Molecular Dynamics Simulation of Nanoscale Sliding Friction Process between Sphere and Plane

2012 ◽  
Vol 268-270 ◽  
pp. 1134-1142 ◽  
Author(s):  
Xiao Jing Yang ◽  
Sheng Peng Zhan ◽  
Yi Lin Chi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Friction Force ◽  
Basal Body ◽  
Contact Surface ◽  
Sliding Friction ◽  
Dynamics Simulation ◽  
Sliding Speed ◽  
Contact Depth ◽  
Macro Scale

Contact surface of nanoscale sliding friction represent some new features that are different from the macro scale sliding friction, which need to seek new analysis methods. Molecular dynamics simulation is an effective method to describe microscopic phenomena. Therefore, Molecular dynamics method was used to study mechanical behavior of contact surface of nanoscale sliding friction. A molecular dynamics model of hemisphere sphere sliding on rectangular solid plane was built. State change of the micro contact area and friction force variation in the process of sliding friction were observed and analyzed after solution and simulation. The results show that, at the beginning position of the sliding, with different contact depth, contact action region of hemisphere and plane generated the atoms displacement, re-arranged and close-packed accumulation is also different. The deeper the contact depth is, the greater the atoms close-packed accumulation is, and the greater the contact deformation is. In the process of sliding friction, the contact surface of the basal body has produced lattice destruction, surface upheaval and silicon atoms close-packed accumulation, and then formed furrow scratches. At the same time the silicon atoms of the hemisphere generated atomic migration obviously and adhered on the basal body surface. The top of the hemisphere was torn and peeled, which resulted in wear. The deeper contact depth is, the more loss of the material of the hemisphere is, and wear become heavier. The curve of friction force and sliding displacement in different contact depths shows that the deeper contact depth is, the greater friction force is. The friction force increases quickly at the beginning of the sliding. Then the friction force remains steady relatively at stable sliding phase. In subsequent sliding process, due to hemisphere was worn and the original contact surface changed in size, shape and configuration state, friction force decreases obviously. Besides, in process of sliding friction, due to stick-slip effect, friction force appears obviously fluctuations. Moreover, if the sliding speed is large the changes of sliding speed have less effect on friction force when the nanoscale sphere sliding on the plane at the different speeds.

scholarly journals Influence of Nanoscale Textured Surfaces and Subsurface Defects on Friction Behaviors by Molecular Dynamics Simulation

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1617 ◽  
Author(s):  
Ruiting Tong ◽  
Zefen Quan ◽  
Yangdong Zhao ◽  
Bin Han ◽  
Geng Liu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Friction Force ◽  
Copper Substrate ◽  
Dynamics Simulation ◽  
Textured Surfaces ◽  
Friction Forces ◽  
Subsurface Structures ◽  
Texture Orientation ◽  
Subsurface Defects

In nanomaterials, the surface or the subsurface structures influence the friction behaviors greatly. In this work, nanoscale friction behaviors between a rigid cylinder tip and a single crystal copper substrate are studied by molecular dynamics simulation. Nanoscale textured surfaces are modeled on the surface of the substrate to represent the surface structures, and the spacings between textures are seen as defects on the surface. Nano-defects are prepared at the subsurface of the substrate. The effects of depth, orientation, width and shape of textured surfaces on the average friction forces are investigated, and the influence of subsurface defects in the substrate is also studied. Compared with the smooth surface, textured surfaces can improve friction behaviors effectively. The textured surfaces with a greater depth or smaller width lead to lower friction forces. The surface with 45° texture orientation produces the lowest average friction force among all the orientations. The influence of the shape is slight, and the v-shape shows a lower average friction force. Besides, the subsurface defects in the substrate make the sliding process unstable and the influence of subsurface defects on friction forces is sensitive to their positions.

Molecular Dynamics Simulation of Thermal Conductivity of Aluminum

2013 ◽  
Vol 336 ◽  
pp. 47-55
Author(s):  
Jamal Davoodi ◽  
Samaneh Khoshkhatti
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Equations Of Motion ◽  
Fixed Number ◽  
Dynamics Simulation ◽  
Many Body ◽  
Macro Scale ◽  
Body Potential ◽  
Increasing Temperature

In this research, the thermal conductivity of aluminum (Al) in macro scale was investigated by the molecular dynamics simulation technique. We used FORTRAN programming in the simulations and used a fixed number of atoms, N, confined to a fixed pressure, P, and maintained at a constant preset temperature, T, i.e. the NPT ensemble. The Sutton-Chen many-body potential was used to calculate energy and force. The temperature and pressure of the system were controlled by Nosé-Hoover thermostat and Berendsen barostat respectively. We could solve the equations of motion using the Velocity Verlet algorithm. We calculated the thermal conductivity of Al in the macro scale using the Green-Kubo method. Moreover, we have studied the effect of increasing temperature on the value of the thermal conductivity of Al. The obtained results showed that the computed thermal conductivities are in good agreement with experimental data.

Molecular Dynamics Simulation of Vibrational Friction Force Due to Molecular Deformation in Confined Lubricant Film

2003 ◽  
Vol 125 (3) ◽  
pp. 587-591 ◽  
Author(s):  
Kentaro Tanaka ◽  
Takahisa Kato ◽  
Yoichiro Matsumoto
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Friction Force ◽  
Lubricant Film ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Magnetic Storage ◽  
Stick Slip ◽  
Molecular Deformation ◽  
Load Conditions

The lubrication by thin film has become a very important role in micro machine, magnetic storage device and so on. As the thickness of lubricant film becomes thinner to several nanometers, the conventional law of lubrication becomes unable to use. Nonequilibrium molecular dynamics simulation (NEMD) was carried out to investigate the dynamic behavior of thin lubricant film confined between walls. The model used in these simulations is composed of two solid walls and fluorocarbon polymer lubricant. One of the walls is supporting a load and at the same time moving at constant velocity. Results indicate that the frictional behavior of confined lubricant varied with load; velocity field in the film retain liquid like structure under low load conditions, on the other hand, under high load conditions lubricant film becomes solidified and periodical stick and slip motion is observed at the layer near the wall. At the same time periodically vibrating friction force is observed. In this case, radius of gyration of lubricant molecules also changes periodically. It is concluded that the periodical vibration of friction force is caused by stick-slip with molecular deformation.

Effect of Defects on Oscillatory Behaviors of Double-Walled Carbon Nanotube Oscillators

2011 ◽  
Vol 308-310 ◽  
pp. 584-588
Author(s):  
Jian Li
Keyword(s):  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulation ◽  
Friction Force ◽  
Vacancy Defect ◽  
Defect Size ◽  
Dynamics Simulation ◽  
Vacancy Defects ◽  
The Core ◽  
Temperature Dependences

Molecular dynamics simulation is performed on the inter-tube friction force and energy dissipation of double-walled carbon nanotube oscillators with vacancy defects. It is found that there are vacancy defect-size and temperature dependences of the friction force between the inner tube and the defective outer tube. The original distance between the “hole” formed by the vacancy carbon atoms and the inserted end of the core has a significant influence on the oscillation profile.

Molecular Dynamics Simulation of Confined n-Alkanes Between Nano-Asperity Walls

2012 ◽  
Author(s):  
Xuan Zheng ◽  
Hongtao Zhu ◽  
A. Kiet Tieu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Chain Length ◽  
Friction Force ◽  
Normal Load ◽  
Dynamics Simulation ◽  
Metal Contact ◽  
Asperity Contact ◽  
Contact Interface ◽  
Local Lattice

A molecular dynamics simulation of confined n-alkanes is conducted to investigate the effect of chain length (C8, C16, C32, C64) and normal load (250, 500, 750, 1000MPa) on friction and asperity contact. The results indicate that the longer chain n-alkanes maintain more monolayer atoms in the asperity contact interface than the shorter ones and as a result significantly reduce the friction force. Under a normal load of 250MPa, the asperity with C32 and C64 are separated by the lubricant with less metal contact. Periodic friction force is observed and it correlates with the deformation of the local lattice that breaks and relocates the atoms during the asperity contact.

Molecular Dynamics Simulation of Sliding Friction Between Crystalline Cotton Fiber and Cr

2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Zhe Yan ◽  
Kaixiang Jiang ◽  
Wenjuan Fang ◽  
Hui Cao ◽  
Youqiang Zhang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Cotton Fiber ◽  
Sliding Friction ◽  
Dynamics Simulation
Sign in / Sign up

Export Citation Format

Share Document