Abstract: Excessive wind turbine blade weight not only affects the structural performance of the blades, but also increases transportation, maintenance and other costs. In order to solve the problem of blade quality, a classic 1.5 MW composite wind turbine blade is selected, and different composite materials are laid in the spar cap, shear web, leading edge and trailing edge of the blade. Due to the laying thickness of the composite material decreases from the bladed root to tip, the failure location is mostly located at the bladed root. Therefore, about 1/3 of the distance from the bladed root was taken as the research object to simplify the problem, and the composite wind turbine blade model was constructed by ANSYS APDL parametric design in order to facilitate optimization. Considering the situation of falling into local optimum, subset simulation optimization method is selected for random optimization. The design variable is the shear web position, and the constraint function is that the blade displacement and the Tsai-Wu criterion are within a reasonable range under the limit load, with the goal of the smallest blade weight. Through the simulation optimization results of 30 sets of subsets, it shows that when the shear web position is about 29.4% and 53.3% of the chord length, compared with the deterministic design, the weight of blade is reduced by about 15.4%. The final results show that the optimization method is feasible in the optimization of wind turbine blade structure, and the optimization results have reference value for engineering design.

Key words: wind turbine blade, composite materials, ANSYS, structural optimization, subset simulation