Széles Levente, Horváth Richárd, Rádics János Péter
Doctoral School on Materials Sciences and Technologies, Óbuda University, H-1034 Budapest, Hungary.
Bánki Donát Faculty of Mechanical and Safety Engineering, Óbuda University, H-1034 Budapest, Hungary.
Polymers (Basel). 2023 Jun 12;15(12):2650. doi: 10.3390/polym15122650.
In this study, we created metamaterials consisting of square unit cells-inspired by fractal geometry-and described the parametric equation necessary for their creation. The area and thus the volume (density) and mass of these metamaterials are constant regardless of the number of cells. They were created with two layout types; one consists solely of compressed rod elements (ordered layout), and in the other layout, due to a geometrical offset, certain regions are exposed to bending (offset layout). In addition to creating new metamaterial structures, our aim was to study their energy absorption and failure. Finite element analysis was performed on their expected behavior and deformation when subjected to compression. Specimens were printed from polyamide with additive technology in order to compare and validate the results of the FEM simulations with real compression tests. Based on these results, increasing the number of cells results in a more stable behavior and increased load-bearing capacity. Furthermore, by increasing the number of cells from 4 to 36, the energy absorption capability doubles; however, further increase does not significantly change this capability. As for the effect of layout, the offset structures are 27% softer, on average, but exhibit a more stable deformation behavior.
在本研究中，我们创建了由受分形几何启发的方形单元组成的超材料，并描述了其创建所需的参数方程。这些超材料的面积以及因此的体积（密度）和质量与单元数量无关，保持恒定。它们通过两种布局类型创建；一种仅由压缩杆单元组成（有序布局），在另一种布局中，由于几何偏移，某些区域会受到弯曲（偏移布局）。除了创建新的超材料结构外，我们的目的是研究它们的能量吸收和失效情况。对它们在受压时的预期行为和变形进行了有限元分析。采用增材技术用聚酰胺打印试样，以便将有限元模拟结果与实际压缩试验结果进行比较和验证。基于这些结果，增加单元数量会导致行为更稳定且承载能力增强。此外，将单元数量从4增加到36，能量吸收能力会翻倍；然而，进一步增加并不会显著改变这种能力。至于布局的影响，偏移结构平均要软27%，但表现出更稳定的变形行为。
