Search results

The purpose of this paper is to investigate and discuss the effect of multi-shape laser surface texturing (LST) steel surfaces on tribological performance.

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.

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.

This paper develops multi-shape LST steel surfaces for improving the friction and wear performance under dry and lubrication conditions.

The purpose of this paper is to investigate the effect of laser surface texturing on the tribological properties of polyimide composites and the output performance of traveling wave rotary ultrasonic motor.

The surface texturing on polyimide composites specimens were fabricated by laser ablation process of different dimple densities, and then the tribological properties were tested by a flat-on-flat tribometer under dry conditions. Finally, the output performance of the traveling wave rotary ultrasonic motor was tested to verify the effectiveness of dimples surface texturing.

The results show that surface texturing can greatly enhance the friction coefficient of contact interface, especially the specimen with a dimple density of 7.06 per cent exhibited the highest friction coefficient among the specimens. When the input voltage is 500 V, the output power, locked-rotor torque and output torque of ultrasonic motor with textured PI of 7.06 per cent dimple density as friction material at the speed of 100 r/min increased by 13.8, 19 and 12.8 per cent compared to that of the untextured PTFE, respectively. When the ultrasonic motor reverses, the output performance is increased by 20.9, 40.3 and 17.7 per cent, respectively.

Surface texturing is an effective way to improve the friction behavior of polyimide composites and then correspondingly enhance the energy conversion efficiency and output performance of the traveling wave rotary ultrasonic motor.

The purpose of this study is to design and process the optimal V-shaped microstructure for 7075 aluminum alloy and reveal its wear resistance mechanism and performance.

The hydrodynamic pressure lubrication models of the nontextured, V-shaped, circular and square microtextures are established. The corresponding oil film pressure distributions are explored. The friction and wear experiments are conducted on a rotating device. The effects of the microstructure shapes and sizes on the wear mechanisms are investigated via the friction coefficients and surface morphologies.

In comparison, the V-shaped microtexture has the largest oil film carrying capacity and the lowest friction coefficient. The wear mechanism of the V-shaped microtexture is dominated by abrasive and adhesive wear. The V-shaped microtexture has excellent wear resistance under a side length of 300 µm, an interval of 300 µm and a depth of 20 µm.

This study is conductive to the design of wear-resistant surfaces for friction components.

This study aims to investigate the sliding friction behaviour and mechanism of engineering surfaces.

A new numerical approach is proposed. This approach derives the macroscale friction coefficient from microscale asperity interactions. By applying this approach, the sliding friction behaviour under different operating conditions were investigated in terms of molecular and mechanical components.

Numerical results demonstrate an independent relationship between normal load and friction coefficient, which is governed by the saturated plastic ratio. Numerical results also demonstrate that under very small load, an increase in load increases the friction coefficient. In addition, numerical results confirm the existence of optimal surface roughness where the friction coefficient is the lowest. For the surface profiles used in the current calculation, an optimal surface roughness value is obtained as Rq = 0.125 μm.

This new approach characterizes the deterministic relationship between macroscale friction coefficient and microscale asperity molecular/mechanical interactions. Numerical results facilitate the understanding of sliding friction mechanism.

This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start.

For the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease.

When point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%.

The introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.

Friction is considered to be one property of cloth that has considerable importance in the fields of both technological and subjective assessment for surface properties of textile fabrics. The purpose of this study is to investigate the affective aspects of yarn and fabric structural parameters on the behavior of surface friction of plain woven fabrics.

In this study, nine varieties of half-bleached cotton plain-woven fabrics with three weft yarn count (tex) and three weft thread density (ppc) are produced and will be examined for their frictional characteristics. The surface frictional properties of plain-woven fabrics were measured by using Kawabata (KES-Fb4) testing instrument. The ANOVA analysis is used to determine how yarn (count) and fabric (density) structural parameters does influence the surface friction properties of the fabrics. Also, the interaction effects between the factors (count and density) on the response variable (surface friction) of plain-woven fabrics.

The findings of this study revealed that the effects of weft yarn count and pick-density have statistically significant on the frictional behavior of the fabric surface properties at a 95% confidence interval. Thus, weft yarn count has a positive correlation with both coefficient of friction (MIU) and mean deviation of coefficient of friction (MMD) on frictional behavior of the fabric surface properties. On the other hand, pick density has a negative correlation with both MIU and MMD on frictional behavior of the fabric surface properties. The weft count, pick density and their interactions (Count X Density) have multicollinearity in the experiment term because the variance inflation factor values were greater than one.

The findings of this study can be routinely used across the textile industries and laboratories to provide a fundamental understanding regarding the surface frictional properties of the woven fabric for different end applications concerning the yarn structural parameters and fabric structural parameters. And the relationship of count and density with surface friction of plain woven fabrics.

This paper aims to clarify the friction properties of 304 steel surface modification. The surface modification includes laser texturing processing and nitriding treatment on 304 steel surface, and then the friction properties’ test was conducted on different friction directions and different upper test samples by using microfriction and wear testing machine.

The diameter and spacing of 100-, 150-, 200-, 300-μm pit array on the surface of 304 steel were calculated using a M-DPSS-50 semiconductor laser device. Then, the textured surface was nitriding-treated using a nitriding salt bath device. The chemical composition, surface morphology and surface microhardness of the composite-modified surface were measured by X-ray diffraction and by using an optical microscope and a microhardness tester. The tribological characteristics of the composite-modified surface were tested by MRTR microcomputer-controlled multifunctional friction and wear testing machine.

The result showed that a rule pit texture surface was obtained by the texture processing. The microhardness of nitriding treatment surface reached 574.27HV0.1, which significantly higher than 222.58HV0.1 of 304 steel. The composite-modified surface has excellent anti-friction and wear resistance properties when the upper specimen was GCr15 steel and ZrO2, respectively. The composite-modified surface has excellent anti-friction and anti-wear properties after long time friction under different angles. However, the friction coefficient and wear morphology of the friction pairs are not affected by the friction angle.

Because of the chosen research approach, the research results may lack generalizability. Therefore, researchers are encouraged to test the proposed propositions further.

The paper conducted a systematic study of the tribological characteristics of 304 steel composite modification surface and provided a good basis for the extensive application of 304 steel.

The study provides a good basis for the extensive application of 304 steel.

This paper fulfils an identified need to study the extensive application of 304 steel.

The purpose of this paper is to explore the sensitive parameters affecting the friction resistance of sliding bearings under different interface slip conditions and the influence of the texture position of circular pits on the friction force of sliding bearings.

Based on the mechanical equilibrium equation and Newton's viscous fluid mechanics formula and wedge oil film model, the calculation model of sliding bearing friction resistance under interface slip state is established, and the influence of interface slip on friction resistance under different slip conditions is analyzed by means of ANSYS. Friction simulation model of circular pit textured journal bearing under different interface slip conditions.

The friction resistance of bearings is mainly determined by journal linear velocity, oil film slip ratio, pressure of inlet and outlet of bearings, oil film thickness and bearing capacity. When both the upper and lower surfaces of the oil film slip, the friction resistance decreases significantly, which is only 4-17 per cent of that without slip. And the friction force of the texture model of circular pit at the exit is better than that at the entrance and the middle of the pit.

Relevant research results will lay a new theoretical foundation for friction reduction and optimization design of sliding bearings.

This paper aims to improve the tribological properties of lithium complex greases using nanoparticles to investigate the tribological behavior of single additives (nano-TiO₂ or nano-CeO₂) and composite additives (nano-TiO₂–CeO₂) in lithium complex greases and to analyze the mechanism of their influence using a variety of characterization tools.

The morphology and microstructure of the nanoparticles were characterized by scanning electron microscopy and an X-ray diffractometer. The tribological properties of different nanoparticles, as well as compounded nanoparticles as greases, were evaluated. Average friction coefficients and wear diameters were analyzed. Scanning electron microscopy and three-dimensional topography were used to analyze the surface topography of worn steel balls. The elements present on the worn steel balls’ surface were analyzed using energy-dispersive spectroscopy and X-ray photoelectron spectroscopy.

The results showed that the coefficient of friction (COF) of grease with all three nanoparticles added was low. The grease-containing composite nanoparticles exhibited a lower COF and superior anti-wear properties. The sample displayed its optimal tribological performance when the ratio of TiO₂ to CeO₂ was 6:4, resulting in a 30.5% reduction in the COF and a 29.2% decrease in wear spot diameter compared to the original grease. Additionally, the roughness of the worn spot surface and the maximum depth of the wear mark were significantly reduced.

The main innovation of this study is the first mixing of nano-TiO₂ and nano-CeO₂ with different sizes and properties as compound lithium grease additives to significantly enhance the anti-wear and friction reduction properties of this grease. The results of friction experiments with a single additive are used as a basis to explore the synergistic lubrication mechanism of the compounded nanoparticles. This innovative approach provides a new reference and direction for future research and development of grease additives.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2023-0291/