Generation Mechanism of Micro/Nano Machined Surfaces Based on Molecular Dynamics

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.

2011 ◽  
Vol 393-395 ◽  
pp. 1475-1478
Author(s):  
Hong Guo

A three-dimensional model of molecular dynamics (MD) was employed to study the nanometric cutting mechanism of monocrystalline silicon. The model included the utilization of the Morse potential function to simulate the interatomic force between the workpiece and the tool, and the Tersoff potential function between silicon atoms. Amorphous phase transformation and chip volume change are observed by analyses of the snapshots of the MD simulation of the nanometric cutting process, energy and cutting forces. Dislocations and elastic recovery in the deformed region around the tool do not appear. Cutting forces initiate the amorphous phase transformation, and thrust forces play an important role in driving the further transformation development. Nanometric cutting mechanism of monocrystalline silicon is not the plastic deformation involving the generation and propagation of dislocations, but deformation via amorphous phase transformation.


2006 ◽  
Vol 315-316 ◽  
pp. 370-374 ◽  
Author(s):  
Yu Lan Tang ◽  
Ying Chun Liang ◽  
X.D. Liu ◽  
J.H. Dou ◽  
D.X. Wang ◽  
...  

A three-dimensional model of molecular dynamics (MD) simulation was employed to study the generation process of nanometric machined surfaces of monocrystalline copper. The model included the utilization of the Morse potential function to simulate the interatomic force between Cu-C and Cu-Cu. By analyses of the MD simulation snapshots of the various stages of the nanometric cutting process and local radial distribution function (RDF), the structure of the bulk and the machined surface with no change and that of the chip with minimal change were observed. Potential energy had significant fluctuations due to generation and propagation of dislocations around the tool. The elastic recovery along the machined surface of the work material was observed after the tool passed. Because the state of machined surface was an important influence on the performance and the physical and chemical properties of product, the effects of surface relaxation on the machined surface state were investigated under the vacuum condition.


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.


2006 ◽  
Vol 315-316 ◽  
pp. 792-795 ◽  
Author(s):  
Yu Lan Tang ◽  
Ying Chun Liang ◽  
D.X. Wang ◽  
J.W. Zhao

A three-dimensional model of molecular dynamics (MD) was employed to study the nanometric machining process of Si. The model included the utilization of the Morse potential function and the Tersoff potential function to simulate the interatomic force between atoms. By analysis of snapshots and local radial distribution function (RDF) during the various stages of the cutting process, amorphous phase transformation of chip and machined surface are observed, but no phase transformation of bulk. Chip volume change is observed due to the amorphous phase transformation. Dislocations around the tool and elastic recovery of the machined surface do not appear. The effects of surface adsorption on machined surface state have been studied on the basis of surface energy and surfaces hardness. Surface energy decreases and hardness increases by adsorption. Oxygen atoms adsorbed are on the machined surface and subsurface region.


2016 ◽  
Vol 1136 ◽  
pp. 184-189
Author(s):  
Zong Xiao Zhu ◽  
Ya Dong Gong ◽  
Zi Hao Gan ◽  
Yun Guang Zhou ◽  
Guo Qiang Yin

In this paper, molecular dynamics (MD) model is explored to study single-crystal nickel micro-nanomachining mechanism. Accordingly, LAMMPS would implement the simulation of nanometric cutting process, and snapshots at different steps are obtained by VMD and OVITO. On this basis, a reasonable explanation is given to the forming mechanism of chip and surface machined in the machining process of single-crystal nickel. The result of work-piece temperature distribution shows that there is a temperature gradient around the machining zone, where chip part achieved the highest temperature. Moreover, a large number of dislocations are observed. Part of dislocation atoms move forward and generate the chips, taking a lot of heat. Another part of dislocation atoms combine with the work-piece surface atoms with elastic recovery, and form the machined surface.


2009 ◽  
Vol 60-61 ◽  
pp. 435-438 ◽  
Author(s):  
Jia Chun Wang ◽  
Ji Min Zhang ◽  
Feng He Wu ◽  
Na Li

In nanometric cutting process, the actual material removal can take place at atomic level, which makes the observation of machining phenomena and the measurement of cutting parameters difficult or impossible in experiments. However, it is crucial to investigate the cutting process in nanoscale. In this work, molecular dynamics (MD) is used to study effects of cutting parameters on nanometric cutting process with the aid of EAM potential. The result of the simulation shows that higher cutting speed leads to a rough machined surface with a relative large deformation in workpiece. It is found that a smaller cutting depth results in less plastic deformation and fewer dislocations in workpiece, and also results in a smoother machined surface. Rake angle has big effect on the chip formation, potential energy and the machined surface.


2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Junye Li ◽  
Wenqing Meng ◽  
Kun Dong ◽  
Xinming Zhang ◽  
Weihong Zhao

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.


Biochemistry ◽  
1990 ◽  
Vol 29 (45) ◽  
pp. 10317-10322 ◽  
Author(s):  
Lennart Nilsson ◽  
Agneta Aahgren-Staalhandske ◽  
Ann Sofie Sjoegren ◽  
Solveig Hahne ◽  
Britt Marie Sjoeberg

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