The Ultimate Strength of Ring Stiffened Cylindrical Shell and Its Influence Factors

Calculating the modes of cylindrical shell, then embed them into ideal perfect cylindrical pressure-resistant shell as the initial geometric imperfections to form the modal. According to the characteristics of each mode, the first 30 modes can be classified into four types, and it is found that the mode of the first type is the worst defect form. By calculation, the cylinder shell has the minimum ultimate strength when the 23rd mode happened. The sensitivity analysis of cylindrical shells with initial geometric defects shows that the critical buckling load has approximate linear relationship with different thickness radius ratio and defect amplitude. Six cylindrical shells of different materials are selected for research, and it is found that although the modal orders of the worst geometric defects of various materials are not the same, they all belong to the first type of mode. The comparison showed that the 921 steel and 909 steel materials are economic.