Static Strength Design of Small Wind Turbine Blade Using Finite Element Analysis and Testing

Abstract

Today, wind power has become the most accepted renewable energy source and contributing major share in renewable energy market. Large wind turbines are now producing power effectively and delivering satisfactory performance to satisfy researchers, scientists, investors and governments. Large wind turbine technology has achieved respectable position across the globe. In addition to large wind turbine technology, it is observed that small wind technology has started movement toward a satisfactory growth. A considerable growth is forecasted by many experts in coming decades. The small wind turbine technology can be accepted by market if industry will provide small wind turbines with good desirable characteristics. Self starting behavior at a low wind speed, affordable compatible cost, maintenance free wind turbine system, low weight, reliable and satisfactory performance in low wind will always receive significant attraction of people for various applications. Low weight tower-top system and hence supporting structure, light weight and efficient generator, rotor’s ability to efficient wind to mechanical energy conversion and components manufacturing simplicity are also always expected by wind turbine users. This work is one of the attempts to design and develop a blade for small wind turbine in the line of objectives stated. Wind turbine blade is most important element in wind turbine system which converts wind energy in to mechanical energy. In addition to efficient aerodynamic blade design its strength design is also important so that it can withstand against various loads acting on it. Wind turbine blades strength has been analyzed by different researchers by conducting their static and fatigue testing. The objective of present work is to perform static strength test for newly developed blade of 1.5 m length. This newly developed blade consists of two new airfoils. A thick airfoil is used at the root and thin airfoil is used for remaining sections. The different loads acting on the blade are calculated using Blade Element Momentum theory at survival wind speed. It is decided to manufacture this blade using glass fiber reinforced plastic. The properties of material combination used are determined as per ASTM norms. The computational strength analysis is carried out using ANSYS. During this analysis blade is considered as a cantilever beam and equivalent load is applied. The blade is also tested experimentally using strain gauges. From both result analyses, it is found that developed blade is capable to take various loads acting on wind turbine blade at survival wind speed.