基于SPH法的金属切削大变形数值模拟

SPH-Based Numerical Simulation for Big Deformation During Metal Cutting

采用光滑质点流体动力学法对金属切削过程中复杂的材料本构行为进行了数值模拟,进而分析了切削加工中的基本规律.模拟结果表明,切削过程是切削层材料受刀具的挤压而产生的以剪切滑移为主的塑性变形过程;堆积在刀尖处的材料屈服强度提高,接触应力增大,使得工件表面产生显微裂纹;切削过程中,切削力逐渐增大,最后保持在一定范围内平稳变动;形成切屑后,前刀面上的最大接触应力在距离切刃一定距离处上下变动,在该位置处刀具的磨损较为严重.

A numerical simulation was conducted using SPH for the constitutive behavior during metal cutting {or complex materials, and the basic rules in metal cutting process were analyzed. The simulation results showed that the cutting process is actually a plastic deformation process in which the material layer being cut forms shearing slip because of the extrusion by cutting tool. The yield strength of the agglomerated material due to extrusion increases in the vicinity of cutting edge. It makes contact stress increase, and eventually results in microcrack on workpiece surface. The cutting force increases gradually, and then varies steadily in a certain range in the cutting process. After the formation of chip, the maximum contact stress on rake fluctuates at a certain distance to the cutting edge, where the cutting-tool is heavily worn.