: 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.
Last. Robert O. Ritchie(University of California, Berkeley)H-Index: 132
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Abstract The structural constituents of tissues in organisms are composed primarily of minerals and proteins. Collagen is the most common protein used to construct such natural materials in vertebrates; among these structures, a wide variety of hierarchical architectures with structural and property gradients have evolved to induce desired combinations of stiffness, strength, ductility and toughness for a diverse range of mechanical functionalities. The soft collagen provides biological material...
Abstract Cellulose nanocrystals (CNCs) is a new family of cellulose materials with outstanding mechanical and chemical properties that have been successfully demonstrated to have potential for many applications. Understanding the mechanical behavior of individual CNCs and their interaction at nanoscale is very important for improving the manufacturing process and mechanical performance of the resulting materials at macroscale. However, due to time and length scale limitations for both, experimen...
Abstract Biological materials such as nacre, bone and spider silk boast unusual combinations of stiffness, strength and toughness. Behind this performance is the staggered arrangement of stiff and elongated inclusions embedded in a softer and more deformable matrix. In this study, we use the discrete element method (DEM) to simulate large fracture models of staggered composites (up to 450,000 tablets). The models explore the combined effects of tablet arrangement, interface properties and statis...
Abstract Lightweight porous engineered materials are advantageous in a broad range of research fields because they combine desirable mechanical properties with the ability to leverage their porous structure. Existing techniques for fabricating porous material structures are limited by material choice, require multiple steps, and/or additional post-processing to create regions of varying material properties within the material structure, and are not easily scalable. In contrast, we implement and ...
Abstract Few systematic structure–property-processing correlations for directionally freeze-cast biopolymer scaffolds are reported. Such correlations are critical to enable scaffold design with attractive structural and mechanical cues in vivo. This study focuses on freeze-cast collagen scaffolds with three different applied cooling rates (10, 1, and 0.1 °C/min) and two freezing directions (longitudinal and radial). A semi-automated approach for the structural characterization of fully hydrated ...
Last. Marc A. Meyers(UCSD: University of California, San Diego)H-Index: 97
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: Additive manufacturing (AM) is a current technology undergoing rapid development that is utilized in a wide variety of applications. In the field of biological and bioinspired materials, additive manufacturing is being used to generate intricate prototypes to expand our understanding of the fundamental structure-property relationships that govern nature's spectacular mechanical performance. Herein, recent advances in the use of AM for improving the understanding of the structure-property relat...
Abstract The Bouligand structure in some arthropods is a hierarchical composite comprised of a helicoidal arrangement of strong fibers in a weak matrix. In this study, we focus on the Bouligand structure present in the dactyl club of the smashing mantis shrimp due to its exceptional capability to withstand repetitive high-energy impact without catastrophic failure. We carry out a combined computational and experimental approach to investigate the high damage resistance of the Bouligand structure...
#1Fuqiang Wan(WUT: Wuhan University of Technology)H-Index: 1
#2Hang Ping(WUT: Wuhan University of Technology)H-Index: 11
Last. Zhengyi Fu(WUT: Wuhan University of Technology)H-Index: 31
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Abstract Biological materials have excellent mechanical properties due to their organized structures from nano- to macro-scale. Artificial manufacture of materials with anisotropic microstructures still remains challenging. We described a stress-induced method to fabricate anisotropic alginate fibers. Organic-inorganic composite fibers were obtained by incorporating aligned hydroxyapatite (HAP) nanowires into the alginate fiber. Detailed structural characterization revealed the bone-like structu...
#2Beom Soo Kim(CBNU: Chungbuk National University)H-Index: 36
Abstract Recently, functionalized graphene has been used in a variety of biomedical applications such as drug delivery systems, nanocarriers, tissue scaffolds, biodetection, biosensors, and bioimaging. Most of the chemicals used to prepare functionalized graphene are generally costly and harmful, requiring the development of a one-step, eco-friendly production process that does not use toxic chemicals. In this study, a simple environmentally friendly exfoliation of graphite to functionalized few...
Abstract Carbon-fibre reinforced polymers (CFRPs) present outstanding mechanical performance per unit of mass; however, they also fail in a brittle manner, with little or no warning of their forthcoming catastrophic failure. In this study, a ‘brick-and-mortar’ design inspired by the structure of nacre was implemented by automated tape lay-up for the first time with the aim of changing the failure response of CFRPs. Standard procedures and materials already implemented in the aerospace industry h...
Abstract The mechanical properties of cellulose nanocrystal (CNC) films critically depend on many microstructural parameters such as fiber length distribution (FLD), fiber orientation distribution (FOD), and the strength of the interactions between the fibers. In this paper, we use our coarse-grained molecular model of CNC to study the effect of length and orientation distribution and attractions between CNCs on the mechanical properties of neat CNCs. The effect of misalignment of a 2D staggered...
Abstract Entheses are complex multi-tissue regions of the musculoskeletal system serving the challenging task of connecting highly dissimilar materials such as the compliant tendon to the much stiffer bone, over a very small region. The first aim of this review is to highlight mathematical and computational models that have been developed to investigate the many attachment strategies present at entheses at different length scales. Entheses are also relevant in the medical context due to the high...
#1Yizhi Zhuo(NTNU: Norwegian University of Science and Technology)H-Index: 14
#2Zhijie Xia(USTC: University of Science and Technology of China)H-Index: 3
Last. Zhiliang Zhang(NTNU: Norwegian University of Science and Technology)H-Index: 33
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Current synthetic elastomers suffer from the well-known trade-off between toughness and stiffness. By a combination of multiscale experiments and atomistic simulations, a transparent unfilled elastomer with simultaneously enhanced toughness and stiffness is demonstrated. The designed elastomer comprises homogeneous networks with ultrastrong, reversible, and sacrificial octuple hydrogen bonding (HB), which evenly distribute the stress to each polymer chain during loading, thus enhancing stretchab...
Last. Xiaoming Ma(Henan Normal University)H-Index: 18
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Nanoparticles are produced by chemical methods which are usually environmentally hazardous because of the use of various perilous chemicals and harsh reaction conditions. The bio-mediated synthesis using microbes has been proved to be a promising substitute for traditional methods to synthesize nanoparticles. Herein, based on the principles of biomimetic mineralization, a bio-mediated strategy was proposed to synthesize biocompatible barium carbonate nanoparticles (nBaCO3) in living yeast cells ...
Last. Hiroaki Imai(Keio: Keio University)H-Index: 71
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The adequate manipulation of nanometer-scale building blocks using dispersion systems is regarded as a fundamental technique to fabricate elaborate microstructures. Although a liquid flow with evaporation is generally regarded as an essential factor for the self-assembly of floating blocks, experimental evidence has not been sufficient to clarify the importance of the flow in the dispersion systems. In the present study, 2D nematic layers of sterically stabilized nanoscale calcite rods were achi...
Abstract The simultaneous attainment of high strength and high toughness of transparent cellulose nanofibril (CNF) film can expedite its uses in advanced applications. In this work, a wood-inspired strategy is proposed to address the conflict between strength and toughness by using natural derived lignosulfonic acid (LA) as a reinforcing additive. Only 1 wt% LA addition can double the toughness (11.0±1.3 MJ/m3) of pure CNF film. Consequently, the as-prepared CNF/LA-1 nanocomposite film not only ...