Yu Siwon, Park Seunggyu, Lee Kang Taek, Hwang Jun Yeon, Hong Soon Hyung, Marrow Thomas James
Department of Materials, University of Oxford, Oxford, OX1 3PH, UK.
Department of Material Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
Nat Commun. 2024 Nov 4;15(1):9532. doi: 10.1038/s41467-024-53850-w.
Materials scientists have taken a learn-from-nature approach to study the structure-property relationships of natural materials. Here we introduce a nature-inspired composite architecture showing a hierarchical assembly of granular-like building blocks with specific topological textures. The structural complexity of the resulting architecture is advanced by applying the concept of grain orientation internally to each building block to induce a tailored crack resistance. Hexagonal grain-shaped building blocks are filled with parallel-oriented filament bundles, and these function as stiff-blocks with high anisotropy due to the embedded fiber reinforcements. Process-induced interfacial voids, which provide preferential crack paths, are strategically integrated with cracks to improve fracture toughness at the macroscopic scale. This study discusses the structural effects of the local/global orientations, stacking sequences, feature sizes, and gradient assemblies of granular blocks on crack tolerance behavior. Alternating stacking sequences induce cracks propagating in the arrestor direction, which boost the fracture energy up to 2.4 times higher than the same layup stacking sequence. Gradient arrangements of feature sizes from coarse to fine or fine to coarse result in the coexistence of stiffness and toughness. Our approach to applying crystallographic concepts to complex composite architectures inspires for original models of fracture mechanics.
材料科学家采用向自然学习的方法来研究天然材料的结构-性能关系。在此，我们介绍一种受自然启发的复合结构，它展示了具有特定拓扑纹理的粒状构建块的分层组装。通过在每个构建块内部应用晶粒取向的概念来诱导定制的抗裂性，从而提升了所得结构的结构复杂性。六边形晶粒形状的构建块填充有平行取向的细丝束，由于嵌入的纤维增强材料，这些细丝束起到具有高各向异性的刚性块的作用。工艺诱导的界面空隙提供了优先的裂纹路径，它们与裂纹进行策略性整合，以在宏观尺度上提高断裂韧性。本研究讨论了粒状块的局部/全局取向、堆叠顺序、特征尺寸和梯度组装对裂纹容忍行为的结构影响。交替的堆叠顺序会诱导裂纹沿阻裂方向扩展，这使得断裂能比相同铺层堆叠顺序高出2.4倍。从粗到细或从细到粗的特征尺寸梯度排列导致了刚度和韧性的共存。我们将晶体学概念应用于复杂复合结构的方法为断裂力学的原始模型提供了灵感。
