Preparation of Bouligand biomimetic ceramic composites and the effect of different fiber orientations on mechanical properties

The multilevel helical arrangement of the Bouligand structure endows it with excellent mechanical properties when subjected to external stresses. In this study, Al₂O₃ ceramic scaffolds with Bouligand structures incorporated with continuous carbon fibers were prepared using vat photopolymerization (VPP) 3D printing technology. A series of biomimetic Bouligand–ceramic matrix composites with different fiber orientations were prepared using the epoxy penetration method. The flexural strength, fracture toughness, and work of fracture of the composites were evaluated at different fiber initiation and rotation angles. The effects of different fiber arrangements on the crack extension mode of the composites were revealed using the finite element method and peridynamics dynamics simulations. Molecular dynamics simulations, scanning electron microscopy, and energy-dispersive spectroscopy analyses revealed the material microstructure and interfacial bonding properties. The experimental results indicated that a specific combination of initiation and rotation angles can effectively promote crack twisting during the fracture process, thereby increasing the dissipation of fracture energy in the part and improving its fracture toughness. In this study, additive manufacturing technology was used to overcome the challenges of fabricating complex bionic structures through a simple and flexible production process. This method provides a practical solution for the development of lightweight, high-strength, and high-toughness bionic materials.