多裂纹结构中的多部位/多元件相互影响因子

Multiple Site/Multiple Element Interactive Factors of Multiple Cracks Structure

多裂纹损伤严重影响飞机连接结构的损伤容限能力,针对多裂纹损伤结构引入了多部位相互影响因子(MSIF)和多元件相互影响因子(MEIF)的概念,以此来反映裂纹之间的相互影响,并给出了获得这两个影响因子的有限元计算过程。对典型的含多裂纹结构进行了模拟计算,获得了了不同开裂状态下各裂纹尖端处的多部位相互影响因子和多元件相互影响因子的数值拟合结果,在此基础上,进一步计算并对比分析了含多裂纹结构的裂纹扩展寿命和剩余强度,结果表明:多部位相互影响和多元件相互影响对裂纹扩展寿命和剩余强度有显著的影响,在结构损伤容限评定中对多裂纹损伤应当予以重视。

Multiple cracks severely affect damage tolerance capability of aircraft connection structure. Damage with multiple cracks, which has a strong impact on the capability of damage tolerance of aircraft structure, is difficult for damage tolerance assessment of aircraft structures. For one solution to this problem, two interactive factors, which are multiple site interactive factor （MSIF） and multiple element interactive factor （MEIF）, are introduced to structures with multiple cracks in order to reflect the interaction between cracks. The finite element calculation to obtain the two factors for certain structure with multiple cracks is also given. Two typical structures with multiple cracks are simulated to obtain the MSIF and MEIF under various cracking patterns. Based upon the factors obtained above, the crack propagation life and residual strengths of structures are predicted and compared. The conclusion is that MSIF and MEIF can be used to describe the interaction between cracks and elements and play an important role in analysis of crack propagation life and residual strength.