Papers by Author: Jia Xuan Chen

Abstract: Nanometric uniaxial tension tests of single crystal copper nanorod are simulated using multiscale simulation method, which has combined molecular dynamics (MD) and finite element method (FEM). New tension models of nanorod are constructed. Tension processes of ideal nanorod without notches and that with notches are performed to analyze their mechanical properties. Deformation mechanism of tension process is discussed in detail. Yield strength and elastic modulus are calculated according to the obtained stress-strain curves. Finally, the results show that the notches have obvious influence on the mechanical properties of copper nanorod. Due to the existence of notches, the section area of single crystal nanorod decreases by 40%; however, the yield strength and elastic modulus decreases by 39.0% and 10.2% respectively in our simulations. This research is helpful for identifying the mechanical properties of single crystal copper nanorod, and for understanding the deformation mechanism of tension process of nanorod.

Abstract: Molecular dynamics (MD) simulations of nanometric scratching with diamond tip are conducted on single crystal copper crystal plane (010), and MD simulations are carried out to investigate the mechanism of material removal and the generation of defects on the surface, subsurface and inner of material. During the process of diamond tip scratching the surface of single crystal copper on conditions of different scratching speeds, depths and widths. We achieved the forming details of the chip. While the generation and moving process of defects, such as dislocation, are recorded. The different times of atomic displacement and interaction force are also shown through MD simulation. The evolvement of the lattice pattern in the abrasive processes are analysed by radial distribution function (RDF) and computing the changes of workpiece’s atomic displaces and forces. At the same time, the lattice reconfiguration and the onset and the evolvement process of defects and are analysed by RDF and atomic perspective method, respectively. The simulation results show that scratching speed play role in the course of the form of removing chips, and that different scratching widths and depths of tool have effect on onset and evolvement of lattice defects of workpiece in abrasive processes. This study can give more fundamental understanding of nanosconstruction from atomistic motions and contribute to the design, manufacture and manipulation of nano-devices