Numerical modeling of corrosion pit propagation using the combined extended finite element and level set method

A sharp-interface Eulerian formulation for modeling the propagation of localized pitting corrosion is presented. This formulation allows for an accurate representation of the corrosion front independent of the underlying finite element mesh and handles complex morphological transitions such as pit merging without requiring remeshing or mesh-moving procedures. First, the governing equations of the moving interface problem associated with pit growth are derived for the two-phase (metal-solution) system. Next, the implementation of the combined extended finite element and level set method and the procedure to enforce interface conditions are discussed. Finally, the method is validated by conducting several benchmark numerical studies, and comparing the results with published experimental data and existing numerical studies. Simulation studies indicate that: during diffusion-controlled corrosion an isolated pit grows as a semi-circular shape, whereas closely spaced pits merge and grow into an elongated elliptical shape; and only during activation-controlled corrosion the initial pit morphology is preserved.