Multiscale modelling of joining processes taking account of the thermomechanical-chemical behavior in the boundary layer

连接过程，如本文所考虑的辊接、冷锻和夹紧过程，其特点是塑性变形和热机械耦合效应的复杂相互作用。此外，必须考虑到过程中涉及的微观结构之间的相互作用。设计新的或改进的连接技术需要对机制有基本的了解，这很难通过单独的实验来实现。因此，本项目处理的是一个健全的多尺度建模的基本影响特征连接。项目的重点是接缝强度和多材料接缝的力学性能。我们区分了微观模型，微观模型允许对连接过程中发生的物理过程进行独立的研究，宏观力学模型部分考虑了混凝土过程的结构特征。这里的重点是尽可能准确但尺度足够的界面热力学行为的分辨率，这是通过内聚区技术的显著扩展来实现的。宏观力学模型将通过一个数据库来开发，该数据库是在微观尺度上详细参数研究的基础上产生的，并由伙伴项目和本项目的实验数据补充。微观和宏观力学工艺参数对连接的影响必须在每个建模尺度上精确捕获。该研究项目的最终目标是开发一种强大的新型仿真工具，能够预测各种连接过程的结果。此外，它应允许在这些稳健性和可重复性的过程中，为定义的要求组合选择合适的连接工艺，而不需要额外的实验调查。

Joining processes, such as the here considered processes of roll bonding, cold forging and clinching, are characterized by a complex interaction of plastic deformation and thermomechanical coupling effects. Additionally the interactions between the microstructures involved in the process have to be taken into account. The design of new or improved joining technologies requires a fundamental understanding of the mechanisms which is difficult to achieve by working solely experimentally. The present project therefore deals with a sound multiscale modelling of the essential effects characterizing joining. The emphasis of the project is on the joint strength and the mechanical properties of multi-material joints. We distinguish between microscale modelling which allows the process-independent investigation of the physical processes taking place during joining, and the macromechanical modelling part which takes the structural characteristics of concrete processes into account. The focus is here on the as accurate as possible but scale adequate resolution of the thermomechanical behaviour in the interface which is to be achieved by a significant extension of the cohesive zone technique. The macromechanical modelling is to be developed by means of a database that is generated on the basis of detailed parameter studies at the microscale and is complemented by experimental data from partner projects and the present project. The influence of the micro- and macromechanical process parameters on joining must be precisely captured at each modelling scale. The final objective of the research project is to develop a powerful new simulation tool that enables the prediction of results of diverse joining processes. Furthermore, it shall allow the choice of a suitable joining process for defined combinations of requirements, among these robustness and reproducibility of the process, without the need of additional experimental investigations.