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

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.

2013 ◽  
Vol 690-693 ◽  
pp. 2559-2562
Author(s):  
Ying Zhu ◽  
Shun He Qi ◽  
Zhi Xiang ◽  
Ling Ling Xie

Molecular dynamics model of the polysilicon material under the micro/nanoscale is established by using molecular dynamics method, make variety of the typical defects distribute to the polysilicon model reasonable and relax the simulation model, obtain the system potential energy curves in the relaxation process and the atomic location figure after the relaxation. Conduct molecular dynamics simulation of nanometric cutting process relying on the development of simulation program, get instant atom position image and draw the cutting force curve. Discusses the typical defects impact on the polycrystalline silicon nanometric cutting process, those mainly include cutting force changes in the cutting process, potential energy changes and processed surface quality etc.


Author(s):  
R Komanduri ◽  
L M Raff

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.


2014 ◽  
Vol 536-537 ◽  
pp. 1431-1434 ◽  
Author(s):  
Ying Zhu ◽  
Yin Cheng Zhang ◽  
Shun He Qi ◽  
Zhi Xiang

Based on the molecular dynamics (MD) theory, in this article, we made a simulation study on titanium nanometric cutting process at different cutting depths, and analyzed the changes of the cutting depth to the effects on the work piece morphology, system potential energy, cutting force and work piece temperature in this titanium nanometric cutting process. The results show that with the increase of the cutting depth, system potential energy, cutting force and work piece temperature will increase correspondingly while the surface quality of machined work piece will decrease.


2011 ◽  
Vol 312-315 ◽  
pp. 983-988
Author(s):  
Seyed Vahid Hosseini ◽  
Mehrdad Vahdati ◽  
Ali Shokuhfar

Nowadays, the nano-machining process is used to produce high quality finished surfaces with precise form accuracy. To understand and analyze the chip formation mechanism of nano-machining process on an atomistic scale, since the experimentation is not an easy task, numerical simulation such as molecular dynamic (MD) simulation is a very useful method. In this paper, MD simulation of the nano-metric cutting of single-crystal copper was performed with a single crystal diamond tool. The model was solved with both pair wise Morse potential function and embedded atom method (EAM) potential to simulate the inter-atomic force between the work-piece and a rigid tool. The chip formation mechanism, dislocation generation, tool forces and generated temperature were investigated. Results show that the Morse potential cannot perform an appropriate defect formation and plastic deformation in nano-metric cutting of metals. Also, tool forces in Morse potential are more than the forces in EAM potential. Furthermore, the fluctuations of resultant forces in Morse potential are greater than that of EAM. In addition, using many-body interaction potentials like EAM can lead to substantial changes in surface energies, elastic-plastic properties and atomic displacement, compared with the pair-wise potentials like Morse. Finally, the atomic displacement investigation shows that in EAM potential study, only the atoms in a local region near the cutting process are displaced, but in Morse potential a large portion of atoms has affected during cutting process. Subsequently, the chip temperature in EAM potential is more than that of Morse potential.


2010 ◽  
Vol 97-101 ◽  
pp. 3104-3107 ◽  
Author(s):  
Yu Lan Tang ◽  
Qiang Liu ◽  
Yu Hou Wu ◽  
Ke Zhang

A three-dimensional model of molecular dynamics (MD) was employed to study the nanometric cutting mechanism of monocrystalline copper. The model included the utilization of the Morse potential function to simulate the interatomic force. By analyses of the snapshots of the various stages of the nanometric cutting process, the generation and propagation of the dislocations around the tool are observed. Some of these dislocations are observed to travel through the entire depth of the workpiece. Those that could most escape completely through the machined surface due to elastic recovery were found to introduce atom step on the machined surface. By analyses of the cutting forces during the entire nanometric cutting process, significant fluctuations are observed in the cutting force curves. The stress distribution plots of the various stages of the nanometric cutting process show that the mechanism of chip formation is significantly different from the conventional shear ahead of the tool in the case of a polycrystalline material. Most atoms ahead of tool are compressed, but forces of one or two layers atoms contact the cutting tool are tensile. With the chip formation, a small tensile zone ahead of tool generates in the compression zone and moves with the tool.


Author(s):  
Ding Jia ◽  
Longqiu Li ◽  
Andrey Ovcharenko ◽  
Wenping Song ◽  
Guangyu Zhang

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.


2016 ◽  
Vol 683 ◽  
pp. 626-631 ◽  
Author(s):  
Ivan Konovalenko ◽  
Igor S. Konovalenko ◽  
Andrey Dmitriev ◽  
Serguey Psakhie ◽  
Evgeny A. Kolubaev

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


RSC Advances ◽  
2016 ◽  
Vol 6 (75) ◽  
pp. 71409-71424 ◽  
Author(s):  
Saeed Zare Chavoshi ◽  
Xichun Luo

Nanometric cutting of single crystal 3C–SiC on the three principal crystal orientations at various cutting temperatures spanning from 300 K to 3000 K was investigated by the use of molecular dynamics (MD) simulation.


2004 ◽  
Vol 471-472 ◽  
pp. 144-148 ◽  
Author(s):  
Hui Wu ◽  
Bin Lin ◽  
S.Y. Yu ◽  
Hong Tao Zhu

Molecular dynamics (MD) simulation can play a significant role in addressing a number of machining problems at the atomic scale. This simulation, unlike other simulation techniques, can provide new data and insights on nanometric machining; which cannot be obtained readily in any other theory or experiment. In this paper, some fundamental problems of mechanism are investigated in the nanometric cutting with the aid of molecular dynamics simulation, and the single-crystal silicon is chosen as the material. The study showed that the purely elastic deformation took place in a very narrow range in the initial stage of process of nanometric cutting. Shortly after that, dislocation appeared. And then, amorphous silicon came into being under high hydrostatic pressure. Significant change of volume of silicon specimen is observed, and it is considered that the change occur attribute to phase transition from a diamond silicon to a body-centered tetragonal silicon. The study also indicated that the temperature distributing of silicon in nanometric machining exhibited similarity to conventional machining.


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