The landing gear strut is mainly subjected to eccentric compression load during service, and the calculation of its stress intensity factor is often considered as a challenge to calculate the surface crack growth life. Based on the bulging effect, we modify the stress intensity factor of the surface cracked cube, and obtain the stress intensity factor formula of the surface cracked strut. It calculates the stress intensity factor by using geometric characteristics and load characteristics, and calculates the crack growth life without meshing finite element model. In the study of surface fatigue crack growth of steel strut under eccentric compression load, the proposed approach to calculate the crack growth life of surface cracked strut is proved to be feasible. The method is simple and conservative.

起落架支柱在服役过程中主要承受偏压载荷，其应力强度因子的计算常被认为是计算表面裂纹扩展寿命的挑战。基于鼓胀效应，对表面开裂立方体的应力强度因子进行修正，得到表面开裂支柱的应力强度因子公式。它利用几何特性和载荷特性计算应力强度因子，计算裂纹扩展寿命，无需网格化有限元模型。在偏压载荷作用下钢支柱表面疲劳裂纹扩展研究中，证明了所提出的计算表面开裂支柱裂纹扩展寿命的方法是可行的。该方法简单且保守。