Performance of a bio-mimetic 3D printed conch -like structure under quasi-static loading

The conch shell is known for its excellent ability to initiate, deflect and bridge cracks to maintain its strength whilst enhancing its toughness. Impressively, it is mainly composed of aragonite, a brittle ceramic, but boasts a high fracture toughness. Understanding and mimicking the unique mechanisms of the structure of conch shells can toughen lightweight materials. However, due to the complexity of the hierarchical architecture of conch, studies have focused on mimicking it as a bi-material composite. In this research, 3D printing is employed to develop a proof-of-concept single edge notched panel that mimics the composite structure of conch. The instructions (G-code) of the dual extrusion 3D printer were programmed to produce a multi-layer composite architecture. The conch-like panel was tested under tension, and a numerical model was developed and validated using experimental observations. Parametric studies were conducted to improve the performance of the conch-like structure. The conch-like panel was benchmarked against a bulk panel and showed noticeable improvements in strength and toughness. Several key parameters were identified, which can guide the future design of lightweight materials for applications requiring high energy dissipation. This preliminary proof-of-concept study can thereby guide the development of more complex bio-mimetic structures for protective applications. © 2020 Elsevier Ltd