High Strength Steel Fatigue Crack Growth Database for Offshore Renewable Energy Applications

ABSTRACT High strength steels can reduce costs and carbon emissions in offshore renewable energy, but their effect on structural integrity remains unclear. In welded structures, such as support structures for offshore wind and tidal turbines, fatigue life is dominated by crack growth from flaws at weld toes. Although some fatigue crack growth data for modern high strength steels exist, they are sparse compared to the widely used S355 grade. Standards such as BS 7910:2019, used to assess flaw acceptability in welded structures, therefore cautiously limit their application to high strength steels. In this study, a database of fatigue crack growth data in high strength steels, extracted from the literature, is developed and analyzed using single‐ and two‐stage linear regression. The analysis highlights a distinct lack of data for high strength steels in the corrosive offshore environment. Conversely, analysis of tests in air suggests that existing fatigue crack growth rate laws may be extendable to higher strength steels. In addition to comparing high strength steels with S355, the study investigates the transition points in BS 7910:2019 for two‐stage fatigue laws and evaluates the potential use of a three‐stage law. The database and regression analyses presented provide a foundation for developing improved fatigue crack growth rate laws for high strength steels, supporting more accurate life assessments for next‐generation offshore renewable energy structures.