Buckling and strength failure for unstiffened and ring-stiffened composite shells

An experimental method was applied to study the buckling pressure and failure strength for the unstiffened and ring-stiffened fiber reinforced composite cylindrical shells under the external hydrostatic pressure. Both the strain and pressure data are collected and discussed. The FE simulation models are also analyzed as comparison to investigate the relation among the critical buckling pressure, failure strength and the final structure failure strength. The results indicate that the ring-stiffened structure can improve the buckling pressure more significantly than increasing the failure pressure. The experimental burst pressure of the ring-stiffened cylindrical shell is increased by 23.2%. The buckling mode is changed and the buckling behavior can be improved and eliminated by the ring-stiffened structure before the cylinder bursts under the hydrostatic pressure load.