ABSTRACT
Wind turbines operate under various loading conditions in stochastic weather environments. The increasing size and weight of components of utility-scale wind turbines escalate the loads and thus the stresses imposed on the structure. As a result, modern wind turbines are prone to experiencing structural failures. Of particular interest in a wind turbine system are the extreme events under which loads exceed a threshold, called a nominal design load or extreme load. Upon the occurrence of a load higher than the nominal design load, a wind turbine could experience catastrophic structural failures. To assess the extreme load, turbine structural responses are evaluated by conducting physical field measurements or performing aeroelastic simulation studies. In general, data obtained in either case are not sufficient to represent various loading responses under all possible weather conditions. An appropriate extrapolation is necessary to characterize the structural loads in a turbine’s service life. This chapter focuses on the extreme load analysis based on physical bending moment measurements. Chapter 11 discusses load analysis based on aeroelastic simulations.
