3D Plate-Lattices: An Emerging Class of Low-Density Metamaterial Exhibiting Optimal Isotropic Stiffness
3D Plate-Lattices: An Emerging Class of Low-Density Metamaterial Exhibiting Optimal Isotropic Stiffness
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DOI：
10.1002/adma.201803334
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发表时间：
2018-11-01
影响因子：
29.4
通讯作者：
Mohr, Dirk
中科院分区：
文献类型：
--
作者：
Tancogne-Dejean, Thomas;Diamantopoulou, Marianna;Mohr, Dirk
在轻量化工程中，人们不断寻求具有高质量特定刚度和强度的低密度材料。增材制造的超材料是特别有前途的候选材料，因为控制孔隙度的引入可以调整其密度，同时激活纳米和微米结构水平的强化尺寸效应。在这里，板状晶格是通过沿着晶体结构的最密堆积平面放置板来构想的。基于理论分析，开发了立方对称弹性各向同性板晶格的通用设计图。除了验证设计图之外，详细的计算分析表明甚至存在提供近各向同性屈服强度和弹性各向同性的板晶格组合物。板状晶格最显着的特征是它们的刚度和屈服强度在各向同性多孔固体理论极限的百分之几以内。这意味着各向同性板晶格的刚度比同等质量的最硬桁架晶格的刚度高出三倍。通过直接激光写入制造的桁架和板晶格样本的实验也证实了这种刚度优势。由于其多孔的内部结构，这里报道的新型超材料的潜在影响超出了轻质工程，包括热交换、隔热、声学和生物医学工程的应用。
In lightweight engineering, there is a constant quest for low-density materials featuring high mass-specific stiffness and strength. Additively-manufactured metamaterials are particularly promising candidates as the controlled introduction of porosity allows for tailoring their density while activating strengthening size-effects at the nano- and microstructural level. Here, plate-lattices are conceived by placing plates along the closest-packed planes of crystal structures. Based on theoretical analysis, a general design map is developed for elastically isotropic plate-lattices of cubic symmetry. In addition to validating the design map, detailed computational analysis reveals that there even exist plate-lattice compositions that provide nearly isotropic yield strength together with elastic isotropy. The most striking feature of plate-lattices is that their stiffness and yield strength are within a few percent of the theoretical limits for isotropic porous solids. This implies that the stiffness of isotropic plate-lattices is up to three times higher than that of the stiffest truss-lattices of equal mass. This stiffness advantage is also confirmed by experiments on truss- and plate-lattice specimens fabricated through direct laser writing. Due to their porous internal structure, the potential impact of the new metamaterials reported here goes beyond lightweight engineering, including applications for heat-exchange, thermal insulation, acoustics, and biomedical engineering.