Influence of imperfection distributions for cylindrical stiffened shells with weld lands

• Knowledge of imperfection critical areas are obtained for stiffened shells.
• The influence of imperfection position is examined for single perturbation load.
• The influence of imperfection distribution is studied for multiple perturbation load.
• The confidence of the equivalent multiple perturbation load is verified.

The influence of imperfection distributions considering manufacturing characters on the buckling response of stiffened shells has not been satisfactorily understood. Stiffened shells with three types of weld lands were established, including axial weld lands, circumferential and sequential axial weld lands, as well as staggered axial weld lands. As a concept of equivalent imperfection, dimple-shape imperfections produced by perturbation loads were adopted to substitute the measured imperfections, in order to reduce experimental and computational costs. Firstly, the influence of imperfection positions on the collapse load was examined for single perturbation load. Then, the influence of imperfection distributions was investigated for multiple perturbation load based on Monte Carlo Simulation. Finally, detailed comparison of three types of weld lands was made from the point-of-view of load-carrying capacity and imperfection sensitivity. Results can provide general instructions about imperfection-critical areas for axially compressed stiffened shells, which are particularly crucial for the manufacturing process.