Hybrid experimental-numerical analysis of basic ductile fracture experiments for sheet metals
Hybrid experimental-numerical analysis of basic ductile fracture experiments for sheet metals
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DOI：
10.1016/j.ijsolstr.2009.12.011
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发表时间：
2010-05-01
影响因子：
3.6
通讯作者：
Mohr, Dirk
中科院分区：
文献类型：
--
作者：
Dunand, Matthieu;Mohr, Dirk
对TRIP 780钢板的拉伸试样进行了基本的延性断裂试验程序，其中包括带有中心孔和圆形缺口的拉伸试样。此外，进行等双轴冲压试验。使用二维和三维数字图像相关来测量表面应变场。由于在拉伸试样的测试过程中的塑性变形的局部化，有限元模拟进行每个测试，以获得在断裂开始的材料点的应力和应变的历史。误差估计是基于预测和测量的局部应变之间的差异。具有中心孔的拉伸试样的测试结果以及冲孔试验结果表明，在约0.3和0.66的近似恒定应力三轴度断裂时，可以实现大于0.8的等效应变。误差分析表明，无论是等效塑性应变和应力三轴度是非常敏感的实验测量和数值模型假设的不确定性。当应变硬化从实验到很大的应变识别时，从非常细的实体单元网格的计算结果与实验吻合得很好。(C)2009爱思唯尔有限公司保留所有权利。
A basic ductile fracture testing program is carried out on specimens extracted from TRIP780 steel sheets including tensile specimens with a central hole and circular notches. In addition, equi-biaxial punch tests are performed. The surface strain fields are measured using two- and three-dimensional digital image correlation. Due to the localization of plastic deformation during the testing of the tensile specimens, finite element simulations are performed of each test to obtain the stress and strain histories at the material point where fracture initiates. Error estimates are made based on the differences between the predicted and measured local strains. The results from the testing of tensile specimens with a central hole as well as from punch tests show that equivalent strains of more than 0.8 can be achieved at approximately constant stress triaxialities to fracture of about 0.3 and 0.66, respectively. The error analysis demonstrates that both the equivalent plastic strain and the stress triaxiality are very sensitive to uncertainties in the experimental measurements and the numerical model assumptions. The results from computations with very fine solid element meshes agree well with the experiments when the strain hardening is identified from experiments up to very large strains. (C) 2009 Elsevier Ltd. All rights reserved.