The present work presents a hierarchical Rayleigh-Ritz based model to analyze the aeroelastic response of wind turbine blades. The blade is modeled as a cantilever beam, its structural model takes into account the pre-stress loads induced by centrifugal and gravitational forces. The formulation is based on the Hamilton's principle combined with the Rayleigh-Ritz method. An unsteady aerodynamic model is used to calculate the incremental aerodynamic forces in the frequency domain using Theodorsen's and Loewy's formulations. The solution of the resultant eigenvalue problem is based on the PK method. The occurrence of aeroelastic flutter is observed in ? ? ? and ? ? g by varying the blade rotation and wind velocity. Numerical predictions obtained using the proposed semi- analytical model have been compared with numerical results reported in the literature for the Sandia 100-meter glass made wind turbine blade. An overall good agreement between predictions obtained using the proposed model and results reported in the open literature is found.