Fatigue life analysis of cracked aluminum 6061-T6 plate repaired by composite patches

Bonded patches are widely used in industries for repairing of the damaged plate, cracks in metallic structures, and reinforcement of deficient structures. Composite patches have select properties such as high strength to weight ratio, easy to apply, flexibility, and do not damage the parent plate. Because of the rapid growth in the aerospace industry, analyses of adhesively-bonded patches to repair cracked structures have been the focus for many years. In the present study, the fatigue behavior of the aluminum alloy, repaired by double-sided glass/epoxy composite patch, is investigated numerically. The 3D finite element model is performed to analyze the fatigue life of both repaired and unrepaired aluminum plates by Abaqus software. In order to calculate the fatigue life of aluminum plate, first, the hysteresis loop is determined, then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. Results reveal that composite patches increase the fatigue life of cracked structures significantly. Furthermore, by increasing the stiffness of the composite patch, fatigue life increases.

Keywords:

composite patch , finite element model , fatigue life