Influence Of Texture Parameters Research Articles

The optimization design for the journal-thrust couple bearing surface texture based on particle swarm algorithm

Journal-thrust coupled bearings (JTC bearings), unlike conventional journal or thrust bearings, require consideration of both reducing friction coefficient in the journal part while increasing the load-carrying capacity in the thrust part during lubrication design. This study established a thermal-elastohydrodynamic mixed lubrication model for JTC bearings considering flow, pressure, and thermal continuity conditions, validated through experiments. Based on this, the influence of texture parameters on lubrication under real heavy load conditions was preliminarily investigated. The orthogonal test design was then used to determine the texture parameter that had the greatest impact on optimization. Subsequently, particle swarm optimization (PSO) algorithm was employed for synchronous optimization design of textures for both journal and thrust parts.

Effect of texture parameters on the lubrication performance of static and dynamic pressure thrust bearings and multi-objective optimization

PurposeThis paper aims to study the influence of cylindrical texture parameters on the lubrication performance of static and dynamic pressure thrust bearings (hereinafter referred to as thrust bearings) and to optimize their lubrication performance using multiobjective optimization.Design/methodology/approachThe influence of texture parameters on the lubrication performance of thrust bearings was studied based on the modified Reynolds equation. The objective functions are predicted through the BP neural network, and the texture parameters were optimized using the improved multiobjective ant lion algorithm (MOALA).FindingsCompared with smooth surface, the introduction of texture can improve the lubrication properties. Under the optimization of the improved algorithm, when the texture diameter, depth, spacing and number are approximately 0.2 mm, 0.5 mm, 5 mm and 34, respectively, the loading capacity is increased by around 27.7% and the temperature is reduced by around 1.55°C.Originality/valueThis paper studies the effect of texture parameters on the lubrication properties of thrust bearings based on the modified Reynolds equation and performs multiobjective optimization through an improved MOALA.

Influence of Surface Texture on Sealing Performance of PTFE Materials

Due to the hydrodynamic pressure effect, the bearing capacity of the oil film on the surface of a textured friction pair is greater than that of a smooth surface. In this paper, the effects of PTFE surface texture parameters (shape, depth, width, and area ratio) on the oil film bearing capacity and leakage of the sealing system under lubrication are studied using the FLURNT simulation. It is found in this present study that greater texture depths do not necessarily lead to better sealing performance. When the texture depth exceeds a certain level, a reverse flow occurs at the bottom of the texture, thereby weakening the hydrodynamic pressure effect. An optimal texture depth of 5–10 μm maximizes the oil film bearing capacity. Within a certain range, the oil film bearing capacity increases along with texture widths. In addition, leakage of the rectangular texture rises significantly with growing texture widths. Larger texture area ratios result in higher leakage, but the bearing capacity first rises and then falls with an increase in the area ratio, with a maximum value of 70–80%. Considering the influence of texture parameters on oil film bearing capacity and leakage, selecting the most appropriate texture parameters for surface texture treatment optimizes the performance of the sealing system. The findings of this paper provide a theoretical basis for improving the sealing performance of high-end aviation equipment using texture treatment, thereby enabling the application of surface texture technology to improve the tribological properties of materials.

Tribological performance of laser‐textured steel surfaces in unidirectional sliding line‐contact (block‐on‐ring)

AbstractThe following theoretical and experimental work presents a study on the influence of texture parameters on the tribological performance of dimpled steel surfaces. Different texture parameters were selected through hydrodynamic lubrication modeling based on the two‐dimensional Reynolds equation and literature search. For the experimental work, microscopic spherical cavities (i.e., dimples) were created by laser on 25 mm steel discs. The textured specimens were tested in a unidirectional sliding line‐contact block‐on‐ring set‐up at different rotational speeds. The experiments showed that the area‐density‐ratio, dimple‐depth, and dimple‐diameter can significantly affect the tribological performance of steel surfaces. Specimens containing dimples with lower depth, lower area‐density‐ratio, and smaller diameters, exhibited significant improvements over a smooth steel surface. The most remarkable achievement was a 28.6% friction reduction at 20 RPM and an overall improvement of 13% considering all speeds.

Effect of rake surface textures spacing and width on the cutting performance of inserts in dry machining of titanium alloy

One of the crucial parameters that can be altered to improve machining efficiency in metal cutting is reducing the friction between tool and chip, especially along the rake surface of the tool. Studies have shown that many parameters of the micro or nanoscale texturing on the tool surface may influence its competence in reducing friction. However, the influence of texture parameters like width, spacing, etc. is not well understood, especially in the dry machining of hard alloys. In this experimental investigation, uncoated single point cutting tool inserts with different texture geometries on their rake surface were tested for adequacy in the typical turning operation of titanium alloy. The novelty of the study involves identifying the influence of texture spacing and width on the cutting parameters at different feeds in the dry machining of the Ti-6Al-4V alloy. The surface characterisation of the inserts shows how the textured surface was damaged under the machining regime. Chip morphology analysis was conducted to study the effect on chip thickness and shear plane angle. Inferences were made on the effect of texture dimensions on the frictional forces during machining.

Preparation and tribological properties of micro-textured diamond/WSx coatings

Severe friction is the primary cause of fracture and delamination of diamond coating in tribological applications. Therefore, a surface technology is urgently needed to improve the tribological behavior of diamond coating. The synergistic antifriction effect of transition metal sulfides and texture can alleviate this issue. Micro-textures with precise parameters (width and area ratio) were prepared by Inductively Coupled Plasma Etching techniques (ICP) on the silicon substrate and then coated with diamond and WSx coating. The influence of texture parameters on friction under different normal loads was studied by orthogonal experiments. Results revealed that, compared with the width and load, the area ratio of the texture has a more significant influence on the friction coefficient. The textured diamond/WSx coating with the area ratio of 30% and width of 30 μm showed relatively low friction coefficient (~0.0457) under 5 N load. Then the reducing friction mechanism of the textured diamond/WSx coatings was analyzed based on the variation law of friction coefficient and wear marks. In addition, building on those tests an analytical model for the friction was developed to explain the differences in friction coefficient and predict the optimal texture parameters under different loading conditions.

Research on the micro and dynamic characteristics of combination surface based on fractal theory

Abstract. The dynamic characteristics of the mechanical joint surface are important aspects of the dynamic theoretical analysis and optimization design of the machine tool. In this paper, the typical mechanical joint surface is taken as the research object. Through the combination of theoretical analysis and experimental analysis, the dynamic characteristics of typical joint surface parameters with different surface textures and the influence of texture parameters on the dynamic characteristics of the joint surface are studied. Based on the Hertz elastic contact theory and the contact fractal theory, the normal and tangential contact fractal models of the joint surface are derived, and then a mathematical model of the joint surface normal and tangential contact stiffness considering the domain expansion factor is established. The influence of surface texture parameters on the dynamic characteristics of the surface is further studied according to the model. In addition, the design of the experimental device and experimental scheme design are completed by the contact resonance method and the ERA algorithm, and the joint surface parameter identification experiment with texture is conducted. The normal and tangential frequency response functions of the joint surface, the dynamic characteristic parameters of the joint surface and the influence law of the joint surface parameters on the contact characteristics are obtained through the dynamic test analysis technology.

Influence of textural parameters on detrital-zircon age spectra with application to provenance and paleogeography during the Ediacaran−Terreneuvian of southwestern Laurentia

Multiple sedimentary structures of different scales and representative of various flow conditions were sampled from single, sand-dominated, fluvial channels in the Neoproterozoic (Ediacaran) upper member of the Stirling Quartzite and the Cambrian (Terreneuvian) middle member of the Wood Canyon Formation. Sampling was designed to determine if sorting of detrital-zircon populations by their textural properties affects detrital-zircon age spectra in fluvial sandstones. Grain sizes of the sampled host sandstones range from fine to coarse sand, and sorting ranges from moderately well to poorly sorted. Four Wood Canyon Formation samples contain detrital-zircon grains of similar size, whereas detrital zircons in samples of the Stirling Quartzite differ greatly in size between two samples. Paired Kolmogorov-Smirnov, overlap, and likeness statistical tests demonstrate that all samples from each channel are similar. Comparing size, sphericity, and roundness of detrital-zircon grains to their ages yielded no linear correlation. Sorting of sediments by their textural properties did not affect detrital-zircon age spectra in either unit. In this study, different sedimentary structures within a single fluvial channel do not control the age distribution of detrital zircons. Furthermore, the two braidplain systems (Wood Canyon Formation, Stirling Quartzite) have substantially different detrital-zircon age spectra, indicating that the fluvial environment in general is not responsible for selecting specific age populations. The dominant ca. 1.1 Ga Grenvillian peak in the middle member Wood Canyon Formation results from provenance, not sampling bias. Uplift and erosion of Grenvillian rocks along the Ouachita rift flank during the earliest Cambrian may have generated a pulse of sediment that entered a northwestward-flowing braidplain.

Control of bioclast abundance on natural joint density in carbonate rocks: data from Oman, Provence and Languedoc (France)

Joint density in sedimentary rocks is highly dependent on many factors such as tectonic stress, fluid pressure, interbedded layers and bed thickness. Data from Cretaceous carbonate rocks in Oman, Provence and Languedoc (France) show that bed thickness has a general control on joint density in all areas but other parameters also influence joint density. In order to understand the influence of textural parameters on volume joint density, all joint sets were measured in several beds. Data show that joint density decreases when the percentage of figured grains increases in Oman and Provence but that this relationship is more complex in Languedoc. The major textural parameter controlling joint density is the percentage of bioclasts: joint density decreases with an increase of the percentage of bioclasts in the three sectors.