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In order to be competitive in the energy market, the cost of wind power has to be driven down. Current blade designs exhibit a cubic relationship between length and mass. The aim of this project is to improve on this trend by exploring new structural concepts. Optimization techniques and high performance composites are used here as tools to devise novel ideas for the production of longer, more cost e cient blades that deliver cheaper kWh.

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 bendtwist 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.

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