Fatigue life estimation of large-scale composite wind turbine blades

The fatigue life of a large-scale 5MW composite wind turbine blade is carried out in accordance with the simplified stress-based fatigue life estimation method recommended by Germanischer-Lloyd regulations. Two kinds of composite layups, ply-level and laminate-level, for the blade are developed and evaluated. The fatigue loads are computed from aero-servo-elastic simulations for the turbine power production conditions as per International Electrotechnical Commission 61400-1 standard. The discrepancy in the estimated fatigue life estimates for the ply-level and laminate-level composite layups is discussed.