7A04铝合金的本构关系和失效模型

使用万能材料试验机、扭转试验机和Taylor撞击实验研究了高强铝合金7A04在常温至250 ℃的 准静态、动态本构关系和失效模型。基于实验结果,修改了Johnson-Cook强度模型中的应变强化项以及 Johnson-Cook失效模型中的温度软化项,并结合数值模拟标定了模型参数。实验结果表明,7A04铝合金的 应变和应变率强化效应不显著,失效应变随温度的增加、应力三轴度的减小和应变率的减小而增加。

Constitutive relation and fracture model of 7A04 aluminum alloy

The quasi-static and dynamic constitutive relation as well as the fracture model of 7A04 aluminum alloy,from room temperature to 250 ℃,were investigated by using a universal testing machine,a torsion testing machine and the Taylor impact test.Based on the experimental results,the strain hardening term of the Johnson-Cook strength model and the temperature softening item in the Johnson-Cook fracture model were modified.The material constants were calibrated by a combination of experimental tests and numerical simulations.Experimental results show that both the strain and strain rate hardening effect are not significant and that fracture strain increases with the increase of temperature and the decrease of either stress triaxiality or strain rate.