Mechanical design of the highly porous cuttlebone: A bioceramic hard buoyancy tank for cuttlefish
Mechanical design of the highly porous cuttlebone: A bioceramic hard buoyancy tank for cuttlefish
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DOI：
10.1073/pnas.2009531117
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发表时间：
2020-09-22
影响因子：
11.1
通讯作者：
Li, Ling
中科院分区：
文献类型：
--
作者：
Yang, Ting;Jia, Zian;Li, Ling
乌贼是一种独特的海洋软体动物，它产生一种内部生物矿化的外壳，称为乌贼骨，这是一种超轻质的细胞结构（孔隙率，类似于93体积%），用作动物的硬浮力箱。虽然乌贼骨主要由一种易碎的矿物文石组成，但其结构具有高度的耐损伤性，并且可以承受约20个大气压（atm）的水压。目前，我们的知识的结构起源的乌贼骨的显着的力学性能是有限的。结合定量的三维（3D）结构表征，四维（4D）力学分析，数字图像相关性和参数模拟，在这里，我们揭示了乌贼骨的特征性腔室“壁隔”微观结构，与其他天然或工程细胞固体截然不同，允许在加载时同时具有高比刚度（8.4 MN.m/kg）和能量吸收（4.4 kJ/kg）。我们证明，在腔乌贼骨微观结构的垂直壁已经发展出一个最佳的波度梯度，这导致压缩占主导地位的变形和不对称的壁断裂，实现高刚度和高能量吸收。此外，壁的分布被发现，以减少水平隔板内的应力集中，有利于更大的腔室破碎应力和更显着的致密化。本文提出的设计策略可为低密度、刚性和耐损伤多孔陶瓷的开发提供重要的借鉴。
Cuttlefish, a unique group of marine mollusks, produces an internal biomineralized shell, known as cuttlebone, which is an ultra-lightweight cellular structure (porosity, similar to 93 vol%) used as the animal's hard buoyancy tank. Although cuttlebone is primarily composed of a brittle mineral, aragonite, the structure is highly damage tolerant and can withstand water pressure of about 20 atmospheres (atm) for the species Sepia officinalis. Currently, our knowledge on the structural origins for cuttlebone's remarkable mechanical performance is limited. Combining quantitative three-dimensional (3D) structural characterization, four-dimensional (4D) mechanical analysis, digital image correlation, and parametric simulations, here we reveal that the characteristic chambered "wallsepta" microstructure of cuttlebone, drastically distinct from other natural or engineering cellular solids, allows for simultaneous high specific stiffness (8.4 MN.m/kg) and energy absorption (4.4 kJ/kg) upon loading. We demonstrate that the vertical walls in the chambered cuttlebone microstructure have evolved an optimal waviness gradient, which leads to compression-dominant deformation and asymmetric wall fracture, accomplishing both high stiffness and high energy absorption. Moreover, the distribution of walls is found to reduce stress concentrations within the horizontal septa, facilitating a larger chamber crushing stress and a more significant densification. The design strategies revealed here can provide important lessons for the development of low-density, stiff, and damage-tolerant cellular ceramics.