Experimental and numerical modeling and analysis of microstructural residual stresses in hot bulk forming parts under specific cooling

特定冷却下热批量成形零件微观结构残余应力的实验和数值建模与分析

• 批准号: 374871564
• 负责人: Professor Dr.-Ing. Bernd-Arno Behrens
• 金额: --
• 依托单位: Institut für Mechanik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/374871564?language=en
• 关键词: Experimental; numerical; modeling; analysis; microstructural

In formed metallic components, the avoidance or minimization of residual stresses has so far been the main objective, with the aim of improving service life and manufacturability. A goal-oriented use of residual stresses for improvement of properties e.g. the operational strength in the field of forming technology has received rare attention until now. The aim of this project is to analyse the influences on distribution and stability of the residual stress development in thermo-mechanically processed components by means of a targeted process control using both experiments as well as numerical simulations. For this purpose, cylindrical specimen with eccentric holes are thermo-mechanically treated in various process cases in order to investigate the resulting inhomogeneous residual stress states. For the experimental as well as numerical analysis of the evolution and distribution of residual stresses in the used material a comprehensive characterisation of the thermal, metallurgical and mechanical properties was carried out in the first funding period. Due to the classification of residual stresses in 1st, 2nd and 3rd type multiscale numerical models were taken into account. The close interaction between experiment and numerical simulation allowed a calibration and validation of models and material descriptions. With these models a good prediction on the development of residual stresses in the reference process was gained. Furthermore, the developed numerical models are used during the second funding period and enhanced as well as optimized with respect to the new work program. Thereby, a macroscopic, phenomenological description in the framework of the Finite Element Method (FEM) based on thermo-mechanical and metallurgical properties is used for the representation of the residual stresses of the 1st type. For modelling microstructural residual stresses (2nd and 3rd type) and microstructure evolution phasefield models and multiscale FEM simulations are applied. After the validation of material data, the current aim is to investigate the controllability of residual stresses with regard to improve the properties of the hot-formed components. Besides specific control of the forming parameters, spray field cooling for active temperature management will be integrated into the forming process, which makes also further modification of the numerical models necessary. Subsequent numerical and experimental studies are used to analyse the interactions between process parameters and residual stresses. In the long term, a methodology should be developed which allows a deeper understanding of the thermo-mechanical material phenomena in connection with the resulting residual stress evolution occuring during the hot forming. Based on this knowledge, it is aimed for a simulation-aided process design with regard to the goal-oriented adjustment of defined, stable residual stresses, which positively influence the component properties.

在成形的金属部件中，迄今为止，避免或最小化残余应力一直是主要目标，目的是提高使用寿命和可制造性。迄今为止，在成形技术领域中，以目标为导向使用残余应力来改善性能（例如，操作强度）很少受到关注。该项目的目的是通过使用实验和数值模拟的有针对性的过程控制来分析对热机械加工部件中残余应力发展的分布和稳定性的影响。为此，圆柱形试样偏心孔热机械处理在各种工艺情况下，以调查所产生的不均匀的残余应力状态。为了对所用材料中残余应力的演变和分布进行实验和数值分析，在第一个资助期内对热性能、冶金性能和机械性能进行了全面表征。由于残余应力的分类，第一，第二和第三类多尺度数值模型考虑。实验和数值模拟之间的密切互动允许模型和材料描述的校准和验证。利用这些模型对参考工艺中残余应力的发展进行了较好的预测。此外，开发的数值模型在第二个供资期使用，并根据新的工作方案进行了改进和优化。因此，基于热机械和冶金性质的有限元法（FEM）框架中的宏观唯象描述用于表示第1类残余应力。为了对微观结构残余应力（第二和第三类）和微观结构演变进行建模，应用了相场模型和多尺度有限元模拟。材料数据的验证后，目前的目标是调查的可控性残余应力方面，以提高热成形部件的性能。除了成形参数的特定控制之外，用于主动温度管理的喷射场冷却将被集成到成形过程中，这也使得有必要进一步修改数值模型。随后的数值和实验研究被用来分析工艺参数和残余应力之间的相互作用。从长远来看，应该开发一种方法，它允许更深入地了解与热成形过程中产生的残余应力演变有关的热机械材料现象。基于这一知识，它的目的是进行模拟辅助工艺设计，以目标为导向调整确定的、稳定的残余应力，这对部件性能有积极影响。