Experimental and numerical investigation of low-velocity impact response of bouligand carbon/epoxy composites

This study investigates the low-velocity impact behaviour of Bouligand polymer composites in comparison with conventional three-dimensional (3D) composite architectures. Bouligand, bias, and orthogonal preforms were fabricated using carbon fibre filaments and subsequently infused with epoxy resin to produce laminated composite panels. Instrumented drop-weight impact tests were performed at energy levels of 10, 15, and 20 J to evaluate the load–displacement and load–time responses. These experimental results were complemented by finite element simulations to correlate the dynamic response and damage evolution. The analyses focused on impact-induced force histories, damage initiation, post-peak behaviour, and impact tolerance. The results show that Bouligand laminates exhibit distinctly different impact response mechanisms compared with conventional architectures. Although bias laminates sustained the highest peak loads at all impact energies, Bouligand laminates demonstrated prolonged contact duration (up to ∼6–8 ms longer at 15 J) and more pronounced post-peak load oscillations, indicative of progressive damage and enhanced energy dissipation. At 20 J, bias laminates experienced full penetration, whereas Bouligand laminates resisted perforation and exhibited global crack deflection with the smallest projected damage area among all architectures. Damage area increased approximately linearly with impact energy for all laminates; however, Bouligand structures consistently showed the lowest damage extent, while orthogonal laminates exhibited the largest damaged regions. Numerical predictions showed good agreement with experimental data, particularly at lower impact energies, confirming the reliability of the adopted modelling approach.