含MSD共线多孔平板应力强度因子有限元分析

利用FRANC2D/L对含MSD某型飞机增压舱蒙皮搭接接头进行了有限元分析,得到了不同损伤模式下的应力强度因子(SIF)的计算曲线,和已有的文献比较表明,数值结果精确,方法可靠,即不同长度裂纹的SIF计算可有效地通过FTRANC2D/L的裂纹扩展功能来实现。计算结果表明,在某些情况下,MSD裂纹的SIF可按单裂纹的SIF进行计算;影响MSD裂纹SIF的因素主要是临近裂纹的长度、裂纹间或裂尖与钉孔间的距离。最后给出裂纹连通前后MSD裂纹SIF随裂纹扩展历程变化的规律。

Finite element analysis of SIF of flat MSD panels with a number of collinear holes

Pressure cabin lap joint of certain model military aircraft with multi-site damage (MSD) is analyzed using finite element method. The stress intensity factors (SIF) of different MSD model are computed and showing that the analysis results have good coherence with the literature data. It is shown that the SIF at each crack tip can be calculated by the crack growth simulation capability of FRANC2D/L. For the particular problem under investigation, the results show that SIF of MSD crack can be directly estimated from knowledge of the solution for a single crack. Based on SIF, some factors that will affect SIF general, such as MSD crack length, the space between cracks, are discussed. This paper also summarizes the changing law of SIF at each crack tip as a function of crack length with and without lead crack.