Investigation of the buckling behavior of conical shells under weld-induced imperfections

The initial depression of shell skins is usually created through various panel processes such as rolling or welding. It is important to create some basic design regulations associated with the existing codes. A longitudinal imperfection caused by the continuous welding of a panel's edge to form a cone is the most important case in this context. The present paper discusses 14 laboratory specimens in 2 groups, labeled Shallow Conical Caps (SCC) and Deep Conical Caps (DCC), loaded under uniform hydrostatic pressure. The samples were modified to include either 1 or 2 line imperfections with amplitudes of 1t, 2t and 3t in depth (t the thickness of conical shell). The results presented here are in general agreement with international codes as well as theories concerning initial and overall buckling and collapse.

► Fourteen test specimens with various imperfections were loaded under hydrostatic pressure.
► For the shallow conical shells, the collapse load ranged from 88% to 119% of the theory.
► Collapse pressure for deep specimens ranged from 74% to 93% of the theoretical load.
► In shallow specimens, the stiffening effect of local imperfection was higher than the tall cones.
► In spite of the international codes, geometric imperfections do not always have a reduction effect.