Form-fit in-mould connection between FRP and a sheet metal insert structured with friction drilled bushings

Hybrid lightweight construction with integral components made of fibre-plastic composites and metals is a promising approach for further reducing vehicle weight under the production conditions of large-scale automotive production. However, integral hybrid composites represent a technological challenge for joining processes. This research project, in collaboration with the Institute for Machine Tools and Manufacturing Technology at the Technical University of Braunschweig, is developing a new technique for implementing a form-fit connection between a fibre-reinforced plastic (FRP) and a structured metal insert that is suitable for loads and requirements. The research project aims to use friction drilled bushings and their collars as elements of sheet metal structuring to produce a multiaxial loadable material composite by hybrid injection moulding processes. Numerical methods are used in the development process to enable a realistic prediction of the flow and failure behaviour of the materials used and of the friction drilled bushing geometry to be achieved. Both the bushing and the collar are set by the parameters of the friction drill process and by its tool geometry. The process parameter and tool geometry are varied, so that bushing geometries suitable for the requirements are identified and characterised by the bond strength in shear tests of hybrid specimen. The technology carrier of the project is the friction drill newly developed in this research project together with the process for load-path-compatible structuring of the sheet metal inserts. The numerical mapping of the applied joining technology helps to apply this technology in a targeted manner and to reduce the development time for the process design.