使用准静态压缩实验和切削实验相结合的方法,拟合出2Crl3材料的Johnson--Cook模型。在低应变率范围内采用压缩实验的方法来获得材料模型的系数,使用切削实验来获得高应变率条件下的材料系数。由于压缩实验所能获得的最大应变率仍然比切削实验中所能达到的最低应变率低几个数量级,因此实验采用应变外推的方法来获得符合Johnson--Cook公式应用范围的材料参数。在切屑成形仿真模型中,使用新建立的Jonhson--Cook材料模型,将仿真结果同实验进行对比,验证了模型的准确性。
The prediction accuracy of cutting process simulation is related with the description of nonlinear behavior of material at extremely high strain, strain rate and temperature in machining. An integral Johnson--Cook model was presented herein to characterize the mechanical behavior of work materials in machining, and the parameters in the model were determined by fitting the data from both quasi--static compression and cutting tests. Then the material equation of 2Crl3 stainless steel was derived with this method and used in the finite element model of orthogonal cutting with carbide tools. At last, the simulation results were verified with experimental data.