Lubrication Science最新文献

{"title":"Numerical Simulation Study on the Directional Transportation of Lubricating Oil Induced by Bionic Concave and Convex Structures","authors":"Deliang Liu,&nbsp;Zhenyao Liu,&nbsp;Chuanlong He,&nbsp;Jun Liu,&nbsp;Chengda Gao,&nbsp;Meihua Jin","doi":"10.1002/ls.70036","DOIUrl":"https://doi.org/10.1002/ls.70036","url":null,"abstract":"<div>\u0000 \u0000 <p>We use computational fluid dynamics (CFD) simulations to clarify that geometric microstructures can affect the directional transportation of lubricating oil and analyse its transportation mechanism. Two types of geometric microstructures were designed: concave (Open Cylindrical Groove Surface and Cylindrical Groove and Spherical Pit Surface) and convex (Inclined Trapezoidal Surface, Cactus Spine-Inspired Inclined Surface, and Araucaria Leaf-Inspired Surface). The CFD method was employed to analyse the lubricating oil transport on these structures. Additionally, 3D printing experiments were conducted on the Araucaria Leaf–Inspired Surface (ALIS) structure for verification. The research findings indicate that in concave structures, lubricating oil transport depends more on groove shape, while in convex ones, it is due to gaps between adjacent rows. Vertically, the wedge-shaped cavity of ALIS generates a larger Laplace pressure, allowing the oil to reach a 24.6 mm height in 20 s. Adjusting the area occupancy of ALIS from 43.8% to 50.7% increases the transport height, which peaks at 50.7% and then drops. The comparison of 3D printing and simulation strongly validates the CFD method, as their heights and states are highly consistent.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 6","pages":"347-359"},"PeriodicalIF":2.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the Contact Characteristics Between Non-Gaussian Rough Spheres and Rigid Smooth Surfaces Under Mixed Lubrication Conditions","authors":"Yu Zhang,&nbsp;Zhiqiang Gao,&nbsp;Haonan Dong,&nbsp;Jinfa Liu,&nbsp;Xian Wei,&nbsp;Weiping Fu,&nbsp;Wen Wang","doi":"10.1002/ls.70035","DOIUrl":"https://doi.org/10.1002/ls.70035","url":null,"abstract":"<div>\u0000 \u0000 <p>The ball screw serves as one of the primary transmission modes in the feed system of machine tools, where the contact performance between the roller and the track during operation is a crucial factor influencing machining accuracy. Traditional research has often simplified the contact between two rough surfaces to a rigid plane and a Gaussian-distributed rough surface; however, it has been observed that the actual surface exhibits non-Gaussian roughness characteristics. Consequently, this study proposes a mixed lubrication contact model that incorporates non-Gaussian rough surfaces. This model analyses the effects of surface topography parameters on normal and tangential contact forces, as well as the actual contact area. Additionally, the fluid Reynolds equation for lubrication on non-Gaussian rough surfaces is established to explore the coupling relationship between fluid parameters and non-Gaussian surface parameters. Through these analyses, the impact of multi-factor coupling on the frictional contact performance between rollers and tracks under mixed lubrication conditions is revealed, thereby providing a theoretical foundation for optimising the static and dynamic analysis of precision feed systems in machine tools.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 6","pages":"360-379"},"PeriodicalIF":2.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic Response of Faults Cylindrical Bearings Under Starved Lubrication","authors":"Zinan Wang,&nbsp;Haohua He,&nbsp;Peng Zhou,&nbsp;Xiaotian Bai,&nbsp;Jian Zhang","doi":"10.1002/ls.70033","DOIUrl":"https://doi.org/10.1002/ls.70033","url":null,"abstract":"<div>\u0000 \u0000 <p>The stable operation of cylindrical roller bearings is crucial for the proper functioning of machinery. However, uneven loading of the bearings may lead to roller faults and starved lubrication, which can seriously affect bearing operation. The dynamic mechanism of the bearing is varying greatly with the normal condition. In this study, considering the roller fault and starved lubrication effect, a dynamic model is established through Hertz contact theory and elastohydrodynamic lubrication theory. Then, the evolution of lubricant film thickness in faulty rollers is analysed. Meanwhile, through phase trajectory diagrams, Poincaré diagrams, time-domain diagrams and frequency-domain diagrams, the effects of different fault sizes on the bearing vibration are also researched. In addition, the dynamic and lubrication experiment platform is set up, and the experiment data can be obtained. The results show that with the increase of roller faulty sizes, the oil film distribution becomes uneven and the lack of oil becomes more obvious, and nonlinear vibration signals become more complex. Finally, the frequency related to the roller fault frequency in the spectrogram can be clearly identified, such as <i>nf</i>_<i>c</i> and <i>mf</i>_<i>b</i> <i>± nf</i>_<i>c</i>. The maximum frequency error between simulation and experiment data is 3.8%, and the model accurately describes the fault frequency characteristics caused by roller faults in cylindrical roller bearings.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 6","pages":"329-346"},"PeriodicalIF":2.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Wheel-Rail Adhesion Performance Under Water-Contaminated Conditions Considering Interface Geometry","authors":"Congcong Fang,&nbsp;Jiaming Tang,&nbsp;Xiaodong Xiao,&nbsp;Wei Zhou","doi":"10.1002/ls.70037","DOIUrl":"https://doi.org/10.1002/ls.70037","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper, a numerical model of wheel-rail adhesion under water-contaminated conditions is established. Wheel-rail profile and surface roughness are included to describe wheel-rail adhesion behaviour more accurately. The Average Reynolds equation, Boussinesq elasticity equation and the Greenwood-Tripp (GT) asperity contact formula are coupled to resolve mixed elastohydrodynamic lubrication (EHL) problem at the wheel-rail interface. The proposed model is validated by comparing the calculated wheel-rail adhesion coefficients with the experimental outcomes. Numerical simulations are carried out to observe the influence of running speeds, surface roughness and axle loads on the wheel-rail adhesion with water layer at the interface. In addition, the results of the simplified model based on the elliptical assumption were compared with those of the precise model that considers the actual wheel-rail contact geometry. The study results indicate that using the elliptical simplification can lead to significant errors in the estimation of wheel-rail adhesion. Therefore, when analysing wheel-rail adhesion behaviour, the variations in the geometric shape of the wheel-rail contact surface should not be neglected.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 6","pages":"380-392"},"PeriodicalIF":2.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148862489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal Elastohydrodynamic Lubrication Analysis of Offset ZI Worm Drive","authors":"Yaoting Yu,&nbsp;Yaping Zhao,&nbsp;Jiayue Ma,&nbsp;Zhiqiang Hao","doi":"10.1002/ls.70031","DOIUrl":"https://doi.org/10.1002/ls.70031","url":null,"abstract":"<div>\u0000 \u0000 <p>Thermal elastohydrodynamic lubrication (TEHL) performance of the offset ZI worm drive is analysed. To this end, the meshing process of the drive is first investigated to obtain the key meshing parameters within the conjugating zone. Based on these parameters, a TEHL numerical model for the offset ZI worm drive is subsequently established. Based on the meshing parameters within the conjugating zone which were obtained before, the TEHL characteristics of different positions within the entire conjugating zone are analysed. The working conditions that influence TEHL oil film formation and temperature rise are deliberated. The numerical results show that under different rotational speed and input torque conditions, the offset ZI worm drive exhibited excellent lubrication properties. Within the entire conjugating zone, a negative correlation is observed between oil film pressure and the equivalent curvature radius. The temperature is higher at the toe of the worm gear than the heel and exhibits a positive correlation with the slide-roll ratio (SRR). This study establishes a theoretical framework for the TEHL analysis of the line-conjugate spatial gearing with staggered axes.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 5","pages":"225-253"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of hBN Nanoparticle–Enhanced Engine Oil on the Tribological Behaviour of Al7075 Alloy","authors":"Cevher Kursat Macit,&nbsp;Merve Horlu,&nbsp;Burak Tanyeri,&nbsp;Bunyamin Aksakal","doi":"10.1002/ls.70027","DOIUrl":"https://doi.org/10.1002/ls.70027","url":null,"abstract":"<div>\u0000 \u0000 <p>Aluminium alloys, particularly Al7075, are extensively employed in aerospace and automotive applications owing to their high strength-to-weight ratio; however, their limited wear resistance under severe sliding conditions restricts wider utilisation. In this study, the tribological behaviour of Al7075 was systematically investigated under dry sliding, base oil lubrication, and lubrication with SAE 5 W-30 engine oil reinforced with hexagonal boron nitride (hBN) nanoparticles. The lubricant was modified with 1, 5, and 10 wt.% hBN, and the corresponding rheological behaviour was characterised prior to tribological testing. Pin-on-disc experiments were conducted under normal loads ranging from 10 to 50 N. In parallel, a tactile sensor–based approach was employed to reconstruct three-dimensional wear topographies, enabling quantitative assessment of wear depth and surface morphology. The results demonstrate that hBN nanoparticle reinforcement significantly enhances frictional and wear performance. The addition of hBN increased lubricant viscosity by approximately 25%, thereby improving load-bearing capacity and interfacial film stability. Under the highest applied load (50 N), dry sliding resulted in severe material loss (622 mg), whereas lubrication with 10 wt.% hBN reduced wear loss to 44 mg. The coefficient of friction decreased monotonically with increasing hBN concentration, reaching an overall reduction of approximately 90% relative to dry sliding conditions. SEM/EDS and cross-sectional analyses confirmed the formation of continuous hBN-rich tribo-layers with thicknesses in the range of ~200–500 nm. These tribo-layers acted as low-shear solid-lubricating films that filled surface grooves, reduced crack initiation, and promoted self-replenishing behaviour through debris compaction. Combined cross-sectional, topographical and tactile sensor analyses revealed a clear transition in dominant wear mechanisms. While unreinforced Al7075 exhibited severe abrasive, adhesive, and delamination wear, hBN-reinforced lubrication transformed the wear response toward milder abrasion coupled with controlled oxidative wear. The strong agreement between gravimetric wear measurements and sensor-based reconstructions further validated the reliability of the tactile sensing methodology for high-resolution wear characterisation. Overall, the integration of hBN-enhanced lubrication with tactile sensor–based wear quantification provides a robust and cost-effective strategy to reduce friction, suppress severe wear, and extend the service life of Al7075 components operating under high-load and boundary lubrication conditions.</p>\u0000 </div>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 5","pages":"254-284"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of Oleic Acid-Modified Graphite/Biodiesel Composite Lubricants and Its Synergistic Lubrication Mechanism in Water Based Drilling Fluids","authors":"Congcong Ma,&nbsp;Runkang Jiang,&nbsp;Guangbin Yang,&nbsp;Yujuan Zhang,&nbsp;Shuguang Fan,&nbsp;Pingyu Zhang,&nbsp;Shengmao Zhang","doi":"10.1002/ls.70029","DOIUrl":"https://doi.org/10.1002/ls.70029","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;With the gradual shift of global oil and gas exploration and development toward offshore, deep, ultra-deep, and high-displacement unconventional wells, the drilling process is increasingly challenged by excessive torque and high frictional resistance, which severely restrict drilling efficiency and operational safety. Meanwhile, under the background of increasingly stringent global environmental protection regulations, traditional oil-based drilling fluid lubricants are gradually becoming inapplicable due to poor biodegradability and severe environmental pollution. Thus, developing high-performance, environmentally friendly water-based drilling fluid lubricant has become an urgent demand in the oil and gas drilling industry. To address this critical issue, this study proposes a two-step strategy for modified graphite/biodiesel (MG/BD) composite lubricants: graphite was first surface-modified with oleic acid to enhance its dispersibility and compatibility with organic phases, followed by compounding with biodiesel (a renewable biomass derivative) to obtain the composite lubricant. Systematic tribological tests were conducted to assess the lubricating performance of the composite lubricant. The results demonstrate that the MG/BD composite lubricant exhibits excellent friction-reducing and anti-wear properties at room temperature. When 1.0 wt% of the MG/BD composite lubricant with 60% MG content was added to the base slurry, the friction coefficient was reduced by 89% compared with the base slurry without lubricant; even after thermal aging at 150°C for 16 h, the friction coefficient still maintained a 73% reduction efficiency, indicating good thermal stability. Comparative experiments with commercial water-based drilling fluid lubricants further confirm that the MG/BD composite lubricant has superior lubricating performance. The mechanism analysis reveals that the excellent tribological properties of the composite lubricant stem from a synergistic effect of bentonite dispersion regulation and solid–liquid composite lubrication. On one hand, BD components adsorb on bentonite surfaces to form a steric hindrance layer, while nano-MG particles intercalate into bentonite interlayers, jointly inhibiting bentonite agglomeration and enhancing drilling fluid stability. On the other hand, a stable solid–liquid composite lubricating film is formed on the metal friction pair surface: a composite solid film consisting of a continuous graphite solid lubricating film and an inorganic reaction film formed by iron oxides was formed to reduce direct contact between friction pairs. Simultaneously, BD forms a complementary liquid lubricating film to fill micro-pits and reduce shear resistance between the solid film and metal substrate. Even after 150°C aging, partial decomposition of BD and increased defects in the graphite film slightly degrade anti-wear performance, but the residual solid–liquid composite film still maintains effective lu","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 5","pages":"285-300"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Static and Dynamic Analysis of Porous Gas Bearings Lubricated With Air, Refrigerant R-134a, Helium and Hydrogen","authors":"S. Bechiri,&nbsp;B. Bouchehit,&nbsp;B. Bou-Saïd","doi":"10.1002/ls.70032","DOIUrl":"https://doi.org/10.1002/ls.70032","url":null,"abstract":"<p>Porous gas bearings (PGBs) enable high-speed, oil-free operation in modern rotating machinery. This study develops a coupled thermo-hydrodynamic (THD) model for a cylindrical porous gas bearing lubricated with four working fluids—air, R-134a, helium and hydrogen. The modified Reynolds equation is derived by combining the Navier–Stokes and continuity equations with the Morgan–Cameron approximation, Darcy–Forchheimer law and Beavers–Joseph slip condition. Gas compressibility and vapour–liquid transition are represented through the Peng–Robinson equation of state. Steady-state and dynamic analyses are performed to evaluate the influence of permeability and slip on load capacity, pressure distribution, flow rate, friction torque, temperature field and stiffness and damping coefficients. Results show that increasing permeability decreases pressure and load capacity but promotes better thermal uniformity, whilst higher slip coefficients improve film stability and reduce shear losses. Amongst the gases considered, hydrogen exhibits the lowest film thickness due to its low viscosity, whereas helium yields superior thermal behaviour. The combined model provides a reliable computational framework for optimising porous gas bearings under realistic operating conditions.</p>","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 5","pages":"301-326"},"PeriodicalIF":2.1,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ls.70032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148062996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":18114,"journal":{"name":"Lubrication Science","volume":"38 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148062997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}