AbstractThe design of a wind turbine system (sizing, control) according to specifications in terms of quality of produced electricity, stability and safety, needs the use of performing simulation tools able to change from simple static calculations assuming a constant wind to dynamic simulation that, from the unsteady aerodynamic loads, models the aero elastic response of the entire wind turbine system, including blades, tower, drive train, rotor and control system. In the paper, a bond graph model of a blade is proposed. It consists in considering the blade as a Rayleigh beam composed of a number de sections submitted to aerodynamic forces calculated using the BEM theory. The model is validated using data from a NACA 4415 blade profile.