Modal analysis for optimal design of offshore wind turbine blades

International audienceThroughout their operating life, offshore wind turbine blades are subjected to considerable wind forces. In order to ensure their durability and strength the intrados and extrados are bounded around spars, which are the skeleton that provide the necessary rigidity to the blade. Wind turbine blades are complex structures given the various scientific fields involved in their study, from aerodynamic to composite fatigue and failure analysis. Wind turbine blade is under coupled process of forces, so when we have the same natural frequency for the blade and exciting forces, the resonance is occurred. Which make the modal analysis of the blade of great importance, hence the scope of the present work, which deal with determining, the natural modes shapes and frequencies of three spars forms during free vibration, as well as for a 5MW horizontal axis floating wind turbine blade, to prevent and avoid resonance effect, using ABAQUS Finite element analysis software. The results show that the resonance effect does not occur for the blade and the proposed layup model provide enough resistance to the structure