Influence Of Surface Texture Research Articles

Influence of Surface Texture on the Variation of Electrokinetic Streaming Potentials.

The electrokinetic streaming potential (Vs) obtained through electrolyte flow in a microchannel is shown to be related to the underlying surface pattern. Pillar, mesh, and groove patterns were studied for comparing the relative magnitudes of the Vs with air-/liquid-filled surfaces. A record value of the related figure of merit, in terms of the developed Vs per-unit applied pressure, of ∼0.127 mV/Pa, was observed in a mesh texture liquid-filled surface (LFS) impregnated with an electrolyte-immiscible oil. The study indicated that increasing the solid fraction of the pattern surface decreases the effective slip length while enhancing the overall channel ζ potential. Consequently, maximizing the obtained Vs implies a balancing of the slip with the surface potential, with plausibly more significance of the latter. The work has implications for higher-efficiency electrical voltage sources.

Analysis of the Influence of Textured Surfaces and Lubrication Conditions on the Tribological Performance between the Compression Ring and Cylinder Liner

The objective of the present investigation is to analyze the tribological performance between the union of the cylinder liner and the compression ring under the influence of surface texturing and different lubrication boundary conditions. The analysis is carried out by developing a numerical model, which involves hydrodynamic pressure, lubrication film thickness, textured surface, dynamic forces, and lubrication boundary conditions (starved lubrication and fully flooded lubrication). MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used to solve the equations developed. The results show that the application of a textured surface on the cylinder liner allows obtaining a reduction of 20% and 5% in the asperity contact force and in the total friction force. Additionally, the textured surface allows for a 4% increase in MOFT. In this way, it is possible to reduce the power loss. The implementation of a boundary condition of fully flooded lubrication produces an overestimation in the total friction force due to the greater prominence of the lubrication film. Implementing a textured surface in the ring profile is an alternative way to reduce power loss. The results show that this alternative allows an 8% reduction in power loss.

Influence of Surface Texture on the Performance of Hydrodynamic Journal Bearing Operating under Turbulent Regime

Influence of Surface Texture on the Performance of Hydrodynamic Journal Bearing Operating under Turbulent Regime

Study on the Influence of Surface Texture on the Dynamic Performance of Sliding Bearing

Rotor bearing system is an important part of mechanical equipment. The vibration of equipment caused by rotor system has become a more important problem in engineering. In this paper, the texture technology of the inner surface of the bearing is studied to explore the influence of the surface texture on the vibration reduction characteristics of the bearing. The results show that reasonable texture parameters and texture distribution can reduce the friction of the bearing and increase the end discharge. There is an optimal texture density and texture region. In this paper, a bearing test platform is set up to test and study the tiles with different surface texture. The test results show that the amplitude of the axis orbit of the sliding bearing with texture is significantly reduced, the principal stiffness and cross stiffness of the textured bearing are larger than those without texture, the damping is slightly larger under high speed and light load than that without texture, and the texture has obvious damping effect on the bearing shell.

Textured Polymer Surfaces Mimicking the Tactile Friction Between Wood and Skin

Polymer-based furniture with wood-like visual printing is widely used in domestic and office applications. Although polymers could fulfil the high quality requirements of strength and appearance, they cannot mimic the feel of wood during touch. In this study, polymers with textured surfaces were designed to mimic the tactile friction and naturalness of wood. The influence of a series of factors on tactile friction was assessed. Textured polypropylene surfaces showed a 14.8% reduction in friction, and were more similar to wood compared to un-textured rough polypropylene surface, indicating the significant influence of surface texture on tactile friction. The touch perception test further proved that polymer samples were perceived as more natural with a rough or textured surface than with a smooth surface. This study suggests that, with a detailed design of the surface texture parameter, it is possible to mimic the tactile friction and naturalness of wood by using textured polymers.

Bond between concrete and rigid foam in precast concrete sandwich construction

AbstractIn precast concrete sandwich construction mechanical connectors are used to transfer loads between the two concrete shells. Omitting these connectors seems economically interesting for realizing novel sandwich elements with lightweight facings made of textile‐reinforced concrete or other materials. Then, the adhesion between the isolating layer and the cover layers becomes the decisive parameter. In order to evaluate the basic influence of surface texture and type of concrete on the bond strength, an experimental study including different rigid foams and ordinary performance concrete (OPC) as well as ultra‐high performance concrete (UHPC) was carried out. The results of 120 tensile bond tests and 30 shear tests on concrete‐rigid foam composites show that technically relevant bond strengths can be achieved by pouring the concrete onto the rigid foam. For OPC, the tensile bond strength is 50% higher than the minimum value required for external thermal insulation composite systems without mechanical connectors. For UHPC significantly higher bond strengths are obtained, which can be attributed to a better micromechanical interlock. In some cases, the strength of the composite was limited by the strength of the foam. The results are valuable for identifying promising rigid foam‐concrete configurations.

Study on deformation behaviors of nanopillar textured AlN in nanoindentation using molecular dynamics

Although nanoscale textured surfaces are widely used in mechanical components to improve mechanical properties, how the texture-parameters such as the shape and density of the surface textures affect the contact deformation behaviors of AlN remains elusive. Therefore, the design of surface textures of AlN micro/nanoelectromechanical systems (MEMS/NEMS) is still challenging. To study the influence of surface textures on deformation behaviors of AlN at nanoscale, in this work we study the nanoindentation process of AlN textured surface using molecular dynamics simulations. The force and deformation behaviors in the nanoindentation process of AlN textured surface are thoroughly investigated. We find that the pop-in event in the indentation of AlN textured surface is mainly due to the phase transformation and amorphization of AlN, specifically caused by the nucleation of amorphous structure and the formation of the sixfold-coordinated B1-AlN. And the plastic deformation behaviors of textured AlN are associated with the phase transformation, amorphization and dislocation motion. It is also found that due to the existence of grooves in the textured surface, the vacant part can absorb some wear atoms. Therefore, the texture pattern has a beneficial effect on reducing the influence of surface deformation. The results demonstrate that the geometric parameters of the textures have great effect on the indentation load and deformation behaviors of AlN materials. The insights gained in this work can guide the design of AlN MEMS/NEMS with surface textures.

Influence of Surface Texture and Composition on Graphene Growth by Chemical Vapor Deposition on Cu–Ni Alloys for Field Emission Application

The present investigation is aimed to find a thread between various surface textures of polycrystalline Cu–Ni alloys, in cold-rolled and annealed conditions, and the nature of graphene, grown by the chemical vapor deposition (CVD) method, on these substrates. High-quality graphene grown on Cu–Ni alloys was transferred to various nanostructures, such as CuO nanorods and carbon nanotubes, for field emission application. In this work, Cu–Ni (100Cu–0Ni, 84.65Cu–15.35Ni, 72.6Cu–27.4Ni, and 63Cu–37Ni) alloy buttons were prepared by arc melting, and texture in the samples were engineered by cold rolling (plastic deformation) and annealing (recrystallization) processes. Study of surface texture by X-ray method demonstrates characteristically different deformation and recrystallization texture components, compared to conventional rolling and annealing textures. The evolution of texture has been explained based on the effects of surface friction, shear stress, and addition of Ni. Unusual appearance of {111} orientations, though less in volume, after annealing at 1000 °C, was observed in Cu–Ni alloys through the suppression of cube texture component. The underlying deformation and recrystallization mechanisms are explained through the changes in strain hardening, extended recovery, and continuous recrystallization effects. The effects of Ni content are correlated with the number of graphene layers, while an increase in the fraction of {111} orientations could be linked with defect density in graphene layers. Results of the present study will be motivating for selection of various polycrystalline Cu–Ni alloys, with different surface textures, for controlling quality of graphene, synthesized by the chemical vapor deposition method.

COMBINED PLASMA NITRIDING AND SURFACE TEXTURING FOR IMPROVING TRIBOLOGICAL PERFORMANCE OF 316 STAINLESS STEEL

Combined plasma nitriding and surface texturing approach were conducted on 316 stainless steel to enhance the tribological performance. Five different surfaces (316 substrates, plasma-nitrided 316, surface-textured 316, plasma-nitrided surface-textured 316, and surface-textured plasma-nitrided 316) were investigated. The tribological behaviors were studied using a ball-on-disk rotary tribometer against counterparts of Si3N4 balls in the air and under oil lubrication conditions. The results were analyzed from the aspects of friction coefficient, mass loss, and surface morphology about the tested specimens. The results presented that the frictional properties of the surface of plasma-nitrided surface-textured 316 were optimal under both friction conditions. Under dry friction conditions, the influence of plasma nitriding on mass loss was greater than that of surface texturing. Under oil lubrication conditions, the influence of surface texturing on mass loss was greater than that of plasma nitriding, and the processing sequence of surface texturing and plasma nitriding had little effect on the mass loss. The better wear resistance of plasma-nitrided surface-textured 316 resulted from the following aspects: first, the nitriding layer improved the surface hardness of the material. Secondly, the surface texture can capture the debris under dry friction conditions and provide continuous lubrication under oil lubrication condition.

Sensitivity of the Stribeck curve to the pin geometry of a pin-on-disc tribometer

A considerable number of surface texture investigations is based on pin-on-disc tribometers. This work shows that a crucial role in the reproducibility of the results, e.g. Stribeck curves, is played by the geometry of the pin surface. The investigation is based on an elastohydrodynamic model of a pin-on-disc tribometer which is validated with experimental data. Characteristic roughness and pin shapes are introduced in this model to evaluate the sensitivity of the Stribeck curve to these operating conditions. The obtained significant variations in the friction coefficient indicate that studies which aim at quantifying the influence of surface textures in the mixed lubrication regime need to provide information about the pin geometry in order to enable a meaningful comparison among literature data.

Wettability alteration of sandstone rock by surfactant stabilized nanoemulsion for enhanced oil recovery—A mechanistic study

Oil wettability of reservoir rock hinders the hydrocarbon recovery by conventional recovery techniques. This study aims to examine the potency of nanoemulsion systems (nanoemulsion and nanoemulsion + SiO2 nanoparticles) for enhanced oil recovery (EOR) application by thoroughly investigating their influence on wettability change for sandstone (quartz) rock. Nano-size (<100 nm) oil droplets formation in continuous aqueous phase through ultrasonication examined by dynamic light scattering (DLS) technique confirmed the formulation of nanoemulsion. Accumulation of silica (SiO2) nanoparticles (NPs) at oil-aqueous interface further strengthens the electrostatic repulsion, reducing the oil droplet size with improved nanoemulsion stability. Fourier-transform infrared spectroscopy (FTIR) and Zeta (ʐ) potential analysis quantified the oil-wet state of quartz rock. Contact angle assessed by sessile drop method on crude oil aged quartz rock over wide temperature range (303 K – 343 K) decreased significantly making surface favorably water-wet by nanoemulsion systems. Roughness parameters determination by atomic force microscopy (AFM) revealed the influence of surface texture on wettability transformation. Oil-wet state to enriched water-wet condition of quartz rock was visually analyzed by microscopic imaging. The effectiveness of nanoemulsion and nanoemulsion + SiO2 systems for EOR by sand-pack flooding experiment gained additional recovery of 26.40 % and 34.94 % respectively over water flooding.

Influence of dimple location and depth on the performance characteristics of the hydrodynamic journal bearing system

This paper concerns with theoretical investigation to predict the influence of cylindrical textures on the static and dynamic performance characteristics of hydrodynamic journal bearing system and the performance is compared with smooth surface bearing. The Reynolds equation governing the fluid–film between the journal and the bearing surface is solved numerically with the assistance of finite element method and the performance characteristics are evaluated as a function of eccentricity ratio, dimple depth and its location. In this study, four journal bearing configurations viz: smooth (non-textured), full-textured, partially textured-I, and partially textured-II are considered for the evaluation of theoretical results. The simulated results indicate that the influence of surface textures is more significant when the textures were created in upstream zone of 126°–286° and dimple aspect ratio nearly 1.0.

Influence of surface texturing on adhesive joint strength

Influence of surface texturing on adhesive joint strength

The effect of resolution on the deterministic finite element elastic-plastic rough surface contact under combined normal and tangential loading

Three-dimensional deterministic models of rough surfaces can enrich the understanding of the influence of surface texture on contact and friction. However, most of the existing finite element contact models simply use the data measured from real rough surfaces directly and consider the shape between every two neighboring points to be a straight line. In this study, we proposed a possible harmonic description for the shape between the measured points. This is accomplished by using harmonic interpolation. The effect of resolution on the contact properties under normal loading and combined normal and tangential loading are investigated. This study provides a methodology to the finite element analysis of rough surface contact that may push the simulation results closer to reality.

Influence of surface textures on the hydrodynamic performance of parallel sliding contacts in turbulent regime

Generally, turbulent flow in bearings occurs mainly due to two reasons: high operational speed and use of unconventional lubricants. The present work is focused to investigate the effects of both positive and negative textures in terms of texture shape, size, height, orientation and number of textures in transverse direction, on the hydrodynamic performance of parallel sliding contacts in turbulent regime. Ng and Pan model is used to incorporate turbulent flow condition in pressure governing equation. It has been noticed that Reynolds number, texture shape, size and height play significant role in enhancing the lubrication performance. In turbulent flow, friction parameter shows higher magnitude as compared to laminar flow which is undesirable.

Effect of geometric shape of micro-grooves on the performance of textured hybrid thrust pad bearing

A numerical simulation is performed to investigate the synergizing influence of surface texture (micro-grooves) and electrically conducting lubricant on static and dynamic performance of hybrid thrust pad bearings operating under transverse magnetic field. Linear momentum and mass conservation equation are solved simultaneously to derive modified Reynolds equation for magnetohydrodynamic lubrication. Finite element approach has been used to obtain couple solution of modified Reynolds equation and restrictor (orifice) flow equation. A mass conserving algorithm (Jakobsson–Floberg–Olsson boundary condition) has been implemented to simulate cavitation phenomenon within micro-grooves. A parametric investigation (based on load-carrying capacity/fluid film pressure) is carried out to obtain optimum attributes for various micro-grooves shapes. Providing micro-groove on bearings surfaces results in a significant increase in load-carrying capacity, stiffness coefficient and reduction in frictional power loss of the bearing. Employing of electrically conducting lubricant is seen to be enhancing the load-carrying capacity and damping characteristics of the bearing.

Influence of micro-groove attributes on frictional power loss and load-carrying capacity of hybrid thrust bearing

PurposeMicro-surface texturing is emerging as a possible way to enhance the tribological performance of hydrodynamic fluid film bearings. In view of this, numerical simulations are carried out to examine the influence of surface texture on performance of hybrid thrust bearing system. This paper aims to determine optimum attributes of micro-grooves for thrust bearing operating in hybrid mode.Design/methodology/approachAn iterative source code based on finite element formulation of Reynolds equation has been developed to numerically simulate flow of lubricant through the bearing. Mass-conserving algorithm based on Jakobsson–Floberg–Olsson (JFO) condition has been used to numerically capture cavitation phenomenon in the bearing. Gauss Siedel method has been used to obtain steady state performance parameters of the bearings.FindingsA parametric study has been performed to improve the load supporting capacity of the bearing by optimizing micro-groove attributes and configuration. It is noticed that use of full-section micro-groove is beneficial in improving the efficiency of bearing by enhancing the fluid film reaction and reducing the film frictional power losses.Originality/valueThis study is helpful in examining the usefulness of micro-groove textured surfaces in hybrid thrust bearing applications.

The influence of different surface textures on wears in cylinder liner piston rings

Wear is a crucial factor that limits the operational lifespan of the cylinder liner-piston ring (CLPR) in marine diesel engines. Efforts had been made to reduce wear by grooving textures on the cylinders. Besides, the influence of surface textures on mechanical wear can be evaluated by wear particle analysis. This study aims to characterize features of wear particles generated from different surface textured cylinder liners and investigate the relationship between the texture and wear particle features. Wear particles generated from liners of different groove angles (30°, 45°, 60°) and different widths (1 mm, 2 mm, 3 mm, 4 mm) were collected from friction tests, and the characteristics were obtained using a 3D laser microscope. Then, comparative studies on the 2D characteristics and 3D surface topographies of wear particles were performed. Results revealed that the characterization parameters of wear particles can be used to identify the different types of surface texture and reflect the lubrication performance of the friction pairs. Specifically, wear particles generated from the 2 mm width with 30° angular grooved texture were different from the others, and it effectively improved lubrication in the CLPR friction pair. These results can be used as a reference for the application of surface textures on CLPR pairs for improved lubrication.

Friction reduction in EHL contacts by surface microtexturing – tribological performance, manufacturing and tailored design

Purpose This paper aims to derive tailor-made microtextures for elastohydrodynamically lubricated (EHL) contacts under consideration of manufacturing possibilities. Design/methodology/approach Component tests were used for the evaluation of the influence of surface texturing on the friction behavior in the cam/tappet contact. Furthermore, the manufacturing possibilities and limitations of a combined μEDM and micro-coining process and the feasibility of integration into a forming process were studied. Finally, a methodology based on transient EHL simulations and a meta-model of optimal prognosis was exemplarily used for microtexture optimization. Findings It was found that surface texturing in EHL contacts with high amount of sliding is promising. Moreover, the combination of μEDM and micro coining and the integration into established production processes allow the manufacturing of microtextures with desirable structural parameters and sufficient accuracy. Originality/value This paper gives a holistic view on surface microtexturing over several phases of the product life cycle, from the design, over efficient manufacturing to application-related testing.

The Influence of Surface Texture on Abrasive Wear

Friction happens everywhere. Abrasives generated in tribological process will result in secondary wear. Abrasive wear is a kind of rather common but harmful wear, which is the main reason for the damage of fifty-percent mechanical components by friction. Surface texturing is an effective method to improve the tribological and lubricating performance of tribo-pairs. In this paper, with different-size diamond particles added into the lubricant and a surface of the tribo-pairs textured by different parameters (diameter and depth) with femtosecond laser, the relationship between the surface texture and the abrasive wear was researched, and the influence of the texture on the abrasive wear was analyzed. The friction experiments were carried out on UMT3. The microstructures were tested and analyzed by SEM, microscope and White Light Interferometer respectively. The experimental results showed that the size of the surface texture, compared with that of abrasives, is the main factor which determines the friction coefficient. As the size of the surface texture is much bigger than that of the abrasives, the texture can accommodate the abrasives efficiently, and thus the friction coefficient is reduced efficiently.