Enhanced Tribological Properties Of Aligned Graphene-Epoxy Composites,
2022
Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China
Enhanced Tribological Properties Of Aligned Graphene-Epoxy Composites, Yuefeng Du, Zhenyu Zhang, Dong Wang, Lezhen Zhang, Junfeng Cui, Yapeng Chen, Mingliang Wu, Ruiyang Kang, Yunxiang Lu, Jinhong Yu, Nan Jiang
Friction
The random distribution of graphene in epoxy matrix hinders the further applications of graphene-epoxy composites in the field of tribology. Hence, in order to fully utilize the anisotropic properties of graphene, highly aligned graphene-epoxy composites (AGEC) with horizontally oriented structure have been fabricated via an improved vacuum filtration freeze-drying method. The frictional tests results indicated that the wear rate of AGEC slowly increased from 5.19×10-6 mm3/(N·m) to 2.87×10-5 mm3/(N·m) with the increasing of the normal load from 2 to 10 N, whereas the friction coefficient (COF) remained a constant of 0.109. Compared to the …
Optimizing The Tribological Performance Of Dlc-Coated Nbr Rubber: The Role Of Hydrogen In Films,
2022
Key Laboratory of Science and Technology on Wear and Protection of Materials, 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
Optimizing The Tribological Performance Of Dlc-Coated Nbr Rubber: The Role Of Hydrogen In Films, Changning Bai, Li Qiang, Bin Zhang, Kaixiong Gao, Junyan Zhang
Friction
Diamond-like carbon (DLC) films directly deposited on rubber substrate is undoubtedly one optimal option to improve the tribological properties due to its ultralow friction, high-hardness as well as good chemical compatibility with rubber. Investigating the relationship between film structure and tribological performance is vital for protecting rubber. In this study it was demonstrated that the etching effect induced by hydrogen incorporation played positive roles in reducing surface roughness of DLC films. In addition, the water contact angle (CA) of DLC-coated nitrile butadiene rubber (NBR) was sensitive to the surface energy and sp2 carbon clustering of DLC films. Most importantly, …
Tribological Behavior Of Co-Textured Cylinder Liner-Piston Ring During Running-In,
2022
School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430063, China; Reliability Engineering Institute, National Engineering Research Center for Water Transportation Safety, Wuhan 430063, China
Tribological Behavior Of Co-Textured Cylinder Liner-Piston Ring During Running-In, Chenwei Miao, Zhiwei Guo, Chengqing Yuan
Friction
The running-in of cylinder liner-piston rings (CLPRs) is the most important process that must be performed before a marine diesel engine can be operated. The quality of running-in directly affects the reliability of a CLPR. The surface texture of a CLPR has been proven to significantly affect its lubrication performance. In this study, the tribological behavior of a CLPR during running-in is investigated. Three types of surface textures are generated on the CLPR via laser processing: dimple texture on piston rings, groove texture on cylinder liners, and co-texture on both sides. Subsequently, a series of tests are performed on a …
Investigation Into Gas Lubrication Performance Of Porous Gas Bearing Considering Velocity Slip Boundary Condition,
2022
School of Energy and Power Engineering, Beihang University, Beijing 100191, China; Aircraft/Engine Integrated System Safety Beijing Key Laboratory, Beihang University, Beijing 100191, China
Investigation Into Gas Lubrication Performance Of Porous Gas Bearing Considering Velocity Slip Boundary Condition, Xiangbo Zhang, Shuiting Ding, Farong Du, Fenzhu Ji, Zheng Xu, Jiang Liu, Qi Zhang, Yu Zhou
Friction
Porous gas bearings (PGBs) have a proactive application in aerospace and turbomachinery. This study investigates the gas lubrication performance of a PGB with the condition of velocity slip boundary (VSB) owing to the high Knudsen number in the gas film. The Darcy-Forchheimer laws and modified Navier-Stokes equations were adopted to describe the gas flow in the porous layer and gas film region, respectively. An improved bearing experimental platform was established to verify the accuracy of the derived theory and the reliability of the numerical analysis. The effects of various parameters on the pressure distribution, flow cycle, load capacity, mass flow …
A Finite-Element-Aided Ultrasonic Method For Measuring Central Oil-Film Thickness In A Roller-Raceway Tribo-Pair,
2022
Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi’an Jiaotong University, Xi’an 710049, China
A Finite-Element-Aided Ultrasonic Method For Measuring Central Oil-Film Thickness In A Roller-Raceway Tribo-Pair, Pan Dou, Tonghai Wu, Zhaopeng Luo, Peiping Yang, Zhongxiao Peng, Min Yu, Tom Reddyhoff
Friction
Roller bearings support heavy loads by riding on an ultra-thin oil film (between the roller and raceway), the thickness of which is critical as it reflects the lubrication performance. Ultrasonic interfacial reflection, which facilitates the non-destructive measurement of oil-film thickness, has been widely studied. However, insufficient spatial resolution around the rolling line contact zone remains a barrier despite the use of miniature piezoelectric transducers. In this study, a finite-element-aided method is utilized to simulate wave propagation through a three-layered structure of roller-oil-raceway under elastohydrodynamic lubrication (EHL) with nonlinear characteristics of the i) deformed curvature of the cylindrical roller and ii) …
Experimental And Modelling Studies Of The Transient Tribological Behaviour Of A Two-Phase Lubricant Under Complex Loading Conditions,
2022
Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
Experimental And Modelling Studies Of The Transient Tribological Behaviour Of A Two-Phase Lubricant Under Complex Loading Conditions, Xiao Yang, Lemeng Zhang, Denis J. Politis, Jie Zhang, Mohammad M. Gharbi, David Leyvraz, Liliang Wang
Friction
The transient tribological phenomenon and premature lubricant breakdown have been widely observed in metal forming, leading to excessive friction at the contact interfaces. In this research, the transient tribological behaviour of a two-phase lubricant were studied under complex loading conditions, featuring abrupt interfacial temperature, contact load, and sliding speed changes, thus representing the severe interfacial conditions observed in warm/hot metal forming applications. The strong experimental evidence indicates that the evolution of friction was attributed to the physical diminution and chemical decomposition effects. As such, a visco-mechanochemical interactive friction model was developed to accurately predict the transient tribological behaviour of the …
Experimental And Theoretical Investigation Of Vibro-Impact Triboelectric Energy Harvesters,
2022
University of Texas at Tyler
Experimental And Theoretical Investigation Of Vibro-Impact Triboelectric Energy Harvesters, Mostafa Hassan
Mechanical Engineering Theses
Improving the efficiency of energy harvesting, by investigating different techniques to increase the harvester bandwidth, as well as by exploring the influencing factors and adjusting them to optimal setups. Towards this, multiple Vibro-impact energy harvesters were proposed in this study. First, a Two-Degree of Freedom (2DOF) Vibro-impact Triboelectric Energy Harvester with a single and a double impact configuration is proposed. Multi-modality and piecewise linearity were combined to improve the harvesting bandwidth of triboelectric energy harvesters utilizing two resonant frequencies. The harvester structure consists of a primary cantilever beam attached to a secondary cantilever beam through a tip mass in the …
Tuning Of Frictional Properties In Torsional Contact By Means Of Disk Grading,
2022
Civil Engineering Institute, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
Tuning Of Frictional Properties In Torsional Contact By Means Of Disk Grading, Gianluca Costagliola, Federico Bosia, Nicola M Pugno
Friction
The contact of two surfaces in relative rotating motion occurs in many practical applications, from mechanical devices to human joints, displaying an intriguing interplay of effects at the onset of sliding due to the axisymmetric stress distribution. Theoretical and numerical models have been developed for some typical configurations, but work remains to be done to understand how to modify the emergent friction properties in this configuration. In this paper, we extend the two-dimensional (2D) spring-block model to investigate friction between surfaces in torsional contact. We investigate how the model describes the behavior of an elastic surface slowly rotating over a …
Tribological Performance Of Various Metal-Doped Carbon Dots As Water-Based Lubricant Additives And Their Potential Application As Additives Of Poly(Ethylene Glycol),
2022
School of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, China
Tribological Performance Of Various Metal-Doped Carbon Dots As Water-Based Lubricant Additives And Their Potential Application As Additives Of Poly(Ethylene Glycol), Weiwei Tang, Xuejun Zhu, Yufeng Li
Friction
Advances in nano-lubricant additives are vital to the pursuit of energy efficiency and sustainable development. Carbon dots (CDs) have been widely investigated in the domain of lubricant additives owing to their extraordinary tribological properties, in particular, their friction-reducing and anti-wear properties. Metal-doped CDs are a new type of CDs, and their friction-reducing and anti-wear properties are attracting increasing attention. Therefore, a series of CDs doped with various divalent metal ions have been successfully synthesized via one-pot pyrolysis. The tribological properties of the synthesized CDs as water-based lubricant additives are in the following order: Zn-CDs > Cu-CDs >> Mg-CDs > Fe-CDs > U-CDs. Specifically, adding …
Mono-Dispersed Ag Nanoparticles Decorated Graphitic Carbon Nitride: An Excellent Lubricating Additive As Ppesk Composite Film,
2022
School of Materials and Science Engineering, Institute for Advanced Materials, Jiangsu University, Zhenjiang 212013, China
Mono-Dispersed Ag Nanoparticles Decorated Graphitic Carbon Nitride: An Excellent Lubricating Additive As Ppesk Composite Film, Beibei Chen, Mengjie Zhang, Kan Zhang, Zhe Dong, Jiaye Li, Gai Zhao
Friction
Studies show that two dimensional (2D) nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure. However, the majority of performed investigations about 2D graphitic carbon nitride (g-C3N4) nanosheets are most focused on energy storage, catalysis, adsorption, rarely tribology. In the present study, g-C3N4 supporting mono-dispersed Ag nanoparticle hybrid (g- C3N4/Ag) is prepared, and its microstructure and chemical composition are determined. More specifically, the tribological performance as the lubricating additive of poly phthalazinone ether sulfone ketone (PPESK) composite is investigated using the ball-on-disc friction …
Experimental Investigation Of Granular Friction Behaviors During Reciprocating Sliding,
2022
Institute of Tribology, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
Experimental Investigation Of Granular Friction Behaviors During Reciprocating Sliding, Xuejie Zhang, Wei Sun, Wei Wang, Kun Liu
Friction
Granular friction behaviors are crucial for understanding the ubiquitous packing and flow phenomena in nature and industrial production. In this study, a customized experimental apparatus that can simultaneously measure the time history of normal and tangential forces on the inside-shearing unit is employed to investigate the granular friction behaviors during a linear reciprocating sliding process. It is observed that the evolution behaviors of two normal forces distributed separately on the shearing unit can qualitatively reflect the effects of the force chain network. During the half-loop of the reciprocating sliding, the total normal force, which indicates the load-bearing capacity of the …
Dynamic Friction Energy Dissipation And Enhanced Contrast In High Frequency Bimodal Atomic Force Microscopy,
2022
State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
Dynamic Friction Energy Dissipation And Enhanced Contrast In High Frequency Bimodal Atomic Force Microscopy, Xinfeng Tan, Dan Guo, Jianbin Luo
Friction
Dynamic friction occurs not only between two contact objects sliding against each other, but also between two relative sliding surfaces several nanometres apart. Many emerging micro- and nano-mechanical systems that promise new applications in sensors or information technology may suffer or benefit from noncontact friction. Herein we demonstrate the distance-dependent friction energy dissipation between the tip and the heterogeneous polymers by the bimodal atomic force microscopy (AFM) method driving the second order flexural and the first order torsional vibration simultaneously. The pull-in problem caused by the attractive force is avoided, and the friction dissipation can be imaged near the surface. …
Structure, Tribological Properties, And The Growth Mechanism Of In-Situ Generated Tic In Titanium Cermet,
2022
School of Chemical Engineering&Technology, China University of Mining and Technology, Xuzhou 221116, China
Structure, Tribological Properties, And The Growth Mechanism Of In-Situ Generated Tic In Titanium Cermet, Xiaolei Sun, Yong Luo, Junyang Wang, Qingliang Wang, Jianghao Qiao, Andrew Beadling, Michael Bryant, Zhongmin Jin
Friction
Titanium cermet combining metallic toughness with ceramic wear resistance has been proven to be a potential candidate for implanted joint material. In this work, titanium cermet was synthesized by means of the elevated temperature solid carburizing technology. The Ti13Nb13Zr alloy surface was found to be converted into TiC ceramic layer combined with a carbon strengthened diffusion zone underneath. The overall thickness of the carburized region grew to about 100 μm after 120 min carburization at 1,500 K. In order to clarify the growth behaviors of TiC ceramic layer, a growth mechanism is proposed. At the beginning …
Design Of Bidirectional Frictional Behaviour For Tactile Contact Using Ellipsoidal Asperity Micro-Textures,
2022
Laboratory for Surface Technology and Tribology, Faculty of Engineering Technology, University of Twente, Overijssel 7522 LW, Enschede, the Netherlands
Design Of Bidirectional Frictional Behaviour For Tactile Contact Using Ellipsoidal Asperity Micro-Textures, Dmitrii Sergachev, David Matthews, Emile Van Der Heide
Friction
Tactile perception and friction can be modified by producing a deterministic surface topography. Change of surface feature arrangement and texture symmetry can produce an anisotropic frictional behaviour. It is generally achieved through skin hysteresis by promoting its deformation. This work investigates whether a bidirectional friction can be created with microscale ellipsoidal asperity textures, thus relying on the adhesive component of friction. For this purpose, four textured samples with various asperity dimensions were moulded with a silicone rubber having an elastic modulus comparable to that of the skin. Coefficient of friction measurements were conducted in-vivo in two sliding directions with a …
Comprehensive Review Of Tribometer Dynamics—Cycle-Based Data Analysis And Visualization,
2022
AC2T research GmbH, Wiener Neustadt 2700, Austria
Comprehensive Review Of Tribometer Dynamics—Cycle-Based Data Analysis And Visualization, Josef Prost, Guido Boidi, Thomas Lebersorger, Markus Varga, Georg Vorlaufer
Friction
Tribologists often rely on triboexperiments to investigate factors that affect a tribosystem. The inherent dynamic behavior of the respective tribometer setups and its effect on data interpretation remain often unknown. In this study, a comprehensive analysis of sensor data obtained from lubricated and dry triboexperiments is performed. Data are generated on a pin-on-disc test rig with a silicon nitride ball on a steel disc contact with a rotation frequency of ~3 Hz. High-speed acquisition of sensor data up to 5 kHz is performed to resolve changes in the data within individual cycles. The characteristic frequencies of the system and their …
Novel Three-Body Nano-Abrasive Wear Mechanism,
2022
College of Mechanical Engineering, Donghua University, Shanghai 201620, China
Novel Three-Body Nano-Abrasive Wear Mechanism, Ruling Chen, Shaoxian Li
Friction
Current three-body abrasive wear theories are based on a macroscale abrasive indentation process, and these theories claim that material wear cannot be achieved without damaging the hard mating surface. In this study, the process of three-body nano-abrasive wear of a system including a single crystalline silicon substrate, an amorphous silica cluster, and a polyurethane pad, based on a chemical mechanical polishing (CMP) process, is investigated via molecular dynamics simulations. The cluster slid in a suspended state in smooth regions and underwent rolling impact in the asperity regions of the silicon surface, realizing non-damaging monoatomic material removal. This proves that indentation-plowing …
Inorganic Nanomaterial Lubricant Additives For Base Fluids, To Improve Tribological Performance: Recent Developments,
2022
School of Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China; Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Inorganic Nanomaterial Lubricant Additives For Base Fluids, To Improve Tribological Performance: Recent Developments, Junhai Wang, Weipeng Zhuang, Wenfeng Liang, Tingting Yan, Ting Li, Lixiu Zhang, Shu Li
Friction
In this paper, we review recent research developments regarding the tribological performances of a series of inorganic nano-additives in lubricating fluids. First, we examine several basic types of inorganic nanomaterials, including metallic nanoparticles, metal oxides, carbon nanomaterials, and "other" nanomaterials. More specifically, the metallic nanoparticles we examine include silver, copper, nickel, molybdenum, and tungsten nanoparticles; the metal oxides include CuO, ZnO, Fe3O4, TiO2, ZrO2, Al2O3, and several double-metal oxides; the carbon nanomaterials include fullerene, carbon quantum dots, carbon nanotubes, graphene, graphene oxides, graphite, and diamond; and the "other" …
Interior-Stress Fields Produced By A General Axisymmetric Punch,
2022
School of Automotive Engineering, Geely University of China, Chengdu 641423, China
Interior-Stress Fields Produced By A General Axisymmetric Punch, Longxiang Yang, Zhanjiang Wang, Weiji Liu, Guocheng Zhang, Bei Peng
Friction
This work is a supplement to the work of Sneddon on axisymmetric Boussinesq problem in 1965 in which the distributions of interior-stress fields are derived here for a punch with general profile. A novel set of mathematical procedures is introduced to process the basic elastic solutions (obtained by the method of Hankel transform, which was pioneered by Sneddon) and the solution of the dual integral equations. These processes then enable us to not only derive the general relationship of indentation depth D and total load P that acts on the punch but also explicitly obtain the general analytical expressions of …
Comparison Of Mechanical And Tribological Properties Of Crbn Coatings Modified By Ni Or Cu Incorporation,
2022
National Key Laboratory of Science and Technology on Helicopter Transmission, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Comparison Of Mechanical And Tribological Properties Of Crbn Coatings Modified By Ni Or Cu Incorporation, Qianzhi Wang, Xuxin Jin, Fei Zhou
Friction
To compare the merits of Ni and Cu, the mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation were studied. The results demonstrated that the CrBN-Cu coatings presented a lower friction coefficient than CrBN and CrBN-Ni coatings owing to the improved lubrication effect of the CuO layer originating from the tribochemical reaction. However, the hardness decline due to Cu incorporation was much greater than that of Ni incorporation. Thus, the CrBN-Cu coatings exhibited a higher wear rate than the CrBN coating. In contrast, the plastic deformation enhancement induced by Ni incorporation exceeded the hardness decline. Therefore, …
Drag Reduction Methods At Solid-Liquid Interfaces,
2022
State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
Drag Reduction Methods At Solid-Liquid Interfaces, Min Liu, Liran Ma
Friction
Friction drag is a nonnegligible matter when relative motion happens between solid and liquid phase, which brings many inconveniences in ship navigation, fluid transportation, microfluid devices, etc. Thereby various methods have been developed focusing on friction drag reduction. In this article, a review of several widely studied drag reduction methods is given, specially, their advantages and limitations in practical applications are discussed. Besides, a comparison of different methods is made and the development prospect of drag reduction is concluded.
