Numerical study on cathodic protection effect of deep defects on pipelines with constant load

In this numerical study, the cathodic protection (CP) effect on the deep defects of X100 pipelines with constant load was studied. To simulate the local distribution of electrochemical parameters inside the defect, such as potential and anode/cathode current density, a numerical model was designed. The model employs cylindrical defects as well as ellipsoidal defects to better simulate deep defects found on pipelines in real-life scenarios. The results show that the anodic dissolution current density is higher than that in the stress-free state when the stress is applied, due to the stress concentration at the bottom of the defect. Furthermore, the anodic dissolution current density increases as the width of the defect decreases. The current density increases significantly near the bottom of the defect after applying stress. Therefore, there is no significant change in cathode current density. However, a trend of increasing cathodic current density within a certain range near the bottom of the defect due to stress concentration.