双轴拉伸应力下后继屈服面的演化研究

Investigation of Subsequent Yield Surface Evolution Under Biaxial Tension

屈服面的位置和形状直接影响着材料塑性应变的确定。针对双轴拉伸应力下金属材料的塑性行为,以一种弹塑性损伤本构理论为基础,研究了后继屈服面在拉-拉应力空间中的演化。考虑了有限变形效应和耦合硬化效应,给出了屈服面的确定方法,并预测了拉-拉应力空间中的初始屈服面(IYS)和后继屈服面,预测结果显示本文提出的理论模型能一致描述出后继屈服面演化中的前端尖点效应、尾部包氏效应、膨胀/收缩以及移动和畸变。针对两种加工硬化材料(Al 6061-T 6511和Annealed 1100Al)承受轴向拉伸、环向内压、轴向-环向混合比例加载时的后继屈服面,将模型预测的结果与文献中的实验结果进行对比。结果表明,所提模型能较好地预测后继屈服面的演化,并能分析其物理机制,为后继屈服面的演化研究提供了一种可行的方法。

The shape and position of the yield surface of a metallic material have a direct bearing on the determination of its plastic deformation. In this paper, the evolution of the yield surface in a tension-tension stress space is investigated based on the elasto-plastic damage constitutive theory as an endeavor to understand the plastic behavior of metallic materials under biaxial tension. The initial yield surface （IYS） and subsequent yield surfaces are predicted with the consideration of the finite deformation effect and the mixed hardening effect, which shows the vertex effect in the forward part, Bauschinger effect in the rear part, and expansion/contraction, translation and distortion of the subsequent surfaces. For a low work hardening aluminum alloy （AI 6061-T 6511） and a high work hardening aluminum alloy （annealed 1100 AI） under axial, hoop, and combined axial and hoop loading, the theoretical prediction is favorably compared with the experimental results in the literature. The physical mechanism of the evolution of subsequent yield surfaces is elucidated. It provides a feasible method to study the evolution of subsequent yield surfaces.