Fracture mechanics analysis on the bonded repair of a skin/stiffener with an inclined central crack

The enhancement of the service life of damaged or cracked structures is currently a major issue for researchers and engineers. An analysis for the stress intensity factor (SIF) at a skin/stiffener structure with an inclined central crack repaired by composite stiffened panels is developed. A numerical investigation was conducted to characterize the fracture behavior and crack growth behavior at an inclined crack. In order to investigate the crack growth direction, maximum tangential stress (MTS) criterion are used. Also, this paper studies the performance of an effective bonded composite patch repair of a plate containing an inclined central through-crack. The main objective of this research is the validation of an inclined crack patching design. In this paper, the reduction of SIFs at the crack-tip and prediction of crack growth direction are determined in order to evaluate the effects of various non-dimensional design parameters including: composite patch thickness and stiffener distance. The results of finite element analysis on the stiffener locations and crack slant angles are discussed herein. Research on cracked structure subjected to mixed-mode loading is reported and concludes that more work using a different approach is necessary. The authors hope the present study will aid those who are responsible for the repair of damaged aircraft structures and also provide general repair guidelines.