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通过对分离式Hopkinson压杆进行高温动态压缩实验,得到在冲击压缩中材料航空铝合金7050-T7451在室温到高温550℃的应变、应变率与应力间的数据依赖关系。利用高速切削实验及有限元模拟相结合对该数据关系进行修正以适合高速切削加工的“高温”、“高应变率”及“大应变”状态。选择综合考虑温度软化效应,应变强化和应变率强化效应的经验Johnson-Cook模型,对其数据关系进行量化的描述,并确定铝合金7050-T7451流动应力本构模型中材料常数的值,最后建立了铝合金7050-T7451的本构模型。以实验和模拟中输出主切削力为比较指标,验证了所建模型的正确性。
Through the high-temperature dynamic compression test of the split Hopkinson pressure bar, the data dependence of the strain, strain rate and stress of the material aviation aluminum alloy 7050-T7451 in impact compression at room temperature to high temperature 550 ℃ is obtained. The relationship between “high temperature”, “high strain rate” and “large strain” was corrected by using high speed cutting experiment and finite element simulation. The empirical Johnson-Cook model considering the effects of temperature softening effect, strain hardening and strain rate hardening is selected to quantitatively describe the data relationship and to determine the value of the material constant in the flow stress constitutive model of aluminum alloy 7050-T7451. Finally, The constitutive model of aluminum alloy 7050-T7451. The main cutting force output in experiments and simulations is a comparative index, which verifies the correctness of the model.