线性改变切削深度对单晶铜纳米切削的影响

针对单晶铜纳米切削,利用分数阶微积分理论,建立了切削力主趋势分量对切削深度的依赖模型,以描述非线性的尺寸效应。利用近似熵测度,研究了在不同切削阶段中切削力高频扰动的复杂性。研究表明,在切入阶段,切削力经历了由负值到较大正值的突变,工件材料出现弹性失稳以及初期的弹塑性转变;在切削阶段,切削力的主趋势分量呈现明显的低频峰谷现象和非线性的尺寸效应。通过观测工件材料内部的位错形核及位错运动,详细地解释了切削力在线性改变切削深度条件下呈现这种演变特征的根本原因。

Influence of linearly varying cutting depth on nanocutting of monocrystalline copper

A model was built for the dependence of the principal tendency component of the cutting force on the cutting depth in the nanocutting process of the monocrystalline copper to explain the non-linear size effect. The complexity of the high-frequency disturbance of the cutting force during different cutting phases was examined by the approximate entropy measure. The obtained results show that the cutting force changes abruptly from the negative value to a large positive value in the cutting-in phase, appear the phenomena of the elasticity instability and the incipient elasticity-plasticity transition. During the cutting phase, the principal tendency component of the cutting force varies in low-frequency with distinct peaks and valleys, and there presents the non-linear size effect depending on the cutting depth. Observing the dislocation nucleation and the dislocation motion inside the workpiece material, the radical cause of the evolution characteristic of the cutting force during the linearly varying cutting depth was explained.