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Abstract：
This study examines a hierarchical vertex-based structure that improves the crashworthiness of the conventional multi-cell square, a biological hierarchy of natural origin with exceptional mechanical properties. The vertex-based hierarchical square structure (VHS) is explored for its geometric properties, including infinite repetition and self-similarity. The cut-and-patch method is used to derive an equation for the material thicknesses of different orders of the VHS based on the principle of the same weight. A thorough parametric study of VHS was conducted using LS-DYNA, which examined the effects of material thickness, orders, and various structural ratios. The results were evaluated based on common crashworthiness criteria and demonstrated that the total energy absorption (TEA), specific energy absorption (SEA), and mean crushing force (Pm) of VHS exhibited similar monotonicity concerning the orders. SEA of the first-order VHS with λ1=0.3 and the second-order VHS with λ1=0.3 and λ2=0.1 are improved by at most 59.9% and 102.4% respectively; the second-order VHS with 0.2≤λ1≤0.4 and 0.1≤λ2≤0.15 have the better overall performance of crashworthiness. Then, the half-wavelength equation of VHS and Pm of each fold was established based on the Super-Folding Element method. Meanwhile, a comparative analysis with the simulation results reveals three different out-of-plane deformation mechanisms of VHS. The study indicated that material thickness had a greater impact on crashworthiness. Finally, the comparison with conventional honeycombs demonstrated that VHS holds great promise as a structure for crashworthiness. These results provide a solid foundation for further research and development of new bionic energy-absorbing devices.
摘要：
这项研究研究了一种基于顶点的分层结构，该结构提高了常规多单元正方形的耐撞性，具有特殊机械性能的自然起源的生物等级。探索了基于顶点的分层正方形结构（VHS）的几何特性，包括无限重复和自相似。基于相同重量的原理，采用切块法推导了VHS不同阶数的材料厚度方程。使用LS-DYNA对VHS进行了全面的参数研究，它检查了材料厚度的影响，订单,和各种结构比率。结果基于常见的耐撞性标准进行评估，并证明了总能量吸收（TEA），比能量吸收(SEA)，VHS的平均压碎力（Pm）在阶数方面表现出相似的单调性。λ1=0.3的一阶VHS和λ1=0.3和λ2=0.1的二阶VHS的SEA分别提高了59.9％和102.4％；0.2≤λ1≤0.4和0.1≤λ2≤0.15的二阶VHS具有更好的耐撞性能。然后，基于Super-FoldingElement方法，建立了VHS和Pm的半波长方程。同时,与仿真结果的比较分析揭示了VHS的三种不同的平面外变形机制。研究表明，材料厚度对耐撞性有较大影响。最后,与传统蜂窝的比较表明，VHS作为耐撞性结构具有很大的前景。这些结果为进一步研究和开发新的仿生吸能装置奠定了坚实的基础。
