Calculation of dynamic stresses acting on wind turbine blades using finite element method

Abstract

The aim of this work is the calculation of dynamic loads and stresses acting on wind turbine blades. Theprediction of the dynamic behaviour of the blades constitutes is one of the most important processes in the design of wind turbines. Initially, the blade element theory was used to calculate aerodynamic loads applied on the rotor. This method can be also used to estimate the power coefficient and the total power extracted by the turbine. A modal analysis of the rotor was carried out in order to compute the frequencies and the mode shapes of the blades. This analysis is useful for estimating dynamic loads. Finally, the dynamic stresses were calculated for the root region of the blades using finite element modelling. The resulting curves of stresses versus time, obtained for different wind speeds, may be utilized in a latter study for fatigue analysis, in order to make an optimal choice of blades resistant tofatigue and being energetically efficient.