Browsing by Author "Weaver, James C."

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    Bioinspired design of flexible armor based on chiton scales
    Connors, Matthew; Yang, Ting; Hosny, Ahmed; Deng, Zhifei; Yazdandoost, Fatemeh; Massaadi, Hajar; Eernisse, Douglas; Mirzaeifar, Reza; Dean, Mason N.; Weaver, James C.; Ortiz, Christine; Li, Ling (Springer Nature, 2019-12-10)
    Man-made armors often rely on rigid structures for mechanical protection, which typically results in a trade-off with flexibility and maneuverability. Chitons, a group of marine mollusks, evolved scaled armors that address similar challenges. Many chiton species possess hundreds of small, mineralized scales arrayed on the soft girdle that surrounds their overlapping shell plates. Ensuring both flexibility for locomotion and protection of the underlying soft body, the scaled girdle is an excellent model for multifunctional armor design. Here we conduct a systematic study of the material composition, nanomechanical properties, three-dimensional geometry, and interspecific structural diversity of chiton girdle scales. Moreover, inspired by the tessellated organization of chiton scales, we fabricate a synthetic flexible scaled armor analogue using parametric computational modeling and multi-material 3D printing. This approach allows us to conduct a quantitative evaluation of our chiton-inspired armor to assess its orientation-dependent flexibility and protection capabilities.
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    Strategies for simultaneous strengthening and toughening via nanoscopic intracrystalline defects in a biogenic ceramic
    Deng, Zhifei; Chen, Hongshun; Yang, Tin; Jia, Zia; Weaver, James C.; Shevchenko, Pavel D.; De Carlo, Francesco; Mirzaeifar, Reza; Li, Ling (Springer Nature, 2020)
    While many organisms synthesize robust skeletal composites consisting of spatially discrete organic and mineral (ceramic) phases, the intrinsic mechanical properties of the mineral phases are poorly understood. Using the shell of the marine bivalve Atrina rigida as a model system, and through a combination of multiscale structural and mechanical characterization in conjunction with theoretical and computational modeling, we uncover the underlying mechanical roles of a ubiquitous structural motif in biogenic calcite, their nanoscopic intracrystalline defects. These nanoscopic defects not only suppress the soft yielding of pure calcite through the classical precipitation strengthening mechanism, but also enhance energy dissipation through controlled nano- and micro-fracture, where the defects’ size, geometry, orientation, and distribution facilitate and guide crack initialization and propagation. These nano- and micro-scale cracks are further confined by larger scale intercrystalline organic interfaces, enabling further improved damage tolerance.