Out-of-plane mechanical design of bi-directional hierarchical honeycombs
Out-of-plane mechanical design of bi-directional hierarchical honeycombs
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DOI：
10.1016/j.compositesb.2021.109012
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发表时间：
2021-09
影响因子：
13.1
通讯作者：
Wenzhen Huang;Yong Zhang;Yang Xu;Xiang Xu;Jin Wang
中科院分区：
文献类型：
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作者：
Wenzhen Huang;Yong Zhang;Yang Xu;Xiang Xu;Jin Wang
提出了一种双向分层策略来设计一种新型的分层蜂窝结构。为研究双向分层蜂窝结构的平面外耐撞性，设计了三种双向分层蜂窝结构，包括分层三角形蜂窝、分层四边形蜂窝和分层六边形蜂窝。对采用选择性激光熔化（SLM）方法制备的分层六边形蜂窝结构进行了压缩试验，以研究其变形机理并验证有限元（FE）模型。与相应的规则蜂窝相比，BDHH的特点是在整个网络中的上级材料分布，这有助于破碎力效率和能量吸收。此外，进行了数值研究，揭示分层因素和厚长比（相对密度）的BDHH的面外力学响应的影响。研究发现，双向分层因子和厚长比对BDHH的能量吸收有促进作用。在此基础上，建立了基于简化超折叠单元理论的平均抗压强度解析模型，用于预测双向分级六边形蜂窝的平均抗压强度。理论解与仿真结果具有较好的一致性。研究结果可为轻型防护结构的研制提供有效的指导。
A bi-directional hierarchical strategy is proposed to design a novel hierarchical honeycomb. Three kinds of bi-directional hierarchical honeycombs (BDHH), including hierarchical triangular honeycomb, hierarchical quadrangular honeycomb and hierarchical hexagonal honeycomb, are developed to investigate their out-of-plane crashworthiness. The compression test of a hierarchical hexagonal honeycomb fabricated by selective laser melting (SLM) method is performed to investigate the deformation mechanism and validate the finite element (FE) model. Compared with corresponding regular honeycombs, BDHHs are characterized by the superior material distribution across the network, which contributes to the crushing force efficiency and the energy absorption. In addition, numerical investigation is carried out to reveal the influence of hierarchical factors and thickness-to-length ratio (relative density) on the out-of-plane mechanical response of the BDHH. It is found that bi-directional hierarchical factors and the thickness-to-length ratio can promote the energy absorption of the BDHH. Furthermore, the analytical model of the mean crushing strength based on the simplified super folding element theory is derived to predict the mean crushing strength of bi-directional hierarchical hexagonal honeycomb. As a conclusion, there is a good consistency between theory solution and simulation result. All findings can be considered as effective guidance for the development of a lightweight protective structure.