Fatigue stress concentrations analysis of real corroded steel structures based on replica imprints

The service life of offshore support structures is significantly reduced by corrosion. In particular, pitting corrosion leads to high local stress concentrations and can reduce the expected fatigue strength. Previous studies on corroded specimens have shown that crack development in fatigue tests is correlated with stress concentration. In the context of maintenance of existing offshore wind turbines, there are novel efforts to capture the real surface geometry of corroded components with the so‐called replica technique, in which an imprint of the surface geometry is made and digitized with a 3D‐scanner and used to numerically analyse the stress concentrations due to pitting corrosion. In this study, it was shown that the replica technique is able to reproduce the effective stress concentrations of the original surface with very high accuracy.