Izod impact resistance of 3D printed discontinuous fibrous composites with Bouligand structure

• Main Authors: Guan, Lizhi, Peng, Weixiang, Ng, Rachel Jing Wen, Fan, Jingbo, Le Ferrand, Hortense
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering; 3D Printing; Materials
• Online Access: https://hdl.handle.net/10356/172132
• Institution: Nanyang Technological University

The Bouligand structure found in the dactyl club of the mantis shrimp is known for its impact resistance. Yet, Bouligand-inspired reinforced composites with 3D shapes and impact resistance have not yet been demonstrated. Here, direct ink writing is used to 3D print composites reinforced with glass microfibres assembled into Bouligand structures with controllable pitch angles. The energy absorption of the Bouligand composites under impact was found to surpass that of composites with unidirectional microfibre alignment. Also, the Bouligand composites with a pitch angle of 40˚ exhibited a maximum energy absorption of 2.4 kJ/m2, which was 140 % higher than that of the unidirectional composites. Furthermore, the characterization of the topography of the fractured surface, supplemented with numerical simulations, revealed a combination of crack twisting and crack bridging mechanisms. Flexural tests conducted on the composites with a pitch angle of 40˚ also showed maximum properties, with a flexural strength of 36.9 MPa, a stiffness of 2.26 GPa, and energy absorption of 8 kJ/m2. These findings are promising for the microstructural design of engineered composites using direct ink writing for applications in aerospace, transportation, defence, etc.