Tribology Letters最新文献

{"title":"Transient Thermo-Elastohydrodynamic Response of a Rolling/Sliding Contact Traversing a Stationary Groove: A CFD-FSI Analysis","authors":"Peyman Havaej,&nbsp;Dieter Fauconnier","doi":"10.1007/s11249-026-02121-4","DOIUrl":"10.1007/s11249-026-02121-4","url":null,"abstract":"<div><p>The transient response of a Thermo-Elastohydrodynamic Lubrication (TEHL) contact, comprising a stationary surface with a single groove traversed by a rolling/sliding counter-body, is analysed using Computational Fluid Dynamics coupled with a structural solver. The developed model resolves the transient thermo-mechanical behaviour of TEHL line contacts with surface irregularities, capturing the load fluctuations induced by the groove and providing detailed insight into the evolution of pressure, temperature, Von Mises stress, and film thickness. The influence of groove geometry (depth and width), system equivalent mass, and slide-roll ratio (SRR) on these quantities is examined. The results demonstrate that the passage of the groove amplifies shear heating at the inlet and induces significant pressure perturbations, leading to localised film thinning near the groove edges. Whilst increasing groove depth intensifies pressure spikes and stress concentrations, wider grooves attenuate these fluctuations by enhancing lubricant entrapment and facilitating a more gradual hydrodynamic pressure recovery. These effects are most pronounced under near-rolling conditions (low SRR). By contrast, variations in system equivalent mass were found to have a negligible influence on the local pressure and temperature perturbations associated with the passage of a single groove.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147642404","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}

{"title":"Geometry-Driven Asymmetric Tribological Response in Laser-Patterned Cu Surfaces","authors":"Sebastian Suarez,&nbsp;Bruno Alderete,&nbsp;Fabian Bonner,&nbsp;Silas Schütz,&nbsp;Frank Mücklich","doi":"10.1007/s11249-026-02136-x","DOIUrl":"10.1007/s11249-026-02136-x","url":null,"abstract":"<div><p>This study investigates the fabrication of anisotropic saw-tooth topographies on copper surfaces using direct laser interference patterning (DLIP). By varying the structural periodicity (2, 7.5, and 10 µm) and manufacturing inclination angles (15, 30, and 45°), this work assesses the impact of periodic, deterministic surface topography on tribological performance. Linear reciprocating sliding tests against a hard ceramic counterbody demonstrated that these laser-patterned structures can successfully induce significant frictional anisotropy, while enduring 200 sliding cycles. A maximum frictional asymmetry coefficient of 77% was achieved for structures with a 7.5 µm periodicity manufactured at a 15° inclination angle. The results establish that maximizing asymmetry relies on generating shallower flank slopes; conversely, parameters producing steeper slopes resulted in similar friction coefficients regardless of sliding direction, minimizing the desired anisotropic effect. Regarding wear behavior, the grooves of the structured surfaces acted as effective reservoirs for worn material. Shallower manufacturing angles yielded deeper structures, which improved debris-retention capacity and maintained a mild wear regime by reducing the likelihood of three-body abrasion. The results showcase the ability to systematically tune the friction coefficient through laser-based surface modification techniques, highlighting the effects on friction and wear of deterministic asymmetrical geometries. The findings offer significant potential for applications such as sliding electrical connectors, where optimizing the ratio between insertion and retention forces is critical.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02136-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Understanding Wheel/Rail Interface Problems: The Unique Contributions and Legacy of Ken Johnson","authors":"Stuart L. Grassie","doi":"10.1007/s11249-026-02126-z","DOIUrl":"10.1007/s11249-026-02126-z","url":null,"abstract":"<div><p>Ken Johnson's work in several areas of railway research is explored and placed in the context of both the time that this took place and within previous and more especially subsequent developments. Ken's contributions on corrugation, shakedown, and rail damage are considered, in particular a rolling contact fatigue (RCF) defect known as a squat. Shakedown theory, which was used to propose a mechanism for initiation of squats, is used to demonstrate not only why squats were a consequence of very specific circumstances but also why they ceased to be a widespread problem in the mid-1990s. The work on shakedown undertaken by Ken and his colleagues is relevant not only to understanding modern-day rail defects but also to determining conditions that could help to avoid rail damage.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606688","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}

{"title":"Elucidation of the Low-Friction Mechanism in Sub-nanosecond Laser-Induced Amorphous Fe–C Layers Formed in Lubricating Oil","authors":"Xiaoxu Liu,&nbsp;Masato Yamanaka,&nbsp;Haruka Sasai,&nbsp;Satoru Maegawa,&nbsp;Shingo Ono,&nbsp;Fumihiro Itoigawa","doi":"10.1007/s11249-026-02133-0","DOIUrl":"10.1007/s11249-026-02133-0","url":null,"abstract":"<div><p>To enable in situ, machining-compatible surface modification, sub-nanosecond laser irradiation in polyalphaolefin (PAO) oil was used to directly form amorphous Fe–C layers on medium-carbon steel. In this study, the structural and tribological characteristics associated with the resulting low-friction behavior are investigated. Laser irradiation in oil enables simultaneous carbon incorporation and liquid-confined ultra-fast quenching, producing a fully amorphous Fe–C-rich layer (~ 150–200 nm). Ball-on-disk tests show sustained low friction (<i>μ</i> ≈ 0.10–0.12) only under sufficiently developed irradiation within an intermediate pulse energy range around 500–650 μJ; lower energies yield fragile/discontinuous layers, whereas excessive energy (1000 μJ) promotes crystallization as the solidification path approaches the TTT nose. AFM lateral-force measurements reveal progressive microscale friction reduction upon repeated sliding, accompanied by indentation evidence of softening limited to the topmost ~ 5 nm. Raman spectroscopy and cross-sectional transmission electron microscopy further demonstrate friction-induced partial structural ordering and carbon enrichment within a thin surface zone (~ 5–10 nm), while the underlying layer remains fully amorphous. These results suggest that the observed low-friction behavior is closely associated with a hierarchical structure combining a load-bearing amorphous Fe–C base layer with a dynamically formed, shear-facilitating surface tribo-layer.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147607044","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}

{"title":"Electrical Conductance of Oxidized Rough Sphere Contacts: A Greenwood–Tripp-Based Model","authors":"Vladislav A. Yastrebov","doi":"10.1007/s11249-026-02132-1","DOIUrl":"10.1007/s11249-026-02132-1","url":null,"abstract":"<div><p>Electrical conductance of rough contacts is strongly affected by the presence of surface oxides, particularly when oxide films are discontinuous and no clear separation of length scales exists between roughness, oxide morphology, and contact size. In this work, we develop a statistical model for electrical conductance in oxidized rough sphere contacts. Oxide films are represented as spatially heterogeneous insulating regions generated by thresholded Gaussian random fields, allowing controlled variation of oxide coverage and correlation length. Mechanical contact is treated within a Greenwood–Tripp-based formulation, while electrical conductance is evaluated using Greenwood’s constriction resistance model applied to the resulting population of <u>conducting</u> microcontacts. A comprehensive parametric study reveals the role of oxide morphology and allows to formulate a simple phenomenological model for the average conductance. This new model is in a good agreement with the extended Barber’s model.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147606968","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}

{"title":"Assessment of the Effect of Toothpaste Abrasiveness on Friction and Wear of Dental Fillings","authors":"Pavla Formánková,&nbsp;Veronika Pavliňáková,&nbsp;Pavel Čípek,&nbsp;Petr Svoboda,&nbsp;Alena Dančová,&nbsp;Lucy Vojtová,&nbsp;Martin Vrbka","doi":"10.1007/s11249-026-02128-x","DOIUrl":"10.1007/s11249-026-02128-x","url":null,"abstract":"<div><p>There is a notable deficiency in detailed investigations regarding the impact of abrasive elements on the friction and wear of dental restorations. Therefore, the primary objective of this study was to analyse how abrasive particles in toothpastes affect the friction and wear of dental fillings. The coefficient of friction (CoF) was evaluated as a time course from a brushing simulation conducted on a UMT TriboLab tribometer, which measured frictional and normal forces over a duration of 260 min. The tribological system consisted of three components: a Curaprox Ultra Soft 5460 toothbrush, a sample of dental filling material, and a mixture of artificial saliva (AS) combined with selected toothpaste. Six different toothpastes were evaluated (four for adults and two for children), varying in relative dentin abrasivity (RDA) values. Measurements with AS served as reference data. Wear was quantified by topographical analysis using a Bruker Contour GT-X optical profilometer to assess the samples before and after brushing, followed by volume loss calculations. Particle morphology was studied using a Tescan MIRA3 microscope, and the element analysis of evaluated toothpastes was performed using energy-dispersive X-ray spectroscopy (EDX). Results indicated that friction was highly variable, influenced by the random presence of particles in contact. While wear and particle size generally increased with RDA value, this relationship was not entirely consistent. Finally, it was revealed that the aggregate size of pastes and their density also affected the friction and wear of the fillings.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11249-026-02128-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Eco-Friendly Protic Ionic Liquids Water-Based Lubricant Additives Contributing to Green Tribology","authors":"Jing Yang,&nbsp;Xiao Liu,&nbsp;Qiang Chen,&nbsp;Pingxia Guo,&nbsp;Kai Feng,&nbsp;Meirong Cai","doi":"10.1007/s11249-026-02131-2","DOIUrl":"10.1007/s11249-026-02131-2","url":null,"abstract":"<div><p>As global environmental standards grow increasingly strict, developing eco-friendly, high-efficiency water-based lubrication additives has become a pivotal focus in tribology. In this work, three novel heterocycle-, phosphorus-, and sulfur-free protic ionic liquids (PILs), namely EDG-HA, EDG-OA, and EDG-LA, were successfully synthesized and employed as additives in aqueous lubricant systems with the objective of alleviating the environmental contamination and biological toxicity problems related to conventional lubricant additives. A systematic evaluation of the PILs revealed that lubricants blended with the additives demonstrate significantly superior corrosion protection and lubricating performance when compared to pure water. Specifically, the 1% EDG-LA lubricating solution reduced the friction coefficient (COF) and wear volume (WV) by approximately 69.3% and 94.5%, respectively. By combining quartz crystal microbalance (QCM) adsorption tests and X-ray photoelectron spectroscopy (XPS) analysis, the lubrication mechanisms were clarified: PILs form robust physical adsorption and tribo-chemical reaction film on metal friction pairs, effectively preventing direct metal-to-metal contact. The current research promotes the development of water-soluble additives with potential eco-friendly and high-efficiency through a novel perspective.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559951","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}

{"title":"The Effect of Base Stock Group on Molecular Structure and Tribological Performance","authors":"Feng Zhu,&nbsp;Yixi Shao,&nbsp;Boxi Tian,&nbsp;Zifei Zhao,&nbsp;Yichao Zhu,&nbsp;Liangyan Zheng,&nbsp;Weiwei Wang","doi":"10.1007/s11249-026-02127-y","DOIUrl":"10.1007/s11249-026-02127-y","url":null,"abstract":"<div><p>This study aimed to investigate the influence of molecular structure on the tribological performance. In this study, five types of base stocks were used as test samples. The molecular structures were characterized using gas chromatography–mass spectrometry (GC–MS) and nuclear magnetic esonance (NMR) spectroscopy. Tribological properties were evaluated using a ring–block friction and wear test rig. The results indicate that higher X_t/X_b ratios and higher X_NP values in base stocks correlated with lower friction coefficients and reduced wear-scar widths, which are attributed to the ordered molecular layers. The base stock’s molecular structure remained crucial for overall tribological performance in the presence of lubricant additives.</p></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560162","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}

{"title":"Effect of Contact Geometry on MoS2-Based Dry Film Lubricants","authors":"Samuel Leventini,&nbsp;Ashlie Martini","doi":"10.1007/s11249-026-02129-w","DOIUrl":"10.1007/s11249-026-02129-w","url":null,"abstract":"<div><p>MoS₂-based dry film lubricants are widely used in aerospace mechanisms that have different contact geometries. Standard tribotests for dry film lubricants simplify real geometries as either point or line contact to facilitate comparison of different materials or operating and environmental conditions. However, it remains unclear whether the results of a tribotest with one contact geometry can be generalized to tests or mechanisms with different contact geometries. To assess the effect of contact geometry, we measured friction and wear of three MoS₂-based dry film lubricants using reciprocating block-on-ring and pin-on-disk tests with the same initial Hertzian contact pressure and linear velocity. Friction and wear magnitudes, as well as some comparative trends between the dry film lubricants, differed for the two contact geometries. These findings encourage future studies to consider more than just point contact tribotests when evaluating MoS₂-based dry film lubricants.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441828","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}

{"title":"Multi-scale Study of the Lubricious Behaviour of Two Imidazolium-Based Ionic Liquids, [BMIM][PF6] and [BMIM][TFSI]","authors":"Calixe Bénier,&nbsp;Qianlu Zheng,&nbsp;Anna Igual-Muñoz,&nbsp;Rosa Espinosa-Marzal,&nbsp;Stefano Mischler","doi":"10.1007/s11249-026-02124-1","DOIUrl":"10.1007/s11249-026-02124-1","url":null,"abstract":"<div><p>Ionic liquids have garnered significant interest from the tribological community due to their exceptional physico-chemical properties, such as high thermal stability, tuneable viscosity, and strong surface adsorption. These properties make them promising candidates for advanced lubrication systems, offering potential to reduce friction and wear under diverse operating conditions. Here, the tribological behaviour of two ionic liquids (ILs), [BMIM][PF₆] and [BMIM][TFSI], was investigated across macro-, micro-, and nano-scales, focusing on lubrication regimes and their influence on friction. At the macro-scale, mixed lubrication dominated, with friction decreasing with sliding velocity due to the formation of a fluid film that partially separates the two surfaces; the friction force in this case is related to the ability of the IL to form thicker films and therefore, the IL viscosity. Conversely, at the nano- and micro-scales, boundary lubrication prevailed under much lower velocities and higher contact pressures (at the nano-scale), with adsorbed ion layers mitigating friction. The different friction coefficients of the two ILs are attributed to their different interaction with the steel surface. To eliminate the influence of the hydrodynamic film formation, the friction force at the macro-scale was extrapolated to 1 µm/s, i.e. within the range of velocities probed at nano- and micro-scale. In this regime, a correlation between friction and load across 8 orders of magnitude for each IL was observed. The relevance of plastic deformation and scratching at the level of asperity contacts underlying the tribological performance at the three scales was highlighted and described using the Bowden &amp; Tabor model. Differences between the correlations of the two ILs were attributed to variations in shear strength and the structure of the adsorbed boundary films, with [BMIM][TFSI] forming more cohesive and lubricious layers at low loads. The results emphasize the interplay between lubrication regimes, contact mechanics, and material properties in determining tribological performance across scales, offering insights for advanced lubricant design.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":806,"journal":{"name":"Tribology Letters","volume":"74 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147363244","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}