Abstract
Moderately thick perfect cylindrical shells under axial compression first exhibit axisymmetric deformation patterns, where a localization of buckling patterns, i. e. an elephant foot bulge, occurs at the first plastic bifurcation. However, the transition from the axisymmetric buckling mode to a diamond buckling mode may occur due to the next bifurcation if we continue the loading under displacement control. Herein, this phenomenon is examined based on a rigorous plastic bifurcation analysis. As a result, it is observed that the circumferential wave number of the diamond buckling mode increases with the decrease of the wall thickness. It is also found that the strain concentration is intensified for the diamond buckling mode, compared with the axisymmetric buckling mode.
