A study on time-variant corrosion model for immersed steel plate elements considering the effect of mechanical stress

In this study, the effect of low levels of elastic stress on corrosion behavior of Q235B steel in an aerated 3.5% NaCl solution was investigated through measurements of linear polarization resistance (LPR), potentiodynamic polarization characteristics and electrochemical impedance spectra (EIS). Through theoretical analysis and experimental results, new corrosion models which can distinguish the effect of mechanical stress on the corrosion process of actual marine structures have been respectively proposed on the basis of three representative existing corrosion models. The effect of corrosion models on lifetime assessment was studied by employing a steel plate element subjected to the combined effects of corrosion and mechanical stress. Analytical expressions have been obtained for the structure's lifetime, which is identified with the time when the stress reaches the yield level. An example was presented to demonstrate the combined effects of corrosion and elastic stress on the lifetime assessment of marine structures.