Numerical Estimation of Fatigue Life of Wind Turbines due to Shadow Effect

The influence of tower design on damage accumulation in up-wind turbine blades during tower passage is discussed. The fatigue life of a blade is estimated for a tripod tower configuration and a standard mono-tower. The blade stresses are determined from a dynamic mechanical model with a delay effect included in the normal coefficient used to compute the transverse load. Furthermore, the rotational effect of the turbulence spectrum is included in the model. The proposed tripod configuration of the tower limits the damage accumulation in the turbine blades significantly when compared to the fatigue of a blade from a monotower wind turbine.The influence of tower design on damage accumulation in up-wind turbine blades during tower passage is discussed. The fatigue life of a blade is estimated for a tripod tower configuration and a standard mono-tower. The blade stresses are determined from a dynamic mechanical model with a delay effect included in the normal coefficient used to compute the transverse load. Furthermore, the rotational effect of the turbulence spectrum is included in the model. The proposed tripod configuration of the tower limits the damage accumulation in the turbine blades significantly when compared to the fatigue of a blade from a monotower wind turbine