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蜂窝或胞壁缺失是蜂窝夹层结构缺陷形式的一种,由于蜂窝(壁)的缺失,导致蜂窝芯子的连续性被破坏,并产生应力集中。本文从蜂窝细观尺度出发,通过数值解析与有限元模拟相结合的方式对缺陷周围胞壁正应力进行分析,首先,通过有限元模拟得到胞壁的拉应力结果,结果表明,应力集中带状区上的胞壁标准化拉应力沿横向符合近似卡方概率密度函数的分布形式;存在一个临界位置使蜂窝壁拉应力分布曲线出现反转。其次,对蜂窝缺陷最大拉应力处的壁内弯矩值与胞壁缺失个数的关系进行了推导。最后,给出了预估弯曲应力的公式,并分析了缺陷形状对预估公式参数的影响。
Honeycomb or cell wall loss is a form of honeycomb sandwich defect that results in the destruction of the continuity of the honeycomb core due to the absence of honeycombs (walls) and the resulting stress concentration. In this paper, from the cellular microscopic scale, through the combination of numerical analysis and finite element simulation, the normal stress of the cell wall around the defect is analyzed. First, the tensile stress of the cell wall is obtained by finite element simulation. The results show that the stress concentration band The normalized cell wall tensile stresses in the region conform to the distribution of approximate chi-square probability density functions in the transverse direction. There is a critical position that reverses the distribution curve of tensile stress in the honeycomb walls. Secondly, the relationship between the bending moment at the maximum tensile stress of honeycomb defects and the number of cell wall defects was deduced. Finally, the formula for predicting the bending stress is given, and the influence of defect shape on the parameters of the prediction formula is analyzed.