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

• Applicant: Professorin Dr.-Ing. Stefanie Reese
• Subject Area: Mechanics
• Term: from 2012 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 227716235

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.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1640: Joining by Plastic Deformation
• Co-Investigator: Professor Dr.-Ing. Stephan Wulfinghoff