From lab to rail: A combined mechanical-LCA matrix for fiber-reinforced polymers

Kurzfassung

The design of next-generation vehicle structures increasingly demands novel material systems that combine high mechanical performance with environmental sustainability. While mechanical criteria traditionally dominate material selection, developments in sustainability requirements have exposed a gap in current multi-criteria decision-making (MCDM) tools. In this regard most frameworks focus only on climate-related life-cycle impacts, neglecting other significant environmental impact categories. This study presents a selection matrix tailored for fiber-reinforced polymer (FRP) systems that explicitly integrates all impact categories of the environmental footprint method at the early design stage. Initially, prevailing MCDM approaches are screened and consolidated to identify common decision criteria, weighting schemes, and data sources. Based on these results, a set of application-specific FRP constituents are chosen, encompassing various polymer matrices and reinforcing fibers. Mechanical descriptors can be collated from literature and mechanical testing, while ecological characteristics were derived from life-cycle inventories customized for each polymer/fiber pair. Additional LCIs were assembled using the structure of established databases but modified to capture the heterogeneity of polymer systems. The resulting framework was validated first on individual materials and subsequently on material combinations. Each combination is classified within the matrix reflecting the mechanical and environmental performance. Comparative analyses highlight possibilities, revealing that materials that perform better from a mechanical standpoint can suffer substantial impacts in categories such as ecotoxicity or resource use. Conversely, polymers with lower mechanical properties can achieve better results regarding potential environmental impacts when coupled with appropriate fibers. It is therefore essential to consider both sides simultaneously. The simplified matrix offers practitioners an intuitive, data-driven tool that can be applied early in the design process, thereby enabling concurrent assessment of performance and sustainability. By bridging the methodological divide between mechanical engineers and LCA experts, the matrix facilitates interdisciplinary collaboration and supports evidence-based material decision-making for future structural elements.