Compression experiment on aeronautic composite stiffened panel was conducted to study the buckling load

failure load and failure modes. From the experimental results

the average failure load(968.25kN) was 1.65 times the average buckling load(587.5kN)

indicating that the composite stiffened panel had a relatively high post-buckling bearing ability. Its primary failure modes are the debonding

crack of stiffeners and the splitting of panel. The failure section is usually located in the middle part of composite stiffened panel. The buckling load

failure load and post-buckling damage progress of stiffened panel were analyzed by using finite element software. Buckling load and failure load obtained were in well agreement with the experimental results. Compared with experimental results

the errors were -9.97% and 8.45% respectively

indicating the validity of the finite element model. Sequence of damage occurring in fiber and matrix was studied. The simulation results show that in post-buckling progress

the damage of fiber occurs earlier than that of the matrix

and especially the damage of fiber in middle part of stiffeners is most serious. There is little damage in matrix before the failure of composite stiffened panel.