Bio-based Composites for Sustainable Lightweighting

Kurzfassung

Re-envisioning and bridging the gap between lightweighting industries and sustainable mobility requires further development in the composites value chain. Composites often require highly demanding manufacturing processes and auxiliary materials to bring them into functional components. This paper proposes a hybridization approach using sandwich structure configurations to create a sustainable lightweighting bio-composite solution. By synergistically combining wood as the core and natural fibers as reinforcements, this approach reduces the dependency on synthetic fibers and auxiliary materials required in curing their matrices, thereby reducing the carbon footprint. In the current state of the art, natural fibers such as flax are being advertised as sustainable solutions compared to synthetic counterparts such as carbon fiber. However, life cycle analysis screenings suggest that these solutions remain polluting mainly due to the petro-chemically sourced resins used. These resins are widely used in industries such as automotive, aerospace, and marine, and have a relatively large impact on the transition of these industries to net-zero emissions. To continue driving towards a more circular economy, this research aims to preselect cleaner materials, determine their compatibility in the hybridization process, test the required properties, formability, and characteristics of the solution to bring it to implementation, and assess the overall footprint as well as the end-of-life scenarios. To select cleaner materials, a comprehensive literature review and comparison was conducted on commonly used technical fibers to assess their properties and limitations. Wooden core materials were chosen based on their formability and strength-to-density ratios, while flax fibers were selected with PFA bio-based resin. Veneer-based Albasia wood was used for incomplex formability applications, and Oriented Strand Board-based wood for more complex applications. The proposed path towards results involves material testing for energy absorption, quasi-static and dynamic 3-point bending, formability and delamination. Experimental results demonstrated a 40 % improvement in material flexure and a 70 % improvement in energy absorption properties of the sandwich configurations compared to the core materials, with further improvements observed at higher impact speeds. Elevated temperature testing confirmed the material's high-performance and consistency. Finally, a prototype was manufactured to showcase the material's formability in complex 3D geometries. The proposed bio-composite solution presents a cleaner and more sustainable alternative to conventional counterparts. The production process is clean, and the material's lightweighting effect leads to a cleaner use phase. Additionally, the material offers better opportunities for end-of-life disposal or recycling due to its bio-based nature. Results from this research suggest that the proposed bio-composite has significant potential to promote sustainable lightweighting in use cases such as plane interiors, train or railway body components, and automotive interior and body parts. However, further testing is required to assess limitations and further evaluate compliance with global regulations. The findings of this research will be valuable to stakeholders in the lightweighting industries and sustainable mobility, ultimately contributing to a more sustainable future.