基于用户材料二次开发的Ti6Al4V切削加工三维有限元模拟

Three Dimensional Finite Element Simulation of Ti6Al4V Machining Based on Re-development of User Material

采用Ti6Al4V在大应变、高应变率和高温条件下的流动应力模型,通过用户材料二次开发写入Deform-3D材料库中,在此基础上开展了不同参数条件下Ti6Al4V高速车削加工的热—力耦合有限元模拟试验,对切削力、切削温度和刀具磨损随切削参数的变化进行深入研究。与试验结果的比较表明,采用二次开发的用户材料模型,可以提高切削力仿真精度,实现对整个切削过程的更准确预测。对切削力影响由大到小依次是背吃刀量、进给量、切削速度。从切削力的角度来选择切削参数时,优先选取较高的切削速度,其次考虑较大的进给量。对切削温度影响最大的是切削速度,且切削速度与切削温度呈正比关系,背吃刀量影响最小。从切削温度角度选择切削参数时,应选用较大的进给量和背吃刀量,适当减小切削速度。切削速度对刀具磨损的影响最大,所以,为了延长刀具的使用,必须合理地选择切削速度。

A constitutive relation of Ti6Al4 V under the condition of large strain,high strain rate and high temperature is adopted,and implemented into the Deform-3D material library by re-development of user materials. Then the finite element simulation of Ti6Al4 V turning are carried on different cutting paramters. The changes of cutting force,cutting temperature and tool wear with that of cutting parameters are investigated deeply. The comparison with experimental results shows that the simulation accuracy of cutting force can be improved,and the more accurate prediction of the whole cutting process can be finished by using the re-development user material model. According the influence degree on cutting force from large to small,the sequences of cutting parameters are cutting depth,feed rate and cutting speed. Therefore,from the view of cutting force,the priority selectecting is a higher cutting speed,then considering a higher feeds. The cutting speed has the greatest effect on the cutting temperature,and there is a proportional relationship between them. The cutting depth has the minimum effect on cutting temperature. From the view of cutting temperature,a larger feed rate and cutting depth should be choosed,but the cutting speed should be reduced appropriately. The cutting speed has the largest influence on the tool wear,in order to extend the tool life,a reasonable cutting speed should be used.