Biomechanical fracture mechanics of composite layered skin-like materials
Biomechanical fracture mechanics of composite layered skin-like materials
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复合层状类皮材料的生物力学断裂力学
DOI：
10.1039/d1sm01187a
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发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
German, Guy K.
中科院分区：
文献类型：
--
作者：
Maiorana, Christopher H.;Jotawar, Rajeshwari A.;German, Guy K.
大多数保护性生物组织在结构上由软的底层基底上的硬而薄的外层组成。例子包括哺乳动物的皮肤、鱼鳞、甲壳类动物的壳、坚果和种子的壳。虽然这些复合皮肤样组织在自然界中无处不在，但它们的失效机制以及它们的复合结构提供的潜在机械优势仍不清楚。在这项工作中，复合超弹性弹性体的穿刺力学与不同的无量纲层厚度的变化进行了探讨。这些膜的穿刺行为测量钝和尖锐的锥形压头。刚性外层仅为总复合材料厚度1%的膜表现出与刚性外层厚约20倍的膜相当的穿刺能量。当顶层约为总膜的1%时，这种刺穿能量（按其弯曲能力缩放）达到局部最大值，这与许多哺乳动物物种的结构相似。这些制度的失败模式也进行了研究。与高应力集中引起的尖锐尖端直接下方的穿刺相比，在大压痕深度处出现了一种新型的“取芯”型断裂，这是由于当膜用钝压头变形时沿膜片两侧沿着累积的拉伸应变能造成的。这些结果可以提高用于外科手套、包装和柔性电子产品等产品的可拉伸材料的耐用性和坚固性。
Most protective biological tissues are structurally comprised of a stiff and thin outer layer on top of a soft underlying substrate. Examples include mammalian skin, fish scales, crustacean shells, and nut and seed shells. While these composite skin-like tissues are ubiquitous in nature, their mechanics of failure and what potential mechanical advantages their composite structures offer remains unclear. In this work, changes in the puncture mechanics of composite hyperelastic elastomers with differing non-dimensional layer thicknesses are explored. Puncture behavior of these membranes is measured for dull and sharp conical indenters. Membranes with a stiff outer layer of only 1% of the overall composite thickness exhibit a puncture energy comparable to membranes with a stiff outer layer approximately 20 times thicker. This puncture energy, scaled by its flexural capacity, achieves a local maximum when the top layer is approximately 1% of the total membrane, similar to the structure of numerous mammalian species. The mode of failure for these regimes is also investigated. In contrast with puncture directly beneath sharp tips caused by high stress concentrations, a new type of ‘coring’ type fracture emerges at large indentation depths, resulting from accumulated tensile strain energy along the sides of the divot as the membrane is deformed with a blunt indenter. These results could enhance the durability and robustness of stretchable materials used for products such as surgical gloves, packaging, and flexible electronics.