Abstract: Shear experiment on friction stir welded 2024-T3 aluminum alloy stiffened panel specimens is conducted to obtain the buckling behavior and carrying capability of the structure. Finite element method(FEM) is applied to analyze the stability performance of the simplified structure model and the results are compared with experimental results. It is found that, buckling mode of the structure is local buckling of plate between stiffeners, post-buckling mode is under the state of diagonal tension, the failure patterns mainly contain the plastic deformation and tearing of plate, distortion of stiffeners and local weld debonding. Average carrying capability of specimens failed with weld debonding is 7.7% lower than that of other specimens. Buckling loads obtained by linear and nonlinear analysis are separately 18.4% and 26.2% higher than average experimental result, while carrying capability obtained by nonlinear analysis is 5.7% higher than average experimental result, which indicates that the carrying capability is less sensitive to the weld induced initial imperfections than buckling load. Buckling mode and failure pattern obtained by FEM accords well with experimental phenomenon, which validates the rationality of the finite element model, however, it still needs to be further modified to account for weld induced imperfections to reduce the calculation errors..

Key words: finite element method(FEM), friction stir weld, shear stability, stiffened panel