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Toughening in a nacre-like soft-hard layered structure due to weak nonlinearity in the soft layer

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      Abstract

      Recently, it has been found experimentally that hydrated nacre exhibits a nonlinear mechanical response. While mechanical nonlinearity has been shown to be important in other biological structures, such as spider webs, the implications of mechanical nonlinearity in nacre have not been explored. Here, we show that the nonlinear mechanical response of nacre can be reproduced by an analytical model, which reflects a nacre-like layered structure, consisting of linear-elastic hard sheets glued together by weakly nonlinear-elastic soft sheets. We develop scaling analysis on this analytical model, and perform numerical simulations using a lattice model, which is a discrete counterpart of the analytical model. Unexpectedly, we find the weak nonlinearity in the soft component significantly contributes to enhancing toughness by redistributing the stress at a crack tip over a wider area. Beyond demonstrating a mechanism that explains the unusual properties of biological nacre, this study points to a general design principle for constructing tough composites using weak nonlinearity, and is useful as a guiding principle to develop artificial layered structures mimicking nacre.

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            Author and article information

            Journal
            17 April 2019
            1904.08165

            http://arxiv.org/licenses/nonexclusive-distrib/1.0/

            Custom metadata
            20 pages, 5 figures, submitted to Phys. Rev. Mater. (1st revised version)
            physics.bio-ph cond-mat.mtrl-sci cond-mat.soft

            Condensed matter, Biophysics

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