基于XFEM机翼下壁板裂纹扩展分析与验证

Analysis and Verification for the Crack Growth of Lower-wing Panel Based on XFEM

为研究某大型飞机机翼下壁板裂纹扩展特性,首先分别使用常规有限元法和扩展有限元法对不同裂纹长度下的应力强度因子进行对比研究,然后通过扩展有限元法结合NASGRO方程,对机翼下壁板裂纹扩展进行分析并与试验结果进行对比。结果表明,相比于常规有限元法,扩展有限元法具有同样的计算精度,且裂纹界面与网格划分相互独立,具有裂纹定义简单,对裂纹尖端网格没有特殊要求等优点;基于扩展有限元法的裂纹扩展线与试验结果基本一致,表明了扩展有限元法应用于机翼下壁板裂纹扩展分析的可行性。利用扩展有限元法的裂纹扩展分析方法可以为大型飞机机翼壁板结构损伤容限设计提供参考。

In order to study the crack propagation characteristics of lower-wing panels of a large aircraft,the stress intensity factors under different crack lengths are investigated by conventional finite element method and extended finite element method respectively.Then,the crack propagation of underwing panels is analyzed by extended finite element method combined with NASGRO equation and the experimental results are compared.The results show that compared with the conventional finite element method,the extended finite element method has the same computational accuracy,the crack interface is independent of the mesh division,the crack definition is simple,and there is no special requirement on the mesh at the crack tip.The crack growth lines based on the extended finite element method are in good agreement with the experimental results,which indicates that the extended finite element method is feasible for the crack growth analysis of the lower-wing panel.The crack growth analysis method using the extended finite element method can provide a reference for the damage tolerance design of large aircraft wing panels.