The effect of the cellular core on the stress intensity factor at the tip of a crack in the adhesive layer of a five-layer sandwich composite beam is investigated. A Nomex sheet is used to model the cellular core with honeycomb, square, and triangular cells. The mechanical properties of these cells are obtained by the finite element analysis supported by theoretical two- and three-dimensional equations. Based on the deduced properties, the load-displacement curve is generated for a sandwich beam under mode I fracture. The numerical findings are validated against available experimental data. It is shown that the lowest values of the stress intensity factor are observed for a core with a honeycomb structure as compared to the other two cell shapes used in this study, which are composed of equilateral triangles or squares. An increase in the wall thickness of the cells leads to an increase in the stress intensity factor.

中文翻译：

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蜂窝芯夹层梁中粘合层的力学性能和I型内聚破坏研究

研究了蜂窝芯对五层夹心复合梁粘接层裂纹尖端应力强度因子的影响。Nomex 板用于模拟蜂窝状、方形和三角形单元的蜂窝芯。这些细胞的机械性能是通过有限元分析获得的，并得到了理论二维和三维方程的支持。根据推导出的特性，生成 I 型断裂下夹层梁的载荷-位移曲线。数值结果根据可用的实验数据进行了验证。结果表明，与本研究中使用的其他两种单元形状（由等边三角形或正方形组成）相比，蜂窝结构芯的应力强度因子值最低。