涂层刀具前后刀面摩擦下界面应力分析

基于任意拉格朗日欧拉方法(ALE)建立金属正交切削加工的热力耦合的有限元模型,获得不同速度下切削稳定时涂层刀具前后刀面的接触应力、剪应力以及温度场。通过对涂层刀具施加已获得的刀具表面的应力场和温度场,分析了不同速度下摩擦分界点变化的规律以及对涂层基体界面应力的影响。结果表明,随着速度的增大,摩擦分界点逐渐有向前刀面移动的趋势,表明磨损的方式开始从后刀面磨损向前刀面月牙湾磨损转变,这与切削试验结果一致。同时随着速度的增大,涂层界面应力突变更加显著,表明高速条件下涂层更容易破坏,且速度越高,前刀面涂层破坏的几率越大。

Analysis of Interface Stresses of Coated Tool under Friction on Rake and Flank Faces

Based on ALE method, a finite element model of thermal-mechanical orthogonal cutting process was established to obtain contact stresses, shear stresses and temperature on rake and flank faces when the cutting process was steady. Then tile stresses and temperature were applied to the coated tool to analyze the rules of friction demarcation point at different speeds and the influence of it on interface stresses between substrate and coatings. The results show that there is a mobile tendency of friction demarcation point from tool flank face to rake face which means the pattern of tool wear is changed from flank face wear to rake crescent wear, and it is consistent with the result of cutting experiment. Simultaneously with the in- creasing of speeds, the mutation of coating interface stresses become much obvious which means coatings is more easily failure in high speed cutting and the probability of coating failure may occur at rake face with high speed cutting.