采用扫描电镜和图像分析对高强韧X80管线钢的拉伸断口特征进行观察以及统计分析,根据断口特征参数设计孔洞体胞模型,并应用有限元数值模拟计算研究孔洞扩张比的演化规律.结果表明,在低应力三轴度的条件下,随着等效应变的增加,夹杂物导致的孔洞体积扩张比也不断缓慢增加,等效应变与孔洞体积扩张比的自然对数成正比,线性关系吻合良好,在后期高应力作用下应考虑M-A岛二次形核形成的孔洞片导致韧性断裂.在任何加载的条件下,对于高的应力三轴度,有限元数值模拟计算孔洞扩张比的演化规律与传统的R-T模型有较大的差异,夹杂物导致的孔洞体积扩张比迅速增加,最终由孔洞间韧带颈缩引起韧性断裂.
Tensile fracture characteristics of X80 pipeline steel with high strength and ductility was observed andanalyzed by SEM and image statistical analysis.The void-cell model was designed in terms of the fracture characteristic parameters and a finite element numerical simulation was used to research the evolution regular of void expansion ratio.The results show that the expansion ratio of void volume caused by the inclusions increased slowly with increasing the equivalent strain under low stress triaxiality condition,and the equivalent strain was proportional to the natural logarithm of the volume expansion ration of the void,so linear relationship was in a good agreement.The holes formed by the secondary nucleation of M-A island leading to ductile fracture should be considered lately under high stress condition.The evolution regular of void expansion ration calculated by finite element numerical simulation was different from traditional R-T model for high stress triaxiality under any loading conditions.The expansion ratio of void volume caused by the inclusions increased rapidly and eventually led to ductile fracture.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%