Enhancing mechanical properties of 3D-printed continuous carbon fibre-reinforced composites via bio-inspired design

•Both quasi-static and dynamic properties of 3DP-CFRPs are reported.•3DP continuous fibre-reinforced composites has enhanced the impact resistance.•3DP-CFRPs behaves like that of laminated CFRPs.•The bio-inspired 3DP-CFRPs performed best compared with the control groups. This paper explores the mechanical properties of 3D-printed continuous carbon fibre (CCF)-reinforced helicoidal laminates inspired by the laminar structures found in crustacean exoskeletons. For comparison, conventional cross-ply layups, both with and without CCF reinforcement, were also examined. The laminate specimens were manufactured layer by layer through a 3D printer using short carbon fibre-reinforced nylon and CCFs. To evaluate their mechanical properties, both quasi-static and dynamic tests were conducted using a universal testing machine and an instrumented drop-weight impact facility. Experimental data were collected to analyse the progression of mechanical failure and energy absorption in these 3D-printed composites. Additionally, micro-computed tomography (μ-CT) scans were used to analyse internal damage, such as fibre fracture and delamination, in the tested samples. The results revealed distinct dynamic failure mechanisms in the 3D-printed composites compared to their quasi-static behaviour, indicating potential real-world applications. The inclusion of CCFs in 3D-printed composites significantly enhanced their mechanical performance. While the cross-ply laminates outperformed the bio-inspired helicoidal laminates under quasi-static bending loads, the helicoidal laminates exhibited greater stiffness and superior energy absorption during low-velocity, out-of-plane impacts, surpassing their cross-ply counterparts. [Display omitted]