Horizontal Axis Wind Turbine Blade Finite Element Design Modeling with Structure and Vibration Modal Analyses to Optimize Wind Power for Offshore Applications

Offshore wind farms are subject to complex stresses with respect to the wind influence on the turbine blades. When air flows through the airfoil surface of a wind turbine blade's element profile, the relative wind velocity causes the aerodynamic forces (axial and tangential) to act upon blade-element. This article presents axial induction factor "a" and the tangential induction factor "b" of the Wilson design, depending on the blade element momentum theory to deduce the blade's spanwise force distribution. The aerodynamic analysis has been performed at the blade with wind having a velocity of 12m/s. The pressure produced at the blade surface is evaluated. Structural analysis is presented from imported CFD pressure load at a rotational speed of 21 rpm. In contrast, the blade's finite element model analysis was performed combined with aerodynamic force to obtain the vibration pattern. It is concluded that the blade's axial force increased linearly with the increase of the "r" radius, which mainly affects the wave vibration. The blade's tangential force increases initially and decreases with the rise of the "r" radius, which primarily affects the shimmy vibration. The combination of aerodynamics forces, pressure distributions, and structural vibration analysis provides an absolute reference for the subsequent design optimization of the wind turbine blade and its power.