Lubricants最新文献_第9页

Tribological Improvement of Low-Viscosity Nanolubricants: MoO3, MoS2, WS2 and WC Nanoparticles as Additives 低粘度纳米润滑剂的摩擦学改进：作为添加剂的 MoO3、MoS2、WS2 和 WC 纳米粒子

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-10 DOI: 10.3390/lubricants12030087

José M. Liñeira del Río, Carlos Fernandes, Jorge H. O. Seabra

引用次数: 0

Calculation and Analysis of Equilibrium Position of Aerostatic Bearings Based on Bivariate Interpolation Method 基于双变量插值法的空气静力轴承平衡位置计算与分析

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-07 DOI: 10.3390/lubricants12030085

Shuai Li, Yafu Huang, Hechun Yu, Wenbo Wang, Guoqing Zhang, Xinjun Kou, Suxiang Zhang, Youhua Li

{"title":"Calculation and Analysis of Equilibrium Position of Aerostatic Bearings Based on Bivariate Interpolation Method","authors":"Shuai Li, Yafu Huang, Hechun Yu, Wenbo Wang, Guoqing Zhang, Xinjun Kou, Suxiang Zhang, Youhua Li","doi":"10.3390/lubricants12030085","DOIUrl":"https://doi.org/10.3390/lubricants12030085","url":null,"abstract":"The solution of equilibrium positions is a critical component in the calculation of the dynamic characteristic coefficients of aerostatic bearings. The movement of the rotor in one direction leads to bidirectional variations in the air film force, resulting in low efficiency when using conventional calculation methods. It can even lead to iterative divergence if the initial value is improperly selected. This study concentrates on the orifice throttling aerostatic bearings and proposes a novel method called the bivariate interpolation method (BIM) to calculate the equilibrium position. The equilibrium equation for the rotor under the combined influence of air film forces, gravity, and external loads is established. A calculation program based on the finite difference method is developed to determine the equilibrium position. The process of solving the equilibrium position and the convergence is compared with the secant method and the search method. Furthermore, the variation trend of the equilibrium position and stiffness when the external loads changes are studied based on the BIM. Finally, the correctness of the BIM to solve the equilibrium position is proved by comparing it with the experiment results. The calculation results indicate that the BIM successfully resolves the problem of initial value selection and exhibits superior computational efficiency and accuracy. The equilibrium position initially moves away from the direction of the external load as the load increases, and then this gradually approaches the load direction. The main stiffness increases with increases in the external load, while the variation in cross stiffness depends on the direction of the external load.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140259323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic Effect Analysis of Cryogenic Solid-Lubricated Ball Bearings with Geometrical-Frictional Defects 有几何摩擦缺陷的低温固体润滑球轴承的动态效应分析

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-06 DOI: 10.3390/lubricants12030084

Yuhao Zhao, Zhenyi Chen, Yanyang Zi, Mingquan Zhang, Tao Tang

{"title":"Dynamic Effect Analysis of Cryogenic Solid-Lubricated Ball Bearings with Geometrical-Frictional Defects","authors":"Yuhao Zhao, Zhenyi Chen, Yanyang Zi, Mingquan Zhang, Tao Tang","doi":"10.3390/lubricants12030084","DOIUrl":"https://doi.org/10.3390/lubricants12030084","url":null,"abstract":"The traction behavior in cryogenic solid-lubricated ball bearings (CSLBBs) of liquid rocket engines (LREs) has a significant effect on the dynamic response of the bearing–rotor system. To reveal the fault mechanism of CSLBBs, a tribo-dynamic model is proposed in this paper that considers the solid-lubricated traction, six-DOF motion of the ball and contact collisions between the ball and the cage. The modified traction model uses fan-shaped and arched sections to discretize the contact area to eliminate the meshing error. The newly developed fault model, called ‘geometrical-frictional defects’, can more realistically represent solid-lubrication coating defects. The results show that the frictional excitation can significantly increase bearing vibration by increasing the traction force on the raceway. The change in the amplitude of the bearing vibration and its derivative can be used as a reference to determine the depth of defects. The width of the defect can be diagnosed by monitoring the double-pulse time interval and spectrum of the bearing vibration signal. This research may provide some theoretical guidance for the design and condition monitoring of CSLBBs.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140262651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A New Plasticity Index including Size-Effects in the Contact of Rough Surfaces 粗糙表面接触中包含尺寸效应的新塑性指数

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-06 DOI: 10.3390/lubricants12030083

M. Ciavarella

{"title":"A New Plasticity Index including Size-Effects in the Contact of Rough Surfaces","authors":"M. Ciavarella","doi":"10.3390/lubricants12030083","DOIUrl":"https://doi.org/10.3390/lubricants12030083","url":null,"abstract":"It is known that contact of rough surfaces occurs over an area much smaller than the nominal contact area, and at asperity scale, increased hardness results in experimentally observed asperity “persistence”, namely that it is hard to flatten asperities. Here, we consider Persson’s elasto-plastic solution for rough contact together with an hardness equation proposed by Swadener, George and Pharr for spherical indentation, including size effects depending on sphere radius, in particular to define a new plasticity index that defines the tendency to plastic deformation. While the classical plasticity index shows that at sufficiently small scales, there will be plastic deformations unless surfaces are extremely smooth, and with size effects, the small roughness scales the content of spectrum matter in defining the real state of asperities. In particular, what may appear as plastic at a bulk scale returns to an elastic behaviour at a small scale, as suggested by the “asperity persistence” experimental observation. Some illustrative examples are shown, but clearly, our index and elasto-plastic solution are mainly qualitative, as a realistic investigation is much more complex and still computationally too demanding.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140262454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tribological Properties of Al2O3/Graphite-Al2O3 Laminated Composites under Water Lubrication Conditions 水润滑条件下 Al2O3/石墨-Al2O3 层状复合材料的摩擦学特性

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-05 DOI: 10.3390/lubricants12030081

Zhengxian Di, Zhijia Wang, Xiaoyu Zhang, Jiaxin Si, Junjie Song, Hengzhong Fan, Yunfeng Su, Litian Hu, Yongsheng Zhang

{"title":"Tribological Properties of Al2O3/Graphite-Al2O3 Laminated Composites under Water Lubrication Conditions","authors":"Zhengxian Di, Zhijia Wang, Xiaoyu Zhang, Jiaxin Si, Junjie Song, Hengzhong Fan, Yunfeng Su, Litian Hu, Yongsheng Zhang","doi":"10.3390/lubricants12030081","DOIUrl":"https://doi.org/10.3390/lubricants12030081","url":null,"abstract":"High-performance Al2O3/graphite-Al2O3 laminated composites exhibit an excellent self-lubricating ability for moving components, such as sliding shaft sleeves and dynamic seals. The tribological behaviors of Al2O3/graphite-Al2O3 laminated composites should be studied extensively under water working conditions. Here, we attempted to explore the practicability of the Al2O3/graphite-Al2O3 laminated composite as a sealing material from a tribological point of view under water lubrication conditions. The tribological properties and mechanism of friction and wear of laminated composite ceramics were investigated under dry sliding friction, water environment, and suspended particle working conditions. It was found that the Al2O3/graphite-Al2O3 laminated composite has a better friction performance under water lubrication compared to dry sliding because of the separation effects formed by a water molecule film and a transfer film. Meanwhile, the wear rate under dry contact was found to be approximately six times that under water lubrication conditions. Under the water lubrication conditions, the formation of graphite films and water-adsorbed layers improved the anti-wear properties of the laminated materials, and the friction coefficient and the wear rate were as low as 0.16 and 1.76 × 10−6 mm3/Nm, respectively. Under the suspended particle working condition, the solid particles destroyed the graphite lubricating film and abrasive wear dominated the wear mode. The Al2O3/graphite-Al2O3 laminated composite demonstrates a potential for application in dynamic sealing and sliding components.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydrophilized MoS2 as Lubricant Additive 作为润滑油添加剂的亲水 MoS2

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-05 DOI: 10.3390/lubricants12030080

M. H. Kabir, Darrius Dias, K. Arole, Reza Bahrami, Hung-Jue Sue, Hong Liang

{"title":"Hydrophilized MoS2 as Lubricant Additive","authors":"M. H. Kabir, Darrius Dias, K. Arole, Reza Bahrami, Hung-Jue Sue, Hong Liang","doi":"10.3390/lubricants12030080","DOIUrl":"https://doi.org/10.3390/lubricants12030080","url":null,"abstract":"Molybdenum disulfide (MoS2) has been used in a variety of lubrication products due to its highly tunable surface chemistry. However, the performance of MoS2-derived tribofilms falls short when compared to other commercially available antiwear additives. The primary objective of this study is to improve the tribological performance of MoS2 as an additive for lithium-based greases. This was achieved by functionalizing the particle with hydrophilic molecules, such as urea. Experimental results indicate that the urea-functionalized MoS2 (U-MoS2) leads to a notable decrease in the coefficient of friction of 22% and a substantial reduction in the wear rate of 85% compared to its unmodified state. These results are correlated with the density functional theory (DFT) calculation of U-MoS2 to theorize two mechanisms that explain the improved performance. Urea has the capability to reside both on the surface of MoS2 and within its interlayer spacing. Weakened van der Waals forces due to interlayer expansion and the hydrophilicity of the functionalized U-MoS2 surface are catalysts for both friction reduction and the longevity of tribofilms on hydrophilic steel surfaces. These findings offer valuable insights into the development of a novel class of lubricant additives using functionalized hydrophilic molecules.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140078622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on Grease Lubrication and Electric Erosion Characteristics in AC Electric Fields 交流电场中的润滑脂润滑和电腐蚀特性研究

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-04 DOI: 10.3390/lubricants12030079

Ziying Li, Feng Guo, Zhaogang Jing, Bing Li, Li Zhang, Xiaobo Wang

{"title":"Study on Grease Lubrication and Electric Erosion Characteristics in AC Electric Fields","authors":"Ziying Li, Feng Guo, Zhaogang Jing, Bing Li, Li Zhang, Xiaobo Wang","doi":"10.3390/lubricants12030079","DOIUrl":"https://doi.org/10.3390/lubricants12030079","url":null,"abstract":"Protecting motor bearings from electric erosion is crucial as electric vehicles evolve. To better understand how lubrication interacts with electric discharge within motor bearings during varying speeds of vehicle operation, an optical ball-on-disk tribometer was modified to investigate the influence of alternating current (AC) electric fields on film thickness, friction force under various lubrication regions, and discharge characteristics. The study revealed that in AC electric fields, as the lubrication state shifts from mixed lubrication to fluid lubrication region, the electrical characteristic of the lubricating oil film changes from resistive to capacitive, accompanied by an increase in discharge frequency. Under the elastohydrodynamic lubrication (EHL) region, an electrical potential difference between the surfaces separated by the lubrication film leads to a reduction in film thickness, which can be attributed to the generation of Joule heating. If the potential difference across the oil film increases to the threshold voltage, destructive discharge occurs with the emission of a significant amount of purple light. Joule heating generated by the AC electric fields also results in a reduction in the friction coefficient under the fluid lubrication region. However, due to the reduction in film thickness, the lubrication state eventually moves to mixed lubrication, leading to a substantial increase in the friction coefficient. In addition, the study also investigated the use of grease with a nanographite conductive additive. It was found that inappropriate additive amounts can lead to discharge phenomena occurring outside the contact region.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140266655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Composite of Carboxymethyl Cellulose/MXene and Span 60 as Additives to Enhance Tribological Properties of Bio-Lubricants 羧甲基纤维素/MXene 和 Span 60 复合物作为添加剂增强生物润滑剂的摩擦学特性

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-03-01 DOI: 10.3390/lubricants12030078

D. Gasni, Dieter Rahmadiawan, R. Irwansyah, Aldi Em Khalid

{"title":"Composite of Carboxymethyl Cellulose/MXene and Span 60 as Additives to Enhance Tribological Properties of Bio-Lubricants","authors":"D. Gasni, Dieter Rahmadiawan, R. Irwansyah, Aldi Em Khalid","doi":"10.3390/lubricants12030078","DOIUrl":"https://doi.org/10.3390/lubricants12030078","url":null,"abstract":"Bio-lubricants are the future of lubricants as a substitute for mineral lubricants; however, bio-lubricants have drawbacks, such as poor thermal-oxidative stability. In addition, during the friction process, the temperature of the lubricant increases, so the lubricant must have good thermal conductivity to conduct heat to the environment. To combat the drawbacks of bio-lubricants, some additives have been used to improve their performance as lubricants. Composites of carboxymethyl cellulose (CMC)/MXene and Span 60 as surfactants were used as additives in CPO with different compositions. The physicochemical properties of the addition of CMC/MXene and Span 60 in CPO have changed, including kinematic viscosity, TAN, thermal conductivity, and fatty acids, which have a positive impact on lubrication performance in terms of reducing oxidation processes and increasing thermal conductivity. From fatty acid composition tests and FTIR analysis, the additives work to suppress the oxidation process. A pin-on-disk test was performed to evaluate the tribological performances of bio-lubricants. The results show that CM 10 SP (0.5% wt of CMC and MXene and 1% wt Span 60) demonstrated a significant decrease in CoF and wear rate by 49% and 74%, respectively, at a load of 50 N and a speed of 1400 rpm compared to CPO without additives. An interface layer of CMC/MXene and Span 60, separating two surfaces, could induce wear on the surface of the disk and pin.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140269653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluating the Tribological Behaviour in Cutting Operations Using a Modified Ball-on-Disc Open Tribotester 使用改进型盘上球开放式摩擦磨损试验机评估切削作业中的摩擦学行为

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-02-28 DOI: 10.3390/lubricants12030077

Belal G Nassef, Florian Pape, G. Poll, Jan Schenzel, B. Bergmann, B. Denkena

{"title":"Evaluating the Tribological Behaviour in Cutting Operations Using a Modified Ball-on-Disc Open Tribotester","authors":"Belal G Nassef, Florian Pape, G. Poll, Jan Schenzel, B. Bergmann, B. Denkena","doi":"10.3390/lubricants12030077","DOIUrl":"https://doi.org/10.3390/lubricants12030077","url":null,"abstract":"Predicting the tribological behaviour in the secondary shear zone in the metal-cutting processes is considered a significant challenge in contemporary research. This work investigated the frictional performance in the secondary shear zone of a planing process using a modified ball-on-disc open tribometer. The values of the coefficient of friction (COF) were tracked between an AISI4140 + QT disc (chip) and a cemented carbide ball (cutting tool) coated with TiAlN under three contact pressures of 0.5, 1, and 2 GPa at a range of sliding speeds starting from 0.2 m/s to 1.6 m/s. The tests were conducted under both dry and lubricated conditions using three commercial cutting fluids of CSF 35 straight oil, Vasco 6000, and Zubora 67H emulsions. Also, the MWFs were tested for their rheological properties and wettability. The tribometer results validated the same COF trend as that in the actual metal-cutting experiments, particularly at 0.5 and 1 GPa in dry conditions. Moreover, Zubora 67H emulsion is proven to be the optimal choice due to it reducing the COF between the rubbing contacts by up to 78%. Furthermore, it showed the lowest contact angle and viscosity index, revealing its ability to easily penetrate, especially at higher temperatures, within the secondary cutting zone.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140422715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study of the Effect of Static Eccentricity on Vibration Damping Properties of Squeeze Film Dampers Considering the Two-Phase Flow Case 考虑两相流情况下静态偏心率对挤压薄膜阻尼器振动阻尼特性的影响研究

IF 3.5 3区工程技术

Lubricants Pub Date : 2024-02-27 DOI: 10.3390/lubricants12030075

Hai Zhou, Liang Fang, Ming Zhang, Gangyi Cao, Jianyang Su

{"title":"Study of the Effect of Static Eccentricity on Vibration Damping Properties of Squeeze Film Dampers Considering the Two-Phase Flow Case","authors":"Hai Zhou, Liang Fang, Ming Zhang, Gangyi Cao, Jianyang Su","doi":"10.3390/lubricants12030075","DOIUrl":"https://doi.org/10.3390/lubricants12030075","url":null,"abstract":"To analyze the effect of static eccentricity on the air ingestion distribution and vibration damping properties of the SFD, a numerical simulation study of SFDs considering two-phase flow was carried out based on CFD using a transient solution method and dynamic mesh technique. The results show that the angle between the static eccentricity direction and the circumferential direction of the oil supply hole increases and the air ingestion area in the oil film expands. In contrast, the oil film damping decreases, and the larger the static eccentricity distance, the greater its effect on the air ingestion area in the oil film. When the circumferential angle is small, the oil film damping increases with the increase of static eccentricity distance, and when the circumferential angle is large, the oil film damping decreases with the increase of static eccentricity distance and then increases. With the increase of static eccentricity distance, the air ingestion area at both ends of the oil film increases. At the same time, studying the effect of dynamic eccentricity shows that as the dynamic eccentricity increases, the oil film damping first decreases and then increases, and the air ingestion area increases. Comparing the 1 hole, the 2 hole, and the 3 hole oil supplies, the air ingestion area is significantly larger in the 1 hole oil supply than in the 2 hole or the 3 hole oil supplies, and the oil film damping of the 1 hole oil supply is smaller than the oil film damping of the 2 hole or the 3 hole oil supplies. It can be seen from the present study that in the actual installation of the SFD, when the circumferential angle is less than 60°, the static eccentricity can be increased appropriately. When the circumferential angle is greater than 60°, the static eccentricity can be appropriately reduced.","PeriodicalId":18135,"journal":{"name":"Lubricants","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140426614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0