含多裂纹结构的剩余强度有限元分析  

Finite element analysis of residual strength of a structure with multiple cracks

作　　者：邢春辉[1] 曹启武 吴伟东[1] 卢翔[1] 

机构地区：[1]中国民航大学航空工程学院,天津300300 [2]上海飞机客户服务有限公司,上海200241

出　　处：《中国科技论文》2015年第10期1220-1224,共5页China Sciencepaper

基　　金：中央高校基本科研业务费专项资金资助项目(2014SY-11)

摘　　要：铝合金蒙皮表面上出现的广布疲劳损伤极易引起结构的剩余强度降低而发生破坏,采用平均应力准则方法,对不同裂纹深度和裂纹间距的多裂纹损伤结构进行了剩余强度有限元模拟分析,分别讨论了在相同裂纹深度与不同裂纹间距、相同裂纹间距与不同裂纹深度、不同裂纹间距与不同裂纹深度对剩余强度的变化规律。结果表明:平均应力准则的计算值与塑性连通准则的计算值误差在1%左右;当裂纹连通间距以2mm逐步减少时,剩余强度以10 MPa的幅度逐步减少;当裂纹深度与结构厚度之比低于40%时,剩余强度的下降幅度为40 MPa左右,否则,剩余强度的下降幅度为20 MPa左右;当裂纹深度达到板厚50%时,裂纹间距对剩余强度的影响几乎为零。因此,采用平均应力准则方法可以对铝合金蒙皮的多裂纹深度、间距和剩余强度进行预测和评估。Widespread fatigue damages in the aircraft skin of aluminum alloy will reduce the structural residual strength easily and accordingly lead to failure. Structures with multiple crack damages varied in depth and spacing were studied by finite element a nalysis（FEA）, employing the average stress criterion method of residual strength. The pattern of residual strength was discussed respectively with different depth and the same spacing, different spacing and the same dcpth, and different depth and spacing both. The error is about 1% between the calculations in accordance with average stress criterion and plastic connectivity criterion. The residual strength declines accordingly in the pace of 10 MPa, when the distance of crack narrows every 2 mm. The residual strength declines around 40 MPa, when the ratio of crack depth to structural thickness is blow 40%. Otherwise, the residual strength declines by around 20 MPa. However, the crack spacing had little influence on the residual strength when cracks pene-trated beyond half thickness of the structure. The employment of the average stress criterion is efficient in prediction and assessment of cracks and residual strength of aluminum alloy skin.

关 键 词：多部位损伤 裂纹间距 裂纹深度 剩余强度 有限元 

分 类 号：V215.4[航空宇航科学与技术—航空宇航推进理论与工程]