possibility to reduce the coefficient of friction and we observe a pronounced direction dependency for surfaces fabricated by Laser Beam Interference Ablation. Furthermore, Laser-Induced Periodic Surface Structures result in a load-dependent friction reduction for lubricated linear reciprocating movements. This work helps to identify the modification behaviour of laser generated micro structures with feature sizes of approximately 1 µm and reveals new possibilities for surface engineering.

Femtosecond laser full and partial texturing of steel surfaces to reduce friction in lubricated contact

2014 ◽  
Vol 3 (5-6) ◽  
Author(s):  
Antonio Ancona ◽  
Giuseppe Carbone ◽  
Michele De Filippis ◽  
Annalisa Volpe ◽  
Pietro Mario Lugarà
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Texturing ◽  
Femtosecond Laser Ablation ◽  
Areal Density ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Effective Contact ◽  
Local Reduction ◽  
Lubricated Contact

AbstractMinimizing mechanical losses and friction in vehicle engines would have a great impact on reducing fuel consumption and exhaust emissions, to the benefit of environmental protection. With this scope, laser surface texturing (LST) with femtosecond pulses is an emerging technology, which consists of creating, by laser ablation, an array of high-density microdimples on the surface of a mechanical device. The microtexture decreases the effective contact area and, in case of lubricated contact, acts as oil reservoir and trap for wear debris, leading to an overall friction reduction. Depending on the lubrication regime and on the texture geometry, several mechanisms may concur to modify friction such as the local reduction of the shear stress, the generation of a hydrodynamic lift between the surfaces or the formation of eddy-like flows at the bottom of the dimple cavities. All these effects have been investigated by fabricating and characterizing several LST surfaces by femtosecond laser ablation with different features: partial/full texture, circular/elliptical dimples, variable diameters, and depths but equivalent areal density. More than 85% of friction reduction has been obtained from the circular dimple geometry, but the elliptical texture allows adjusting the friction coefficient by changing its orientation with respect to the sliding direction.

State of the Art in Laser Surface Texturing

Volume 1 ◽  
2004 ◽  
Author(s):  
Izhak Etsion
Keyword(s):  
Surface Engineering ◽  
State Of The Art ◽  
Load Capacity ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Mechanical Seals ◽  
Current Effort ◽  
Hydrodynamic Bearing ◽  
Micro Dimples

Surface texturing has emerged in the last decade as a viable option of surface engineering resulting in significant improvement in load capacity, wear resistance, friction coefficient etc. of tribological mechanical components. Various techniques can be employed for surface texturing but Laser Surface Texturing (LST) is probably the most advanced so far. LST produces a very large number of micro-dimples on the surface and each of these micro-dimples can serve either as a micro- hydrodynamic bearing in cases of full or mixed lubrication, a micro-reservoir for lubricant in cases of starved lubrication conditions, or a micro-trap for wear debris in either lubricated or dry sliding. The present paper reviews the current effort being made world wide on surface texturing in general and on laser surface texturing in particular. It presents the state of the art of LST and the potential of this technology in various lubricated applications like mechanical seals, piston rings and thrust bearings. The paper also describes some fundamental on going research around the world with LST.

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