Shock response of unidirectional carbon fibre-reinforced polymer composites: Influence of fibre orientation and volume fraction

This study investigates the shock wave propagation in unidirectional carbon fibre-reinforced polymer (UD-CFRP) composites, focusing on the effects of varying fibre orientations (0°, 30°, 45°, 60°, and 90°) and fibre volume fractions (64 % and 51 %). Through a series of plate impact experiments at approximately 400 m/s, the results revealed that longitudinal stress was highest at 0° orientation (around 3 GPa) and decreased by nearly 50 % at 90°, where the bulk response mirrored that of pure epoxy. A distinct two-wave structure, consisting of an elastic precursor and a plastic shock wave, was observed at 0° orientation and higher impact velocities, requiring a minimum stress of 3 GPa. Fibre content showed only a marginal influence on shock behaviour, with the epoxy matrix playing a dominant role at higher orientations. These findings highlight the critical role of fibre alignment and matrix properties in governing shock resistance of the composite, suggesting the need for further exploration of matrix materials and composite design optimisation. • Fibre orientation of UD-CFRP significantly affects stress transmission. • Fibre volume fraction has a minimal effect on shock behaviour. • A two-wave structure appears at 0° orientation at high impact stress. • At 90° orientation, the composite behaves similarly to pure epoxy, showing little contribution from carbon fibres. • Findings highlight the importance of fibre alignment in composite design, suggesting matrix optimisation and tailored fibre orientation for improved shock resistance.