Buckling analysis of composite stiffened panels with pre-damage under uniaxial compression

In this paper, the failure modes of T-shaped composite stiffened panels under uniaxial compression are analyzed through experiments and Finite Element Method(FEM). The composite stiffened panels' buckling and post-buckling behaviors with different pre-damage locations and sizes are studied. Three pre-damage locations and four damage sizes are considered. Comparing the critical buckling loads and the maximum failure loads of these pre-damaged composite stiffened panels, three conclusions are obtained: there are a few influences on the critical buckling loads and the maximum failure loads, when the pre-damages are located at the skin between the stringers; the critical buckling loads obviously decreased by 50% at maximum when the damages are located at the skin under the stringer; the maximum failure loads decrease due to the damage size increasing when the pre-damages are located at the skin under the stringer's edge, and the maximal decreasing value is 25%. Finally maps about the critical buckling and the maximum failure loads' ratios with respect to the pre-damage locations and sizes are shown.