Molecular Dynamics Simulation of a Rigid Sphere Indenting a Copper Substrate

2012 ◽  
Author(s):  
Ding Jia ◽  
Longqiu Li ◽  
Andrey Ovcharenko ◽  
Wenping Song ◽  
Guangyu Zhang
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Copper Substrate ◽  
Three Dimensional ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Rigid Sphere ◽  
Displacement Curve ◽  
Loading And Unloading ◽  
Force Displacement

Three-dimensional molecular dynamics (MD) simulation is used to study the atomic-scale indentation process of a spherical diamond tip in contact with a copper substrate. In the indentation simulations, the force-displacement curve is obtained and compared with a modified elastic solution of Hertz. The contact area under different indentation depths is also investigated. The force-displacement curve under different maximum indentation depths is obtained to investigate elastic-plastic deformation during the loading and unloading processes.

AFM-Based Nanoscratching: A 3D Molecular Dynamics Simulation With Experimental Verification

2014 ◽  
Author(s):  
Rapeepan Promyoo ◽  
Hazim El-Mounayri ◽  
Kody Varahramyan
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Md Simulation ◽  
Three Dimensional ◽  
Dynamics Simulation ◽  
Dimensional Model ◽  
Gold Substrate ◽  
Three Dimensional Model ◽  
Friction Forces ◽  
Defect Mechanism

In this paper, a developed three-dimensional model for AFM-based nanomachining is applied to study mechanical scratching at the nanoscale. The correlation between the scratching conditions, including applied force, scratching depth, and distant between any two scratched grooves, and the defect mechanism in the substrate/workpiece is investigated. The simulations of nanoscratching process are performed on different crystal orientations of single-crystal gold substrate, Au(100), Au(110), and Au(111). The material deformation and groove geometry are extracted from the final locations of atoms, which are displaced by the rigid indenter. The simulation also allows for the prediction of normal and friction forces at the interface between the indenter and substrate. An AFM is used to conduct actual scratching at the nanoscale, and provide measurements to which the MD simulation predictions are compared. The predicted forces obtained from MD simulation compares qualitatively with the experimental results.

A review on the molecular dynamics simulation of machining at the atomic scale

2001 ◽  
Vol 215 (12) ◽  
pp. 1639-1672 ◽  
Author(s):  
R Komanduri ◽  
L M Raff
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Burr Formation ◽  
Depth Of Cut ◽  
Second Phase ◽  
Nanometric Cutting ◽  
Subsurface Deformation ◽  
Work Material

Molecular dynamics (MD) simulation, like other simulation techniques, such as the finite difference method (FDM), or the finite element method (FEM) can play a significant role in addressing a number of machining problems at the atomic scale. It may be noted that atomic simulations are providing new data and exciting insights into various manufacturing processes and tribological phenomenon that cannot be obtained readily in any other way—theory, or experiment. In this paper, the principles of MD simulation, relative advantages and current limitations, and its application to a range of machining problems are reviewed. Machining problems addressed include: (a) the mechanics of nanometric cutting of non-ferrous materials, such as copper and aluminium; (b) the mechanics of nanometric cutting of semiconductor materials, such as silicon and germanium; (c) the effect of various process parameters, including rake angle, edge radius and depth of cut on cutting and thrust forces, specific force ratio, energy, and subsurface deformation of the machined surface; the objective is the development of a process that is more efficient and effective in minimizing the surface or subsurface damage; (d) modelling of the exit failures in various work materials which cause burr formation in machining; (e) simulation of work materials with known defect structure, such as voids, grain boundaries, second phase particles; shape, size and density of these defects can be varied using MD simulation as well as statistical mechanical or Monte Carlo approaches; (f) nanometric cutting of nanostructures; (g) investigation of the nanometric cutting of work materials of known crystallographic orientation; (h) relative hardness of the tool material with respect to the work material in cutting; a range of hardness values from the tool being softer than the work material to the tool being several times harder than the work material is considered; and (i) the tool wear in nanometric cutting of iron with a diamond tool. The nature of deformation in the work material ahead of the tool, subsurface deformation, nature of variation of the forces and their ratio, and specific energy with cutting conditions are investigated by this method.

Mass Transfer at Atomic Scale in MD Simulation of Friction Stir Welding

2016 ◽  
Vol 683 ◽  
pp. 626-631 ◽  
Author(s):  
Ivan Konovalenko ◽  
Igor S. Konovalenko ◽  
Andrey Dmitriev ◽  
Serguey Psakhie ◽  
Evgeny A. Kolubaev
Keyword(s):  
Molecular Dynamics ◽  
Mass Transfer ◽  
Friction Stir Welding ◽  
Molecular Dynamics Simulation ◽  
Md Simulation ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Friction Stir ◽  
Embedded Atom ◽  
Atom Potential

Mass transfer has been studied at atomic scale by molecular dynamics simulation of friction stir welding and vibration-assisted friction stir welding using the modified embedded atom potential. It was shown that increasing the velocity movement and decreasing the angle velocity of the tool reduce the penetration depth of atoms into the opposite crystallite in the connected pair of metals. It was shown also that increasing the amplitude of vibrations applied to the friction stir welding tool results in increasing the interpenetration of atoms belonging to the crystallites joined

MOLECULAR DYNAMICS SIMULATION OF NANOMETRIC CUTTING PROCESS

2006 ◽  
Vol 05 (04n05) ◽  
pp. 633-638
Author(s):  
Q. X. PEI ◽  
C. LU ◽  
F. Z. FANG ◽  
H. WU
Keyword(s):  
Molecular Dynamics ◽  
Cutting Force ◽  
Chip Formation ◽  
Md Simulation ◽  
Cutting Process ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Tool Geometry ◽  
Nanometric Cutting ◽  
Eam Potential

Nanoscale machining involves changes in only a few atomic layers at the surface. Molecular dynamics (MD) simulation can play a significant role in addressing a number of machining problems at the atomic scale. In this paper, we employed MD simulations to study the nanometric cutting process of single crystal copper. Instead of the widely used Morse potential, we used the Embedded Atom Method (EAM) potential for this study. The simulations were carried out for various tool geometries at different cutting speeds. Attention was paid to the cutting chip formation, the cutting surface morphology and the cutting force. The MD simulation results show that both the tool geometry and the cutting speed have great influence on the chip formation, the smoothness of machined surface and the cutting force.

Cyclic Plasticity of CoCrFeMnNi High-Entropy Alloy (HEA): A Molecular Dynamics Simulation

2021 ◽  
Vol 13 (01) ◽  
pp. 2150006
Author(s):  
Xin Du ◽  
Xiaochong Lu ◽  
Siyao Shuang ◽  
Zhangwei Wang ◽  
Qi-lin Xiong ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Cyclic Plasticity ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Lattice Disorder ◽  
Partial Dislocations ◽  
Effects Of Temperature

The CoCrFeMnNi high-entropy alloy (HEA) is a potential structural material, whose cyclic plasticity is essential for its safety assessment in service. Here, the effects of twin boundaries (TBs) and temperature on the cyclic plasticity of CoCrFeMnNi HEA were studied by the molecular dynamics (MD) simulation. The simulation results showed that a significant amount of lattice disorders were generated due to the interactions between partial dislocations in CoCrFeMnNi HEA during the cyclic deformation. Lattice disorder impeded the reverse movement of dislocations and then weakened Bauschinger’s effect in the HEA. The cyclic plasticity of CoCrFeMnNi HEA, especially Bauschinger’s effect, depends highly on the temperature and pre-existing TBs. Such dependence lies in the effects of temperature and pre-existing TBs on the extent of lattice disorder. This study helps further understand the cyclic plasticity of CoCrFeMnNi HEA from the atomic scale.

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.

MODELING OF THREE DIMENSIONAL STRUCTURE OF HUMAN ALPHA-FETOPROTEIN COMPLEXED WITH DIETHYLSTILBESTROL: DOCKING AND MOLECULAR DYNAMICS SIMULATION STUDY

2012 ◽  
Vol 10 (02) ◽  
pp. 1241012 ◽  
Author(s):  
ALEXANDER A. TERENTIEV ◽  
NURBUBU T. MOLDOGAZIEVA ◽  
OLGA V. LEVTSOVA ◽  
DMITRY M. MAXIMENKO ◽  
DENIS A. BOROZDENKO ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Binding Site ◽  
Simulation Study ◽  
Md Simulation ◽  
Hydrophobic Interactions ◽  
3D Structure ◽  
Three Dimensional ◽  
Alpha Fetoprotein ◽  
Dynamics Simulation ◽  
Dimensional Structure

It has been long experimentally demonstrated that human alpha-fetoprotein (HAFP) has an ability to bind immobilized estrogens with the most efficiency for synthetic estrogen analog — diethylstilbestrol (DES). However, the question remains why the human AFP (HAFP), unlike rodent AFP, cannot bind free estrogens. Moreover, despite the fact that AFP was first discovered more than 50 years ago and is presently recognized as a "golden standard" among onco-biomarkers, its three-dimensional (3D) structure has not been experimentally solved yet. In this work using MODELLER program, we generated 3D model of HAFP on the basis of homology with human serum albumin (HSA) and Vitamin D–binding protein (VTDB) with subsequent molecular docking of DES to the model structure and molecular dynamics (MD) simulation study of the complex obtained. The model constructed has U-shaped structure in which a cavity may be distinguished. In this cavity the putative estrogen-binding site is localized. Validation by RMSD calculation and with the use of PROCHECK program showed good quality of the model and stability of extended region of four alpha-helical structures that contains putative hormone-binding residues. Data extracted from MD simulation trajectory allow proposing two types of interactions between amino acid residues of HAFP and DES molecule: (1) hydrogen bonding with involvement of residues S445, R452, and E551; (2) hydrophobic interactions with participation of L138, M448, and M548 residues. A suggestion is made that immobilization of the hormone using a long spacer provides delivery of the estrogen molecule to the binding site and, thereby, facilitates interaction between HAFP and the hormone.

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