Experimental study on the mechanical properties and ultimate strength of accelerated corrosion on hull plates

Abstract

This study employed an accelerated corrosion method to investigate the impact of corrosion on the mechanical properties and ultimate strength of S420 steel hull plates. Initially, corrosion was accelerated using H₂O₂ as a depolarizing agent, and corrosion parameters of the specimens were measured. Subsequently, ten tensile specimens representing five different corrosion states of S420 steel were prepared to test the mechanical properties after corrosion. Simultaneously, 60 ship hull plate specimens, each measuring 146 mm in length, were prepared for ultimate strength experiments under four accelerated corrosion cycles and five slenderness conditions, resulting in a total of 20 operating conditions. The results revealed a linear decrease in various mechanical properties with increasing corrosion degradation. A bilinear stress-strain model considering the corrosion degradation was fitted. The ultimate strength of the hull plates linearly decreased with the increasing corrosion degradation, and the rate of decrease slowed with greater slenderness. Even at the same corrosion level, there was still a certain variability in ultimate strength, which gradually converged with increasing corrosion levels. A predictive formula for ultimate strength considering corrosion level, slenderness, and variability was fitted. The accuracy of the formula was verified through detailed error analysis, providing a practical reference for future structural design and corrosion management.