Residual strength of damaged ring-stiffened cylinders subjected to external hydrostatic pressure

This paper presents the experimental and numerical investigation results of the residual strengths of damaged ring-stiffened cylinders subjected to external hydrostatic pressure. The damage generation procedure adopted in this paper could represent the collision accidents of marine ring-stiffened cylinders with floating subjects or support vessels. Three steel ring-stiffened cylinder models were fabricated and among them two were damaged by drop testing using a rigid knife-edge indenter. Hydrostatic pressure tests were conducted on one intact model and two damaged ones. The test results demonstrated that the ultimate strengths of the two damaged models were significantly reduced compared with that of the intact model. The denting and collapse processes were simulated using the Abaqus FEA software package. The numerical predictions show a good agreement with the test results. Further analyses were also conducted on ring-stiffened cylinders using various striker headers with knife-edge, rectangular and hemispherical indenters to clarify the effect of damage shapes on the residual strengths of damaged ring-stiffened cylinders. •This study reports the ultimate strength tests on one intact and two damaged ring-stiffened cylinders subjected to external hydrostatic pressure.•The damages were generated by the collision of a striker having a knife edge.•The failure mode of locally damaged ring-stiffened cylinders under hydrostatic pressure can be the overall buckling mode regardless of the failure mode of its intact state.•The accuracy and reliability of the numerical methods employed for collision analysis and residual strength analysis can allow performing further parametric studies to develop any design guidance.•The residual strength tests performed in this study show that when the energy ratios (λE), which is the ratio of impact energy to energy absorption capacity, are 0.901 × 10−3 and 1.228 × 10−3, the strength reduction can be 23.6% and 35.2%, respectively.