Physical experimental static testing and structural design optimisation for a composite wind turbine blade

This study presents experimental testing on a 13 m long glass-fibre epoxy composite wind turbine blade. The results of the test were used to calibrate finite element models. A design optimisation study was then performed using a genetic algorithm. The goal of the optimisation was to minimise the material used in blade construction and, thereby, reduce the manufacturing costs. The thickness distribution of the composite materials and the internal structural layout of the blade were considered for optimisation. Constraints were placed on the objective based on the stiffness of the blade and the blade surface stresses. A variable penalty function was used with limits derived from the blade test and the structural layout of the turbine. The model shows good correspondence to the test results (blade mass within 6% and deflection within 9%) and the differences between test and model are discussed in detail. The genetic algorithm resulted in five optimal blade designs, showing a reduction in mass up to 24%. Structural modelling in combination with numerical search algorithms provide a powerful tool for designers and demonstrates that the reader can have confidence in the claimed potential savings when the reference blade models are calibrated against physical test data.