双向荷载条件下八边形蜂窝结构因胞壁缺失所致应力集中分析

因胞壁缺失引起的应力集中现象是蜂窝结构在增材制造过程中亟待解决的问题，通过将胞壁缺失所致的缺陷等效成椭圆，基于复变函数方法得到了预测拉伸应力的解析公式和预测弯矩应力的分析方法，进而得到八边形蜂窝结构在双向荷载条件下缺失单行和多行胞壁产生的应力组合值。与数值模拟结果的对比分析验证了所提理论解析公式的有效性；同时得出距离缺陷最近胞壁上的拉伸应力解析解与数值解吻合良好，弯矩应力数值解与胞壁上的应力梯度呈明显的线性关系。与规则六边形蜂窝在多行缺陷条件下的应力集中程度进行对比，得出八边形蜂窝结构在荷载系数 和 时应力集中程度小于规则六边形蜂窝结构，从而为蜂窝结构增材制造设计提供理论指导。

Stress concentration in octagonal honeycombs due to missing cell walls subjected to the biaxial loading

Stress concentration due to missing cell walls is an urgent problem to be solved in the additive manufactured process of cellular structures. Approximated the defect region with an elliptical hole and based on the complex function method, analytic formulas of the tensile stress and analytical method of the bending stress are proposed. Stress of the octagonal honeycombs with missing cell walls along one row and more rows under the biaxial loading are calculated and compared with the results of FEM, verifies the effectiveness of the proposed method. Results indicate that the analytical solutions of the tensile stress are fitted well to the numerical simulation results and there is an obvious linear relationship between the bending moment and the stress gradient. Moreover, comparison with the hexagonal honeycomb, stress concentration effects of the octagonal honeycomb with more rows defects in the case of and are found lower, which provide some theoretical guidance for the design of additive manufactured honeycombs.