中文摘要：

对于延性损伤破坏材料，为了确定缺口试件在拉伸试验中的应力三轴度，建立应力三轴度相关的材料失效破坏函数关系，基于缺口试件在整个拉伸过程中的应变路径和应力三轴度在最小横截面上的分布效应，结合数值模拟，对现有的缺口试件应力三轴度确定方法进行了比较研究，给出了缺口试件更为合理的应力三轴度确定方法。

英文摘要：

For notched specimens of ductile metals, the stress triaxiality varies greatly during tensile deformation. Considerifig strain path and distribution effect in the neck cross section, the existing formulas for the calcula- tion of stress triaxiality should be improved for a more reasonable material fracture function. Based on the numerical simulations, several methods to determine the stress triaxiality of notched specimens were compared. A more rea- sonable method to determine the stress triaxiality of notched specimens is proposed.