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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.

This paper aims to research the effect of the different structures of dimpled textures on the rod bearing surfaces on improving the engine’s lubrication efficiency and friction power loss (LE-FPL).

Based on the hydrodynamic model of the rod bearing, the effect of different structures of dimpled surfaces including circular dimples (CD), square dimples (SD), wedge-shaped dimples (WSD), circular-square dimples (CSD) and square-wedge-shaped dimples (SWSD) on ameliorating the LE-FPL is analyzed under the different operating conditions of the engine. The oil film pressure (p), asperity contact force (W_ac), friction force (F_f) and coefficient of friction (COF) of the rod bearing are chosen to evaluate the LE-FPL.

The SD’s performance on improving the LE-FPL is better than all other structures of the CD, WSD, CSD and SWSD. Particularly, the average values of W_ac, F_f and COF with the SD is significantly reduced by 14.5%, 28.5% and 33.3% compared to the optimal dimensions of the rod bearing; and by 26.4%, 34.5% and 43.7% compared to the optimal CD (n = m = 6).

The generated friction between surfaces of rod bearings of the engine not only reduces the engine power but also affects the durability of the structures. Thus, the optimal design of the SD to further improve the LE-FPL is very necessary.

This study aims to investigate the effect of compound pit textures on the tribological properties of thrust cylindrical roller bearings (TCRBs) using several parameters, such as compound type, pit diameter, pit depth and pit area density.

The surface texture parameters of the shaft washer (WS) raceway include pit diameter (D; 100, 300 and 500 µm), pit depth (H; 10 and 20 µm) and pit area density (S; 10%, 13% and 18%). Pits were produced on the WS of the TCRBs using laser marking equipment. The friction and wear performances of compound pit-textured TCRBs under starved lubrication conditions are studied using a friction and wear test rig. The influence mechanisms of the compound pit texture on the friction and wear properties of TCRBs are discussed through real tests and discussions.

Compared with nontextured bearings, the average coefficient of friction (ACOFs) and wear loss of TCRBs with single/compound pit textures are reduced when rotating under starved lubrication. D has the greatest effect on the COFs curve. When D = 300 µm, H = 10 µm and S = 10%, the ACOF and wear loss are the lowest, that is, 0.0207 and 3.38 mg, respectively. Under the same lubrication conditions, compared with the nontextured bearing group, the COF and wear loss are reduced by 41.4 and 59.6%, respectively.

This study provides a useful reference for the raceways of textured TCRBs.

The purpose of this paper was to carry out an experimental study to investigate tribodynamics at the interface of chrome steel pin with the plain and textured surface cast iron discs in a fully flooded condition.

A friction and wear tester (tribometer) was used for conducting the experiment at different operating parameters. Lubricating oil used in this experiment was SAE-15W40, which directly supplied at the interface and ensured a fully flooded lubricating condition. Measurements of different parameters, such as friction coefficient, the rate of wear, the amplitude of vibration, rise in temperature and intensity of sound, were considered at different loads. The input parameters were taken in a range viz. Loads from 1.9 MPa to 3.1 MPa, sliding speeds from 2 to 10 m/s and distance travelled ranged from 1000 to 5000 m.

In the investigation, it was found that there was a decrease in friction coefficient and wear rate at the interface formed by the chrome steel pin with textured surface cast iron disc when compared with friction coefficient and wear rate at the interface formed by the chrome steel pin and the plain surface disc of cast iron.

Also, it was inferred that temperature, vibration and noise level, at the interface formed by the chrome steel pin and plain surface cast iron disc, increased, which governed the interface stability. The novelty of this investigation lies in the identification of the parameters on which interface stability depends.

This paper aims to investigate the effect of frictional materials and surface texture on the energy conversion efficiency and the mechanical output performance of the ultrasonic motor (USM).

A newly designed testing system was set up to measure the mechanical output performance of the USM. The influence of different frictional materials on the output performance of the USM was studied under the same assembly process and parameters. The surface texture was fabricated by laser ablation processing. The effects of surface texture and input parameters on the energy conversion efficiency and mechanical output performance of the USM were studied.

The results show that polyimide (PI) composites as frictional material can significantly improve the output performance of the USM compared to polytetrafluoroethylene (PTFE) composites. When the pre-load is 240 N, the energy conversion efficiency of the USM using textured PI composites as frictional material can reach 41.93 per cent, increased by 29.21 per cent compared to PTFE composites, and the effective output range of the USM is increased to 0.7-1.1 N m. Besides, the pre-load and surface texture have a great influence on the output performance of the USM.

PI composites can improve the mechanical output performance of the USM. Surface texture can also improve the interface tribological properties and the energy conversion efficiency based on the advanced frictional materials, which will contribute to the increment of the output performance of the USM under the same input conditions.

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.

The purpose of this paper is to describe the tribological characteristics with different area density of concave-convex micro-texture on the mold surface. It is a new technology to improve the quality of the workpiece to control the tribological properties through the application of concave-convex micro-texture on the mold surface.

Five groups of laser micro-texture with different area density (ratio of the concave-convex micro-texture area to the all-area) were processed on the surface of the mold steel, and the tribological properties were compared with the smooth surface of the reference sample.

The time of the running-in stage in different experimental groups was about 300 s. The fluctuation amplitude of concave-convex micro-texture friction coefficient is much larger than that of smooth plane specimen in the running-in stage. After the running-in stage, the friction coefficients were lower than that in the smooth condition and decreased with the increase of the concave-convex micro-texture area density. When the area density reached 25%, the friction coefficients no longer decreased significantly. In addition, the wear of concave-convex micro-texture surface is much lower than that of smooth surface and decreases with the increase of concave-convex micro-texture area density.

Domestic and foreign scholars have done a lot of research on the relationship between concave micro-texture and tribological properties. However, the object of this paper is a new concave-convex micro-texture, which is rarely studied in the field of tribology.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0081/

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 study aims to compare tribological properties between laser dimple textured surface and drilled dimple textured surface, and to analyze the influence of dimple hardened edges and ability of trapping wear debris on wear properties of dimple textured surfaces.

Circular textured dimples were produced on AISI 1,045 specimen surfaces using laser surface texturing (LST) and drilled surface texturing (DST) methods. Tribological behaviors of LST, DST and non-textured specimens were studied using ball-on-disc tribo-tester. Metallographic structures, dimples and worn surface morphologies were observed using a three-dimensional digital microscope. Hardnesses of substrate and dimple edges were measured.

There was no obvious difference in wear and friction coefficients between LST and DST specimens. Hardnesses of laser dimple edges were much higher than that of drilled dimple edges and specimen substrate. The hardened materials of laser dimple edge included recast zone and heat affect zone. Laser dimple was cone-shaped and drilled dimple was cylinder-shaped. Drilled dimple had a better ability of trapping wear debris than laser dimple. Non-uniform wear phenomenon occurred on worn surfaces of LST dimple specimens.

The ability of textured dimples to trap wear debris is affected by single dimple volume. Hardened edges of dimples cause non-uniform wear on worn surfaces of LST specimens.

This paper aims to investigate the influence of sinusoidal texture (ST) with different morphology parameters on the corresponding tribological effects.

The STs with different amplitudes, ranging from 0.05 to 0.3 mm, and frequencies, ranging from 5 to 17.5, are fabricated using nanosecond pulsed laser equipment. The friction experiments and the finite element analysis method are combined to investigate the tribological properties, under dry friction conditions.

Test results show that when the amplitude is 0.15 mm and frequency is 10, ST surface has the lowest friction coefficient of 0.373, and exhibits great anti-friction effect. It also possesses a complete texture edge after friction. The friction reduction effect of ST with larger or smaller amplitude and frequency is worse.

The results of this study can provide a guidance for the design optimization of ST of reciprocating sliding contact surfaces, under dry friction conditions.