Structural design of a novel aeroelastically tailored wind turbine blade

•The design for a novel adaptive wind turbine blade is presented.•Adapting the blade twist across different wind speeds can improve performance.•The adaptation is achieved by means of spatially varying bend–twist coupling.•The coupling enables the blade sections to twist nose down while bending flapwise.•A complete blade structure is analysed by using refined finite element models.

The structural design for a recently presented aeroelastically-tailored wind turbine blade is produced. Variable elastic twist has been shown to improve performance in response to load variation across different wind conditions. This load variation is exploited as a source of passive structural morphing. Therefore, the angle of attack varies along the blade and adjusts to different operating conditions, hence improving both energy harvesting and gust load alleviation capability, below and above rated wind speed, respectively. The twist variation is achieved by purposefully designing spatially varying bend–twist coupling into the structure via tow steering and using a curved blade planform. This process enables the blade sections to twist appropriately while bending flapwise.To prove the feasibility of the proposed adaptive behaviour, a complete blade structure is analysed by using refined finite element models, with structural stability and strength constraints imposed under realistic load cases. Nonlinear structural effects are analysed as well as modal dynamic features. In addition, the weight penalty due to aeroelastic tailoring is assessed using structural optimisation studies.