Recyclable multi-material design for lightweight structures (MM4R)
Subject and objectives
Lightweight automotive structures are a key factor on the way to resource-efficient mobility. In view of current climatic and political developments, environmental and social aspects are playing an increasingly important role in addition to technical and economic criteria. In recent years, light-weight construction has increasingly seen the establishment of hybrid construction methods that synergistically combine material, design and functional lightweight construction. The use of reinforced plastics in combination with steel, for example, can significantly reduce environmental footprints compared with aluminum/magnesium structures. The recyclability of the new materials resp. the vehicle structures also shows great potential for improved environmental impacts. In this respect, the combination of thermoplastic fiber reinforced composite (FRP) hollow sections, organic sheets and injection molding (FuPro design) is predestined. With only one material system, easily recyclable (e.g. GF/PP), maximum design freedom can be achieved. Due to its integral character, the FuPro construction method has considerable economic potential compared to classic monomaterial solutions. The project focuses on the transfer of this lightweight construction method to industrial application with the lowest possible environmental impact, taking into account all phases of the product's life cycle. In addition to the proven lightweight potential, the substitution of magnesium, the consistent use of low-CO2 materials and a waste-free production with maximum use of recycled materials offer the possibility to reduce the environmental impact of such components by about 90%.
Fraunhofer IWS contributes its long-standing expertise in the field of laser-based surface modification. Prior to merging the composite, the multi-material interfaces are specifically laser structured. As a result, additional adhesion promoters can be avoided and the recyclability of the component can be ensured. The aim of the subproject is to develop and optimize the laser processes for surface pretreatment. The objectives are to increase the bonding strength, to transfer the laser processes from 2D samples to the complex, three-dimensional shape of the demonstrator, and to achieve process times that are suitable for industrial use.