FrictionPub Date : 2025-03-18DOI: 10.26599/frict.2025.9441019
Boyu Zhang, Yongyong He, Zhengwei Wang
{"title":"Contact fatigue limit prediction method for heavy-duty gears considering hardness gradient characteristics","authors":"Boyu Zhang, Yongyong He, Zhengwei Wang","doi":"10.26599/frict.2025.9441019","DOIUrl":"https://doi.org/10.26599/frict.2025.9441019","url":null,"abstract":"<p>Hardening gradients have been introduced to heavy-duty gears to enhance their bearing capacity, but this has led to an increase in the complexity and difficulty of fatigue analysis. To explore ways to mitigate this, in this work, a contact fatigue model of an 18CrNiMo7-6 gear pair with a hardness gradient was established, and the Brown‒Miller‒Morrow multiaxial fatigue criterion was adopted to calculate the contact fatigue lifespan under different contact pressures. The gear contact fatigue limit was then determined by fitting the stress–number of cycles (<i>S</i>‒<i>N</i>) curve. The results of this method are verified by gear contact fatigue tests. Furthermore, the effects of case hardening depth (CHD) and surface hardness (SH) on the contact fatigue lifespan and limits were explored, and we found that the contact fatigue limit of a typical carburized gear was more affected by SH than CHD. In addition, we also examined which hardness gradients were more beneficial for the fatigue performance of gears with atypical hardening gradients.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"25 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640347","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}
FrictionPub Date : 2025-03-18DOI: 10.26599/frict.2025.9441100
Jianping Lai, Mengli Liu, An Zhang, Amit Datye, Udo D Schwarz, Fan Zhao, Fei Zhao, Jiaxin Yu
{"title":"Scratch-induced work hardening of an atomically flat bulk metallic glass by stress-driven structural ordering","authors":"Jianping Lai, Mengli Liu, An Zhang, Amit Datye, Udo D Schwarz, Fan Zhao, Fei Zhao, Jiaxin Yu","doi":"10.26599/frict.2025.9441100","DOIUrl":"https://doi.org/10.26599/frict.2025.9441100","url":null,"abstract":"<p>Although the enhanced structural relaxation is usually believed to be an important contributor to work hardening of metallic glasses subjected to triaxial stress state, an direct observation of relaxation process in response to work hardening has not been achieved in metallic glasses. Here we show that by nanoscratching on an atomically flat bulk metallic glass surface, the small atomic force microscopy tip with a radius of ≈ 10 nm brings about a large hydrostatic stress within stressed volume, which enables a densifying plastic flow via enhanced structural relaxation and leads to the work hardening behavior, as evidenced by an obvious decrease in friction force signals within scratched regions. Further examination on the atomic structure beneath the scratched surface using high resolution transmission electron microscopy reveals a relaxed structural configuration, which is indicated by disperse clusters of medium-range order scale in the case of line scratching and nucleated nanocrystals in the case of cyclic scratching. This study provides a compelling evidence for stress-driven structural relaxation, greatly deepening the understanding of work hardening mechanism in metallic glasses.</p>","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":"143640349","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}
FrictionPub Date : 2025-03-14DOI: 10.26599/frict.2025.9441021
Yujin Jeon, Sumit Barthwal, Jae-Kang Kim, Si-Hyung Lim
{"title":"Surface modification of steel runner with improved hydrophobicity for reducing the coefficient of friction for ice","authors":"Yujin Jeon, Sumit Barthwal, Jae-Kang Kim, Si-Hyung Lim","doi":"10.26599/frict.2025.9441021","DOIUrl":"https://doi.org/10.26599/frict.2025.9441021","url":null,"abstract":"<p>The advancement of equipment technology is very important for winter sports competitions, but there has been a lack of research on ice friction via the modification of runner surface. In this study, we modify the surfaces of steel runners that are commonly used in winter sports to reduce ice friction by improving water repellency. A custom-built tribotester that can measure ice friction under high-speed conditions was developed. Three surface treatment processes—vapor deposition, immersion, and spraying—are applied to the steel surface to improve its hydrophobicity. The results confirm that surface treatment techniques for large areas can effectively reduce the coefficient of friction between the steel runner and ice, which is strongly related to the water contact angle of the steel runner. This highlights the effect of surface wettability on the coefficient of friction between metal surfaces and ice. The developed surface treatment methods can be applied to runner surfaces that are used in various winter sports.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"55 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619043","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}
FrictionPub Date : 2025-03-14DOI: 10.26599/frict.2025.9441023
Samuel David Fernández-Silva, Miguel Ángel Delgado, Claudia Roman, Tobias Amann, Felix Gatti, Andreas Kailer, Moisés García-Morales
{"title":"Active control of friction in electrified ball bearing prototypes using electro-sensitive clay mineral-based lubricating fluids","authors":"Samuel David Fernández-Silva, Miguel Ángel Delgado, Claudia Roman, Tobias Amann, Felix Gatti, Andreas Kailer, Moisés García-Morales","doi":"10.26599/frict.2025.9441023","DOIUrl":"https://doi.org/10.26599/frict.2025.9441023","url":null,"abstract":"<p>The aim of this research is to present the use and advantages of electro-active eco-fluids as smart biolubricants. Polarizable clay mineral nanoparticles, such as the layered nanosilicate montmorillonite Cloisite 15A and the fiber-like sepiolite Pangel B20, were dispersed in a sustainable fluid, castor oil, at concentrations of 0.5, 2, and 4 wt%. These dispersions exhibit electro-viscous behavior, which was characterized by higher yield stress values with increasing electric field strength. Based on this, the influence of electric potentials was investigated in an electrified axial ball bearing device. The coefficient of friction (COF) was changed as needed and reversibly when different electric fields of 100 and 200 V/mm were applied. A 10.7% increase in the coefficient of friction was observed with a 4 wt% Cloisite 15A in castor oil at 200 V/mm. In the case of Pangel B20, the application of an electric field of 200 V/mm successfully prevented the lubricant from being displaced from the contact zone at 500 r/min. In addition, the dielectric breakdown resistance of these clays was analyzed. Cloisite 15A yielded better results than Pangel B20, probably due to its greater electro-responsive and thus film-forming potential. Finally, the load-carrying capacity was also evaluated. Under the action of an electric field, an opposite vertical force was observed when a ball was pressed onto a plate with a lubricating film in between. Consequently, the study allows conclusions to be drawn about a new lubrication concept based on electro-active control of friction in electrified tribological contacts by fully sustainable electro-rheological (ER) lubricating fluids.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"56 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619044","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}
FrictionPub Date : 2025-03-14DOI: 10.26599/frict.2025.9440989
Yanmin Liu, Dong Wang, Ke Zhang, Haijun Wu, Guoqing Yu, Qiang Zhang, Yuanzi Zhou, Tianbao Ma, Aisheng Song
{"title":"Superlubricating electrical contact between graphite layers","authors":"Yanmin Liu, Dong Wang, Ke Zhang, Haijun Wu, Guoqing Yu, Qiang Zhang, Yuanzi Zhou, Tianbao Ma, Aisheng Song","doi":"10.26599/frict.2025.9440989","DOIUrl":"https://doi.org/10.26599/frict.2025.9440989","url":null,"abstract":"<p>High-conductivity sliding electrical contact with low friction plays a significant role in the long life and high reliability of electromechanical systems. Reducing friction needs weak interfacial electronic coupling; in contrast, enhancing conductivity requires strong coupling; thus it is a serious challenge to achieve high conductivity with low friction. Here, using our self-developed thermally assisted mechanical exfoliation and transfer (TAMET) method, we experimentally achieved superlubricating electrical contact by establishing a sliding electrical system between graphite layers (Gr); the friction coefficient was as low as 0.0004, and the electric current density was as high as 510 A/cm<sup>2</sup>. Compared with the commercial Ir atomic force microscopy (AFM) tip–Gr contact, the friction force of incommensurate graphene layer friction is an order of magnitude lower, yet it has a similar high electrical conductivity. On the basis of the electronic property fluctuation (EPF) model and first principles calculations, we revealed that the sliding energy barrier remains almost unchanged under an applied current because of the negligible electron transfer variation during the sliding process. We offer a method for achieving superlubricating electrical contact with high conductivity and low friction, shedding light on improving the service life and reliability of sliding electrical contacts in a wide range of electromechanical systems.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"6 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618915","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}
FrictionPub Date : 2025-03-12DOI: 10.26599/frict.2025.9440975
Shuli Li, Guolai Yang, Liqun Wang
{"title":"Cross-scale prediction for thermochemical–mechanical damage of barrel weapons under high-temperature and supersonic environments","authors":"Shuli Li, Guolai Yang, Liqun Wang","doi":"10.26599/frict.2025.9440975","DOIUrl":"https://doi.org/10.26599/frict.2025.9440975","url":null,"abstract":"<p>Thermochemical–mechanical damage prediction suitable for high-temperature and supersonic conditions is essential for evaluating the life span of barrel weapons. This paper proposes a thermochemical–mechanical damage prediction method in extreme environments by combining the cross-scale damage framework and scale expansion strategy. For the cross-scale damage framework, macroscale surface damage is converted into mesoscale particulate impacts via two-phase flow interior ballistics. The particulate impact is transformed into microscale crystal impacts via velocity decomposition and synthesis. For the scale expansion strategy, the dislocation features of discretized crystals are obtained via the momentum mirror. The first proposed boundary dislocation can solve the boundary coupling of discretized crystals and modify the hardening criterion. A damage agent model is constructed on the basis of sufficient samples to generalize mesoscale crystal damage to macroscale surface damage. A simulation experiment is executed to verify the accuracy of the calculation method for determining crystal impact damage under high-temperature supersonic environments. A launching experiment with 100 projectiles is executed to prove the accuracy of the thermochemical–mechanical damage prediction method.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"21 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599169","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}
{"title":"Effects of graphite-based material size on mechanical and tribological performance of polyimides under drying sliding condition","authors":"Changxin Wan, Dan Jia, Shengpeng Zhan, Wulin Zhang, Tian Yang, Yinhua Li, Jian Li, Haitao Duan","doi":"10.26599/frict.2025.9441093","DOIUrl":"https://doi.org/10.26599/frict.2025.9441093","url":null,"abstract":"<p><strong> </strong>The present investigation evaluates the effect of graphite-based filler (GBF) size on the mechanical and tribological performance of polyimide (PI) solid lubricant composites. During dry sliding tribological experiments, micron-, nano-graphite (MG, NG), and ultrathin graphene (GN) additives were considered. The results revealed that atomic-thickness GN outperformed micron- and nano-sized GBF filler in terms of mechanical and tribological performance when added into PI matrix. It was inferred that the GN was able to generate sufficient lubricating phases at the frictional interface due to their small size and ultrathin morphology, which provided them with enhanced tribological properties in comparison with the micro and nano-sized GBF fillers. GN oxidized by reciprocating shear force and friction heat at friction interface and subsequently formed lubricating layer consisting of graphene oxide (GO), as characterized by FTIR and Raman, spectroscopy. Atomistic modeling techniques was also used to elucidate the surface/interface lubrication mechanism, where GO was tightly adsorbed at frictional interfaces by van der Waals. The results facilitate better understanding of size effect on wear mechanism for solid lubricants.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"31 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599168","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}
{"title":"Gecko-inspired contact-sensible and self-adaptive soft gripping of curved flexible surfaces","authors":"Wenhui Cui, Yuanzhe Li, Tianhui Sun, Tong Ling, Shiyang Guo, Wenling Zhang, Yu Tian","doi":"10.26599/frict.2025.9441027","DOIUrl":"https://doi.org/10.26599/frict.2025.9441027","url":null,"abstract":"<p>Soft grippers are key manipulation tools for robotics and end effectors for securely grasping objects of various shapes and sizes on demand. However, critical challenges, including self-adaptive grasping to curved surfaces and monitoring the contact state, remain. Here, a gecko-inspired curved flexible surface adaptive gripper (CSAG), which consists of a variable-bending pneumatic actuator, a triboelectric sensor (T-sensor), and a gecko-inspired microwedge adhesive, is proposed. The contact-sensitive triboelectric sensor can sense the critical contact state of objects to trigger a variable-bending pneumatic actuator with sufficient shear loading for the geckoinspired microwedge adhesive. A set of experiments are implemented to verify that the proposed soft gripper can adaptively grasp diverse curved objects, including quail eggs, cans, shuttlecocks, expanding objects with varying volumes (such as balloons, the range of diameter variation is 20–115 mm), and spherical acrylic cylinders (20–40 mm) at low pressures (20–25 kPa) with a maximum weight of 37 g. Additionally, the tracking and grasping of a moving ball is demonstrated via a mean-shift algorithm based on image recognition coupled with coordination tracking of a robotic arm. The soft gripper provides a new paradigm to achieve switchable grasping of curved flexible surfaces, which broadens future applications for versatile unstructured human‒robot‒environment interactions, such as adaptive robots and medical devices.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"16 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599172","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}
FrictionPub Date : 2025-03-12DOI: 10.26599/frict.2025.9441000
Tengfei Zhang, Jie Su, Liaoliang Ke
{"title":"Fretting wear behavior of silicone rubber with biomimetic surface texture","authors":"Tengfei Zhang, Jie Su, Liaoliang Ke","doi":"10.26599/frict.2025.9441000","DOIUrl":"https://doi.org/10.26599/frict.2025.9441000","url":null,"abstract":"<p>Surface texture, as an important surface engineering technique, can enhance the tribological properties of contact surfaces. This work presents an experimental investigation of the fretting wear behavior of silicone rubber films with a biomimetic surface texture under a spherical indenter. Inspired by human fingerprints and tree frog toe pads, hexagonal loop textures with three different texture spacings are created on the surface of silicone rubber films. Three types of indenters are considered: stainless steel, polypropylene, and silicone rubber. The impacts of the texture spacing, displacement amplitude, normal force, frequency, and indenter material on the fretting wear behavior are discussed in detail. The wear volume was measured via a three-dimensional white light profiler. The surface wear morphology and fretting wear mechanism of the textured surfaces were analyzed by scanning electron microscopy. Adding a surface texture can effectively decrease the coefficient of friction (COF) of silicone rubber. In addition, the smaller the texture spacing is, the more pronounced the COF decreases and the lower the specific wear rate.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"17 2 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599171","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}
FrictionPub Date : 2025-03-06DOI: 10.26599/frict.2025.9440998
Adis A. Tukhbatullin, Glyus L. Sharipov, Roman A. Nevshupa
{"title":"Non-trivial role of surrounding gases in triboluminescence: A comprehensive review","authors":"Adis A. Tukhbatullin, Glyus L. Sharipov, Roman A. Nevshupa","doi":"10.26599/frict.2025.9440998","DOIUrl":"https://doi.org/10.26599/frict.2025.9440998","url":null,"abstract":"<p>Research on triboluminescence phenomena has been comprehensively reviewed, with a focus on the activation mechanisms resulting from the dissipation of mechanical energy at interfaces. The complexity and interdisciplinary nature of this phenomenon, along with its dependence on gas composition and pressure, have been analyzed. Special attention was given to air, inert gases, polyatomic gases, and hydrocarbon gases. The influence of gas composition on triboluminescence is not straightforward. This is because at least three components are associated with different physical and chemical processes and activation mechanisms. These components include TL1: gas discharge luminescence. This occurs because of the generation of an electric field and dielectric breakdown of gases surrounding the mechanically activated zone of the material; TL2: photoluminescence of mechanically activated material. This results from the excitation of luminescent centers by the absorption of ultraviolet radiation from the gas discharge; TL3: material luminescence not related to photoluminescence. This is the least studied and most complex component. This can be related to the direct coupling of the mechanical force with the energy landscape of defects, impurities, and other centers. These centers can be excited and emit light during deexcitation. Other possibilities include luminescence excited by electric fields, exoelectron emission, etc. Therefore, the gas environment is crucial not only for gas discharge (as various gases can promote or quench it) but also for controlling other excitation and deexcitation processes. These processes occur through interactions of adsorbed films with stressed materials, tribochemical reactions, photochemical reactions, and so on. Furthermore, the potential application of triboluminescence for sensing gas composition is highlighted.</p>","PeriodicalId":12442,"journal":{"name":"Friction","volume":"2 1","pages":""},"PeriodicalIF":6.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560820","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}