The aim of this work was the study of the durability of stiffened composite panels submitted to the post-buckling regime under compressive loads. The study was based on fatigue test using compression loads in specimens made with initial failures in the bonded area. To monitor the delamination process, the ultrasonography technique was used as a non-destructible test. In the end, it was possible to observe the relationship between delamination propagation and the quantity of cyclic loads that the material supports. It was concluded that the stiffened panels supported a series of cycles with a low rate of delamination propagation. This shows that the applications of these materials as aeronautical structures are safe.
