Framework for probabilistic calibration of fatigue design factors for offshore wind turbine support structures

摘要

In this paper is described a reliability-based approach to calibrate Fatigue Design Factors (FDF) for offshore wind turbine support structures. The FDFs are calibrated to a specific minimum reliability level and a particular inspection and maintenance strategy. A similar approach has been used for offshore Oil & Gas (O&G) sub-structures. Based on representative stochastic models and response functions a set of FDF values are calculated which depend on the degree of accuracy of the fatigue analysis and the consequences of fatigue failure of a critical detail. Generally lower FDF values are obtained for offshore wind turbines than for oil & gas structures and reduced FDF values are obtained when inspections are taken into account. Thereby the basis is available for selecting a cost-effective fatigue design for offshore wind turbines substructures. Further, the results can be used as basis for recommendations in standardization.