Simplified approaches for material characterization – an alternative for advanced fatigue design methods

Integral parts of the Sustainable Development Goals of the United Nations are to ensure a sustainable and robust infrastructure as well as affordable and clean energy. To satisfy these societal needs, wind energy plays a considerable role and an overall functionality of wind turbines is essential. Taking into account the current age of the installed onshore wind turbines in Germany, elongated service life and economic further operation are indispensable. The application of local concepts, such as the Two Stage Model, enables elongated service life by a detailed consideration of structural and fracture mechanics input parameters. For these advanced assessment methods, amongst others, material characterization is needed for a more accurate lifetime prediction. The required cyclic material properties are usually derived by time‐consuming incremental step tests. In this paper, simplified approaches for the cyclic material characterization, such as the easy‐to‐use Hardness Method, are presented as an alternative. The applicability of the Hardness Method is demonstrated by a proof‐of‐concept study for structural steels and butt welds to determine the cyclic material properties. The study proves the potential of the easy‐to‐use Hardness Method for local concepts, such as the Two Stage Model.