Research on Mixed Lubrication Problems of the Non-Gaussian Rough Textured Surface With the Influence of Stochastic Roughness in Consideration

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Shuwen Wang ◽  
Xiaohong Ding
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Mixed Lubrication ◽  
Textured Surface ◽  
Asperity Contact ◽  
Textured Surfaces ◽  
Negative Skewness ◽  
Non Gaussian ◽  
Stribeck Curves ◽  
Average Flow Model

Abstract In order to find the effects of surface topography on the tribological properties of the rough textured surfaces, an improved mixed lubrication model allowing specifying the standard deviation, the skewness, and the kurtosis was developed. In this model, by considering the non-Gaussian properties of rough surfaces, an improved average flow model was combined with a modified statistical elastoplastic asperity contact model. The performances of the slider bearings with two arrays of anisotropic textures were studied in terms of Stribeck curves. It appears that the tribological properties of the anisotropic textures are sensitive to the sliding direction. Meanwhile, the surfaces with more negative skewness or the lower kurtosis can obtain better tribological performances related to friction and wear.

The influence of surface texturing on the transition of the lubrication regimes between a piston ring and a cylinder liner

2016 ◽  
Vol 18 (8) ◽  
pp. 785-796 ◽  
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Di Zhang
Keyword(s):  
Piston Ring ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Mixed Lubrication ◽  
Textured Surface ◽  
Asperity Contact ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Mixed Lubrication Regime ◽  
Stribeck Curves

This article employs a mixed lubrication model to investigate the performance of the textured surface. The Jakobsson–Floberg–Olsson model is used to obtain the hydrodynamic support of the textured conjunction, while the calculation of the asperity contact load is based on the load-sharing concept. Based on the simulated Stribeck curves of the smooth surface and the textured surface, comparisons are conducted to study the effect of texturing under different lubrication regimes. It appears that the transition of lubrication regimes is influenced by the texturing parameters and the convergence degrees of conjunction. The presence of textures delays the appearance of the mixed lubrication regime and the boundary lubrication regime.

Numerical and experimental study on the effect of surface texture with roughness orientation considered under a mixed lubrication state

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junru Wang ◽  
Quandai Wang ◽  
Yueyan Li ◽  
Meiling Guo ◽  
Pengyang Li ◽  
...  
Keyword(s):  
Surface Texture ◽  
Surface Texturing ◽  
Mixed Lubrication ◽  
Laser Surface ◽  
Geometric Parameters ◽  
Laser Surface Texturing ◽  
Textured Surface ◽  
Asperity Contact ◽  
Content Type ◽  
Texture Parameters

Purpose The purpose of this paper is to investigate the effects of surface texture with roughness orientation considered on tribological properties under a mixed lubrication state numerically and experimentally. Design/methodology/approach Based on the average Reynolds equation and asperity contact model, the impacts of surface texture parameters and roughness orientation on lubrication properties have been calculated using finite difference method. Tin–bronze samples with various prescribed surface texture geometric parameters and roughness orientation were fabricated by laser surface texturing technique, and the tribology performance of the textured surface was studied experimentally. Findings The effects of surface geometric parameters and roughness orientation parameters have been discerned. The experimental observations are in good agreement with the numerical prediction, which suggests that the numerical scheme adopted in this work is suitable in capturing the surface texture and roughness effect under mixed lubrication state. Originality/value By meticulously controlling the surface roughness and surface texture geometric characteristics based on the laser surface texturing process, samples with prescribed surface texture parameters and roughness orientation consistent with that in theoretical studies were fabricated and the theoretical model and results were verified experimentally.

Study on the mutual influence of surface roughness and texture features of rough-textured surfaces on the tribological properties

2020 ◽  
pp. 135065012094021
Author(s):  
Chunxing Gu ◽  
Xianghui Meng ◽  
Shuwen Wang ◽  
Xiaohong Ding
Keyword(s):  
Surface Roughness ◽  
Tribological Properties ◽  
Gaussian Distribution ◽  
Mutual Influence ◽  
Surface Texturing ◽  
Texture Features ◽  
Tribological Performance ◽  
Mixed Lubrication ◽  
Non Gaussian ◽  
Skewness And Kurtosis

In recent years, the efforts to better control friction and wear have focused on surface topography modification through surface texturing. To study the mutual influence of surface roughness and texture features, this paper developed one comprehensive mathematical model of mixed lubrication to study the tribological performance of the rough-textured conjunction. The typical ring-liner conjunction was chosen as the research object. In particular, the effects of skewness and kurtosis were considered based on the non-Gaussian distribution of asperity height. In this way, the influences of non-Gaussian distribution properties and surface texturing on the tribological performance were analyzed. The results show that the influences of skewness and kurtosis on the tribological performance are nontrivial and should not be neglected in the mixed lubrication. Compared to the Gaussian distribution, considering the non-Gaussian distribution can represent the physical rough surfaces more accurately. Surfaces with negative skewness were found to generally result in better tribological properties. Moreover, the tribological performance improved by surface texturing can also be improved or reduced by the effect of skewness and kurtosis. As a result, the optimization of surface texturing should take the effects of roughness parameters into account.

Friction, wear, and fatigue analysis for micro-textured cemented carbide

2019 ◽  
Vol 233 (17) ◽  
pp. 5989-6004 ◽  
Author(s):  
Xin Tong ◽  
Shucai Yang ◽  
Xianli Liu ◽  
Weiwei Liu ◽  
Chunsheng He
Keyword(s):  
Smooth Surface ◽  
Friction And Wear ◽  
Processing Parameters ◽  
Textured Surface ◽  
Surface Phase ◽  
Textured Surfaces ◽  
Wear Properties ◽  
Fatigue Wear ◽  
Optimal Processing ◽  
Cutting Processes

In the research regarding laser-processed micro-textured carbide tool surfaces, there remains a lack of research on the relationship between micro-textured preparation processes and the degree of fatigue wear experienced by micro-textured surfaces. To study the effect of a laser-textured surface on the friction and wear properties of friction pairs, it first of all conducted friction and wear tests to obtain optimal processing parameters. By using a scanning electron microscope, the fatigue wear mechanism for a micro-textured surface was observed. Experimental results based on fatigue wear theory show that a micro-textured surface phase has better fatigue resistance than a smooth surface. Under the same friction conditions and selected test parameters, a micro-textured surface phase can reduce the maximum fatigue and friction wear of a smooth surface by 38.4%. This study provides a theoretical basis and source of reference for the rational formulation of micro-texture parameters and improvements in the performance of micro-textures during cutting processes.

Applicability of Interrupted Micro Cutting Process “Tilling” as Surface Texturing

2017 ◽  
Vol 749 ◽  
pp. 241-245 ◽  
Author(s):  
Hatsuhiko Usami ◽  
Toshiki Sato ◽  
Yasuyuki Kanda ◽  
Satoru Nishio
Keyword(s):  
Friction Coefficient ◽  
Tribological Properties ◽  
Cast Alloy ◽  
Effective Means ◽  
Frictional Resistance ◽  
Cnc Machining ◽  
Cutting Process ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Micro Cutting

Tribological properties of textured surfaces fabricated using a discontinuous microcutting process were investigated. Aluminum cast alloy (AC8A) discs were used for the specimens. The texturing process was carried out using a CNC machining center with a cutting edge with a novel geometry. The resulting surface morphology consisted of micro dimples with a diameter of 200-300 μm and a depth of 5-10 μm, with controlled area fractions of 10 and 40% and a top region finished with a milling cut. The tribological properties were evaluated using a ring-on-disc type testing apparatus under lubricated conditions, and showed that the friction coefficient of the textured surfaces was low and stable from the beginning of the experiment. A dependence of the friction coefficient on the area fraction was also found. Further reductions in the friction coefficient were achieved on a textured surface with a polished top region. It can be concluded that the proposed discontinuous micro cutting process is an effective means of fabricating a micro texture for the reduction and stabilization of frictional resistance.

An EHD-mixed lubrication analysis of main bearings for diesel engine based on coupling between flexible whole engine block and crankshaft

2015 ◽  
Vol 67 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Lidui Wei ◽  
Haijun Wei ◽  
Shulin Duan ◽  
Yu Zhang
Keyword(s):  
Diesel Engine ◽  
Flow Model ◽  
Mixed Lubrication ◽  
Engine Block ◽  
Contact Theory ◽  
Asperity Contact ◽  
Block Model ◽  
Content Type ◽  
Oil Film ◽  
Average Flow Model

Purpose – The purpose of this paper is to develop a good calculation model to accurately predict the lubrication characteristic of main bearings of diesel engine and improve the service life. Design/methodology/approach – Based on the coupling of the whole flexible engine block and the flexible crankshaft reduced by the Component Mode Synthesis (CMS) method, considering mass-conserving boundary conditions, the average flow model equation and Greenwood/Tripp asperity contact theory, an elastohydrodynamic (EHD)-mixed lubrication model of the main bearings for the diesel engine is developed and researched with the finite volume method and the finite element method. Findings – Obviously, the mixed lubrication of bearings is normal, while full hydrodynamic lubrication is transient. The results show that under the whole flexible block model, maximum oil film pressure, maximum asperity contact pressure and radial shell deformation decrease, while minimum oil film thickness increases. Oil flow over edge decreases, and so does friction loss. Therefore, coordination deformation ability of whole engine block is favorable to mean load. In the whole block model, friction contact happens on both upper shell and lower shell positions. In addition, average oil film fill ratio at the key position becomes smaller in the whole engine block model, and consequently increases the chances of cavitations erosion more. So, wearing resistance of both upper and lower shells and anti-cavitations erosion ability must be enhanced simultaneously. Originality/value – Based on the coupling of the whole flexible engine block and the flexible crankshaft reduced by the CMS method, considering mass-conserving boundary conditions, the average flow model equation and Greenwood/Tripp asperity contact theory, an EHD-mixed lubrication model of the main bearings for the diesel engine is built, which can predict the lubrication of journal bearings more accurately.

scholarly journals Surface Texture Influences on the Running-in Behavior and Friction Reduction

2018 ◽  
Vol 159 ◽  
pp. 02017
Author(s):  
Zhouyong Hou ◽  
Tomomi Honda
Keyword(s):  
Surface Texture ◽  
Internal Combustion Engines ◽  
Friction And Wear ◽  
Fuel Efficiency ◽  
Surface Profile ◽  
Friction Reduction ◽  
Profile Measurement ◽  
Textured Surface ◽  
Combustion Engines ◽  
Textured Surfaces

For improving automobile fuel efficiency, the internal combustion engines must be required to reduce the friction and wear. Changing viscosity of lubricant and surface pressure could succeed, but the seizure is easy to happen in engines. However, the surface texture can solve those problems. The running-in behavior affects friction and wear on whole combustion engines. If the running-in is not carefully designed, catastrophic accident can happen. This experiment investigates that the running-in behavior is influenced by textured surfaces and the tested materials are the cast iron and the different area ratio of dimple of aluminum alloy combination. The friction coefficient and the number and size of wear particles are measured by the friction sensor and particle counter. After the tests, the worn surfaces are measured through using surface profile measurement systems, and some significant phenomena are observed and analyzed. The textured surface verifies good consequence and tribological advantages.

A Deterministic Mixed Lubrication Model for Mechanical Seals

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Christophe Minet ◽  
Noël Brunetière ◽  
Bernard Tournerie
Keyword(s):  
Flow Model ◽  
Hydrodynamic Lubrication ◽  
Industrial Applications ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Mechanical Seals ◽  
Optimal Point ◽  
Lubrication Regimes ◽  
Face Seals ◽  
Stribeck Curves

Mechanical seals are commonly used in industrial applications. The main purpose of these components is to ensure the sealing of rotating shafts. Their optimal point of operation is obtained at the boundary between the mixed and hydrodynamic lubrication regimes. However, papers focused on this particular aspect in face seals are rather scarce compared with those dealing with other popular sealing devices. The present study thus proposes a numerical flow model of mixed lubrication in mechanical face seals. It achieves this by evaluating the influence of roughness on the performance of the seal. The choice of a deterministic approach has been made, this being justified by a review of the literature. A numerical model for the generation of random rough surfaces has been used prior to the flow model in order to give an accurate description of the surface roughness. The model takes cavitation effects into account and considers Hertzian asperity contact. Results for the model, including Stribeck curves, are presented as a function of the duty parameter.

Comparisons of tribological properties between laser and drilled dimple textured surfaces of medium carbon steel

2017 ◽  
Vol 69 (4) ◽  
pp. 516-526 ◽  
Author(s):  
Chenchun Shi ◽  
Aibing Yu ◽  
Jianzhao Wu ◽  
Weiyang Niu ◽  
Yanlin Wang
Keyword(s):  
Tribological Properties ◽  
Wear Debris ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Heat Affect Zone ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Wear Properties ◽  
Content Type ◽  
Worn Surfaces

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.

A Model of Mixed Lubrication for the Repeated Sliding Problem Considering the Reloading Characteristic: Application to Ring/Liner Conjunction

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Chunxing Gu ◽  
Di Zhang ◽  
Xiaohong Ding ◽  
Shuwen Wang
Keyword(s):  
Mathematical Model ◽  
Cyclic Loading ◽  
Rough Surface ◽  
Mixed Lubrication ◽  
Metal Contact ◽  
Asperity Contact ◽  
Surface Contact ◽  
Loading Problem ◽  
Non Gaussian ◽  
Gaussian Surface

Abstract Loading, unloading, and reloading of rough surface contacts are common for most friction pairs. However, usually, only loading characteristic is concerned in the modeling of the cyclic loading problem. In this paper, a comprehensive mathematical model of mixed lubrication was developed for the lubricated friction pairs under cyclic loading. The metal contact was calculated by an improved asperity contact model of elastic–plastic with the loading, unloading, and reloading characteristics in consideration. The developed model was applied to the ring/liner conjunction, as its contact problem was the typical cyclic loading problem. Different from the previous studies, assuming the “virgin” topography of the rough surface, the current one accounts for the plastic deformation of surface asperities, occurring during the first few cycles and leading to the significant roughness modification. It appears that considering the reloading characteristics is necessary, whether it is a Gaussian surface contact or a non-Gaussian surface contact.

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