纯铁材料动态力学性能测试及本构模型

Dynamic Mechanical Property Tests and Constitutive Model of Pure Iron Material

研究纯铁材料的动态力学性能并建立其本构模型是开展纯铁材料工程应用和数值模拟研究的基础,利用Instron材料试验机和分离式Hopkinson压杆试验装置,对纯铁材料进行了常温下不同应变率（10 3～5×104 s-1）和应变率为104 s-1时不同温度下（200～800℃）的动态力学性能测试,获得了各种载荷下的应力应变曲线.试验结果表明,纯铁材料的塑性流动应力对应变率和温度非常敏感,具有明显的应变强化效应、应变率强化和增塑效应以及热软化效应.基于Power-Law本构方程,通过试验数据拟合得到了纯铁材料的动态本构模型参数,拟合曲线与试验数据吻合较好,表明该模型能较好描述纯铁材料在动态载荷下的力学行为.

To study the dynamic mechanical property and built constitutive model of pure iron material are the basis of engi- neering application and numerical simulation. The dynamic mechanical property test of pure iron material are carried out using Instron material testing system and split Hopkinson pressure bar apparatus under different strain rates （10^-3-5 x 10^4 s^-1） at room temperature and different temperature （200-800 ℃） at high strain rate 10^4 s^-1. The stress-strain curves of pure iron are measured at high temperatures and high strain rates. The test results show that the plastic flow stress of pure iron mate- rial is sensitive to strain rate and temperature and has the effect of strain hardening, strain rate hardening plasticizing effect and thermal softening. Based on the Power-Law constitutive model, the dynamic constitutive model parameter with high strain rates and high temperatures of pure iron material is obtained by fitting the test results. The model predictions have a good agreement with test data and the dynamic constitutive model can make a satisfied prediction to the mechanial behavior of pure iron materials under dynamic loads.