Aerospace Manufacturing Technology Center, National Research Council Canada, Montreal, QC H3T 2B2, Canada.
Bioinspir Biomim. 2022 May 18;17(4). doi: 10.1088/1748-3190/ac6921.
Superior material properties have been recently exhibited under the concept of biomimetic designs, where the material architectures are inspired by nature. In this study, a computational framework is developed to present novel architectured bi-material structures with tunable stiffness, strength, and toughness to be used for additive manufacturing (AM). The structure of natural nacre is mimicked to design robust multilayered structures constructed from hexagonal brittle and hard building blocks bonded with soft materials and supports. A set of computational models consisting of fully bonded zones, while allowing for interlayer interactions are created to accurately mimic the interplay between the hard and soft organic phases. As required for such complex designs, the numerical constraints are properly set to run quasi-static non-linear explicit analysis, which allow for a 3× faster analysis with higher efficiency and 2× lower computational cost, when compared to static analysis. The models are used to assess the stiffness, strength and toughness of bi-material beams when subjected to a flexural three-point bending load. The influence of structural features like the soft-to-hard volume ratio (i.e. the distance between each building block, its aspect ratio, and overlap length), material features (e.g. the stiffness ratio of the hard-to-soft phases), the plastic strain failure of soft phase, and AM features (e.g. different types of within-layer/sandwiched supports) are systematically investigated. The results revealed that the toughness of the architectured beams was enhanced by up to 25% when compared to a monolithic structure. This improvement is due to the frictional tile sliding in the brittle phase and the extensive shear plastic deformation of the soft interfaces. This work provides compatible designs to facilitate the AM of nacre-based bi-martial structures with balanced/tailored mechanical performance and to understand the influence of the architectural parameters.
最近，在仿生设计的概念下展示了卓越的材料性能，其中材料结构受到自然的启发。在这项研究中，开发了一种计算框架，以呈现具有可调节刚度、强度和韧性的新型结构的双材料结构，用于增材制造 (AM)。模仿天然珍珠母的结构来设计由硬脆性和硬建筑块与软材料和支撑构建的坚固多层结构。创建了一组由完全结合区域组成的计算模型，同时允许层间相互作用，以准确模拟硬和软有机相之间的相互作用。对于这种复杂的设计，需要正确设置数值约束以运行准静态非线性显式分析，与静态分析相比，该分析允许更快地进行 3 倍分析，效率更高，计算成本降低 2 倍。该模型用于评估在弯曲三点弯曲载荷下双材料梁的刚度、强度和韧性。研究了结构特征（例如软-硬体积比（即每个建筑块之间的距离、其纵横比和重叠长度）、材料特征（例如硬-软相的刚度比）、软相的塑性应变失效和 AM 特征（例如不同类型的层内/夹层支撑）对结构的影响。结果表明，与整体结构相比，结构梁的韧性提高了 25%。这种改进是由于脆性相中的摩擦瓦片滑动和软界面的广泛剪切塑性变形。这项工作提供了兼容的设计，以促进基于珍珠母的双相结构的 AM，实现平衡/定制的机械性能，并了解结构参数的影响。
