Predicting ductile fracture of low carbon steel sheets: Stress-based versus mixed stress/strain-based Mohr-Coulomb model
Predicting ductile fracture of low carbon steel sheets: Stress-based versus mixed stress/strain-based Mohr-Coulomb model
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DOI：
10.1016/j.ijsolstr.2012.11.026
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发表时间：
2013-04-01
影响因子：
3.6
通讯作者：
Mohr, Dirk
中科院分区：
文献类型：
--
作者：
Ebnoether, Fabien;Mohr, Dirk
莫尔-库仑破坏模型的两个不同的实现结合使用一个非关联的二次塑性模型来描述在低碳钢板断裂的发生。基于应力的版本对应于应力空间中的原始莫尔-库仑模型。对于应力应变混合模型，首先将Mohr-Coulomb破坏准则转换到应力三轴度、矿脉角参数和等效塑性应变空间，然后将其作为损伤指示模型中与应力状态相关的权函数。基本的断裂实验，包括不同的缺口半径的拉伸试样和冲压试验进行校准各自的模型的材料参数。随后，该模型被用来预测裂纹萌生在Hasek测试和冲压过程中的抗冲结构。与校准实验不同，冲压过程中的加载历史是高度非线性的。这两种模型都可以以相似的精度进行校准，但是基于应变的模型在冲压实验中以更高的精度预测断裂发生的瞬间，这是经验损伤累积规则的优点。(C)2012爱思唯尔有限公司保留所有权利。
Two distinct implementations of the Mohr-Coulomb failure model are used in conjunction with a non-associated quadratic plasticity model to describe the onset of fracture in low carbon steel sheets. The stress-based version corresponds to the original Mohr-Coulomb model in stress space. For the mixed stress/strain-based version, the Mohr-Coulomb failure criterion is first transformed into the space of stress triaxiality, Lode angle parameter and equivalent plastic strain and then used as stress-state dependent weighting function in a damage indicator model. Basic fracture experiments including tensile specimens of different notch radii and a punch test are performed to calibrate the material parameters of the respective models. Subsequently, the models are used to predict the crack initiation in a Hasek test and during the stamping of an anticlastic structure. Unlike for the calibration experiments, the loading history during stamping is highly non-linear. Both models can be calibrated with similar accuracy, but the strain-based model predicts the instant of onset of fracture with greater accuracy in the stamping experiment which is an advantage of the empirical damage accumulation rule. (C) 2012 Elsevier Ltd. All rights reserved.