Three‐Dimensional Stress Intensity Factor and Fatigue Crack Growth Analysis for Complex Hole‐Edge Crack Using Weight Function Method

ABSTRACT Three‐dimensional (3D) cracks emanating from various stress concentrations are frequently encountered in aircraft structures. The stress intensity factor (SIF) is a key element for damage tolerance analysis. In this paper, 3D SIFs are calculated by the slice synthesis weight function method (SSWFM) and used for fatigue crack growth (FCG) analysis. The FCG behaviors for complex crack configurations and geometric features are analyzed. The obtained 3D SIFs from SSWFM have good accuracy when compared to the results from commercial finite element software Abaqus/Franc3D. The calculated crack growth lives are in good agreement with those from Abaqus/Franc3D and experimental tests. FCG analysis based on the SIFs from SSWFM programmed in MATLAB is about three orders of magnitude faster than the finite element method (FEM). The SSWFM can rapidly determine 3D SIFs for complex 3D hole‐edge crack configurations, which are currently unavailable in the NASGRO software, and therefore provides a useful tool for damage tolerance analysis of complex aircraft structures.