Estimating the effects of corrosion pits on the fatigue life of steel plate based on the 3D profile

• Conduct 3D profile and fatigue test to investigate the effects of corrosion pits on fatigue life.
• Analyze pitting characterizations and establish a qualitative relationship with fatigue life.
• Propose a nondestructive method based on 3D profile and AFGROW to predict fatigue life.

The effects of corrosion pits on the fatigue life of pre-corroded Q235 steel plates were investigated. 3D profile measurements were conducted to obtain the distribution and morphology characterization of corrosion pits. Three types of pits were observed and categorized for thoroughly understanding their effects on fatigue behavior. Results indicate that corrosion pits reduce the fatigue life significantly, particularly the sharp pits and the interacting pits. A nondestructive methodology based on 3D profile data for fatigue life prediction has been presented. This method (a) provides a finite element method (FEM) to determine the dimensions of critical pits, (b) considers pit-to-crack transition and (c) considers the effect of multiple critical pits. The predictions are shown to compare well against experimental results.