The mechanical response of cellular materials with spinodal topologies
The mechanical response of cellular materials with spinodal topologies
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DOI：
10.1016/j.jmps.2019.01.002
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发表时间：
2019-04-01
影响因子：
5.3
通讯作者：
Valdevit, Lorenzo
中科院分区：
文献类型：
--
作者：
Hsieh, Meng-Ting;Endo, Bianca;Valdevit, Lorenzo
通过数值和实验研究了具有旋节线拓扑的多孔材料的机械响应。旋节线微观结构是通过 Cahn-Hilliard 方程的数值解生成的。研究了两种不同的拓扑：“固体模型”，其中两相之一被建模为固体材料，其余体积为空隙空间；和“壳模型”，其中两相之间的界面被假定为实心壳，其余体积被建模为空隙空间。在这两种情况下，都研究了各种相对密度和旋节线特征特征尺寸。所有数值生成模型的拓扑和形态都经过仔细表征，以提取关键几何特征，并确保曲率分布和老化规律与旋节线分解的物理原理一致。为每个模型生成有限元网格，并提取单轴压缩刚度和强度。我们表明，虽然密度范围为 30-70% 的固体旋节线模型效率相对较低（即，它们的强度和刚度与相对密度呈高倍比例），但密度范围为 0.01-1% 的壳旋节线模型却异常坚硬和坚固。旋节线壳材料也被证明对缺陷非常不敏感。这些发现通过直接激光写入 (DLW) 以微米尺度打印的聚合物样品的原位单轴压缩得到了实验验证。在低相对密度下，壳旋节线模型的强度和刚度优于大多数晶格材料，并接近各向同性多孔材料的理论界限。最重要的是，这些材料可以通过自组装技术在一定长度范围内生产，从而提供独特的可扩展性。 (C) 2019 Elsevier Ltd. 保留所有权利。
The mechanical response of cellular materials with spinodal topologies is numerically and experimentally investigated. Spinodal microstructures are generated by the numerical solution of the Cahn-Hilliard equation. Two different topologies are investigated: 'solid models,' where one of the two phases is modeled as a solid material and the remaining volume is void space; and 'shell models,' where the interface between the two phases is assumed to be a solid shell, with the rest of the volume modeled as void space. In both cases, a wide range of relative densities and spinodal characteristic feature sizes are investigated. The topology and morphology of all the numerically generated models are carefully characterized to extract key geometrical features and ensure that the distribution of curvatures and the aging law are consistent with the physics of spinodal decomposition. Finite element meshes are generated for each model, and the uniaxial compressive stiffness and strength are extracted. We show that while solid spinodal models in the density range of 30-70% are relatively inefficient (i.e., their strength and stiffness exhibit a high-power scaling with relative density), shell spinodal models in the density range of 0.01-1% are exceptionally stiff and strong. Spinodal shell materials are also shown to be remarkably imperfection insensitive. These findings are verified experimentally by in-situ uniaxial compression of polymeric samples printed at the microscale by Direct Laser Writing (DLW). At low relative densities, the strength and stiffness of shell spinodal models outperform those of most lattice materials and approach theoretical bounds for isotropic cellular materials. Most importantly, these materials can be produced by self-assembly techniques over a range of length scales, providing unique scalability. (C) 2019 Elsevier Ltd. All rights reserved.