Multiscale Modeling of Frictional Behavior of Highly-Ordered Carbon Nanotube/Ceramic Nanocomposites

2006 ◽  
Vol 978 ◽  
Author(s):  
Zhenhai Xia ◽  
William A Curtin ◽  
Pradeep Guduru
Keyword(s):  
Carbon Nanotube ◽  
Coefficient Of Friction ◽  
Md Simulation ◽  
Interaction Force ◽  
Thick Wall ◽  
Low Friction ◽  
Frictional Behavior ◽  
The Coefficient Of Friction ◽  
Cnt Arrays ◽  
Ceramic Nanocomposites

AbstractMicromechanics model incorporating with molecular dynamics (MD) simulation is developed to simulate the frictional behavior of carbon nanotube (CNT) arrays in ceramic nanocomposites. MD model is used to compute the interaction force and simulate failure mechanisms of individual nanotube at atomic length scale. The force and deformation calculated from MD simulation are passed to the continuum model to simulate the interaction between nanotube arrays and AFM tips. The coefficient of friction is determined at different load levels. The simulation shows that the low friction in the thick-wall CNT systems occurs because the stiffer CNTs are more resistant to collapse under the applied loads. The predictions for the coefficient of friction are consistent with nanoscale tests.

Study of the micro/nano-texture design to improve the friction properties of DLC thin films

2021 ◽  
pp. 2140027
Author(s):  
Young Woo Kwon ◽  
Mun Ki Bae ◽  
Ri-Ichi Murakami ◽  
Tae Hwan Jang ◽  
Tae Gyu Kim
Keyword(s):  
Thin Film ◽  
Coefficient Of Friction ◽  
Surface Friction ◽  
Low Friction ◽  
Frictional Wear ◽  
The Coefficient Of Friction ◽  
Surface Contact Area ◽  
Photolithography Process ◽  
Texture Design ◽  
Pattern Width

In this study, a DLC pattern was fabricated through a photolithography process that constitutes a part of the semiconductor process, to investigate the frictional wear characteristics. The photolithography was used to produce negative patterns with a pattern width of 10 [Formula: see text]m or 20 [Formula: see text]m and a pattern depth of 500 nm on the DLC surface. The change in the coefficient of friction of the surface was investigated through a ball-on-disk tribology test on the fabricated micro/nano-sized DLC pattern. The DLC pattern fabricated by the photolithography process showed a superior coefficient of friction to that of the general DLC sample. These results show that the decrease in the surface friction coefficient of the patterned DLC thin film is due to the reduction in the surface contact area owing to the modification of the micro/nano-texture of the surface as well as the low friction characteristics of the DLC.

Al-Film/Si-Substrate System Nanoscratching Response Based upon Molecular Dynamics Simulation in NEMS

2011 ◽  
Vol 316-317 ◽  
pp. 107-117
Author(s):  
M. Rizwan Malik ◽  
Tie Lin Shi ◽  
Zi Rong Tang ◽  
Ping Peng
Keyword(s):  
Molecular Dynamics ◽  
Coefficient Of Friction ◽  
Md Simulation ◽  
Three Dimensional ◽  
Rake Angle ◽  
Dynamics Simulation ◽  
Si Substrate ◽  
Embedded Atom ◽  
Thin Film Adhesion ◽  
The Coefficient Of Friction

A growing scientific effort is being devoted to the study of nanoscale interface aspects such as thin-film adhesion, abrasive wear and nanofriction at surfaces by using the nanoscratching technique but there remain immense challenges. In this paper, a three-dimensional (3D) model is suggested for the molecular dynamics (MD) simulation and experimental verification of nanoscratching initiated from nano-indentation, carried out using atomic force microscope (AFM) indenters on Al-film/Si-substrate systems. Hybrid potentials such as Morse and Tersoff, and embedded atom methods (EAM) are taken into account together for the first time in this MD simulation (for three scratching conditions: e.g. orientation, depth and speed, and the relationship between forces and related parameters) in order to determine the mechanisms of nanoscratching phenomena. Salient features such as nanoscratching velocity, direction and depth - as well as indenter shape- and size-dependent functions such as scratch hardness, wear and coefficient of friction - are also examined. A remarkable conclusion is that the coefficient of friction clearly depends upon the tool rake-angle and therefore increases sharply for a large negative angle.

Friction of a Steel Ball on a Single Crystal of Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 225-235 ◽  
Author(s):  
Katutosi Tusima
Keyword(s):  
Single Crystal ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Steel Ball ◽  
Low Friction ◽  
Prismatic Plane ◽  
Ice Friction ◽  
The Coefficient Of Friction ◽  
Pressure Melting ◽  
Definite Temperature

Abstract This paper presents the results of a study carried out to explain the low friction on ice. Friction of a steel ball on a single crystal of ice was measured as a function of load, velocity, temperature, and diameter of slider. It was found that even when the velocity was very small (1.5 - 10-7 to 1.8-10–3 m/s) the coefficient of friction was very small ranging from 0.005 to 0.2, although friction on the prismatic plane was twice as large as that on the basal plane. The coefficient of friction increased with load, which means that Amonton’s classical law of friction is not applicable to ice. The coefficient of friction increased with decreasing velocity, which may result from the creep of ice in the contact area. The friction strongly increased as the temperature became close to °C. A minimum friction was observed for a definite temperature. It was found that the explanation of the results obtained is given satisfactorily neither by the classic pressure-melting theory nor by the friction-melting theory, but only by adhesion theory.

scholarly journals Friction of a Steel Ball on a Single Crystal of Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 225-235 ◽  
Author(s):  
Katutosi Tusima
Keyword(s):  
Single Crystal ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Steel Ball ◽  
Low Friction ◽  
Prismatic Plane ◽  
Ice Friction ◽  
The Coefficient Of Friction ◽  
Pressure Melting ◽  
Definite Temperature

AbstractThis paper presents the results of a study carried out to explain the low friction on ice. Friction of a steel ball on a single crystal of ice was measured as a function of load, velocity, temperature, and diameter of slider. It was found that even when the velocity was very small (1.5 - 10-7 to 1.8-10–3 m/s) the coefficient of friction was very small ranging from 0.005 to 0.2, although friction on the prismatic plane was twice as large as that on the basal plane. The coefficient of friction increased with load, which means that Amonton’s classical law of friction is not applicable to ice. The coefficient of friction increased with decreasing velocity, which may result from the creep of ice in the contact area. The friction strongly increased as the temperature became close to °C. A minimum friction was observed for a definite temperature. It was found that the explanation of the results obtained is given satisfactorily neither by the classic pressure-melting theory nor by the friction-melting theory, but only by adhesion theory.

scholarly journals Achieving Ultra-Low Friction with Diamond/Metal Systems in Extreme Environments

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3791
Author(s):  
Pantcho Stoyanov ◽  
Rolf Merz ◽  
Markus Stricker ◽  
Michael Kopnarski ◽  
Martin Dienwiebel
Keyword(s):  
Coefficient Of Friction ◽  
Wear Track ◽  
High Vacuum ◽  
Extreme Environments ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Low Friction ◽  
The Coefficient Of Friction ◽  
On Line ◽  
Low Wear

In the search for achieving ultra-low friction for applications in extreme environments, we evaluate the interfacial processes of diamond/tungsten sliding contacts using an on-line macro-tribometer and a micro-tribometer in an ultra-high vacuum. The coefficient of friction for the tests with the on-line tribometer remained considerably low for unlubricated sliding of tungsten, which correlated well with the relatively low wear rates and low roughness on the wear track throughout the sliding. Ex situ analysis was performed by means of XPS and SEM-FIB in order to better understand the underlying mechanisms of low friction and low-wear sliding. The analysis did not reveal any evidence of tribofilm or transferfilm formation on the counterface, indicating the absence of significant bonding between the diamond and tungsten surfaces, which correlated well with the low-friction values. The minimal adhesive interaction and material transfer can possibly be explained by the low initial roughness values as well as high cohesive bonding energies of the two materials. The appearance of the wear track as well as the relatively higher roughness perpendicular to the sliding indicated that abrasion was the main wear mechanism. In order to elucidate the low friction of this tribocouple, we performed micro-tribological experiments in ultra-high vacuum conditions. The results show that the friction coefficient was reduced significantly in UHV. In addition, subsequently to baking the chamber, the coefficient of friction approached ultra-low values. Based on the results obtained in this study, the diamond/tungsten tribocouple seems promising for tribological interfaces in spacecraft systems, which can improve the durability of the components.

scholarly journals Study on friction behavior at the interface between prosthetic socket and liner

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Jingyang Xie ◽  
Xidong Liu ◽  
Jianhua Tang ◽  
Xi Li ◽  
Wei Li
Keyword(s):  
Energy Dissipation ◽  
Coefficient Of Friction ◽  
Temperature Increase ◽  
Friction Behavior ◽  
Friction Characteristics ◽  
Frictional Behavior ◽  
Prosthetic Socket ◽  
The Coefficient Of Friction ◽  
3D Printed ◽  
Frictional Energy Dissipation

Purpose: The friction characteristics at the interface between prosthetic socket and liner have an important influence on the walking function and wearing comfort of amputees. The frictional behavior at the prosthetic socket/liner interface can provide theoretical guidance for the design and selection of prosthetic materials. So it is of great significance to study the friction behavior at prosthetic socket/liner interface. Methods: The surface roughnesses of the prosthetic socket and liner materials were measured by a laser confocal microscope. The frictional behavior at the prosthetic socket/liner interface was studied on a UMT TriboLab Tribometer by simulating the reciprocating sliding contact mode. An infrared camera was used to take thermal images and then calculated the temperature increase at the socket/liner interface. Results: The coefficient of friction of the silicon rubber fabric are significantly smaller than that of the foam liner materials. The frictional energy dissipation at the liner/acrylic socket interface is the smallest, while it is greater for 3D-printed socket materials. Meanwhile, the temperature increase has a positive correlation to the coefficient of friction and frictional energy dissipation. Conclusions: The three kinds of 3D-printed materials with high surface roughness have higher interface coefficient of friction and energy dissipation than acrylic material. The stiffness and energy consumption play an important role in the interface friction characteristics of the prosthetic liner materials. The appropriate coefficient of friction at the surface between prosthetic socket and liner is essential. A type of the reinforcement fiber has influence on the friction behavior of the 3D-printed reinforced nylon.

Effect of Directionality of Grinding Marks on Friction at Different Surface Roughness Using Inclined Scratch Test

2005 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Kishore ◽  
Satish V. Kailas
Keyword(s):  
Surface Roughness ◽  
Coefficient Of Friction ◽  
Scratch Test ◽  
Layer Formation ◽  
Transfer Layer ◽  
Frictional Behavior ◽  
Mating Surface ◽  
The Coefficient Of Friction ◽  
Angle Effect ◽  
Scratch Tests

Surface topography of a tool plays an important role as it predominantly controls the frictional behavior at the interface. In the present study, Inclined Scratch Tester was used to understand the effect of directionality of surface grinding marks on coefficient of friction and transfer layer formation. EN8 steel flats were ground to attain different surface roughness with unidirectional grinding marks. Then Al-Mg alloy pins were scratched against the prepared EN8 steel flats. Grinding angle (angle between direction of scratch and grinding marks) was varied between 0° and 90° during the scratch tests. It was observed that the coefficient of friction and transfer layer formation depend primarily on the directionality of grinding marks of the harder mating surface, and independent of surface roughness of harder mating surface. The grinding angle effect on coefficient of friction was attributed to the variation of plowing component of friction with grinding angle.

scholarly journals Wear of Fluorapatite Single Crystals : II. Frictional Behavior

1972 ◽  
Vol 51 (2) ◽  
pp. 605-610 ◽  
Author(s):  
J.M. Powers ◽  
R.G. Craig
Keyword(s):  
Strain Rate ◽  
Single Crystals ◽  
Coefficient Of Friction ◽  
Frictional Behavior ◽  
The Coefficient Of Friction

The frictional behavior of natural fluorapatite single crystals under sliding was evaluated. Strain rate did not influence the coefficient of friction. Low and high regimes of friction were related to the amount of penetration; higher values of friction were associated with deeper penetration.

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