BUCKLING BEHAVIOR OF RING STIFFENED-ALUMINUM CYLINDERS SUBJECTED TO EXTERNAL PRESSURE

Abstract

Ring stiffeners are preferably used to enhance thin-walled cylindrical shell buckling resistance while subjected to external lateral pressure. A comprehensive finite element (FE) numerical study investigated the influence of external ring stiffeners varying from 3 to 17 on the buckling strength of thin-walled stiffened aluminum cylinders. Ten ring-stiffened cylinders were modelled using an ANSYS workbench 2021, whose stiffener dimensions were varied such that the overall weight for all ring-stiffened cylinders remained constant. The FE results indicate that specimens with nine and a larger number of stiffeners with lower strength failed in the overall flexural buckling mode (OFBM), and the other with seven and a lesser number of stiffeners with higher strength failed in the local shell buckling mode (LSBM). The optimum number of stiffeners is obtained when both failure modes occur simultaneously. Experimental results and the theoretical solution with reasonable accuracy substantiate the FE results. The experimental, theoretical, and finite element (FE) results indicate that the ring stiffener’s optimum size and spacing can improve the stiffened cylinder buckling strength since critical buckling pressure and failure mode shape were influenced by the ring stiffener’s size and spacing.