Texture Area Density Research Articles

Wear Characteristics of Textured Floating Oil Seal Surfaces: A Simulation and Experimental Study

This study aimed to analyze the effects of surface texture on the wear amount of floating oil seals and how these effects are related to the texture parameters. To achieve this, a finite element model was constructed to simulate the frictional behavior of seal discs under both textured and non-textured conditions. The study focused on a specific set of texture parameters. The texture depth was held constant, while the area density and diameter of the textures were varied. Three different area densities were considered: 10%, 20%, and 30%. Similarly, three different texture diameters were included in the study: 100, 200, and 300 μm. For each combination of area density and diameter, three different texture depths were evaluated: 50, 100, and 150 μm. The results show that compared with the non-texture, the wear loss of the texture is significantly reduced, and the wear loss is reduced by 56.8%. As the texture depth increases, the corresponding increase in wear remains relatively small. In contrast, increasing the texture diameter and area density leads to a more significant increase in wear, indicating that these two parameters have a more significant effect on the wear behavior of the seal. Under the condition of dry friction, the average friction coefficient analysis shows that the texture area density is 30%, the texture diameter is 200 μm, and the minimum value is about 0.602. Under the lubrication condition, the lowest average friction coefficient is about 0.147, the texture area density is 20%, and the texture diameter is 300 μm.

Effect of micro-surface-texturing on the friction between cam/tappet interface of a commercial vehicle engine

Reduced wear and friction are directly related to longer component service lives and increased energy efficiency. The mechanisms used to achieve this goal in mechanical systems include the study of lubricant chemistry, surface coating, and surface modification. Significant research has been conducted on friction reduction of valve trains of internal combustion engines using surface modifications such as coatings and surface texturing. Here, an experimental approach has been adopted to investigate the effect of micro surface texturing on Thermo-Elastohydrodynamically Lubricated cam/tappet contact in a direct-acting valve train. A commercial vehicle valve train has been instrumented to study the effect of varying surface texture area density on friction under realistic engine operating conditions. Fiber laser surface texturing has been used to microtexture three samples of tappet shims with texture densities of 5%, 8%, and 10%. The tests have been run at four engine speeds—300, 500, 700, and 900 RPM—and three temperatures—30 °C, 60 °C, and 90 °C. The experimental results show a significant friction reduction of up to 18.33% for textured shims at the temperature of 90 °C. The friction reduction performance of the 8% textured shim has been optimum for all RPMs at the higher temperatures.

Evaluation of tribological performance in contact pairs by implementing the biomimetic surface textures with lubricant flow using CFD techniques

PurposeThis paper aims to investigate the tribological benefits of a biomimetic teardrop surface texture inspired by snakeskin compared to conventional surface textures with the help of geometrical and flow parameters using computational fluid dynamics techniques.Design/methodology/approachThe lubricant is assumed to be Newtonian, and the flow is laminar with constant viscosity and isothermal property. The governing equations, continuity and Navier–Stokes equation, are discretised by the finite volume method, and cavitation modelling is included. The discretisation for the momentum equations is carried out using the second-order difference method for the SIMPLEC algorithm of pressure–velocity coupling.FindingsThe results indicate that biomimetic teardrop surface texturing performs better than conventional shapes surface textures in improving tribological performance. Furthermore, the parallel texture orientation along with the flow generates a high-pressure distribution relative to other orientations. Surface texture area density also highly influences the load-carrying capacity, which is optimum at 29%. Zigzag pattern arrangement performs better compared to linear pattern arrangement of texturing.Originality/valueThe paper proposes that this unique biomimetic teardrop shape can give better tribological performance than conventional shapes.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0053/

Effect of surface micro-grooved textures in suppressing stick-slip vibration in high-speed train brake systems

Efficient strategies for controlling low-frequency stick-slip vibrations during high-speed train braking are crucial for safe operations. This study applies surface texturing with micro-grooved textures on friction blocks and conducts tests to validate their suppression effect on stick-slip vibrations. Vibration analysis indicates that micro-grooved textures effectively mitigate system vibration intensity, decreasing amplitude and stick time as texture area density increases within a certain range. Further analysis reveals that these textures improve the contact behavior at the disc-block interface, reducing eccentric wear angle and contact plateau size. Changes in contact characteristics result in variations in the vibration response, thereby suppressing stick-slip vibrations. The research establishes a solid theoretical foundation and offers practical recommendations for reducing stick-slip vibrations in high-speed train brake systems.

Insight Into Surface Texture-Induced Dual Effects on Friction of WC-Co Dry Sliding Against Continuous Carbon Fiber-Reinforced Thermoplastic and Thermosetting Composites

To elucidate both positive and negative surface texture-induced effects on friction under dry conditions and to reveal polymer transfer properties on inert tungsten carbide-cobalt (WC-Co), tribological properties of line-, sawtooth-, dimple-, and triangle-textured WC-Co discs dry sliding against continuous carbon fiber-reinforced thermoplastic poly-ether-ether-ketone and thermosetting epoxy (CCF-PEEK and CCF-epoxy) pins were investigated in ambient atmosphere. Texture edges yielded a microcutting effect, resulting in frictional increase and material removal from the pin. Higher texture area density usually implied a stronger microcutting effect. Accumulated CCF-PEEK wear chips developed into a self-lubricious tribofilm that offset frictional increase, but CCF-epoxy wear chips could not evolve into tribofilms and the resultant abrasive wear increased friction. Reservoir effects of texture and reduction in real contact area were beneficial for frictional reduction, whereas they were insignificant compared with the microcutting effect. The findings suggest that a frictional counterpart with a self-lubricious component is crucial for the coefficient of friction (COF) reduction in the textured tribosystem under dry conditions. Surface texture does not necessary lead to frictional reduction, and further research should systematically analyze texture-induced dual effects on tribological performance.

Tribological behavior of nanosecond laser-textured leaded Ni-rich NiTi shape mamory alloy fabricated by laser powder bed fusion

NiTi alloys with pseudoelastic properties at room temperature were fabricated by laser powder bed fusion (LPBF) processes. The tribological behavior of nanosecond laser-textured leaded LPBF-fabricated NiTi alloys under dry conditions was investigated. The results showed that the reduction in friction coefficient were derived from the fabrication of the bionic tree frog toe end structure formed by nanosecond laser compared with the un-textured surface. The synergetic effects of pseudoelastic properties of LPBF-fabricated NiTi alloys and nanosecond laser surface texturing (LST) on the tribological performances were investigated in detail. The maximum rate of decrease of friction coefficient was 82% when the textured area density was 54.7% and then the mechanism of wear reduction was further studied. Experimental results indicated that the formation of tribo-oxide layers was critical for increasing friction reduction and wear resistance. The implementation of biomimetic hexagonal micro-textures on the surface of LPBF-fabricated NiTi alloy exhibited excellent wear resistance.

Anti-friction mechanism of sinusoidal texture with various intervals: The synergistic effect of dynamic pressure and tribofilm

Reasonable texture intervals can effectively generate a local dynamic pressure effect and promote the tribofilm formation. A friction experiment combined with simulation analysis is employed to investigate the effect mechanism of sinusoidal texture intervals on surface friction properties. The synergistic antifriction mechanism between the hydrodynamic pressure effect of texture and the tribofilm is discussed. The results display that synergistic texture lubrication has a beneficial effect on improving tribological properties. The surface with a textured area density of 25% displays the optimal tribological properties. Moreover, friction reduction mechanism under different working conditions is discussed. Higher sliding speed is beneficial to anti-friction property by promoting dynamic pressure lubrication, while larger load mainly facilitates the formation of surface friction film to reduce friction.

Effect of volcano-like textured coated tools on machining of Ti6Al4V: an experimental and simulative investigation

The present study was to reduce the adhesion and wear that happened on the rake face during machining of Ti6Al4V alloys by employing volcano-like textured coated tools. A combination of experimental and simulative investigation was adopted. DEFORM-3D software with updated Lagrangian formulation was used for numerical simulation, and the thermo-mechanical analysis was performed using Johnson–Cook material model to predict the cutting forces, cutting temperature, chip morphology, and tool wear. In cutting experiments, volcano-like textures with different area densities (10%, 20%, 30%) were fabricated by fiber laser on the rake face of cemented carbide tools close to the main cutting edge. Then, these textured tools were deposited with CrAlN coating through cathodic vacuum arc ion plating technique. Experiments in cutting Ti6Al4V alloys were carried out with the textured coated tools and non-textured coated tool under dry and wet cutting conditions. Then, cutting forces, chip morphology, and tool wear were investigated. The results showed that textured coated tools were superior to the conventional tool. Especially in wet cutting, the main cutting force and radial force of the coated tool with texture area density of 20% (VCT2) were reduced by 11.6% and 21.25%, respectively. Surface morphology of VCT2 tool had lower workpiece adhesion on the rake face. Therefore, VCT2 tool showed a better cutting performance. Finally, the mechanisms of textured coated tools under wet cutting conditions were proposed.

Experimental Study on Texture Coupling Mechanism and Antifriction Performance of Piston Rod Seal Pair.

The effect of the coupling texture on the friction and wear of a piston rod-rubber seal pair under lubricating conditions is studied in this paper. Crescentiform textures with different area densities were fabricated on high carbon chromium bearing steel (GCr15) and ethylene propylene diene monomer (EPDM) materials by using a laser marking machine. We compare and analyze the effects of untextured, single-textured, and coupling-textured surfaces on the friction characteristics of the piston rod-rubber seal pair by conducting tests on the reciprocating module of the UMT-2 friction and wear testing machine. The results showed that the coupling-textured surface had the lowest coefficient of friction and wear compared to the untextured and single-textured surfaces. When the normal load was 10 N under the optimal coupling texture area density (6.4%), the friction and wear of the sealing pair decreased the most. Compared with the untextured surface, the friction coefficient was reduced by 27.9% and the wear amount was reduced by 30.0%; compared with the single-textured surface, the friction coefficient was reduced by 18.9%, and the wear amount was reduced by 23.8%. The coupling effect generated by the coupling texture effectively enhanced the formation and stabilization of the oil lubricant film and effectively captured wear debris, preventing it from continuously scratching the surface and reducing wear and roughness.

Effects of Laser Surface Texturing and Lubrication on the Vibrational and Tribological Performance of Sliding Contact

Various textures are fabricated by a picosecond laser machine on the surfaces of circular stainless steel specimens. Vibrational and tribological effects of laser surface textures are investigated by means of a tribometer and a data acquisition and signal processing (DASP) system. Experimental results show that surface textures can reduce the coefficients of friction (COFs), enhance the wear resistance, and improve the dynamical performance of frictional surfaces. In this study, the surface with micro circular dimples in diameter of 150 μm or textured area density of 25% has the best tribological and dynamical performance. Compared with the non-textured surface, the surface with circular dimples in diameter of 150 μm and 15% textured area density has 27% reduction of COFs, 95% reduction of frictional vibrations, and 66% reduction of frictional noise. The frictional vibrations and noise in the sliding contacts can be effectively reduced by adding graphene to the lubrication oil, and the surface textures enhance the frictional noise reduction performance of lubrication.

Experimental characterization of friction and wear behavior of textured Titanium alloy (Ti-6Al-4V) for enhanced tribological performance

Laser surface texturing (LST) is an effective surface engineering technique that can improve the efficiency and reliability of a tribosystem. In this study, surface textures with combined dimple patterns were prepared on a Ti-6Al-4V alloy surface using a Nd:YAG pulsed laser. Sliding dry and MoS2 solid-lubricated experiments were performed to assess the tribological characteristics of these specimens using a ball-on-disk mode. An L9 (34) orthogonal array table was used to prepare an experimental plan, which contained three parameters: the sliding speed, applied load, and the area density of dimple on the friction properties. The results show that the MoS2-added textured surface effectively decreased the coefficient of friction and reduced adhesion wear compared to an untextured surface. Analysis of variance (ANOVA) suggested that the texture area density has a major effect on the friction coefficient at a confidence level of 99%, followed by the applied load and sliding speed. Scanning electron microscopy (SEM) revealed that the wear mechanisms were adhesive and abrasive wear, and a transfer layer from the Ti-6Al-4V alloy was obtained on the counterpart ceramic ball. In conclusion, a higher texture area density is advantageous to increase the friction and wear performance of the Ti-6Al-4V alloy surface.

Microstructured ceramic and metallic implant surfaces and their impact on the viscosity of a synovia fluid substitute

Abstract This study evaluates the effect of ring-shaped microstructures on the rheological properties of a synovial fluid substitute. Two different materials that are frequently used in endoprostheses have been chosen in order to study the lubricating effect of femtosecond-laser microstructured implant surfaces by measuring the apparent dynamic viscosity of the lubrication fluid. The two different materials are the ceramic Al2O3 and the metal alloy CoCrMo. The results show that an increase in the viscosity of the synovia fluid substitute can be achieved by specific microstructuring. An increase of viscosity of up to 40% compared to an unstructured reference was observed with ring-shaped microstructures with a diameter of 100 μm, a texture area density of 2.5 % and an aspect ratio of 0.66. The measurements have also shown that the ceramic material resulted in slightly higher viscosity values, compared to the metal alloy which can explained by dimensional deviations of the microstructures caused by the laser microstructuring.

Experimental and numerical studies of positive texture effect on friction reduction of sliding contact under mixed lubrication

Textured surfaces have been remarkable in improving the frictional performance of sliding contacts, particularly at instances such as boundary or mixed lubrication regimes. This article reports the results of an experimental and numerical study carried out by introducing surface textures in the form of protrusions to investigate its effects on friction performance under a mixed lubrication regime. The surface textures produced by the chemical etching process are tested on the pin on disc test rig by varying area density and height of the texture. In numerical simulation, the modified Reynolds equation (Patir–Cheng flow model) and asperity contact model (Greenwood–Tripp model) are solved for hydrodynamic and asperity pressures, respectively. The results indicate that the experimental measurements are qualitatively in good agreement with numerical predictions. Furthermore, the simulations are performed for different texture shapes by varying texture area density, height, and sliding velocity. The results depict that a maximum friction reduction of 87% with elliptical textures compared to the un-textured case.

Role of dimple textured surface on tribological properties of Ti/Al-codoped diamond-like carbon films

Surface textured diamond-like carbon (DLC) films with Ti and Al dopants (Ti/Al-DLC) were fabricated by a two-step process, including the photo- and anisotropic-etching of silicon substrate for micro-dimple texturing and the hybrid ion beam deposition for Ti/Al-DLC film. The role of different dimple-textured area densities (0~40%) on the tribological behavior of Ti/Al-DLC film was mainly investigated; the corresponding surface topographies and atomic bond structure of intrinsic films, wear tracks, and wear scars were evaluated systematically to disclose the fundamental mechanism. Results revealed that the dimple-textured structure on film surface had a significant effect on the tribological property of Ti/Al-DLC film rather than the microstructure and mechanical performances. Compared to the untextured Ti/Al-DLC film, the case with dimple-textured area density of 5% exhibited the reduction in coefficient of friction by 17.8% and in wear rate by 44.5%, respectively. This attributed to the synergistic effect of the tribo-induced graphitization and the capturing efficiency of micro-dimples to the wear particles. However, with further increasing the textured area density from 5% to 40%, the locally high contact pressure resulted in the lack of graphitization and the increase of roughness at the friction interface, which prohibited the sliding of friction interface following the weakened tribological property.

Surface micro-texturing design for improving tribological behaviour of graphene oxide thin films

Effect of micro-scale surface texture with different densities on wear resistance of graphene oxide (GO) films was studied using a revolving ball-on-flat tribometer in humid environments. The micro-scale surface texture was produced by depositing about 363 nm thick GO films onto silicon substrates pre-textured with the patterns of dimples. The goal of the surface patterning was to improve the wear resistance of the GO films so that to extend lubricating life. The experimental results demonstrated excellent ability of the textured films to improve wear resistance of the silicon substrate. Furthermore, the GO films with an appropriate dimple area density (4%) were effective in reducing the friction coefficient (0.024) and exhibiting outstanding wear resistance owing to the entrapment of wear particles in the dimples. Finally, a simple friction mechanism model was drawn to explain the frictional properties of the different textured area density GO films.

Feasibility study of micro-groove cross hatched surface texturing on Ti6Al4V for improved biotribological performance in metal-on-polymer hip implant

ABSTRACTThis study investigates the feasibility of micro-groove cross hatched textures on Ti6Al4V articulating with Ultra High Molecular Weight Polyethylene (UHMWPE) for a Metal-on-Polymer (MoP) hip implant to improve biotribological performance. Keeping 10% texture area density with 10 µm groove depth, micro-grooves ranging from 50 µm to 250 µm in width are fabricated by Laser Surface Texturing (LST) technique over polished Ti6Al4V samples. Tribological performance of UHMWPE pins against Ti6Al4V plate is tested for the different loading conditions under biological environment using linear reciprocating tribometer. Worn out pin samples are examined for their surface interactions, wear mechanism, and morphology using Scanning Electron Microscope (SEM). The result shows that the selection of micro-groove texture width is critical for obtaining the maximum tribological benefits. Texture width equal or more than the Hertzian contact is reducing friction and wear up to 14% and 57%, respectively, at the tribo-pair and similarly decrease in pitch also enhances tribological performance.

Tribological and vibrational effects of laser surface texturing on steel-steel sliding contact

Laser surface texturing (LST) not only can significantly improve the tribological performance of various tribological contacts, but also can significantly reduce the frictional noise and vibrations generated from sliding contacts. In order to investigate the tribological effect of laser surface texturing, sixteen stainless steel specimens with different surface textures, and different textured area ratios are designed and processed on the surfaces of specimens by means of laser surface texturing technique. Four different operation speeds are carried out using a standard friction and wear testing machine (UMT-TriboLab) under rich oil lubrication condition. The experimental results show that the diameter of surface circular dimple had the most significant effect on the tribological properties of steel-steel sliding contacts, followed by texture depth, texture area density, and sliding speed. The effect of laser surface texturing on the frictional noise and vibration generated from steel-steel in dry sliding contacts is also investigated. Laser surface texture has significant effect on the reduction of noise generated from steel-steel dry sliding contacts in both time and frequency domains. The conclusion is that laser surface texturing has significant effects on the tribological, vibrational, and other physical performance of functional surfaces. To get the best tribological and vibrational performance, the functional surface texture should be optimized considering the coupled effects of surface texture, lubrication, and contact condition.

3D finite element investigations on textured tools with different geometrical shapes for dry machining of titanium alloys

Effect of texture shapes and texture area density for machining applications is a potential topic of investigation. However, it is difficult to fabricate perfect dimensions by using available micromachining techniques. Finite element simulations can be an effective way to understand the effect of texture density, texture depth and different geometric shapes on machining performances. The present study deals with the 3D finite element investigations of different texture shapes to predict cutting forces during machining of titanium alloy under dry condition. Available Johnson–Cook material model parameters have been investigated to select suitable parameters for 3D finite element studies in titanium machining. Different geometrical shapes (circular, square, triangular and elliptical shape) with the constant area are modeled at the rake face of cutting tools to incorporate textures. The effects of texture shape are studied for variation in cutting forces with different texture area density and depth. The effect of texture shape is found to be less influential for dry cutting however area density is found to have the most dominant effect on cutting forces. Further, the linear regression model for tool–chip contact length has been developed for the textured and untextured tools under different machining parameters. The developed model has incorporated the chip serration effect (serration peak and valley heights) in the contact length model. The contact length model for the textured tool has been developed for the first time, and the contact length variation has been compared with the plain tools. The results reveal that textured tools have limited applicability for dry cutting of titanium alloys. Further, the associated mechanism of contact area reduction for textured tools has been found to be not applicable at increased feed and cutting speeds due to chip embedment into textured space.

Tribological effects of laser surface texturing and residual stress

PurposeThe purpose of this paper is to investigate the tribological effects of laser surface texturing (LST) and residual stress on functional surfaces.Design/methodology/approachThree 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.FindingsTest 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/valueThe 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.

Tribological Performance of MoS2-Filled Microtextured Cutting Tools During Dry Sliding Test

Strict environmental laws enforced on manufacturing industries resulted in the development of alternative techniques to reduce or eliminate the use of lubricants during sliding contact as well as machining. Tribology plays a very important role for tool life in machining. To improve the life of cutting tool, cutting fluids are used. However, cutting fluids only penetrate into the region of sliding contact. In this study, the effect of surface texturing on plasma nitrided high-speed steel (HSS) pins during dry sliding test is investigated for understanding the performance of textured HSS tools in machining. Microtextures were fabricated using Vickers hardness tester on the surface of HSS pins. Tribological tests of molybdenum disulphide (MoS2) filled as well as unfilled microtextured HSS with area density of textures varying from 2% to 14% were performed with the aid of pin-on-disk tribometer against an abrasive sheet. Friction and wear performance were assessed in terms of the pin surface temperature, coefficient of friction (COF), wear, weight loss of the pin and wear rate. Worn-out test surfaces were observed under scanning electron microscope to understand the wear mechanism. The best results were obtained with MoS2-filled microtextures having 10% texture area density. Tool–chip interface temperature, cutting force, feed force, and centerline average (CLA) surface roughness were also assessed during machining test with 10% area density of textured cutting tools.