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

连接过程，如这里讨论的滚压、冷锻和紧固过程，具有塑性变形和热力耦合效应的复杂相互作用的特征。此外，还必须考虑到这一过程中所涉及的微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构有基本的了解，而单靠实验很难实现这一点。因此，本项目涉及对连接的基本影响进行合理的多尺度模拟。该项目的重点是多材料接头的接头强度和力学性能。我们区分了微观模型和宏观力学模型部分，微观模型允许对连接过程中发生的物理过程进行独立于过程的研究，宏观机械模型部分考虑了具体过程的结构特征。这里的重点是尽可能精确但尺度足够的界面热机械行为的分辨率，这将通过显著扩展粘聚区技术来实现。宏观机械模型将通过一个数据库进行开发，该数据库是在微观参数详细研究的基础上产生的，并辅之以伙伴项目和本项目的实验数据。必须在每个模型尺度上准确地捕捉到微观和宏观机械工艺参数对连接的影响。该研究项目的最终目标是开发一种强大的新模拟工具，能够预测不同连接过程的结果。此外，它应允许在不需要额外的实验调查的情况下，在这些过程的稳健性和重现性之间，为规定的要求组合选择适当的结合过程。

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.