颗粒微切削表面创成的分子动力学仿真研究

颗粒微切削的性能和行为直接影响工件的表面质量,从材料去除规律和能量变化规律的角度对颗粒微切削作用的表面创成机理进行研究,分别采用EAM势、Morse势、Tersoff势描述单晶铜原子间、工件与颗粒、颗粒刀具原子间的作用力。分析纳米尺度下颗粒切削方向、颗粒切削速度、系综温度对颗粒微切削作用,通过探讨体系动能、体系势能、体系总能对工件原子运动规律的影响及颗粒微切削加工前后键角的变化形态,为阐述颗粒微切削作用的表面创成机理提供理论依据。研究结果表明正交切削比斜切削能获得更好的表面质量,颗粒速度与能量不存在线性关系,颗粒温度对体系能量有直接影响。通过分子动力学数值模拟得到体系的结构信息及相关热力学性质并对分子动力学的微观统计量进行分析计算,寻找合适的加工参数,为颗粒微切削加工工艺的发展提供技术支持。

Molecular Dynamics Simulation Research into Generative Mechanism of Particles Micro-cutting Surface

The performance of monocrystalline particles micro cutting has direct influence on surface finish quality. So the study angle is regularity of material removal and energy change in surface formation mechanism of monocrystalline particles micro cutting. A three dimensional model of molecular dynamics is employed to study the monocrystalline copper micro cutting mechanism. The model include the utilization of the EAM potential function, Morse potential function, and tersoff potential function to simulate the interatomic force between copper atoms, the workpiece and copper particles. The effect of particles cutting direction and velocity and ensemble temperature on particles micro cutting in nano scale with the model are analyzed. Through discussing the effect of system kinetic energy and potential energy and total energy on workpiece-atomic movement rule, and the change of bond angle with particles micro cutting, it provides theoretical basis for surface formation mechanism of monocrystalline particles micro cutting. The results show that the surface finish is better in orthogonal cutting than that in bevel cutting, linear relationship of particles velocity and energy don’t exist and particles temperature have direct influences on system energy. Molecular dynamics simulation is carried out to get system structural information and thermodynamic property and provides a method to search appropriate machining parameter. Through the simulation, the technical support for the study on particles micro cutting processing technology is provided.