Multiscale Toughening Mechanisms in Biological Materials and Bioinspired Designs

• Published in: Advanced materials (Weinheim) 2019-10, Vol.31 (43), p.e1901561-n/a
• Main Authors: Huang, Wei, Restrepo, David, Jung, Jae‐Young, Su, Frances Y., Liu, Zengqian, Ritchie, Robert O., McKittrick, Joanna, Zavattieri, Pablo, Kisailus, David
• Format: Article
• Language: English
• Subjects: Animals; bioinspired designs; Biological materials; Biomimetic materials; Biomimetic Materials - chemistry; Biopolymers; Biopolymers - chemistry; Breakage; Chemical bonds; computational modeling; Crystal defects; Damage tolerance; Energy dissipation; Fracture toughness; Humans; Lamellar structure; Materials science; Mechanical Phenomena; Morphology; multiscale materials; Nacre; Nanoparticles; Nanorods; Optimization; Organic chemistry; Reconfiguration; Time; Toughening; toughening mechanisms; Twisting; Weight reduction
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201901561

Biological materials found in Nature such as nacre and bone are well recognized as light‐weight, strong, and tough structural materials. The remarkable toughness and damage tolerance of such biological materials are conferred through hierarchical assembly of their multiscale (i.e., atomic‐ to macroscale) architectures and components. Herein, the toughening mechanisms of different organisms at multilength scales are identified and summarized: macromolecular deformation, chemical bond breakage, and biomineral crystal imperfections at the atomic scale; biopolymer fibril reconfiguration/deformation and biomineral nanoparticle/nanoplatelet/nanorod translation, and crack reorientation at the nanoscale; crack deflection and twisting by characteristic features such as tubules and lamellae at the microscale; and structure and morphology optimization at the macroscale. In addition, the actual loading conditions of the natural organisms are different, leading to energy dissipation occurring at different time scales. These toughening mechanisms are further illustrated by comparing the experimental results with computational modeling. Modeling methods at different length and time scales are reviewed. Examples of biomimetic designs that realize the multiscale toughening mechanisms in engineering materials are introduced. Indeed, there is still plenty of room mimicking the strong and tough biological designs at the multilength and time scale in Nature. Toughening mechanisms of light weight, strong, and tough biological materials constructed from the atomic‐ to macroscale are reviewed. The multiscale toughening mechanisms are validated via computational modeling, and subsequently translated to engineering materials through bioinspired processing such as freeze casting and additive manufacturing.