The Effect of Alternating Wet-Dry Conditions in the Fatigue Life of S355G10+M Steel under Corrosion-Fatigue Testing

In addition to corrosion, offshore wind turbines are subjected to a spectrum of structural loads that lead to dynamic stresses that increase corrosion pit growth kinetics. Alternation of wet and dry stages is a very important factor to be considered, due to significant pitting corrosion rate increment. In this work, the effect of wet-dry conditions in the remaining life of structural steel S355G10+M was investigated. Combined corrosion-fatigue tests were performed in samples of S355G10+M steel with an artificially generated corrosion pit, under simulated wet-dry conditions at different axial load levels. Experimental results were compared with existing fatigue data in air of S355 steels and design curves for free corrosion in seawater. Additionally, these results were contrasted with S-N curves for corrosive environment obtained from theoretical models available in the literature. This approach enabled the evaluation of fatigue life from a phenomenological perspective.