Abstract: The structure of wind turbine blade is usually shell at the maximum chord region of the trailing edge. It have a large deformation under the wind load, and it is the more frequent damage area. The finite element eigenvalue buckling analysis method is adopted in this paper. We analyzed the effect on buckling factor and blade weight (cost) of several different structure forms about skin design, add ribs and install third web. The relationship between blade weight and the buckling factor under the different structure was compared, in order to find the best stability and cost optimal design scheme. The results show that install third web is the best design scheme of optimal cost, light weight, when the buckling factor is the same.

Key words: wind blade, buckling analysis, structural design, finite element analysis, composite materials