Experiments on curved hat-stiffened composites panel with 7 stringers and 4 frames were conducted to investigate the buckling load

buckling mode

post-buckling carrying capacity and failure characterization under combined internal pressure and axial compression. The results show that the axial buckling load of the curved hat-stiffened composites panel is increased by the internal pressure when the panel is subjected to combined mechanical loads

and the panel has no buckle before failure. Based on the linear stability theory of shallow composites shell

the analytical methods for the buckling load of the curved hat-stiffened composites panel were presented by utilizing Rayleigh-Ritz method and Kirchhoff hypothesis under internal pressure

axial compression

combined internal pressure and axial compression

an empirical method was proposed to estimate the failure load of the curved hat-stiffened composites panel under combined internal pressure and axial compression. The results by both the present methods and experiments agree very well

the empirical method is clear and concise

which is easy to be applied in design of curved hat-stiffened composites panel.