Out-of-Plane Load-Bearing and Mechanical Energy Absorption Properties of Flexible Density-Graded TPU Honeycombs
Out-of-Plane Load-Bearing and Mechanical Energy Absorption Properties of Flexible Density-Graded TPU Honeycombs
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DOI：
10.1016/j.jcomc.2022.100284
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
I. A. Anni;K. Uddin;N. Pagliocca;N. Singh;Oyindamola Rahman;G. Youssef;B. Koohbor
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文献类型：
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作者：
I. A. Anni;K. Uddin;N. Pagliocca;N. Singh;Oyindamola Rahman;G. Youssef;B. Koohbor
蜂窝结构广泛用于需要在低结构重量下出色地减轻应变能的应用。蜂窝结构的承载和能量吸收能力很大程度上取决于它们的孔壁厚度与边缘的比率。这项工作研究了不同孔壁厚度的六边形蜂窝结构响应面外载荷条件的机械响应和应变能吸收特性。具有各种标称密度的蜂窝结构首先由柔性热塑性聚氨酯 (TPU) 增材制造。综合实验研究表征了结构的机械强度、能量吸收性能和应变恢复性。然后通过堆叠蜂窝的多个密度层来制造密度分级结构。密度梯度结构的机械特性表明它们在大变形条件下具有优异的承载响应。从应变能吸收的角度来看，密度分级结构在小变形条件下表现优于均匀密度结构。这项工作中获得的结果强调了密度分级作为开发具有高度可定制、特定于应用的机械性能的蜂窝结构的实用手段的重要性。
Honeycomb structures are widely used in applications that require excellent strain energy mitigation at low structural weights. The load-bearing and energy absorption capacity of honeycomb structures strongly depend on their cell wall thickness to edge ratios. This work studies the mechanical response and strain energy absorption characteristics of hexagonal honeycomb structures with various cell wall thicknesses in response to out-of-plane loading conditions. Honeycomb structures with various nominal densities are first additively manufactured from flexible thermoplastic polyurethane (TPU). A comprehensive experimental study characterized the mechanical strength, energy absorption performance, and the strain recoverability of the structures. Density-graded structures are then fabricated by stacking multiple density layers of the honeycombs. Mechanical characterization of the density-graded structures points to their superior load-bearing response at large deformation conditions. From a strain energy absorption perspective, density graded structures are shown to outperform their uniform density counterparts at small deformation conditions. The results obtained in this work highlight the significance of density gradation as a practical means for the development of honeycomb structures with highly tailorable, application-specific mechanical properties.