Modeling of corrosion pit growth for prognostics and health management

Pitting corrosion is one of the most destructive types of metal degradation and it can result in catastrophic failure of components due to transition of pits to stress corrosion cracks under loading. To facilitate the implementation of corrosion prognostics and health management, in paper presents a finite element approach for the simulation of stable pit growth with stress loads through a multi-physics field coupling technique. A potential drop (IR)-controlled corrosion is assumed to governing the pit evolution, whereas the potential distribution in electrolyte is solved by Laplace equation with a time-dependent solution. As the metal equilibrium potential varies with loads, a time-discrete stationary mechanical analysis was coupled with the corrosion modeling for stress distribution computing and updating. A case study of pitting corrosion growth with stress loads was used to demonstrate the proposed approach, in which the stress effects for pit depth, width and stress concentration factor were discussed.