DESIGN OPTIMIZATION OF SMALL WIND TURBINE BLADE BASED ON STRUCTURAL AND FATIGUE LIFE ANALYSES

Abstract

In this study, a horizontal axis wind turbine blade model with a power of 5 kW was designed using a new MATLAB code based on the blade element momentum theory. The three-dimensional finite-element method was used to simulate and validate the wind turbine blade under normal and extreme operating conditions in order to evaluate the stress and deflection effects. International Standard IEC 61400.2 was applied to obtain the fatigue loads, estimate the damage, and predict the life of the blade. Based on the optimization approach, the flap-wise deflections were reduced by 11% and the trailing and leading edges were reduced by 31%. Based on the optimized design of the blade, the mass of the blade was reduced by 22%. Furthermore, the fatigue life of the blade was investigated and analyzed, in which the simplified load model (SLM) and the aeroelastic FAST software program were employed to predict the lifetime of the blade. Finally, it was found that based on the SLM method the design life of a 5-kW blade is 20 years when carbon fiber material is used.