Assessment of artificial neural network for thermohydrodynamic lubrication analysis

2020 ◽  
Vol 72 (10) ◽  
pp. 1233-1238 ◽  
Author(s):  
Nenzi Wang ◽  
Chih-Ming Tsai
Keyword(s):  
Peer Review ◽  
Surrogate Model ◽  
Content Type ◽  
Lubrication Performance ◽  
Fast Solution ◽  
Artificial Neural ◽  
Computationally Intensive ◽  
Hidden Layer ◽  
Maximum Minimum ◽  
Generalized Reynolds Equation

Purpose In this study, artificial neural networks (ANNs) are constructed and validated by using the bearing data generated numerically from a thermohydrodynamic (THD) lubrication model. In many tribological simulations, a surrogate model (meta-model) for obtaining a fast solution with sufficient accuracy is highly desired. Design/methodology/approach The THD model is represented by two coupled partial differential equations, a simplified generalized Reynolds equation, considering the viscosity variation across the film thickness direction and a transient energy equation for the 3-D film temperature distribution. The ANNs tested are having a single- or dual-hidden-layer with two inputs and one output. The root-mean-square error and maximum/minimum absolute errors of validation points, when comparing with the THD solutions, were used to evaluate the prediction accuracy of the ANNs. Findings It is demonstrated that a properly constructed ANN surrogate model can predict the THD lubrication performance almost instantly with accuracy adequately retained. Originality/value This study extends the use of ANNs to the applications other than the analyses dealing with experimental data. A similar procedure can be used to build a surrogate model for computationally intensive tribological models to have fast results. One of such applications is conducting extensive optimum design of tribological components or systems. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0109/

Influence of microdimple on lubrication performance of textured plunger pump

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hekun Jia ◽  
Zeyuan Zhou ◽  
Bifeng Yin ◽  
Huiqin Zhou ◽  
Bo Xu
Keyword(s):  
Peer Review ◽  
Surface Texture ◽  
High Performance ◽  
Combustion Engine ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Content Type ◽  
Lubrication Performance ◽  
Simulation Results ◽  
The Cost

Purpose The purpose of this study is to investigate the influence of dimple radius, depth and density on the lubrication performance of the plunger. Design/methodology/approach A lubrication model was adopted to consider eccentricity and deformation during the working process of the plunger, and a rig test was performed to confirm the simulation results. The texture was fabricated using laser surface texturing. Findings The simulation results suggested that when dimple radius or depth increases, oil film thickness of the plunger increases before decreasing, and asperity friction displays an opposite trend. Therefore, appropriate microdimple texture could facilitate lubrication performance improvement and reduce the wear. Microdimples were then lased on the plunger surface, and a basic tribological test was conducted to validate the simulation results. The experimental results suggested that the average friction coefficient decreased from 0.18 to 0.13, a reduction of 27.8%. Social implications The introduction of microdimple on a plunger couple to reduce friction and improve lubrication is expected to provide a new approach to developing high-performance plunger couple and improve the performance of the internal combustion engine. If applied, the surface texture could help reduce friction by around 27% and cap the cost relative to the plugger friction. Originality/value The microdimple texture was introduced into the plunger couple of a vehicle to reduce the friction and improve the performance. Findings suggested that surface texture could be used in the automotive industry to improve oil efficiency and lubrication performance. Peer review The peer review history for this article is available at: http://dx.doi.org/10.1108/ILT-07-2020-0259.

Tribological properties of MoS2 powder-lubricated interface

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cong Liu ◽  
Yanguo Yin ◽  
Baohong Tong ◽  
Guotao Zhang
Keyword(s):  
Peer Review ◽  
Tribological Properties ◽  
Testing Machine ◽  
Point Contact ◽  
Contact Friction ◽  
Content Type ◽  
Friction Noise ◽  
Sliding Interface ◽  
Lubrication Performance ◽  
Powder Lubrication

Purpose This study aims to investigate the effect of MoS2 powder on tribological properties of sliding interfaces. Design/methodology/approach Loose MoS2 powder was introduced in the gap of point-contact friction pairs, and sliding friction test was conducted using a testing machine. Friction noise, wear mark appearance, microstructure and wear debris were characterized with a noise tester, white-light interferometer, scanning electron microscope and ferrograph, respectively. Numerical simulation was also performed to analyze the influence of MoS2 powder on tribological properties of the sliding interface. Findings MoS2 powder remarkably improved the lubrication performance of the sliding interface, whose friction coefficient and wear rate were reduced by one-fifth of the interface values without powder. The addition of MoS2 powder also reduced stress, plastic deformation and friction temperature in the wear mark. The sliding interface with MoS2 powder demonstrated lower friction noise and roughness compared with the interface without powder lubrication. The adherence of MoS2 powder onto the friction interface formed a friction film, which induced the wear mechanism of the sliding interface to change from serious cutting and adhesive wear to delamination and slight cutting wear under the action of normal and shear forces. Originality/value Tribological characteristics of the interface with MoS2 powder lubrication were clarified. This work provides a theoretical basis for solid-powder lubrication and reference for its application in engineering. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0150/

Coupling analysis of the fatigue life and the TEHL contact behavior of ball screw under the multidirectional load

2020 ◽  
Vol 72 (10) ◽  
pp. 1285-1293
Author(s):  
Jia-Jia Zhao ◽  
Ming-Xing Lin ◽  
Xian-Chun Song ◽  
Nan Wei
Keyword(s):  
Fatigue Life ◽  
Film Thickness ◽  
Peer Review ◽  
Elastohydrodynamic Lubrication ◽  
Contact Model ◽  
Ball Screw ◽  
Content Type ◽  
Entrainment Velocity ◽  
Contact Points ◽  
Lubrication Performance

Purpose This paper aims to provide thermal elastohydrodynamic lubrication (TEHL) contact model to study all balls’ lubrication performance of the ball screw when the multidirectional load is applied. Design/methodology/approach A new TEHL contact model combining the multidirectional load and the roughness surface texture is established to describe fatigue life of the ball screw. Meanwhile, the authors use the Reynolds equation to study the lubrication performance of the ball screw. Findings When the multidirectional load is applied, contact load, slide-roll ratio and entrainment velocity of all balls have a periodic shape. The TEHL performance values at the ball-screw contact points including contact stress, shear stress, minimum film thickness and temperature rise are higher than that at the ball-nut contact points. The TEHL performance values increase with the increase of root mean square (RMS) except for the film thickness. In addition, the radial load of the ball screw has a significant effect on the fatigue life. Originality/value The results of the studies demonstrate the new TEHL contact model that provides the instructive significance to analyze the fatigue life of the ball screw under the multidirectional load. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0097/

Load carrying capacity of a novel magnetic-liquid double suspension fixed pad thrust bearing

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shengtong Wang ◽  
Ouyang Wu ◽  
Zhe Li ◽  
Bin Wang
Keyword(s):  
Peer Review ◽  
Magnetic Force ◽  
Thrust Bearing ◽  
Hydrodynamic Pressure ◽  
Magnetic Liquid ◽  
Content Type ◽  
High Speeds ◽  
Halbach Array ◽  
Lubrication Performance ◽  
New Type

Purpose Proposing a new type of water-lubricated thrust bearing meets the load-bearing requirements of high-power shaft-less rim driven thrusters. Design/methodology/approach The designs were tested by establishing a bearing thermal-fluid-magnetic comprehensive simulation model and developing bearing fluid film force and magnetic simulation. Lubrication performance tests were carried out on the bearing test rig. Findings The Halbach array of magnet blocks is able to reach the maximum magnetic force. The material of sheath can help increase the magnetism. The magnetism is able to reduce wear during low-speed and the start-stop phase, while the eddy current loss at high speeds will lead to a decrease in magnetic force. The experiment found that the bearing was more stable at low speeds and would not demagnetize due to the temperature rise, but it is necessary to pay attention to the running stability at high speeds to prevent rubbing and impact. Originality/value An innovative combination of hydrodynamic pressure and permanent magnetic repulsion was observed to form a magnetic-liquid double suspension bearing with large bearing capacity. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2020-0295

An improved TEHL analysis of textured roller bearings consider various texture parameters and slip

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junning Li ◽  
Ka Han ◽  
Wuge Chen ◽  
Xiaojie Tang ◽  
Qian Wang
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Contact Area ◽  
Surface Texturing ◽  
Elastohydrodynamic Lubrication ◽  
Content Type ◽  
Roller Bearings ◽  
Texture Parameters ◽  
Lubrication Performance ◽  
Texture Size

Purpose The purpose of this study is to reveal the lubrication performance of textured roller bearings under various texture size, texture depth, texture types and slip. Design/methodology/approach In the present study, the improved thermal elastohydrodynamic lubrication method based on the surface texturing of the textured roller bearings is proposed, and then the effect of texture size, texture depth, texture types and slip on the contact pressure, film thickness and temperature distribution are analyzed systematically. Findings The results show that the pressure decreases and the film thickness increases on the contact area because of the surface texturing. The temperature increases first and then decreases as the texture size increases, and then the temperature increases as the texture depth and the slip increases. Compared to circle and square texture, cross texture can obviously decrease the temperature on the contact area. The effectiveness of the proposed method is verified. Originality/value This study can help to reduce friction and wear of textured roller bearings. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2020-0318/

Study on tribological behavior, lubrication and anti-corrosion properties of W/O microemulsion for cold rolling of copper strip

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hao Wu ◽  
Sang Xiong ◽  
Wei Lin ◽  
Fanxin Kong
Keyword(s):  
Cold Rolling ◽  
Peer Review ◽  
Tribological Behavior ◽  
Copper Surface ◽  
Corrosion Properties ◽  
Copper Strip ◽  
Content Type ◽  
Base Oil ◽  
Lubrication Performance ◽  
Rolling Oil

Purpose The purpose of this paper is to improve lubrication and anti-corrosion properties of the water-in-oil (W/O) microemulsion for rolling of copper strip and sheet to replace the traditional rolling oil. Design/methodology/approach The W/O microemulsion is prepared by using hydrogenated base oil, a deionized aqueous solution of 0.03 mol/L of Na2SO4 and composite emulsifier such as Sp20, Tx-7 or sodium petroleum sulfonate. Tribological behavior of the microemulsions and traditional cold rolling oil was conducted by MR-10A four-ball tester. The lubrication performance of microemulsion for cold rolling of copper strip was performed by cold-rolling experiment. The morphology of worn surface and the rolled copper was characterized. Anti-corrosion properties of microemulsion for rolled copper was investigated, and the corroded surface was analyzed by X-ray photoelectron spectrometer (XPS). Findings The results show that the extreme pressure and antiwear properties of the microemulsions have been improved; the average friction coefficient of the improved microemulsion is 0.065, which is 30% lower than the commercial cold rolling oil. For cold rolling of copper strip, the microemulsion has a higher thinning effect than the commercial cold rolling oil, and a smooth surface is obtained and the surface roughness (Sa) is decreased by 6.8%. The XPS analysis indicated microemulsion adsorbed on the copper surface mitigate the corrosion of oils. Originality/value This paper used the prepared W/O microemulsion as a new lubricant in the process of rolling for copper strip and sheet in industry, demonstrating the microemulsion has broad application prospects in the future. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0227/

Theoretical optimization and experiment on lubrication of floating microgroove cylindrical seal

2020 ◽  
Vol 72 (10) ◽  
pp. 1217-1226
Author(s):  
Junjie Lu
Keyword(s):  
Finite Difference ◽  
Peer Review ◽  
High Precision ◽  
Optimization Model ◽  
Large Scale ◽  
Low Complexity ◽  
Central Difference ◽  
Content Type ◽  
Lubrication Performance ◽  
Optimal Function

Purpose The purpose of this paper is to analyze and improve the lubrication performance of a floating cylindrical seal by investigating micro spiral groove. Design/methodology/approach The lubrication model of is solved by finite difference, considering the influence of convergence eccentricity and Rayleigh step on the gas film period. A lubrication model, which is a gas film of floating microgroove cylindrical seal, is solved under high-precision central difference (finite-difference method-center) for the critical problems of convergence eccentricity and Rayleigh step. And then, an idea on the opening-leakage ratio is proposed, and a multiobjective optimization model is established. Finally, an experiment is conducted on a narrow gap to determine the gas film opening force and leakage by the modules of testing system, and the theoretical results are verified by real tests. Findings The theoretical calculation results agree well with the experimental data, which proves the correctness of the lubrication optimization model, and the optimized groove has better lubrication performance. On the other hand, the sealing pressure plays a more important role in the seal operation. Originality/value The theoretical model carries out low complexity and high sparseness, thus being very suitable for large-scale gas film problems. A multiobjective optimal function is established based on the opening-leakage ratio for optimizing groove. Finally, a curved groove of high precision and gas film opening force is obtained completely. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0048/

Tribological behaviors of water-based drilling mud with oleic acid-filled microcapsules as lubricant additives for steel-steel contact

2020 ◽  
Vol 72 (7) ◽  
pp. 835-843
Author(s):  
Min Ji ◽  
Shuhai Liu ◽  
Huaping Xiao
Keyword(s):  
Oleic Acid ◽  
Peer Review ◽  
Friction And Wear ◽  
Lubricant Additives ◽  
Drilling Mud ◽  
Content Type ◽  
Lubrication Performance ◽  
Water Based ◽  
Practical Implications ◽  
Ball On Disc

Purpose The purpose of this paper is to study the tribology behavior of steel–steel contact under the lubrication of water-based drilling mud with different oleic acid-filled microcapsules as lubricant additives. Design/methodology/approach A ball-on-disc tribometer was used to evaluate the lubrication properties of the steel–steel contact. The wear tracks of the worn surfaces were observed by a scanning electron microscope. Findings Results show that the dependence of both friction and wear on the category of additives shares a consistent pattern. In contrast to oleic acid and empty microcapsules, oleic acid-filled microcapsules achieve the best tribological performance which is related to the lubricant effect of oleic acid and the isolation and rolling abilities of microcapsules. Practical implications This study provides a helpful method of encapsulated lubricant additives to prolong lubrication performance for steel–steel contact. Originality/value This study has applied microcapsules to improve the tribological properties of drilling mud. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0320/

Study on high-temperature wear and mechanism of Al-Si/graphite composites prepared by the die-casting process

2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Peer Review ◽  
Die Casting ◽  
Casting Machine ◽  
Injection Pressure ◽  
Casting Process ◽  
Matrix Alloy ◽  
Content Type ◽  
The Matrix

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/

Socioeconomic effects of pension spending: evidence from Spain

2020 ◽  
Vol 47 (5) ◽  
pp. 599-617
Author(s):  
Fernando Bermejo ◽  
Eladio Febrero ◽  
Andre Fernandes Tomon Avelino
Keyword(s):  
Peer Review ◽  
Social Protection ◽  
Pension System ◽  
Decomposition Analysis ◽  
Value Added ◽  
Total Output ◽  
Alternative View ◽  
Input Output ◽  
Structural Decomposition Analysis ◽  
Content Type

PurposeThe purpose of this study is to provide broader understanding of the significant role that the pension system has in the Spanish economy by estimating the sectoral production, employment and income sustained by pensioners' consumption.Design/methodology/approachBased on input–output tables by the World Input–Output Database and consumption data from the Household Budget Survey by the Spanish Statistical Office, a demoeconomic model is applied to quantify the direct impacts, indirect impacts from interindustry links and induced impacts from income–consumption connections over a nine-year period (2006–2014). Then, the factors driving the evolution of total output, employment and value added during such period have been examined by using structural decomposition analysis.FindingsThe growing participation of consumption by pensioner households in final demand had proven crucial during the 2008 crisis to alleviate the negative trend in production and employment derived from the collapse in consumption suffered by the rest of households.Practical implicationsDetermining the underlying factors driving changes in both employment and income during the 2008 crisis can be of interest in political decision-making on the sustainability of the Spanish pension system.Social implicationsThe results of estimating both the employment and income supported by pensioners' consumption reveal the significant stabilizing effect of the public spending on pensions, particularly during the 2008 crisis.Originality/valueThe current Spanish approach of attaining the pension system sustainability by merely reducing social protection costs ignores the adverse consequences of a lower pensioners' demand. This paper addresses an alternative view in which pension spending is not considered a burden on economic growth but rather a means of improving the level of production and employment.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0047

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