韧性断裂准则的试验与理论研究

Experimental and Theoretical Research on Ductile Fracture Criterion

对不同样式的45钢和6082铝合金试件进行了拉伸、压缩、剪切、扭转等材料试验,对工程中使用的11个韧性断裂准则进行对比研究,并利用专业塑性成形分析软件对试验过程进行二维和三维情形的数值模拟。指出目前使用的韧性断裂准则都不可能对材料在任意应力应变状态和变形累积的情况下给出一个固定阈值,并给出了基于等效应变和应力三轴度的韧性断裂准则修正公式,通过厚板普通冲裁和精密冲裁试验证明了结论的有效性。

Tension, compression, torsion and shearing test on 45 steel and aluminum alloy 6082 were utilized for providing the experimental values of the critical values at fracture, and 11 widely used ductile fracture criteria were selected to simulate the physical experiments and their relative accuracy for predicting and quantifying fracture initiation sites were investigated. The comparing results show that it is impossible to capture all features of ductile fracture in different stress and strain states with a single criterion. A modified criterion based on effective strain and stress triaxiality was presented. The research results are checked experimentally using the blanking and fine blanking tests.