Effect of CFRP on Buckling Performance of Thin-Walled Cylindrical Steel Tanks with Dents and Corrosion.

Thin-walled steel cylindrical shells offer excellent strength-to-weight ratios but are highly sensitive to mechanical imperfections and corrosion-induced degradation. This study investigated the effects of dents and corrosion on the buckling behavior of 0.45 mm-thick thin-walled cylindrical steel shells, as well as the efficiency of carbon fiber-reinforced polymer (CFRP) strengthening under external pressure. Nine specimens were tested, including corroded samples exposed to 2.5% and 5% HCl solutions to simulate material deterioration. The results revealed that both corrosion and dents significantly reduced the buckling capacity and structural stability of the specimens. However, in comparison with earlier investigations on unstrengthened and partially strengthened specimens, the external CFRP layers substantially mitigated capacity losses, improving ultimate load, ductility, and postbuckling behavior. Complementary SEM analysis provided microstructural insight into the corrosion mechanism, illustrating the progressive surface degradation from localized pitting to widespread delamination at higher corrosion levels. Overall, CFRP confinement was confirmed as a highly effective retrofitting solution for restoring strength and stability in imperfect and corroded thin-walled steel shells.