Lightweight wind turbine blades play a crucial role in improving wind turbine technol- ogy. They enforce lower loads on the overall system, making material and cost sav- ings possible. Also, increasingly longer blades can be used, enabling more efficient, economically viable turbines. This thesis investigates how the mass of a rotor blade can be reduced without compromising its structural integrity. The work is based on the OLW934 blade from Olsen Wings A/S. Its mass is reduced using a comprehensive optimization framework .

A structural and aeroelastic optimization process was applied using the gradient-based AESOpt algorithm, finite element analysis (FEM), and aeroelastic checks with HAWC2S. The framework reduced the blade’s mass by 35% while keeping its structural integrity. The redesigned blade was found with improved internal structure and layup. Since the optimization mainly focused on the structure, the aeroelastic performance was checked manually throughout the process. Due to stiffness assumptions in the tip re- gion, no definite validation on the aeroelastic stability of the turbine with the redesigned blade has been found yet, but the results indicate sufficiency.

This behaviour should be verified. Also, the internal structure setup, especially the spar caps and shear webs, should be studied in more detail, as only initial design con- siderations were explored. Additionally, varying initial layup regions and evaluating alternative material options could yield further improvements. Still, the results show that the structural optimization framework used can significantly reduce blade mass and can be applied to other designs. This supports the development of lighter blades and better turbine performance.