Bone-inspired enhanced fracture toughness of de novo fiber reinforced composites

Abstract

Amplification in toughness and balance with stiffness and strength are fundamental characteristics of biological structural composites, and a long sought-after objective for engineering design. Nature achieves these properties through a combination of multiscale key features. Yet, emulating all these features into synthetic de novo materials is rather challenging. Here, we fine-tune manual lamination, to implement a newly designed bone-inspired structure into fiber-reinforced composites. An integrated approach, combining numerical simulations, ad hoc manufacturing techniques, and testing, yields a novel composite with enhanced fracture toughness and balance with stiffness and strength, offering an optimal lightweight material solution with better performance than conventional materials such as metals and alloys. The results also show how the new design significantly boosts the fracture toughness compared to a classic laminated composite, made of the same building blocks, also offering an optimal tradeoff with stiffness and strength. The predominant mechanism, responsible for the enhancement of fracture toughness in the new material, is the continuous deviation of the crack from a straight path, promoting large energy dissipation and preventing a catastrophic failure. The new insights resulting from this study can guide the design of de novo fiber-reinforced composites toward better mechanical performance to reach the level of synergy of their natural counterparts.

Strong, Healable, Stimulus‐Responsive Fluorescent Elastomers Based on Assembled Borate Dynamic Nanostructures

“…In nature, the synergistic effects of micro-nano structure and well-organized interfacial supramolecular interactions provide creatures diverse attractive functions, such as toughness of bones, amazing adhesion of geckos, and structural color of chameleons. [7][8][9] Leveraging these marvelous and exquisite biological architectures, scientists are devoted to create materials for both mechanical high performance and multifunction. [10][11][12] For example, Walther et al imitated nacreous brick-and-mortar structure to prepare a stiff material with flaw resistance based on the cooperative effects of high fraction of nano-clays and quadruple hydrogen bonding.…”

Nature-inspired materials: Emerging trends and prospects

“…Libonati et al 30 reported a bone-inspired structure on fiber-reinforced composites. The geometry mimicked the osteonal secondary structure of mammalian bone.…”

Learning from nature: Bio-inspiration for damage-tolerant high-performance fibre-reinforced composites

“…In order to improve the fracture toughness and the transverse properties of the bone-inspired composite, Libonati et al [187] proposed multilayer osteon structures, adding both fabrics interleaved between the osteons and nano-particles with a platelet shape to the matrix. This bone-inspired microstructure was achieved with a customised technique based on hand preforming and VARTM.…”

“…Depending on the number of hierarchical levels and complexity of features to reproduce, the related manufacturing processes can be complex (e.g. Harvesian bone-like structure devised by Libonati et al [16], [187]). This results in prototyped structures which, due to the current limitations of the available manufacturing techniques, are not yet scalable to large structural components.…”