Optimising lubricated friction coefficient by surface texturing

2013 ◽  
Vol 227 (11) ◽  
pp. 2610-2619 ◽  
Author(s):  
E de la Guerra Ochoa ◽  
J Echávarri Otero ◽  
E Chacón Tanarro ◽  
P Lafont Morgado ◽  
A Díaz Lantada ◽  
...  
Keyword(s):  
Experimental Data ◽  
Friction Coefficient ◽  
Chemical Etching ◽  
Surface Texturing ◽  
Point Contact ◽  
High Load ◽  
Operating Conditions ◽  
Textured Surface ◽  
Lubrication Regimes ◽  
Texture Size

Surface texturing has proved to be a very useful tool for expanding the behaviour under hydrodynamic and elastohydrodynamic regimes instead of mixed or boundary lubrication regimes, and therefore for reducing the friction coefficient under high-load low-speed conditions. This article presents the texturing of different copper test-samples using photolithography and chemical etching to measure the friction coefficient using a point contact machine. The effects of texture size, texturing density, the initial roughness of the samples and the operating conditions have all been studied. Some combinations of texturing density and texture size achieve up to 30% reduction in the friction coefficient. Taking into account experimental data, artificial neural networks are used as a tool for both predicting and optimising the friction coefficient on the textured surface for any given operating condition.

scholarly journals Surface Texturing Technique Based on Ultrasonic Turning for Improving Tribological Properties

2022 ◽  
Vol 16 (1) ◽  
pp. 78-86
Author(s):  
Keisuke Hara ◽  
Toshihiro Fukuda ◽  
Kyosuke Taguchi ◽  
Hiromi Isobe ◽  
◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Radial Direction ◽  
Principal Direction ◽  
Surface Texturing ◽  
Target Surface ◽  
Textured Surface ◽  
Rotation Direction ◽  
Lubrication Performance ◽  
Efficiency Performance

Tribological properties such as lubrication, friction, and wear resistance greatly affect machine operation efficiency, performance, and service life. Surface texturing methods such as scraping can be used to improve these properties. Scraping creates many small depressions on the target surface. These depressions, which are evenly distributed, function as oil holes and thus improve lubrication performance. This paper describes a surface texturing technique based on ultrasonic vibration-assisted turning (UVAT) that simultaneously improves tribological properties and machinability. In UVAT, the cutting tool is oscillated mainly in the principal direction. Vibration in the radial direction, which is induced by Poisson deformation, periodically digs up or pushes the workpiece surface in the radial direction, creating a textured surface. A surface subjected to UVAT has periodic depressions along the workpiece rotation direction. The texturing rate of UVAT is up to 6700 mm2/min, which is higher than that of manual scraping. To evaluate the tribological performance of a surface textured by UVAT, the friction coefficient between a stainless steel pin and the surface was measured under oil dipping conditions. The results of friction experiments show that the friction coefficient of the UVAT-treated surface and its fluctuation were lower than those of a conventional turned surface. The UVAT-treated surface had stable friction properties.

scholarly journals Corrosion Wear Performance of Pure Titanium Laser Texturing Surface by Nitrogen Ion Implantation

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 990 ◽  
Author(s):  
Lin Cao ◽  
Yun Chen ◽  
Jie Cui ◽  
Wei Li ◽  
Zhidan Lin ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Ion Implantation ◽  
Surface Texturing ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Artificial Joints ◽  
Nitrogen Ion Implantation ◽  
Nitrogen Ion

The poor tribological performances of titanium have significantly limited its applications in the field of artificial joints. In order to solve problems regarding the wear and corrosion of artificial joints in the body, we fabricated the composite materials utilizing the combination of laser surface texturing and nitrogen ion implantation technology, and investigated the effect of laser surface texturing, nitrogen ion implantation, and different dimple area densities on tribological performance. The results show that the textured surface could reduce the friction coefficient and improve the wear resistance, and the optimum dimple density was found to be 25%. After N ion implantation, the wear resistance of the textured sample was further improved, due to the formation of the nitride layer. Moreover, as shown by the electrochemical test results, the corrosion resistance was enhanced significantly. The friction coefficient decreased the most, and the wear resistance increased by 405% with the lowest wear rate of 0.37 × 10−3 mm3/N·m. However, the specimen with a dimple density of 60% had the worst wear resistance. The results of the study provide a basis for the development and application of artificial joint materials.

scholarly journals A Pocket-Textured Surface for Improving the Tribological Properties of Point Contact under Starved Lubrication

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1789
Author(s):  
Wei Wang ◽  
Wenhan Zhao ◽  
Yang Liu ◽  
Hui Zhang ◽  
Meng Hua ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Equivalent Stress ◽  
Reduction Rate ◽  
Point Contact ◽  
Operating Conditions ◽  
Experimental Results ◽  
Hertzian Contact ◽  
Textured Surface ◽  
Oil Storage ◽  
Starved Lubrication

This paper reports a novel pocket-textured surface for improving the tribological properties of point contact under starved lubrication by possibly storing and releasing oil, and homogenizing the surface contact pressure. The ball-on-disk experimental results confirmed the coefficient of friction (COF) and wear reduction effect of such pocket-texturing. The maximum reduction rate was 40% compared with a flat surface under the same operating conditions. Analyses on experimental results attributed the oil storage effect and enhanced the secondary lubrication effect within the starved lubrication state, to become the main mechanism. In addition, the plate elasticity and the Hertzian contact principles were employed to estimate the pressure and the load acting on the surface. The experimental results and numerical analysis substantiated the design of pocket-textured surface, making it likely to enlarge about 50% of contact surface and to reduce 90% of equivalent stress in comparison to those of conventional surfaces.

The Effect of Triangle-Shaped Surface Textures on the Performance of the Lubricated Point-Contacts

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Wen-zhong Wang ◽  
Zhixiang Huang ◽  
Dian Shen ◽  
Lingjia Kong ◽  
Shanshan Li
Keyword(s):  
Friction Coefficient ◽  
Electrical Contact ◽  
Tribological Performance ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Point Contacts ◽  
Electrical Contact Resistance ◽  
Coverage Ratio ◽  
Lubrication Regimes ◽  
Ratio Size

It has been recognized that purposefully designed surface texturing can contribute to the improvement of tribological performance of elements and friction reduction. However, its optimal parameters may depend on the operating conditions. This paper investigated the effect of a triangle-shaped dimples array on the tribological performance of the lubricated point-contacts under different lubrication regimes, based on the rotational sliding experiment of a patterned steel disk against smooth steel balls. The dimples arrays were produced by laser process and characterized by the 3D profilometer. A series of tests were conducted with different dimple parameters including depth, coverage ratio, size, and direction. Stribecklike curves were obtained to depict the transition of lubrication regimes, and the electrical contact resistance was utilized to qualitatively characterize the lubrication status. The test results showed that the dimples arrays with different sizes, depths and coverage ratios had a distinct effect on the friction behaviors. Compared with the nontextured surfaces, when the dimple depth decreased from 30μm to zero with fixed coverage ratio and size, the friction coefficient firstly decreased, and then increased. The friction coefficient finally approached that of the nontextured surface, during which the lowest value appeared at the dimple depth of approximately 10∼15μm. The coverage ratio of texture showed the similar effect on the friction coefficient. Usually, the coverage ratio of approximately 10% resulted in the lowest friction coefficient. The dimple size and direction also had obvious effects on the friction coefficient. Thus, it can be concluded that there exists a set of optimal values for the dimple depth, coverage ratio, size, and direction to realize the friction reduction.

scholarly journals A Design of Partial Textured Surface on Gear Washers for Reducing Friction and Wear under Low Speed and Heavy Load Conditions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4666
Author(s):  
Yang Liu ◽  
Hui Zhang ◽  
Guangneng Dong
Keyword(s):  
Friction Coefficient ◽  
Friction And Wear ◽  
Surface Texturing ◽  
Experimental Tests ◽  
Stribeck Curve ◽  
Textured Surface ◽  
Heavy Load ◽  
Low Speed ◽  
Sector Angle ◽  
Load Conditions

This paper presents the effort to reduce friction and wear of gear washers under low-speed and heavy-load conditions by designing the arrangement of surface textures. The influence of distributional parameters of textures on load-bearing capacity and friction coefficient of gear washers are studied numerically to obtain a preferable surface texturing design. Then, experimental tests were carried out to plot the Stribeck curves of the obtained texture arrangement compared with bare surface and another unoptimizable texture distribution arrangement to facilitate the verification of the simulation results. Theoretical predictions illustrate that the annular gear washers with partial surface texturing provide lower friction coefficients than bare washers. Textures having a sector angle of 20°, a coverage angle of 12°, a circumferential number of 8, and a radial number of 6 are selected as the final optimal surface texture distribution design. Experimental results confirm that the obtained texture arrangement moves the Stribeck curve towards the lower left, indicating thickening of oil film thickness and reduction in friction coefficient. In addition, the weight loss caused by wear is also reduced by the optimized texture design.

The influence of surface texturing on the transition of the lubrication regimes between a piston ring and a cylinder liner

2016 ◽  
Vol 18 (8) ◽  
pp. 785-796 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Di Zhang
Keyword(s):  
Piston Ring ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Mixed Lubrication ◽  
Textured Surface ◽  
Asperity Contact ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Stribeck Curves

This article employs a mixed lubrication model to investigate the performance of the textured surface. The Jakobsson–Floberg–Olsson model is used to obtain the hydrodynamic support of the textured conjunction, while the calculation of the asperity contact load is based on the load-sharing concept. Based on the simulated Stribeck curves of the smooth surface and the textured surface, comparisons are conducted to study the effect of texturing under different lubrication regimes. It appears that the transition of lubrication regimes is influenced by the texturing parameters and the convergence degrees of conjunction. The presence of textures delays the appearance of the mixed lubrication regime and the boundary lubrication regime.

On the Behavior of Friction in Lubricated Point Contact With Provision for Surface Roughness

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
H. Sojoudi ◽  
M. M. Khonsari
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Numerical Solutions ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Type Curve ◽  
Lift Off

This paper presents a simple approach to predict the behavior of friction coefficient in the sliding lubricated point contact. Based on the load-sharing concept, the total applied load is supported by the combination of hydrodynamic film and asperity contact. The asperity contact load is determined in terms of maximum Hertzian pressure in the point contact while the fluid hydrodynamic pressure is calculated through adapting the available numerical solutions of elastohydrodynamic lubrication (EHL) film thickness formula for smooth surfaces. The simulations presented cover the entire lubrication regime including full-film EHL, mixed-lubrication, and boundary-lubrication. The results of friction, when plotted as a function of the sum velocity, result in the familiar Stribeck-type curve. The simulations are verified by comparing the results with published experimental data. A parametric study is conducted to investigate the influence of operating condition on the behavior of friction coefficient. A series of simulations is performed under various operating conditions to explore the behavior of lift-off speed. An equation is proposed to predict the lift-off speed in sliding lubricated point contact, which takes into account the surface roughness.

Elastic Behavior of the Plain Journal Bearing Coated With a Textured Surface and a Non-Textured Surface

2020 ◽  
Vol 8 (1) ◽  
pp. 55-77
Author(s):  
Mehala Kadda ◽  
Bendaoud Nadia
Keyword(s):  
Journal Bearing ◽  
Surface Effect ◽  
Rotational Velocity ◽  
Surface Texturing ◽  
Pressure Profile ◽  
Operating Conditions ◽  
Elastic Behavior ◽  
Elastic Behaviour ◽  
Shear Stresses ◽  
Textured Surface

Surface texturing technology has been newly explored technique in the tribological domain, and this method is carried out to improve the displacement and performance of the Babbitt plain journal bearing with a textured surface. The numerical analysis is carried out to study the textured surface effect on the elastic behaviour of the journal bearing. First, the bearing is tested without texture; second, it is examined completely textured, by varying the operating parameters of the bearing. The performance is observed in a pressure profile, displacement, and shear stress, generated for each combination of radial loads, and rotational velocity of the shaft. The numerical modelling is used by solving the displacement equations by the finite element method to analyses bearing displacement for severe operating conditions. The results show that the elastic deformations for textured bearing, are important and preponderant for higher rotational speeds, and shear stresses are important for higher hydrodynamic pressures.

Tribological Behavior of Oil-Lubricated Laser Textured Surfaces in Conformal Flat and Point Contacts

2005 ◽  
Author(s):  
Andriy Kovalchenko ◽  
Oyelayo Ajayi ◽  
Ali Erdemir ◽  
George Fenske ◽  
Izhak Etsion
Keyword(s):  
Wear Behavior ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Operating Conditions ◽  
Laser Surface Texturing ◽  
Stribeck Curve ◽  
Textured Surfaces ◽  
Lubrication Regimes ◽  
Pin On Disc ◽  
Conformal Contact

The effects of laser surface texturing (LST), which involves the creation of an array of microdimples on the surface with laser, on friction and wear behavior of oil-lubricated steel surfaces were evaluated. Tests were conducted in unidirectional sliding in both the conformal and non-conformal contact configurations with a pin-on-disc test rig using fully formulated synthetic oil lubricant. In conformal contact, LST expanded the operating conditions for mixed and hydrodynamic lubrication regimes to higher loads and slower speeds i.e. the Stribeck curve was shifted to the left. LST was also observed to reduce the magnitude of friction coefficients in the boundary regime. For the non-conformal contact configuration, LST produced more wear on the rubbing counterface compared to untreated surfaces. This also accelerated the run-in process in the tests with LST treated surfaces.

The Influence of the Operating Conditions on the Lubrication Regimes of Ball Screws

2013 ◽  
Vol 371 ◽  
pp. 581-585
Author(s):  
George Constantin Puiu ◽  
Vasile Puiu
Keyword(s):  
Numerical Solutions ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Ball Screw ◽  
Minimum Thickness ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Ball Screw Drive ◽  
Ellipticity Parameter

In point contact related applications (ball bearings, ball-screws) the minimum and the central film thickness of lubricant have a particular importance. The literature presents various numerical solutions to determine these parameters in the case of elliptical contacts [1-4]. Most of them refer to the fully developed elastohydrodynamic lubrication regime (EHD). Hamrock [5] proposes four different lubrication regimes depending on the size and importance of two physical phenomena that occur in contact: elastic deformation of the bodies in contact under a given load and lubricant viscosity variation of contact pressure. These four lubrication regimes have specific relations for calculating the two parameters. Also, Hamrock [5] develops a methodology for identifying the lubrication regime in a point contact, depending on three dimensionless parameters: the ellipticity parameter; the viscosity parameter; the elasticity parameter. According to the viscosity and elasticity parameters, for each value of the ellipticity parameter a map of lubrication regimes can be built. These parameters are influenced by the materials and geometry of the bodies in contact and operating conditions. By using the methodology [5] a comprehensive analysis regarding the lubrication regimes in contacts between balls and races of a ball screw drive has been done. Thus, a complex program to draw lubrication regimes maps, starting from an imposed geometry and from given operating conditions, has been developed. The developed maps have revealed the different lubrication regimes that can occur in contacts between the balls and races on the screw and nut. It was also revealed, for a given type of screw, which are the load and speed limits that allow transition from an isoviscous-rigid regime of lubrication (IVR) / hydrodynamic (HD) to an elastohydrodynamic lubrication regime (EHD). For each lubrication regime, relations were used for calculating the appropriate minimum thickness of lubricant film, hence the major importance of accurate knowledge of lubrication regime.

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