Modelling the failure of dual phase steel sheets using a meso-scale finite element - cellular automata framework

车辆结构的重量可以通过由先进高强度钢（AHSS）（例如双相钢）制造金属板汽车车身部件来降低。采用精确的材料模型和损伤模型对冲压成形过程进行数值模拟，可以加速这些AHSS的实现。在有限元元胞自动机（FE+CA）框架中开发了一个全面的细观材料模型，该模型能够根据双相钢部件的力学性能和一些微观结构特征预测双相钢部件的成形行为和断裂发生。该模型预测了延性损伤的发展方面的空隙成核，生长和聚结功能，并根据钢的微观结构特征，将最终确定最终的比例的脆性和韧性断裂。建议将该介观尺度模型校准到Stelco的一系列汽车冷轧双相钢（DP 780，DP 980和DP 1180）的商业等级中的每一个，并验证该模型用于预测具有挑战性的成形过程。这项工作将涉及每个级别的双相钢的力学和显微组织表征，在先进的本构模型和特定的成形过程的模拟的材料参数的拟合。通过将预测结果与实验成形和断裂结果进行比较，验证了这种混合FE+CA模型。这项工作将为Stelco提供一种先进的数值模型，该模型可与用于支持其汽车客户群的商业有限元软件LS-DYNA一起使用。凭借一定的经验，Stelco将能够有效地使用这种细观模型来预测双相钢以及其他等级的AHSS（如多相钢和复相钢）的成形和断裂行为。这是第一个合作研究项目，预计将加强Stelco作为汽车应用首选钢材供应商的地位。

The weight of vehicle structures can be reduced by manufacturing sheet metal automotive body parts from advanced high strength steels (AHSS), such as dual phase steels. And the implementation of these AHSS can be accelerated if accurate material and damage models are adopted into numerical simulations of the stamping process. A comprehensive meso-scale material model has been developed in a finite element cellular automata (FE+CA) framework that is able to predict the forming behavior and the onset of fracture in dual phase steel components based on their mechanical properties and some microstructural characteristics. This model predicts the development of ductile damage in terms of void nucleation, growth and coalescence functions and, depending on the microstructural features of the steel, will ultimately determine the final proportions of brittle and ductile fracture. It is proposed to calibrate this meso-scale model to each of a series of Stelco's commercial grades of automotive cold-rolled dual phase steel (DP780, DP980 and DP1180) and to validate the model for the prediction of challenging forming processes. This work will involve the mechanical and microstructural characterization of each grade of dual phase steel, the fitting of material parameters in the advanced constitutive model and the simulation of specific forming processes. This hybrid FE+CA model will be validated by comparing the predicted outcomes with the experimental forming and fracture results.This work will provide Stelco with an advanced numerical model that can be used with LS-DYNA, the commercial finite element software they use to support their automotive customer base. With some experience, Stelco will be able to effectively use this meso-scale model to predict the forming and fracture behavior of dual phase steels, as well as other grades of AHSS such as multi-phase steels and complex phase steels. This first collaborative research project is expected to strengthen Stelco as a steel supplier of choice for automotive applications.