Crashworthiness of Composite Material Panels for Crash Absorber Applications

Nowadays, the automotive industry has a critical challenge to meet the goals of crashworthiness as well as sustainability. While carbon fiber reinforced polymers (CFRPs) provide excellent specific strength and energy absorption for crash absorber applications, conventional thermoset epoxy resins cannot be recycled. This limitation contradicts the EU End-of-Life Vehicle regulations that necessitate 95% recovery of the vehicle’s mass. Additionally, the lack of standardized testing methods to evaluate the crashworthiness of composite materials obstructs the proper selection and certification for automotive use. This thesis investigates whether ELIUM^(® ) (developed by Arkema), a fully recyclable thermoplastic poly-methyl methacrylate (PMMA) resin, can replace traditional epoxies in automotive crash absorber systems without sacrificing crashworthiness performance and safety aspects of the occupants. Two composite structures were produced using a vacuum infusion process with 3K carbon fiber twill fabric (Pyrofil TR50S, 200 g/m²), reinforced with either epoxy or Elium resin. An experimental program following the building block approach included quasi-static mechanical characterization (compression, tensile, flexural, and shear testing in accordance with ASTM standards), as well as dynamic crashworthiness tests through drop tower impact testing with an innovative anti-buckling fixture based on the standardized procedure proposed by Lorenzo Vigna to enable precise measurement of specific energy absorption (SEA). The compression test showed that 3k epoxy had slightly better strength and stiffness (~3–4% higher) than 3k Elium. However, 3k Elium was much more ductile with a 15% higher failure strain, and it had better manufacturing consistency (~83% lower coefficient of variation). Ongoing quasi-static testing also includes tensile, flexural, and shear characterization, with planned drop tower impact tests and LS-Dyna finite element validation to further evaluate crashworthiness performance. The results obtained from quasi-static testing proved that Elium-based carbon fiber composites with higher ductility and better manufacturing consistency, combined with complete recyclability, can become a potential sustainable alternative for automotive crash absorber applications in next-generation vehicles.