Estimation of dynamic characteristics of a wind turbine blade

Abstract

Wind energy is considered a clean source of energy that can be used efficiently to produce electricity without any harmful emissions. A wind turbine is an electro-mechanical system that converts the wind's kinetic energy into electricity. A typical wind turbine consists of three components, viz. the rotor (which includes the turbine blades), generator and the supporting structure. The turbine blades are a critical component of any wind turbine. They comprise of numerous airfoil sections with varying chord lengths and twist angles, that are combined together to form a three-dimensional blade surface. When generating electrical power through rotating motion, they are subjected to different loads, such as wind, gravitational, and centrifugal loads. The sheer size of the turbine blade necessitates the use of light and strong materials, and composites are well suited for this. The selection and manufacturing of suitable composite material is critical to blade design as it directly affects the efficiency and power of wind power plants. With blades that are continuously exposed to large wind loads, it is essential to determine the natural frequencies of vibrations at which they occur and understand the consequences. Large amplitude vibrations can induce dynamic stresses and accelerate the fatigue of the blade material leading to blade breakage. Thus, it is of significant importance to analyse the dynamic behaviour of these structures. This study aims to investigate the effect of varying fiber orientation and volume fraction on natural frequencies and vibration modes of the turbine blade.