Abstract: The extending blades of wind turbine is the most effective way to improve the annual power generation in low speed wind. At present, the connection of the blades and extension is generally achieved by structural adhesive. The fatigue performance determines the stability of extending blades, and an efficient and accurate analysis method is especially important for engineering application. To this end, the shell element, the solid element, the shell & solid element model are built by the finite element method. The results show that the strain equivalent shear stress method is conservative, and the shell & solid element model is a relatively efficient and exact method for analyzing wind turbine blades extension structural adhesive fatigue strength. Based on this method, the fatigue strength of wind turbine blades extension structural adhesive is satisfied with GL 2010.

Key words: wind turbine blades extension, structural adhesive, fatigue strength, solid element, finite element, composites