Friction最新文献_第8页

An extension of Hertz’s formula for the stiffness of conformal spherical contacts 关于共形球面接触刚度的赫兹公式的推广

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-24 DOI: 10.26599/frict.2025.944113

Alberto Betti, Paola Forte, Enrico Ciulli

引用次数: 0

From sparks to wear: Understanding arc erosion and tribological mechanisms in pantograph-catenary systems under irregular wire conditions 从火花到磨损：了解不规则导线条件下受电弓接触网系统的电弧侵蚀和摩擦学机制

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-24 DOI: 10.26599/frict.2025.9441102

Dehui Ji, Siyang Chen, Haihong Wu, Guoliang Wu, Minhao Zhu, Mingxue Shen

{"title":"From sparks to wear: Understanding arc erosion and tribological mechanisms in pantograph-catenary systems under irregular wire conditions","authors":"Dehui Ji, Siyang Chen, Haihong Wu, Guoliang Wu, Minhao Zhu, Mingxue Shen","doi":"10.26599/frict.2025.9441102","DOIUrl":"https://doi.org/10.26599/frict.2025.9441102","url":null,"abstract":"The pantograph-catenary system bears the crucial task of supplying electrical energy to high-speed trains. However, as train speeds continue to climb, irregularities in the contact wire exacerbate vibrations within the pantograph-catenary system, frequently triggering pantograph arcs. To delve deeper into the characteristics and erosion mechanisms of these arcs, this study employed high-speed cameras and photodiodes to precisely capture the evolution of arc morphology and fluctuations in arc intensity triggered by contact pair irregularities. By adjusting the current intensity, we further analyzed the impact of arc discharge on the friction and wear performance of carbon strips, as well as their current-carrying efficiency. The study found that when the current is sufficiently high, the arc column of the old arc, which forms when the contact pair separates, connects with the arc root of the new arc that is yet to make contact, leading to the formation of a continuous arc. Additionally, under the same current conditions, the arc intensity prior to contact between the tribo-pair is notably weaker than that at the moment of separation. Furthermore, parameters such as arc ignition rate, wear volume, and temperature all positively correlate with current intensity. Severe arc discharge not only deteriorates the electrical performance of the system, causing current distortion, but also exacerbates the instability of system operation. Abrupt changes in the friction coefficient can serve as a harbinger of intense arcs between the contact pair. Arc erosion causes severe damage to the current-carrying tribo-pairs, with ablation pits riddled with thermal cracks and pores, and leaving behind numerous molten copper particles, significantly increasing the wear volume. This study provides strong support for understanding the arc erosion process caused by contact wire irregularities and the mechanisms underlying abnormal wear of carbon strips.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"71 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Improving compatibility and tribological performance via supramolecular gelation of MoS2 nanoparticles in Perfluoropolyether lubricants 全氟聚醚润滑油中二硫化钼纳米颗粒的超分子凝胶化改善相容性和摩擦学性能

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-22 DOI: 10.26599/frict.2025.9441094

Yanyan Bai, Xuzhi Hu, Ming Zhang, Qiangliang Yu, Yijing Liang, Yang Wu, Meirong Cai, Feng Zhou, Weimin Liu

{"title":"Improving compatibility and tribological performance via supramolecular gelation of MoS2 nanoparticles in Perfluoropolyether lubricants","authors":"Yanyan Bai, Xuzhi Hu, Ming Zhang, Qiangliang Yu, Yijing Liang, Yang Wu, Meirong Cai, Feng Zhou, Weimin Liu","doi":"10.26599/frict.2025.9441094","DOIUrl":"https://doi.org/10.26599/frict.2025.9441094","url":null,"abstract":"Perfluoropolyether (PFPE) oils pose challenges in their compatibility with nanoparticle lubrication additives due to their unique molecular structure, limiting their lubrication performance enhancement. To address this issue, we propose the development of nanoparticle composite supramolecular gel lubricants, aiming to maintain the dispersion stability of molybdenum disulfide (MoS2) nanoparticles within PFPE lubricants. It was achieved by harnessing the self-assembled three-dimensional network structure of supramolecular gels to entrap MoS2 nanoparticles. It was observed that MoS2 nanoparticles tended to cluster and settle in PFPE oils. However, the MoS2-composite PFPE supramolecular gel lubricant (gel@MoS2) exhibited exceptional dispersion stability over an extended period. MoS2 nanoparticles used as additives in PFPE-based supramolecular gel lubricants not only enhanced mechanical strength but also retained outstanding thixotropic properties. Additionally, nanoparticles improved extreme pressure performance, anti-friction capabilities and anti-wear properties of PFPE-based supramolecular gel lubricants under high loads of 300N. Furthermore, the lubrication mechanism of gel@MoS2 composites was elucidated using focused ion beam-transmission electron microscopy and X-ray photoelectron spectroscopy. During the friction process, the 3D networks of supramolecular gels, held together by weak interaction forces like H-bonds, halogen bonding, and van der Waals forces, were disrupted under continuous shear forces. Consequently, some of the MoS2 nanoparticles and gelators migrated to the steel surface, forming a protective lubricating film. This research holds significant importance in prolonging the lifespan of equipment in critical sectors such as aerospace and aviation, where high-end lubrication is essential.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"56 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 wear performance and mechanism of pantograph contact strip that contact with damaged contact wire under ambient humidity 环境湿度条件下受电弓接触带与破损接触线接触的磨损性能及机理研究

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-20 DOI: 10.26599/frict.2025.9441101

Xingshuai Zhi, Ning Zhou, Yao Cheng, Haifei Wei, Yongming Yao, Weihua Zhang, Guangxiong Chen

{"title":"Study on wear performance and mechanism of pantograph contact strip that contact with damaged contact wire under ambient humidity","authors":"Xingshuai Zhi, Ning Zhou, Yao Cheng, Haifei Wei, Yongming Yao, Weihua Zhang, Guangxiong Chen","doi":"10.26599/frict.2025.9441101","DOIUrl":"https://doi.org/10.26599/frict.2025.9441101","url":null,"abstract":"Studies have focused on the significant impact of contact wire damage on the abnormal wear of pantograph contact strips. Initially, based on field data analysis, identify the most common types of contact wire damage. Subsequently, experiments and wear performance analysis of contact strip that contact with damaged contact wire were conducted under high and low humidity, respectively. Finally, correlation analysis was employed to explore the influence of various factors on strip wear performance. The results indicate that excessive wear occurs on the contact strip with pitted contact wire (PC), particularly under low humidity, where the strip wear rate is 2.2 times higher than that contact with normal contact wire (NC). While contact with PC, the primary wear mechanisms of the contact strip include material transfer and arcing ablation under high humidity, but involve material transfer, arcing ablation, and microcutting under low humidity. Correlation analysis results show that under low humidity, the parameters related to PC have the greatest impact on the wear rate of the contact strip, with a significant increase in mechanical wear proportion. Based on these findings, it can be concluded that both contact wire damage and reduced humidity contribute to more severe abnormal wear of the contact strip, with the influence of PC conditions being more excessive wear than that of reduced humidity on wear performance.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"40 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Atomistic study of material removal behavior during ultrasonic vibration-assisted nanoscratching of single-crystal AlN 超声振动辅助AlN单晶纳米刮擦过程中材料去除行为的原子学研究

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441097

Shuaicheng Feng, Jian Guo, Jiaqin Yin, Hanqiang Wu, Linmao Qian, Chen Xiao

{"title":"Atomistic study of material removal behavior during ultrasonic vibration-assisted nanoscratching of single-crystal AlN","authors":"Shuaicheng Feng, Jian Guo, Jiaqin Yin, Hanqiang Wu, Linmao Qian, Chen Xiao","doi":"10.26599/frict.2025.9441097","DOIUrl":"https://doi.org/10.26599/frict.2025.9441097","url":null,"abstract":"Molecular dynamics simulations were used to investigate surface material removal and subsurface damage at nanoscale to atomic-scale during ultrasonic vibration-assisted (UVA) nanoscratching of monocrystalline AlN with a single-point diamond tip. Simulation results suggest UVA-scratching exhibits lower tangential force, normal force, and friction coefficient under the same scratching depth as ordinary scratching. UVA-scratching demonstrates stronger material removal than ordinary scratching due primarily to the vibration-induced rise of the local temperature to facilitate atomic bond breakage and lateral extension of stacking faults in the superficial layer. Uniform monolayer removal consisting of the outermost Al atoms and the connected N atoms is easier to achieve in the scratching path with UVA-scratching mode than with the ordinary scratching mode. UVA-scratching produces a smoother scratched surface. For instance, the root mean square of the surface after UVA-scratching is only about one-third of that after ordinary scratching at the same scratching depth. Furthermore, utilizing ultrasonic vibration can reduce scratching-induced material pile-up and the subsurface damage primarily consisting of dislocations and stacking faults. This is because vibration can reduce the stress distribution range and restrain stress concentration. This work can provide useful knowledge for high-quality and efficient ultra-precision surface machining for hard-brittle materials.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"194 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Synthesis of nature inspired, phosphorylcholine moieties and poly(ethylene oxide) brushes containing copolymers which synergise steric repulsion and hydration lubrication for articular cartilage 合成自然启发，磷胆碱部分和聚（环氧乙烷）刷含有共聚物协同立体排斥和水合润滑关节软骨

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441095

Marijus Jurkūnas, Ke Ren, Vaidas Klimkevičius, Prashant K Sharma, Ričardas Makuška

{"title":"Synthesis of nature inspired, phosphorylcholine moieties and poly(ethylene oxide) brushes containing copolymers which synergise steric repulsion and hydration lubrication for articular cartilage","authors":"Marijus Jurkūnas, Ke Ren, Vaidas Klimkevičius, Prashant K Sharma, Ričardas Makuška","doi":"10.26599/frict.2025.9441095","DOIUrl":"https://doi.org/10.26599/frict.2025.9441095","url":null,"abstract":"Inspired by nature, a hydrophilic diblock brush copolymers containing both phosphorylcholine groups and PEO side chains were synthesized by successive RAFT polymerization of the zwitterionic monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) and PEO-containing macromonomer poly(ethylene oxide) methyl ether methacrylate (PEOMEMA) for the first time.  Lubricating effect of several diblock brush copolymers and one gradient copolymer of MPC and PEOMEMA was evaluated by tribological measurements in the systems PDMS–glass and cartilage–glass which were placed in PBS solutions of the polymers. The best lubrication was provided by the diblock copolymer with relatively long pMPC block and the copolymer of gradient structure. Average dynamic coefficient of friction (COF) in the system PDMS–glass at concentration of the copolymers 0.4 mg/ml was only 0.004– 0.007, while COF values of the copolymers in the system cartilage-glass after 450 cycles of sliding 0.06–0.07. Excellent lubrication effect of the diblock and gradient copolymers of MPC and PEOMEMA is attributed to hydration lubrication provided by pMPC synergistically combined with steric repulsion provided by PEOMEMA. Entrapment of diblock brush copolymers between sliding surfaces was sufficient to provide the lubrication effect. This enhances the efficacy of the diblock brush copolymers as potential additives for intraarticular injections.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"18 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Synergistic effects of oleic acid modified TiO2 and alkyl polysulfide in forming extreme pressure tribo-films: A mechanistic study 油酸修饰TiO2和烷基聚硫在形成极压摩擦膜中的协同效应：机理研究

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441098

Kai Zeng, Hongfei Shi, Liang Cheng, Li Zhang, Liang Feng, Hengyi Lu, Wenjing Hu, Jiusheng Li

{"title":"Synergistic effects of oleic acid modified TiO2 and alkyl polysulfide in forming extreme pressure tribo-films: A mechanistic study","authors":"Kai Zeng, Hongfei Shi, Liang Cheng, Li Zhang, Liang Feng, Hengyi Lu, Wenjing Hu, Jiusheng Li","doi":"10.26599/frict.2025.9441098","DOIUrl":"https://doi.org/10.26599/frict.2025.9441098","url":null,"abstract":"The synergistic effect of nanoparticles (NPs) with alkyl polysulfides represents a promising avenue for the enhancement of extreme pressure (EP) performance in lubricants, potentially reducing the reliance on sulfur-containing additives. However, the underlying synergistic mechanism remains unclear. In this study, oleic acid-modified titanium dioxide (TiO2-OA) NPs and dialkyl pentasulfide (DPS) formed a mechanically interlocked EP tribo-film with a maximum thickness of about 1.4 μm, demonstrating excellent load-bearing capabilities up to 7,256 N (6.1 GPa). Under conditions of EP friction, the addition of TiO2-OA NPs facilitates the development of a robust tribo-film of substantial thickness, which in turn bolsters the load-bearing capability of the lubricating oil. Surface analysis of EP wear scars using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) showed that TiO2-OA NPs were rapidly deposited and enriched at the friction interface with increasing load (3,530-7,256 N) and friction time (0-10 s), which in turn compensated in-situ the wear generated by extreme shear. Cross-sectional analysis of EP wear scars indicates that the preferential formation of ferrous sulfide (FeS) and subsequent rapid enrichment and mechanical interlocking of TiO2-OA NPs are essential for preventing welding and improving EP performance. The study presents novel insights into the synergistic mechanisms of NPs with sulfur-containing additives, advancing the widespread implementation and progress of NPs in the field of tribology.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"55 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Mixed and thermal elastohydrodynamic simulation of a low-loss gear considering the gear system 考虑齿轮系统的低损耗齿轮混合热弹流仿真

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441096

Felix Farrenkopf, Thomas Lohner, Karsten Stahl

引用次数: 0

Recent development in understanding the role of lipids in cartilage lubrication 脂质在软骨润滑中的作用的最新研究进展

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441014

Yumeng Xue, Xiaolian Niu, Jin Zhou, Lizhen Wang, Yubo Fan

{"title":"Recent development in understanding the role of lipids in cartilage lubrication","authors":"Yumeng Xue, Xiaolian Niu, Jin Zhou, Lizhen Wang, Yubo Fan","doi":"10.26599/frict.2025.9441014","DOIUrl":"https://doi.org/10.26599/frict.2025.9441014","url":null,"abstract":"Lubrication deficiency in articular cartilage (AC) triggers irreversible and progressive degradation of AC, termed osteoarthritis (OA). Bio-lubrication-based strategies have been proposed as effective ways to restore temporary cartilage lubrication for OA postponement or even OA healing. The design of lubricants has inspired an exploration of the reasons behind the low friction in cartilage and the components responsible for the lubrication function in cartilage. Recently, lipids, as emerging lubrication components in AC, have been extensively studied and confirmed to play essential roles in maintaining cartilage lubrication. This review brings forward the main challenges of establishing a satisfactory functional articular cartilage biomaterial with sufficient lubrication from the perspectives of the complexity of physiology and microenvironment of osteochondral tissue. Next, we comprehensively discuss lubrication models of AC, including the lubrication mechanism of AC, OA associated with lipids, lipid lubrication mechanism and application, and the synergistic effects of phospholipids in lubrication. In particular, we highlight the advantages and application of lipids and their derivatives in lubrication. Finally, we analyze the future prospects of lipid-based biomaterials to achieve the perfect treatment of OA. This comprehensive and instructive review can provide deep insights into our current understanding of lipids and lubrication-related diseases.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"16 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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

Hydrophobic soft cone-assisted rolling robot inspired by sea urchin for gastrointestinal tract delivery 受海胆启发的用于胃肠道输送的疏水软锥辅助滚动机器人

IF 6.8 1区工程技术

Friction Pub Date : 2025-03-18 DOI: 10.26599/frict.2025.9441099

Shenglin Yang, Yixuan Yang, Hongyuan Li, Jie Li, Yunrui Chen, Lin Xu, Bingsuo Zou, Yabin Zhang, Ben Wang

{"title":"Hydrophobic soft cone-assisted rolling robot inspired by sea urchin for gastrointestinal tract delivery","authors":"Shenglin Yang, Yixuan Yang, Hongyuan Li, Jie Li, Yunrui Chen, Lin Xu, Bingsuo Zou, Yabin Zhang, Ben Wang","doi":"10.26599/frict.2025.9441099","DOIUrl":"https://doi.org/10.26599/frict.2025.9441099","url":null,"abstract":"Miniature soft robots have evolved into various therapeutic applications due to good adaptability. Nonetheless, complex terrains inside body, especially soft wrinkled topography with non-Newtonian viscous mucus in the gastrointestinal tract, pose a strict demand on the navigation of such robots. To address the challenge, here a design inspiration derived from sea urchin is proposed to fabricate the soft-cone-assisted rolling robot (SCARBot) by encapsulating blood coagulation gel, creating a hollow cylindrical structure for loading drugs inside. The arrangement of an array of soft cones with manually designed hydrophobicity allows for controlled locomotion of the robots under low-frequency magnetic field, significantly reducing surface friction and improving environmental adaptability. This motion ability is further supported by US-imaging-guided navigation in an ex vivo and even in vivo gastrointestinal tract. When the high-frequency magnetic field is exerted, the drug-loaded blood coagulation gel sealed inside the robot melts by magnetothermal effect, thereby releasing drugs at the targeted location. The synergy of magnetothermal and pharmacological therapy enable this robot to exhibit enhanced antibacterial efficiency for ex vivo and in vivo bacterial infection and inflammation. Such soft robots with exceptional adaptability and therapeutic functions offer high potential for targeted delivery and therapy through lumens inside body.","PeriodicalId":12442,"journal":{"name":"Friction","volume":"100 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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