Hybrids for Re-Manufacturing – Design, Processing and Properties (ReHyb)

• Applicants: Dr.-Ing. Christoph Lohr; Professor Dr.-Ing. Nils Meyer
• Subject Area: Polymeric and Biogenic Materials and Derived Composites ; Engineering Design, Machine Elements, Product Development ; Plastics Engineering ; Lightweight Construction, Textile Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 549797608

In recent years, the development of hybrid materials has been primarily aimed at achieving the best possible component performance. The disadvantage that the combination of dissimilar materials in components is costly in terms of materials technology has been compensated for to a large extent by in-situ hybridization in terms of manufacturing technology - ultimately also in order to save processing steps and thus costs. However, the increasing hybridization of components also means that the resulting material mix represents a growing challenge for recycling. The goal of achieving the best possible component performance during the service life phase is diametrically opposed to simple demanufacturing, especially in intrinsic hybridization. In addition, a "design for remanufacturing" in the case of in-situ hybridization represents a special boundary condition, since per se actually an inseparable bond is created. A "design for remanufacturing" therefore requires the introduction of a "disconnectable" joint, which is an important boundary condition in component design - especially if multiple use of structural subcomponents is planned, which must then be designed in advance for several load cases. This project approaches the issue in a fundamental and industry-independent manner with the help of a generic demonstrator component. This comprises a double-curved shell made of a continuous fiber-reinforced thermoset for reuse, a low-melting thermoplastic film as a "disconnectable" joint and an injection-molded thermoplastic rib structure, which is completely recycled as a new rib structure in a second generation. The underlying concept of a shell component and an injection-molded rib structure for load introduction and adaptation to defined load cases is tried and tested and is already used in many applications today. Specific examples of future re-manufacturing of such structures could be doors and service flaps whose durable shell survives the additional requirements of the molded structure due to changed application scenarios or new add-on components. Here, the shell structure could be recovered thanks to a switchable interface and the injection-molded recyclable thermoplastic could be completely reused for a new load case. Not only is the mechanical performance compared between the generations, but the extent to which demanufacturing damages the constituents and the thermoplastic foil serving as a "disconnectable" joining interface is also investigated. In a concerted numerical and experimental approach, the material circularity capability of the approach is validated.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Kay A. Weidenmann