Aero-Elastic Stability of Horizontal Axis Wind Turbine Blades

Multi-Megawatt wind turbines have long, slender, and heavy blades that can undergo extreme wind loadings. The aero-elastic stability of wind turbine blades is of great importance in both the power production and the load carrying capacity of structure. This paper investigates the aero-elastic stability of wind turbine blades modeled as thin-walled composite box beam utilizing unsteady incompressible aerodynamics. The structural model incorporates a number of non-classical effects such as the transverse shear, warping inhibition, non-uniform torsional model, and rotary inertia. The unsteady incompressible aerodynamics based on the Wagner’s function is used in order to determine the aerodynamic loads. The governing differential equations of motion are obtained using the Hamilton’s principle, and solved using the extended Galerkin’s method. The results obtained are related to clarification of the effects of angular velocity and wind speed on the aero-elastic instability boundaries of the thin-walled composite beams. The results are expected to be useful toward obtaining better predictions of the aero-elastic behavior of composite rotating blades.