On the Improvement of Formability and the Prediction of Forming Limit Diagrams at Fracture by Means of Constitutive Modelling
On the Improvement of Formability and the Prediction of Forming Limit Diagrams at Fracture by Means of Constitutive Modelling
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基于本构模型的成形性能改进及断裂成形极限图预测
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
F. Bach
中科院分区：
文献类型：
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作者：
Y. Kiliclar;M. Engelhardt;I. Vladimirov;Michael P. Pietryga;H. von Senden genannt Haverkamp;S. Reese;F. Bach
金属板成形工艺在用于大批量制造的生产技术中是成熟的。为了提高成形性，可以通过准静态和高速成形工艺的组合来提高单一成形工艺的加工极限。在材料科学研究所（IW）和应用力学研究所（IFAM）的合作研究中，对通过模拟和实验获得的EN AW 6082 T6铝合金两种操作的成形极限进行了研究。实验结果表明，在较高的应变速率的成形极限的显着变化。这里，成形极限曲线移动到右下方。通过有限元分析，模拟了这一过程，并预测了断裂时的FLD。本构模型是基于变形梯度的乘法分裂。它与延性损伤耦合，并结合了非线性运动和各向同性硬化。运动硬化分量代表了Armstrong-Frederick运动硬化的经典流变模型的连续扩展。根据有效应力的概念和应变等效原理，进行了损伤与粘塑性的耦合分析。利用这些强大的工具，动态效应的模拟和成形极限图的预测断裂显示出良好的相关性与实验。
Sheet metal forming processes are well-established in production technology for the manufacturing of large quantities. To increase the formability, the processing limit of a single forming process can be enhanced by a combination of quasi-static and high-speed forming process. The forming limits for both operations for the aluminum alloy EN AW 6082 T6 obtained via simulations and experiment are investigated in a research cooperation between the Institute of Materials Science (IW) and the Institute of Applied Mechanics (IFAM). Significant changes in forming limits with higher strain rates are indicated by the experimental results. Here, the forming limit curves move to the lower right hand side. The processes are simulated and the FLD at fracture are predicted by means of finite element analysis. The constitutive model is based on the multiplicative split of the deformation gradient. It is coupled with ductile damage and combines nonlinear kinematic and isotropic hardening. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong–Frederick kinematic hardening. The coupling of damage and viscoplasticity is carried out following the well-known concept of effective stress and the principle of strain equivalence. Using these powerful tools the simulation of dynamic effects and the prediction of forming limit diagrams at fracture shows good correlation with the experiments.