Influences Analysis of Nanometric Cutting Single-Crystal Copper via Molecular Dynamics Simulation

Abstract

A series of three-dimensional molecular dynamics (MD) simulations are carried out based on hybrid potential model to investigate nanometric cutting process of single-crystal copper using diamond tool. The effects of cutting speed, cutting depth and initial temperature are analyzed using wavelet transform, approximate entropy and polynomial fitting to describe random and stability feathers of cutting force. The techniques of centro-symmetry parameter (CSP) and radial distribution function (RDF) are used to calculate and analyze the detailed mechanism of the dislocation propagation throughout the whole process in which the evolution of lattice symmetry changes and the atomic bonding length can be obtained. In this paper, the mechanism of nanometric cutting proecess of single-crystal copper is given a better understanding. Simulation results also show that the deformation mechanism of single-crystal copper changed when the cutting speed exceeds the plastic wave. In order to have a better understanding of cutting force, the approximate entropy (APEN) is introduced to describe the complexity and uncontrollability of it in different initial temperatures. It is found that the volume of chips increases while the cutting force decreases when the temperature rises. Polynomial fitting method is employed to fit the trend components considering the nonlinear size effect. A deeper understanding of size effect is illustrated by the electron density theory and the distribution of stress.