Porcupine Quill: Buckling Resistance Analysis and Design for 3D Printing

Recently, materials with lightweight and high mechanical strength are on high demand. These characteristics are exceptionally important in various field, particularly in structural engineering. Nature offers inspirational solutions which are beyond our expectations. Plants and animals are made of well-architectured structures and materials to protect themselves against harsh environments and enemies, same goes to porcupines. Under emergency condition, porcupine protects itself by jabbing the quills into the skin of the assailant. The long and sharp cylindrical quill possesses outstanding mechanical properties including lightweight and high buckling resistance. At present, research focusing on the mechanical analysis of porcupine quills in the literature is limited. The extraordinary features of the quills are known but not fully-explored. At different cross-sections within a same quill, different microstructural patterns are observed. To better understand the buckling property of porcupine quill, compression test is performed. This paper is aimed to microstructurally investigate the mechanism of buckling resistance in porcupine quill at different cross-sections. Theoretical analysis is performed via buckling theory proposed in the literature. Based on the understanding of this biological structure, a design approach is proposed to mimic the porcupine quills for 3D printing.