金属切削加工中航空铝合金板材的本构模型

Constitutive model of aviation aluminum-alloy material in metal machining

针对金属切削加工中材料的高温度、高应变、高应变率数据难以获取,无法建立动态本构模型这一技术难题,提出基于有限元模拟和“单因素”流动应力公式计算的联合建模策略。由“单因素”流动应力公式反复计算与模拟应变率对应的流动应力,基于新的流动应力有限元模拟迭代的进行并追求模拟值与实验结果的一致,获取能反映切削材料力学性能的“三高”数据和流动应力数据。数据分析表明,应变率对流动应力具有强化作用,温度对流动应力具有弱化作用,稳态变形后,各应力—应变曲线都变为一条趋于与应变坐标轴平行的直线。根据影响规律选取Zerilli Armstrong经验模型,采用非线性回归分析建立起航空铝合金板材在铣削加工中的动态本构模型。最后进行实验验证,证明了该本构模型的正确性。

High temperature, high strain and high strain-rate of metal material in machining were not easy to get with a general measure method, which made it quite difficult to establish the dynamic constitutive model. To solve this problem, a combined modeling method based on “single factor” flow stress formula calculating and FEM simulation was proposed. The flow stress was repeated by calculated using the “single factor” flow stress formula, the metal machining process was simulated interatively with new flow stress. When simulating value was in good consistent with experimental result, the “three-high” data and flow stress data were obtained. By analyzing these data, it indicates that strain-rate can enhance the flow stress, while temperature will lower flow stress, and after remained in a steady state, each stress—strain curve will be parallel to the strain coordinate axis. Zerilli-Armstrong experience model was selected correspondingly. With the non-liner regression analysis, a dynamic constitutive model of aviation aluminum-alloy material during milling process was established. At last, the constitutive model is proved to be reasonable through test verification.