Stochastic continuum model for mycelium-based bio-foam
Stochastic continuum model for mycelium-based bio-foam
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DOI：
10.1016/j.matdes.2018.09.046
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发表时间：
2018-12-15
影响因子：
8.4
通讯作者：
Picu, R. C.
中科院分区：
文献类型：
--
作者：
Islam, M. R.;Tudryn, G.;Picu, R. C.
菌丝体是真菌的根结构，作为一种可生物降解的有害物质自然生长。这种独特的材料具有高度不均匀的微观结构，密度具有明显的空间变化性，并表现出强烈的非线性机械行为。在这项工作中，我们探索了循环变形下材料在压缩中的响应，并为其力学行为开发了一个经过实验验证的多尺度模型。变形局部化在随机分布的子域中，这些子域最终渗透形成高密度材料的宏观带。这反映在应力-应变曲线中为应变软化。在固定的宏观应变循环导致类似于马林斯效应的变形历史依赖性。为了捕捉这种行为，我们使用双尺度模型。在微观尺度上，使用随机纤维网络，而在宏观尺度上，使用随机连续模型捕获空间密度波动。密度相关的局部本构行为定义的微尺度模型。一个经验的损伤模型被纳入占实验观察到的循环软化行为的菌丝体。通过与一组单独的实验结果进行比较，该模型得到了进一步验证。该模型可用于探索中尺度密度波动对整体力学行为的影响，并设计具有所需力学性能的菌丝体产品。(C)2018 Elsevier Ltd.这是CC BY-NC-ND许可下的开放获取文章
Mycelium, the root structure of fungi, grows naturally as a biodegradable filamentousmaterial. This unique material has highly heterogeneous microstructure with pronounced spatial variability in density and exhibits strongly non-linear mechanical behavior. In this work we explore the material response in compression, under cyclic deformation, and develop an experimentally-validated multiscale model for its mechanical behavior. The deformation localizes in stochastically distributed sub-domains which eventually percolate to form macroscopic bands of high density material. This is reflected in the stress-strain curve as strain softening. Cycling at fixed-macroscopic strain leads to deformation history dependence similar to the Mullins effect. To capture this behavior, we use a two-scale model. At the micro-scale, a random fiber network is used, while at the macroscale the spatial density fluctuations are captured using a stochastic continuum model. The density-dependent local constitutive behavior is defined by the microscale model. An empirical damage model is incorporated to account for the experimentally observed cyclic softening behavior of mycelium. The model is further validated by comparison with a separate set of experimental results. The model can be used to explore the effect of mesoscale density fluctuations on the overall mechanical behavior and to design mycelium-based products with desired mechanical performance. (C) 2018 Elsevier Ltd. This is an open access article under the CC BY-NC-ND license