TC4钛合金动态本构模型与高速切削有限元模拟

利用SHPB实验装置,测试TC4钛合金在20～600℃、应变率为103～104s-1下的流动应力和应变的关系,应用自适应遗传算法(GA)优化建立适合高速切削模拟的Johnson-Cook(JC)热粘塑性本构模型,该模型可在较高温度和较宽应变率范围内精确预测TC4的流动应力。以所建的Johnson-Cook模型为材料本构模型,应用大型商用有限元软件ABAQUS,并使用切屑分离准则,建立高速正交切削有限元模型。将模拟结果与高速正交车削的实验数据进行比较,证实本构模型和有限元模拟的正确性。

Dynamic constitutive model of TC4 alloy material and finite element simulation of orthogonal high-speed cutting

A split Hopkinson pressure bar apparatus(SHPB) is used to measure the true flow stress and true strain relationship for TC4 alloy from a strain rate of 1 000 to 10 000 s-1 and from room temperature to 600 ℃.Based on the experimental data, Genetic Algorithm(GA) determined the parameters for a Johnson-Cook thermo-viscoplastic constitutive equation, and the Johnson-Cook(JC) model can be used to predict flow stress for TC4 alloy under the conditions of higher temperature and higher strain rate.To simulate high speed orthogonal cutting of TC4 alloy, a commercial FE code(ABAQUS/Explicit) has been used.This code adopts JC material model established and shear failure criterion.Finally, by comparison between experimental and numerical cutting force and chip geometry, it is showed that the constitutive model and finite element simulation are reasonable.