塑性变形中应力状态与应力状态参数的关系

Relationship of stress state and stress state parameters in plastic deformation

材料的变形性能不仅与其化学成分和组织状态有关,还与变形时的应力状态有关,应力三轴度、软性系数和罗德参数是研究金属材料变形、损伤、开裂时常用的应力状态参数,本文计算和分析了塑性变形过程中9种不同应力状态和不同应力幅值下各参数值的变化情况,结果表明,应力三轴度与应力状态间有较好的对应关系;软性系数和罗德参数只有在平面屈服应力状态下才与应力状态具有很好的对应关系;在三向屈服应力状态下,软性系数和罗德参数不能直接反映不同的应力状态和变形类型。

The deformation performance of material is not only related to its chemical composition and microstructure, but also related to the stress state of forming. Stress triaxiality, soft coefficient and Rod parameter are commonly used as stress state parameters in studying the deformation, damage and cracking of metal material. The parameters under nine different stress states and stress amplitudes in plastic forming process were calculated and analyzed. The results show that the stress triaxiality and stress state have a good correspondence, while soft coefficient and Rod parameter have a better correspondence only under plane state of yield stress. Under three dimensional state of yield stress, soft coefficient and Rod parameter can not directly reflect different stress states and deformation types.