Experiments on imperfect cylindrical shells under uniform external pressure

The load-carrying behavior of cylindrical thin-walled shell structures under load pressure is strongly dependent on the nature and magnitude of the imperfections invariably caused by various manufacturing/welding processes. Weld-induced geometric imperfections have been reported to have especially detrimental effects on the buckling resistance of shells under uniform external pressure. Buckling and post buckling capacity of the shells depend considerably on the cross-sectional form and depth of the geometric imperfections. It also relies on the H/R and R/t ratios (H=height, R=radius, and t=thickness of a cylindrical shell). In the present study, we manufactured and tested a series of specimens having 4 t and 8 t magnitudes of imperfections with different ratios of H/R and R/t. The results of testing under different codes are compared. This study shows considerable reduction in the buckling resistance of the shells.

► A series of specimens having 4t and 8t magnitudes of imperfections were tested in this research.
► In spite of the higher imperfections the initial buckling load is higher, especially in case of a lower H/R and higher R/t.
► In contrast to international codes, existence of geometric imperfections does not always bring unfavorable outcomes.