Article
Nanoscience & Nanotechnology
Mingjie Tong, Yan Jiang, Liya Wang, Chengyuan Wang, Chun Tang
Summary: The study reveals that nanoporous graphene exhibits unique frictional characteristics, with the size of the nanopore playing a key role in determining the maximum frictional force. Negative friction is observed when the silicon tip scans towards the center of the nanopore.
Article
Multidisciplinary Sciences
Kasra Farain, Daniel Bonn
Summary: Regardless of surface roughness or compression, the stress relaxation of microcontacts is the same as that of bulk material. Friction is not always proportional to the contact area. This allows us to predict frictional aging of rough interfaces based on the bulk material properties of two typical polymers: polypropylene and polytetrafluoroethylene.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Mechanical
Artur Wojcik, Thomas G. Mathia
Summary: This paper analyzes the friction phenomenon of granular cereal materials at low sliding velocities. It is found that the friction force exhibits periodic changes and three characteristic phases are identified. The study confirms the significant influence of velocity and load on the nature of friction force changes.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Chemistry, Applied
Chi Zhang, Sinan Keten, Dominique Derome, Jan Carmeliet
Summary: Through atomistic simulation, the mechanical behavior of cellulose-cellulose nanocrystal hydrophilic interface was studied, showing the central role of interfacial hydrogen bonds in explaining various findings. The friction force generated by a single hydrogen bond was estimated to be around 1.3 E-10 N under a shearing speed of 1 m/s.
CARBOHYDRATE POLYMERS
(2021)
Article
Physics, Multidisciplinary
Shahar Gvirtzman, Jay Fineberg
Summary: Frictional motion between surfaces is initiated by the formation of nucleating rupture fronts, which develop from a certain stress level and have a characteristic velocity. Rapid rupture fronts, similar to earthquakes, mediate the transition to frictional motion and are well described by fracture mechanics. The nucleation of rupture fronts precedes slow nucleation fronts within rough frictional interfaces and is a critical question that remains to be fully understood.
Article
Geosciences, Multidisciplinary
John D. Bedford, Daniel R. Faulkner
Summary: The study found that quartz gouge exhibits unstable stick-slip behavior under high σn conditions, while slow-slip is more prevalent under low σn conditions. Localization and instability are mainly promoted by high effective normal stress and small grain size.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Chemistry, Physical
Wanmin Guo, Qingshun Bai, Yuhao Dou, Shandeng Chen, Hongfei Wang
Summary: This study analyzed the frictional behavior of graphene on stainless-steel surfaces through molecular dynamics simulations. The results revealed that the polycrystalline character and multielement characteristics of stainless-steel play a crucial role in the adsorption state and frictional performance of graphene, providing theoretical foundations for the application of graphene on stainless-steel surfaces.
Article
Engineering, Geological
Omer Aydan, Ryouji Kiyota, Naoki Iwata, Neamatullah Malistani
Summary: The static and dynamic frictional properties of rock discontinuities play a crucial role in evaluating the failure and post-failure motions of rock engineering structures, as well as the rupture and strong motions induced by earthquake faults. However, there are limited experiments on these properties. This study conducted tilting and stick-slip experiments on various natural rock discontinuities to determine their frictional properties, and the results showed that the static and dynamic friction angles were similar. These findings provide valuable information for researchers in fields such as Rock Mechanics, Rock Engineering, and Earthquake Science and Engineering.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Chemical
Shinichi Yuu, Toshihiko Umekage
Summary: The study investigates the occurrence of large shear stress peaks and stress ratio peaks, which are avalanche precursors, in granular layers in an inclining box. The research aims to understand the periodicities of these precursors and how they are related to stick-slip events in the granular structure. Through simulation results using SPH method and DEM equations, the study shows that the precursors have naturally occurring periodicities and are found in both bulk and surface of the granular layer, in agreement with experimental results.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Chemistry, Physical
Xiong-ying Ma, Lin-feng Zhu, Xuan Zou, Xin Kang
Summary: This study investigates the microscale interface stick-slip friction behavior of clay minerals under varying hydrostatic pressure conditions and reveals significant findings regarding the weakening of mechanical properties, water molecular clustering, and intensified stick-slip friction behavior. The study provides valuable insights into clay mineral behavior and failure mechanisms.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Materials Science, Multidisciplinary
Zhiming Xue, Ganbin Chen, Changguo Wang, Rui Huang
Summary: The study investigates the peeling and sliding behaviors of graphene nanoribbons on a graphene substrate, revealing rich dynamics in adhesion, friction, and deformation patterns. Different types of strain solitons are identified during the stick-slip sliding process, depending on the ribbon structure. The study also highlights the influence of constrained displacements on the sliding force and the quasi-linear relationship between ribbon width and sliding friction.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Physics, Fluids & Plasmas
Anna Pomyalov, Yuri Lubomirsky, Lara Braverman, Efim A. Brener, Eran Bouchbinder
Summary: A numerical study is conducted on self-healing slip pulses, which are solitonic structures propagating in frictional systems. The solutions show diverging length and strongly inertial propagation velocities when the driving stress approaches the frictional strength at a local minimum. An approximate scaling theory explains these observations quantitatively. The derived pulse solutions exhibit significant spatially-extended dissipation and an unconventional edge singularity.
Article
Engineering, Chemical
Roberto Guerra-Gonzalez, Vidal Moises Bastida-Silva, Jose Luis Rivera, Fernando Iguazu Ramirez-Zavaleta, Enrique Lima
Summary: We used molecular dynamics simulations to investigate the friction behavior of hydroxyl-passivated silica layers lubricated with n-pentanol chains. Our study focused on constant shear stress, constant normal load, and isothermal conditions. We observed different sliding regimes and proposed a sliding mechanism between the methyl groups of the n-pentanol chains. The critical ordering of hydrogen bonds between the surface hydroxyl groups and the lubricant was found to be crucial for reaching a stationary state.
Article
Nanoscience & Nanotechnology
Chaochen Xu, Shuai Zhang, Hongzhi Du, Tao Xue, Yilan Kang, Yang Zhang, Pei Zhao, Qunyang Li
Summary: Research has shown that the frictional characteristics of graphene can be adjusted by applying strain. In an experiment where graphene is deposited onto a stretchable substrate, it was found that the friction of supported graphene decreases with increasing strain, but the system shows two distinct friction regimes with significantly different strain dependences depending on the adherence state of the graphene/substrate interface.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Nanoscience & Nanotechnology
Chaochen Xu, Shuai Zhang, Hongzhi Du, Tao Xue, Yilan Kang, Yang Zhang, Pei Zhao, Qunyang Li
Summary: Graphene has shown great potential as a surface friction modifier due to its excellent mechanical performance and tribological properties. This study investigates the frictional characteristics of supported graphene under different strains by depositing the graphene on a stretchable substrate and using an in situ tensile loading platform. The experimental results reveal that the friction of supported graphene decreases with increasing strain, similar to suspended graphene. However, the system exhibits two distinct friction regimes depending on the adherence state of the graphene/substrate interface, indicating different strain dependences.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Ceramics
Kuo-Chin Hsu, Bo-Da Chen, Te-Hua Fang, Chao-Ming Hsu
Summary: In this study, tungsten oxide (WO3) nanofibers were prepared using electrospinning technology and combined with La0.8Pb0.2FeO3 (LPFO) perovskite materials to form a heterostructure film for gas sensing applications. The pure WO3 nanofiber gas sensor showed excellent sensing for nitrogen dioxide (NO2) and hydrogen sulfide (H2S), while the WO3/LPFO heterostructure film gas sensor exhibited a high response to H2S but suppressed response to NO2. The WO3/LPFO heterostructure film gas sensor greatly improved gas selectivity, with specific sensitivity towards H2S gas.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Dinh-Quan Doan, Te-Hua Fang, Thi-Bao-Tien Tran
Summary: The tensile deformation behaviors of Cu80Ta20/Cu20Ta80 amorphous/amorphous nanomultilayers (AANMs) were studied using molecular dynamics simulation. The results show that the tensile strength of AANMs is influenced by layer thickness, with thinner layers demonstrating the Hall-Petch relationship and thicker layers exhibiting the inverse Hall-Petch effect. Additionally, the tensile strength increases with higher strain rates and lower temperatures.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Yu-Sheng Lu, Te-Hua Fang
Summary: The aspect ratio has a significant effect on buckling instability, with the critical buckling stress decreasing as the aspect ratio increases. Molecular dynamics simulation shows that the NiCoCr medium-entropy alloy nanotubes exhibit instability when the aspect ratio reaches 10. Single-crystalline specimens have higher compressive strength compared to polycrystalline specimens.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Physical
Thi-Xuyen Bui, Te-Hua Fang, Chun-I. Lee
Summary: The effects of different inclusion types, inclusion radius, and strain rates on the mechanical properties of NiFeCr alloy were investigated through molecular dynamic simulation. It was found that increasing strain rates led to an increase in tensile strength, strain energy, and dislocation densities. Samples without inclusions had higher tensile strength, strain energy, and dislocation densities compared to samples with inclusions. The inclusion radius had a complex effect, with decreasing Young's modulus for all inclusion types. The phase transformations and dislocation lengths were larger in samples without inclusions, and Stair-rod and Shockley partial dislocations were dominant in all samples.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Hoang-Giang Nguyen, Te-Hua Fang, Dinh-Quan Doan
Summary: The impact of temperature and strain rates on the cyclic plasticity of AlCrCuFeNi high entropy alloy (HEA) was investigated using molecular dynamics (MD) simulations. The results revealed that interactions between partial dislocations in the HEA caused lattice disorders, which minimized the Bauschinger effect. The study also highlighted the influence of temperature, strain rates, and grain boundaries on lattice disorder and provided new insights into the deformation mechanism of AlCrCuFeNi HEA.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Condensed Matter
Chia-Wei Huang, Tang-Yu Lai, Te-Hua Fang, Shih-Wei Liang
Summary: With the rapid development of science and technology, the use of solid lubricants, particularly Molybdenum disulfide (MoS2), in microscale machining has gained significant attention. Molecular dynamics simulations were conducted to investigate the influence of scratch depth, speed, and temperature on the mechanical properties of Ni-based MoS2 thin films. The results revealed that higher scratch depths, speeds, and temperatures led to increased friction coefficients and wider dislocation distributions, with the appearance of Shockley dislocation in all cases.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Instruments & Instrumentation
I-Po Tai, Kuo-Chin Hsu, I-Tseng Tang, Te-Hua Fang, Tsung-Chieh Cheng, Wei-Hao Wang, Mustufa Ali Ansari, Chi-Jen Shih
Summary: The degradation characteristics of methylene blue and methyl orange after being mixed with zinc oxide (ZnO) and magnesium oxide (MgO) powders are discussed in this paper. Five types of ZnO/MgO mixed powders with different molar ratios and two different catalyst concentrations were used in the experiment. The results showed that the powder with a molar ratio of 0.9:0.1 had a high degradation efficiency when the catalyst concentration was 0.15 g/L. The degradation of methyl orange was completed within 6 h, and the degradation of methylene orange reached 80% within 2 h.
SENSORS AND MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Man-Ping Chang, Te-Hua Fang, Ting-Yu Zhu, Jau-Wen Lin
Summary: In this study, the mechanical properties and deformation mechanisms of CoCrFeNiMnx high entropy alloys (HEAs) were investigated through molecular dynamics (MD) simulation. Uniaxial tensile tests were conducted at different temperatures and manganese compositions, and a circular defect was created to study the damage tolerance of these HEAs. The results showed that the CoCrFeNiMn HEA exhibited a strong temperature dependence, with the ultimate tensile strength decreasing as the temperature increased. The early stage deformation was dominated by dislocation slip, while grain boundary glide played a major role in the later stage deformation. The higher manganese content led to the formation of hexagonal close-packed (HCP) and amorphous phases, which reduced the strength of CoCrFeNiMnx HEAs. Among the compositions tested, Mn5 HEA showed the best damage tolerance.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Automation & Control Systems
Duy-Khanh Nguyen, Te-Hua Fang, Yu-Cheng Fan, Ching-Chien Huang, Chu-Xun Lin
Summary: This paper investigates the influence of control parameters of a pneumatic valve-controlled dispenser on the positional accuracy and reliability of liquid droplets, and finds that flow rate has the most impact on both criteria. Additionally, using a small needle can significantly improve the quality.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Chemistry, Physical
Thi-Nhai Vu, Van-Trung Pham, Te-Hua Fang
Summary: The deformation properties and mechanical behavior of the lamellar twined Al0.3CoCrFeNi high-entropy alloys (HEA) sample were studied using molecular dynamics (MD) simulations. The results showed different mechanical characteristics under different twin inclination angles and strain rates. It was also found that the flow stress, ultimate strength, and Young's modulus increased with increasing strain rate and decreasing temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Chih-Chieh Mo, Chih-Cheng Kuan, Yung-Hsiang Wang, Yu-Sheng Lu, Tsung-Wei Chang, Wei-Yu Liao, Te-Hua Fang, Mi-Ching Tsai, Ching-Chien Huang
Summary: This study demonstrates an innovative and effective method for recycling waste NdFeB magnets by preparing recycled sintered NdFeB magnets on a large scale. By adding NdCoGa alloy to waste wind turbine NdFeB magnets, the proposed process restores the magnetic properties of the recycled magnets to the level of the original waste magnets, enhances their corrosion resistance, and reduces the cost of magnet remanufacturing.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Duy-Khanh Nguyen, Te-Hua Fang, Yue-Ru Cai, Ching-Chien Huang
Summary: This work utilizes molecular dynamics simulation to investigate the machining mechanism and deformation behavior of NiFeCo during conventional nanoscale cutting and ultrasonic elliptical vibration-assisted cutting (UEVC). The study reveals that under UEVC, there are higher magnitudes of local stress, temperature, and shear strain, and the distribution of stacking fault and dislocation is more influenced by grain boundaries. Furthermore, increasing the vibration frequency and reducing the amplitude ratio positively impact the material removal rate and average cutting force.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2023)
Article
Physics, Condensed Matter
Van-Trung Pham, Thi-Nhai Vu, Te-Hua Fang, Duc-Binh Luu, Van-Thanh Hoang, Ngoc-Hai Tran, Minh-Sang Tran, Quang-Bang Tao
Summary: Molecular dynamics simulations were used to analyze the mechanical behavior of FeNiCrCoCu high-entropy alloys (HEA) during nanoimprint lithography with different structures. The study found that microstructure and vibration parameters significantly affected the loading force, elastic recovery ratio, and deformation behavior. The results showed that the maximum loading force decreased in the order of single-crystal, nano-twinned polycrystal, and polycrystalline structures. Grain size variation in the polycrystalline structure revealed an inverse Hall-Petch relationship. Grain boundaries played a crucial role in material softening, with grain splitting, migration, and rotation being the main deformation mechanisms. Twin boundaries in the nano-twinned polycrystal enhanced material stability and their migration was explored near the imprinted region. The best formability was observed in specimens with a grain size of 9.8 nm in the polycrystalline structure, with a smaller elastic recovery ratio and better forming shape. A mold angle of 10 degrees and 20 degrees resulted in a symmetrical pattern shape, indicating better-imprinted shape compared to other angles. The study also analyzed the effect of high-frequency mechanical vibration and found that the best forming ability was achieved with a vibration amplitude of 3.0 & ANGS;. Changing vibration frequencies showed that a frequency of 50 GHz provided the highest forming ability.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Engineering, Mechanical
Tan-Tai Do, Te-Hua Fang
Summary: This study employed molecular dynamics simulations to investigate the substrate removal methods in beta-SiC polishing. The vibration-coupled rolling motion was found to be the most effective, while the sliding motion showed significant improvement in atom removal. Additionally, increasing the number of asperities and the amplitude of vibration led to improved surface roughness.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Chemistry, Physical
Hoang-Giang Nguyen, Te-Hua Fang
Summary: The deformation mechanism and evolutionary patterns of mechanical behavior in the Alx(CuCrFeNi)1_x high-entropy alloy during nanoindentation are investigated using molecular dynamics. The study reveals that the mechanical attributes and structural changes are influenced by temperature, grain size, and alloy composition. An increase in the Al percentage leads to a reduction in the indentation force, and the concentration of aluminum and larger grain sizes enhance the overall ductility of the alloys. The movement of mobile prismatic dislocations significantly contributes to the deformation process.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
