Validation and application of sustainable fibre composite crash box system

This study focusing on a carbon fibre-reinforced polyamide 6 (CFPA6) crash box system designed, manufactured, and crash-tested within an aluminium environment as part of a novel automotive front-end structure (FES). A key challenge in this work was the multi-material joining required for assembling the carbon fibre reinforced polymer (CFRP) crash box with its aluminium surroundings. Only a limited number of viable joining techniques – such as mechanical fastening (e.g. bolting, riveting) and adhesive bonding – were found to be suitable. Investigations were conducted to evaluate the impact of these joining methods on crash behaviour and overall crash performance. The crash box system was tested under axial crushing conditions to further explore the use of an inversion mechanism, aimed at enhancing energy absorption and crash performance. The adoption of a thermoplastic matrix (PA6) significantly reduced dust and particle emissions during impact, thereby improving environmental and occupational safety. Furthermore, the material’s recyclability and the long service life of the composite structure enable potential reuse in future vehicle generations at the End-of-Life (EoL) stage – a reuse strategy that is also described in this work.