The effect of graphene nanoparticles on the strength of a sandwich panel structure based on foam core, which is inspired by the microstructure characteristics of dragonfly wings, has been investigated experimentally and numerically under low-velocity impact. Sandwich panel structures are made of E-glass/epoxy layers, and different percentages of graphene nanoparticles and combined with their resin. Also, polyurethane foam was used for its central core. For numerical modeling, a nonlinear progressive damage model of composite and nano-composite shells is incorporated into the finite element (FE) code by VUMAT subroutine. The numerical results were compared with the collected experimental data and it shows that there is a good compatibility between them. To check the damage in the structures, the images of the cut view of the samples were taken from the damaged area, and the results were reported. In order to evaluate the distribution of graphene nanoparticles in the polymer structure, the manufactured samples were analyzed using the FE-scanning electron microscopy analysis device. It was concluded that this type of sandwich structure inspired by dragonfly wings can limit damage propagation and keep the rest of the structure healthy under low-velocity impact.

中文翻译：

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石墨烯纳米粒子对低速冲击下夹层结构强度影响的实验和数值研究

受蜻蜓翅膀微观结构特征的启发，石墨烯纳米粒子对基于泡沫芯的夹层板结构强度的影响已经在低速冲击下进行了实验和数值研究。夹心板结构由无碱玻璃/环氧树脂层和不同百分比的石墨烯纳米颗粒制成，并与它们的树脂结合。此外，聚氨酯泡沫用于其中央核心。对于数值建模，复合材料和纳米复合材料壳的非线性渐进损伤模型通过 VUMAT 子程序纳入有限元 (FE) 代码。将数值结果与收集到的实验数据进行比较，表明它们之间具有良好的相容性。为了检查结构中的损坏，样品的切割视图图像是从受损区域拍摄的，并报告了结果。为了评估石墨烯纳米粒子在聚合物结构中的分布，使用 FE 扫描电子显微镜分析装置分析制造的样品。得出的结论是，这种受蜻蜓翅膀启发的夹层结构可以限制损伤传播，并在低速冲击下保持结构的其余部分健康。