Transition of Plastic Buckling Modes in Cylindrical Shells

Publisher Summary This chapter analyzes the plastic buckling behavior of cylindrical shells under axial compression, as well as that under alternate transverse loading. It also discusses the characteristics of buckling behavior with a special emphasis on the buckling mode. Thick cylindrical shells under axial compression buckle axisymmetrically to show an elephant-foot bulge, whereas thin-cylindrical shells commonly exhibit a nonaxisymmetric buckling mode, referred to as a diamond-buckling mode. Moderately thick cylindrical shells under axial compression initially exhibit an axisymmetric buckling mode in the plastic range, but this buckling mode develops into a diamond-buckling mode under subsequent loading. The cylindrical shell first exhibits an axisymmetric deformation mode with two symmetric slight bulges near the upper and lower ends of the cylinder. Without the change of this deformation mode, the equilibrium curve reaches the maximum load point. However, if the loading by displacement control is continued after the maximum load point is reached, a localization of buckling patterns occurs at either bulge of the shell. This phenomenon, referred to as an elephant-foot buckling, is caused by a plastic bifurcation on the decreasing equilibrium path, subsequent to the maximum load point. When the localization develops to some extent, the transition from the axisymmetric mode to a nonaxisymmetric mode may occur due to the next bifurcation.