Contact Stiffness And Damping Of Spiral Bevel Gears Under Transient Mixed Lubrication Conditions,
2022
School of Aeronautics and Astronautics, Sichuan University, Chengdu 610065, China
Contact Stiffness And Damping Of Spiral Bevel Gears Under Transient Mixed Lubrication Conditions, Zongzheng Wang, Wei Pu, Xin Pei, Wei Cao
Friction
Existing studies primarily focus on stiffness and damping under full-film lubrication or dry contact conditions. However, most lubricated transmission components operate in the mixed lubrication region, indicating that both the asperity contact and film lubrication exist on the rubbing surfaces. Herein, a novel method is proposed to evaluate the time-varying contact stiffness and damping of spiral bevel gears under transient mixed lubrication conditions. This method is sufficiently robust for addressing any mixed lubrication state regardless of the severity of the asperity contact. Based on this method, the transient mixed contact stiffness and damping of spiral bevel gears are investigated systematically. …
Morphological Residual Convolutional Neural Network (M-Rcnn) For Intelligent Recognition Of Wear Particles From Artificial Joints,
2022
Department of Computer Science, Technical University of Munich, Garching 85748, Germany
Morphological Residual Convolutional Neural Network (M-Rcnn) For Intelligent Recognition Of Wear Particles From Artificial Joints, Xiaobin Hu, Jian Song, Zhenhua Liao, Yuhong Liu, Jian Gao, Bjoern Menze, Weiqiang Liu
Friction
Finding the correct category of wear particles is important to understand the tribological behavior. However, manual identification is tedious and time-consuming. We here propose an automatic morphological residual convolutional neural network (M-RCNN), exploiting the residual knowledge and morphological priors between various particle types. We also employ data augmentation to prevent performance deterioration caused by the extremely imbalanced problem of class distribution. Experimental results indicate that our morphological priors are distinguishable and beneficial to largely boosting overall performance. M-RCNN demonstrates a much higher accuracy (0.940) than the deep residual network (0.845) and support vector machine (0.821). This work provides an effective …
Origin Of Friction Hysteresis On Monolayer Graphene,
2022
Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
Origin Of Friction Hysteresis On Monolayer Graphene, Deliang Zhang, Yuge Zhang, Qiang Li, Mingdong Dong
Friction
Load-dependent friction hysteresis is an intriguing phenomenon that occurs in many materials, where the friction measured during unloading is larger than that measured during loading for a given normal load. However, the mechanism underlying this behavior is still not well understood. In this work, temperature- controlled friction force microscopy was utilized to explore the origin of friction hysteresis on exfoliated monolayer graphene. The experimental observations show that environmental adsorbates from ambient air play an important role in the load dependence of friction. Specifically, the existence of environmental adsorbates between the tip and graphene surface gives rise to an enhanced tip-graphene …
Identification Of Abnormal Tribological Regimes Using A Microphone And Semi-Supervised Machine-Learning Algorithm,
2022
Laboratory for Advanced Materials Processing (LAMP), Swiss Federal Laboratories for Materials Science and Technology (Empa), Thun CH-3602, Switzerland
Identification Of Abnormal Tribological Regimes Using A Microphone And Semi-Supervised Machine-Learning Algorithm, Vigneashwara Pandiyan, Josef Prost, Georg Vorlaufer, Markus Varga, Kilian Wasmer
Friction
Functional surfaces in relative contact and motion are prone to wear and tear, resulting in loss of efficiency and performance of the workpieces/machines. Wear occurs in the form of adhesion, abrasion, scuffing, galling, and scoring between contacts. However, the rate of the wear phenomenon depends primarily on the physical properties and the surrounding environment. Monitoring the integrity of surfaces by offline inspections leads to significant wasted machine time. A potential alternate option to offline inspection currently practiced in industries is the analysis of sensors signatures capable of capturing the wear state and correlating it with the wear phenomenon, followed by …
Effects Of Solid Friction Modifier On Friction And Rolling Contact Fatigue Damage Of Wheel-Rail Surfaces,
2022
Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China; School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Effects Of Solid Friction Modifier On Friction And Rolling Contact Fatigue Damage Of Wheel-Rail Surfaces, Jingdong Song, Lubing Shi, Haohao Ding, Radovan Galas, Milan Omasta, Wenjian Wang, Jun Guo, Qiyue Liu, Martin Hartl
Friction
In railway network, friction is an important factor to consider in terms of the service behaviors of wheel-rail system. The objective of this study was to investigate the effect of a solid friction modifier (FM) in a railway environment. This was achieved by studying the friction, wear, and rolling contact fatigue (RCF) damage on the wheel-rail materials at different slip ratios. The results showed that when a solid FM was applied, the friction coefficient decreased. After the solid FM was separated from the wheel-rail interface, the friction coefficient gradually increased to its original level. With the application of the solid …
Experimentally Validated Atomistic Simulation Of The Effect Of Relevant Grinding Parameters On Work Piece Topography, Internal Stresses, And Microstructure,
2022
AC2T research GmbH, Viktor-Kaplan-Straße 2/C, Wiener Neustadt 2700, Austria; Institute of Engineering Design and Product Development, TU Wien, Lehárgasse 6—Objekt 7, Vienna 1060, Austria
Experimentally Validated Atomistic Simulation Of The Effect Of Relevant Grinding Parameters On Work Piece Topography, Internal Stresses, And Microstructure, S. J. Eder, P. G. Grützmacher, T. Spenger, H. Heckes, H. Rojacz, A. Nevosad, F. Haas
Friction
In this work, we present a fully atomistic approach to modeling a finishing process with the goal to shed light on aspects of work piece development on the microscopic scale, which are difficult or even impossible to observe in experiments, but highly relevant for the resulting material behavior. In a large-scale simulative parametric study, we varied four of the most relevant grinding parameters: The work piece material, the abrasive shape, the temperature, and the infeed depth. In order to validate our model, we compared the normalized surface roughness, the power spectral densities, the steady-state contact stresses, and the microstructure with …
Numerical Analysis Of Three-Dimensional Thermo-Elastic Rolling Contact Under Steady-State Conditions,
2022
Department of Mechanical Engineering, Pusan National University, Busan SW7 2AZ, Republic of Korea
Numerical Analysis Of Three-Dimensional Thermo-Elastic Rolling Contact Under Steady-State Conditions, Yonghun Yu, Junho Suh
Friction
In this study, a three-dimensional thermo-elastic model that considers the interaction of mechanical and thermal deformation is developed using a semi-analytic method for steady-state rolling contact. Creepage types in all directions are considered in this model. For verification, the numerical analysis results of shear traction and temperature increase are compared separately with existing numerical results, and the consistency is confirmed. The analysis results include heat flux, temperature increase, contact pressure, and shear traction. Under severe rolling conditions, the thermal effect changes the behavior of the contact interface significantly. Furthermore, the effects of creepage, rolling speed, and conformity under different rolling …
Regulating The Nb2C Nanosheets With Different Degrees Of Oxidation In Water Lubricated Sliding Toward An Excellent Tribological Performance,
2022
Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China; University of Chinese Academy of Sciences, Beijing 100049, China
Regulating The Nb2C Nanosheets With Different Degrees Of Oxidation In Water Lubricated Sliding Toward An Excellent Tribological Performance, Hao Cheng, Wenjie Zhao
Friction
Novel two-dimensional (2D) Nb2C nanosheets were successfully prepared through a simple lultrasonic and magnetic stirring treatment from the original accordion-like powder. To further study their water-lubrication properties and deal with common oxidation problems, Nb2C nanosheets with different oxidation degrees were prepared and achieved long-term stability in deionized water. Scanning electron microscope (SEM), transmission electron microscope (TEM), scanning probe microscope (SPM), X-ray powder diffraction (XRD), Raman, and X-ray photoelectron spectrometer (XPS) experiments were utilized to characterize the structure, morphology, and dispersion of Nb2C nanosheets with different degrees of oxidation. The tribological behaviors of Nb2 …
Effect Of Contact Geometry On The Friction Of Acrylamide Hydrogels With Different Surface Structures,
2022
State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China; Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
Effect Of Contact Geometry On The Friction Of Acrylamide Hydrogels With Different Surface Structures, Wenrui Liu, Rok Simič, Yuhong Liu, Nicholas D. Spencer
Friction
Polyacrylamide (PAAm) hydrogels with brush-covered or crosslinked surfaces were produced and their tribological behavior was studied over a wide range of sliding speeds for two different contact geometries: sphere-on-flat and flat-pin-on-flat. Irrespective of the contact geometry, the brushy hydrogel surfaces displayed up to an order of magnitude lower coefficients of friction µ (COF) compared to the crosslinked surfaces, even achieving superlubricity (µ < 0.01). In general, a hydrogel sphere showed a lower coefficient of friction than a flat hydrogel pin at a similar contact pressure over the entire range of sliding speeds. However, after normalizing the friction force by the contact area, the shear stress of hydrogels with either crosslinked or brushy surfaces was found to be similar for both contact geometries at low speeds, indicating that hydrogel friction is unaffected by the contact geometry at these speeds. At high sliding speeds, the shear stress was found to be lower for a sphere-on-flat configuration compared to a flat-pin-on-flat configuration. This can be attributed to the larger equivalent hydrodynamic thickness due to the convergent inlet zone ahead of the sphere-on-flat contact, which presumably enhances the water supply in the contact, promotes rehydration, and thus reduces the friction at high sliding speeds compared to that measured for the flat-pin-on-flat contact.
Review Of Research On Loosening Of Threaded Fasteners,
2022
School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
Review Of Research On Loosening Of Threaded Fasteners, Hao Gong, Xiaoyu Ding, Jianhua Liu, Huihua Feng
Friction
Loosening of threaded fasteners is a key failure mode, which is mainly caused by the slippage and friction behaviors on the thread and bearing surfaces, and will affect the integrity and reliability of products. Numerous scholars have conducted research on the loosening of threaded fasteners; however, comprehensive reviews on the loosening of threaded fasteners have been scarce. In this review article, we define loosening as a loss of preload and divide it into non-rotational and rotational loosening. The causes and mechanisms of non-rotational and rotational loosening are summarised. Some essential topics regarding loosening under transverse vibration have also attracted significant …
Tribological Behavior Of Black Phosphorus Nanosheets As Water-Based Lubrication Additives,
2022
School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China
Tribological Behavior Of Black Phosphorus Nanosheets As Water-Based Lubrication Additives, Qingjuan Wang, Tingli Hou, Wei Wang, Guoliang Zhang, Yuan Gao, Kuaishe Wang
Friction
Black phosphorus (BP) with a layered structure has been used gradually as a lubrication additive in the tribological area. In this study, BP powders are produced via an easy method of high-energy ball milling using red phosphorus as a raw material. Subsequently, BP nanosheets are prepared via liquid exfoliation in N-methyl pyrolidone solvent. The tribological behavior of BP nanosheets as water-based lubrication additives (BP-WL) is evaluated under Ti6Al4V (TC4)/GCr15 contact. The results suggest that the 70 mg/L BP-WL sample exhibits excellent lubrication performance, whose coefficient of friction (COF) and ball wear rate reduced by 32.4% and 61.1%, respectively, compared with …
Direct Observation Of The Impact Of Water Droplets On Oil Replenishment In Ehd Lubricated Contacts,
2022
National Institute of Metrology, Beijing 100029, China
Direct Observation Of The Impact Of Water Droplets On Oil Replenishment In Ehd Lubricated Contacts, Xiang Liu, Jintao Wang, Lu Huang, Jingyue Zhang, Changhong Xu, Lin Tong, Dan Guo
Friction
Water is one of the most significant causes of lubrication failure. There is little research on the direct observation of the impact of water on lubrication properties. In this study, the influence of water on oil replenishment under different elastohydrodynamic (EHD) lubricating conditions is evaluated using optical interferometry and infrared microscopy, and a dimensionless criterion when water influences the film thickness is proposed. Evidence shows that the scour displacing effect and emulsification of water/oil are the main reasons for the reduction in film thickness. Once a water droplet enters an oil reservoir around the critical contact zone, it hardly moves …
Investigation Of The Heat Distribution In Dry Friction Systems During Fade And Recovery Using Fiber-Optic Sensing And Infrared Technology,
2022
IPEK-Institute of Product Engineering, Karlsruhe Institute of Technology, Baden Wurttemberg 76131, Germany
Investigation Of The Heat Distribution In Dry Friction Systems During Fade And Recovery Using Fiber-Optic Sensing And Infrared Technology, Albert Albers, Thomas Klotz, Chris Fink, Sascha Ott
Friction
The design of dry-running friction pairings and systems determines not only their installation space and costs, but also their reliability under critical load conditions, for example in emergencies, in the case of faults, and in the event of misuse. While knowledge of the contact pattern is highly important for the development of clutches and brakes, the contact-related measurement of the temperature of these systems has not yet been solved in a satisfactory manner. Despite its importance, the temperature distribution has only been measured in a few studies. Typically, temperature measurements of complete clutches and brakes are carried out using thermocouples …
Surface Modification Of Ys-20 With Polydopamine For Improving The Tribological Properties Of Polyimide Composites,
2022
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
Surface Modification Of Ys-20 With Polydopamine For Improving The Tribological Properties Of Polyimide Composites, Liangfei Wu, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Peilong Li, Zujun Chen, Xuehu Men
Friction
Recently, great effort has been devoted to prepare various reinforce fillers to improve polymer performances, but ignoring the importance of raw polymer powders which are indispensable parts of hot-pressed polymer composites. Herein, we engineer raw polyimide (PI) powders with the assistance of polydopamine (PDA) in aqueous solutions. After the modification, polymer powders change from hydrophobic to hydrophilic, which makes it is possible to further modification of polymer powders in liquid phase. During the curing process of modified polymer powders, the partial dehydration of the catechol groups and crosslinking of PDA via C-O-C bonds are confirmed. Based on the features of …
Experimental And Modelling Study Of Interaction Between Friction And Galling Under Contact Load Change Conditions,
2022
Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
Experimental And Modelling Study Of Interaction Between Friction And Galling Under Contact Load Change Conditions, Xiao Yang, Yiran Hu, Lemeng Zhang, Yang Zheng, Denis J. Politis, Xiaochuan Liu, Li-Liang Wang
Friction
The galling process remains one of the least understood phenomena in metal forming. The transfer of material from a work-piece onto the tool surface can cause an evolutionary increase in friction coefficient (COF) and thus the use of a constant COF in finite element (FE) simulations leads to progressively inaccurate results. For an aluminium work-piece, material transfer, which has history and pressure dependency, is determined by a dynamic balance between the generation and ejection of wear particles acting as a 'third body’ abrasive element at the contact interface. To address this dynamic interactive phenomenon, pin-on-disc tests between AA6082 and G3500 …
Tribological Behavior Comparisons Of High Chromium Stainless And Mild Steels Against High-Speed Steel And Ceramics At High Temperatures,
2022
Institute of Advanced Wear & Corrosion Resistant and Functional Materials, Jinan University, Guangzhou 510632, China
Tribological Behavior Comparisons Of High Chromium Stainless And Mild Steels Against High-Speed Steel And Ceramics At High Temperatures, Shaogang Cui, Yangzhen Liu, Tong Wang, Kiet Tieu, Long Wang, Dahai Zeng, Zhou Li, Wei Li
Friction
High-temperature tribology, which is often involved during hot metal forming, is controlled via oxidation on a rubbing surface. However, for high chromium stainless steel (ST), where oxidation is strongly inhibited, the effect of counterface materials on tribological behavior is yet to be elucidated. In this study, the effects of counterfaces on the tribological behavior of 253MA ST and mild steel (MS) are investigated via a ball-on-disc test at 900 °C using a 20 N load. The results reveal that high-speed steel (HSS) experiences severe abrasive wear with MS and causes severe sticking problems with ST. Si3N4 and …
Impact-Sliding Wear Response Of 2.25cr1mo Steel Tubes: Experimental And Semi-Analytical Method,
2022
Tribology Research Institute, Key Lab of Advanced Technologies of Materials, Southwest Jiaotong University, Chengdu 610031, China; Univ Lyon, INSA Lyon, CNRS, LaMCoS, UMR5259, Villeurbanne 69621, France
Impact-Sliding Wear Response Of 2.25cr1mo Steel Tubes: Experimental And Semi-Analytical Method, Meigui Yin, Thibaut Chaise, Liwen Wang, Daniel Nélias, Minhao Zhu, Zhenbing Cai
Friction
The impact-sliding wear behavior of steam generator tubes in nuclear power plants is complex owing to the dynamic nature of the mechanical response and self-induced tribological changes. In this study, the effects of impact and sliding velocity on the impact-sliding wear behavior of a 2.25Cr1Mo steel tube are investigated experimentally and numerically. In the experimental study, a wear test rig that can measure changes in the impact and friction forces as well as the compressive displacement over different wear cycles, both in real time, is designed. A semi-analytical model based on the Archard wear law and Hertz contact theory is …
Dynamics Of Lubricated Spiral Bevel Gears Under Different Contact Paths,
2022
School of Construction Machinery, Chang'an University, Xi’an 710064, China;Shantui Construction Machinery Co., Ltd., Jining 272073, China
Dynamics Of Lubricated Spiral Bevel Gears Under Different Contact Paths, Wei Cao, Tao He, Wei Pu, Ke Xiao
Friction
To assess the meshing quality of spiral bevel gears, the static meshing characteristics are usually checked under different contact paths to simulate the deviation in the footprint from the design point to the heel or toe of the gear flank caused by the assembly error of two gear axes. However, the effect of the contact path on gear dynamics under lubricated conditions has not been reported. In addition, most studies regarding spiral bevel gears disregard the lubricated condition because of the complicated solutions of mixed elastohydrodynamic lubrication (EHL). Hence, an analytical friction model with a highly efficient solution, whose friction …
Oscillating Friction Of Nanoscale Capillary Bridge,
2022
Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China;Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China
Oscillating Friction Of Nanoscale Capillary Bridge, Shuai Wu, Yuqing He, Quanshui Zheng, Ming Ma
Friction
The presence of a capillary bridge between solid surfaces is ubiquitous under ambient conditions. Usually, it leads to a continuous decrease of friction as a function of bridge height. Here, using molecular dynamics we show that for a capillary bridge with a small radius confined between two hydrophilic elastic solid surfaces, the friction oscillates greatly when decreasing the bridge height. The underlying mechanism is revealed to be a periodic ordered-disordered transition at the liquid-solid interfaces. This transition is caused by the balance between the surface tension of the liquid-vapor interface and the elasticity of the surface. This balance introduces a …
Applications Of Sum-Frequency Generation Vibrational Spectroscopy In Friction Interface,
2022
Institute of Advanced Manufacturing and Intelligent Technology, Beijing University of Technology, Beijing 100124, China;Beijing Key Laboratory of Advanced Manufacturing Technology, Beijing University of Technology, Beijing 100124, China
Applications Of Sum-Frequency Generation Vibrational Spectroscopy In Friction Interface, Zhifeng Liu, Mengmeng Liu, Caixia Zhang, Hongyan Chu, Liran Ma, Qiang Cheng, Hongyun Cai, Junmin Chen
Friction
Sum-frequency generation (SFG) vibrational spectroscopy is a second-order nonlinear optical spectroscopy technique. Owing to its interfacial selectivity, SFG vibrational spectroscopy can provide interfacial molecular information, such as molecular orientations and order, which can be obtained directly, or molecular density, which can be acquired indirectly. Interfacial molecular behaviors are considered the basic factors for determining the tribological properties of surfaces. Therefore, owing to its ability to detect the molecular behavior in buried interfaces in situ and in real time, SFG vibrational spectroscopy has become one of the most appealing technologies for characterizing mechanisms at friction interfaces. This paper briefly introduces the …
