高速硬加工中切屑成形的有限元模拟

为了研究AISI4340钢高速加工中切屑形成机理，建立了高速加工的有限元模型.该模型采用Johnson-Cook（JC）模型作为工件材料模型，采用JC破裂模型作为工件材料失效准则，刀-屑接触摩擦采用可自动识别滑动摩擦区和黏结摩擦区的修正库仑定律，并采用任意拉格朗日-欧拉方法实现切屑和工件的自动分离.利用建立的有限元模型模拟了四种切削条件下的材料加工，分析了切屑形成过程，模拟得到了不同切削条件下的切削力，并对其进行了比较.研究结果表明，在高速加工条件下形成了不连续状切屑，不连续状切屑形成机理与基于自由表面破裂的锯齿状切屑形成机理不同.

Simulation of chip formation in high-speed hard machining

A finite element model was established to investigate mechanisms of chips formation in high-speed machining steel AISI4340.Johnson-Cook(JC) plasticity model and JC crack model were adopted as workpiece material model and failure criteria respectively.Modified Coulomb friction law identifying automatically sliding region and sticking region was used to define the interaction between tool rake face and chip.An arbitrary Lagrangian-Eulerian approach was used to separate chips from workpiece.Material processes under conditions of four cutting parameters were simulated using the established model,and the chips formation procedure was analyzed.The cutting forces of different cutting speeds were simulated,and the differences of the cutting forces were compared.The simulation results show that discontinuous chips are formed under conditions of the high-speed cutting,and that the mechanisms of chips formation differ from serrated chip based on free surface crack propagation.