中心圆孔薄板试样局部损伤破坏试验与数值分析  

Experiments and Numerical Analysis of Damage and Fracture Process on Plates with a Round Hole

作　　者：余海东[1] 张克实[1] 郭运强[1] 张光[1] 

机构地区：[1]西北工业大学工程力学系,陕西西安710072

出　　处：《机械工程材料》2005年第1期16-19,共4页Materials For Mechanical Engineering

基　　金：国家自然科学基金资助项目(19972055);航空基础科学基金资助项目(00C53022)

摘　　要：对含圆孔的16MnNb矩形薄板试样进行拉伸破坏试验,用扫描电镜分析了断口形貌和断口破坏方式;采用含孔洞材料本构模型,结合有限元数值方法对试样的细观孔洞演化过程和材料微观破坏过程进行了数值模拟分析。结果表明:材料中由于形成的微孔洞在圆孔周围最小横截面上和拉伸后形成的剪切带区域较大,所以微孔洞长大速度最快位置在圆孔周围局部颈缩区域,最后试样在该处起裂,并沿着最小横截面扩展,在裂纹前缘形成两条明显的剪切带,剪切带上试样发生颈缩。计算结果与试验结果相当吻合。Tensile experiments of the 16MnNb plates with a round hole in the center were carried out. According to the results of the experiments and the appearance of the fracture section, the local damage and fracture process were analyzed. The Gurson model modified by Tvergaard and Needleman was employed to describe the development of void and describe the damage and fracture process. The results show that there was a local necking region around the hole after the specimens had been yielded. The region did not extend during the deformation process. The voids grew very fast in the region near the hole in the minimum cross section. The voids nucleated faster in the minimum section and the region of shearing band than in other regions. There were many cracks extending to the tensile orientation in the minimum cross section. Because of the coalesence of voids, the cracks were initiated from the center of specimens and extended to the edge. The process described by the simulation is in reasonable aggreement with the experimental observations.

关 键 词：损伤 断口 微孔洞体积分数 破坏 

分 类 号：O346[理学—固体力学]