Designing durability into large rotor blades
European funding has been earmarked to help the wind energy industry meet the increasing demand for carbon-free energy production from Renewable Energy Sources like the wind. The desire to build bigger systems must first be preceded by research programmes to ensure reliability throughout the system's lifetime. The OPTIMAT BLADES project brought together 17 wind turbine manufacturers, academic institutions and research institutes from eight different EU Member States. Over four years of research culminated in a comprehensive report with nearly 40 specific design recommendations for blade manufacturers. The report's author, Det Norske Veritas (DNV), summarised the results of the 3000+ tests performed during OPTIMAT BLADES. Various blade designs using advanced materials such as Glass Fibre Reinforced Polyester (GFRP) were evaluated for their strength, stiffness and a number of other characteristics. The results were compiled in the OptiDAT database. Current industry practice regarding issues such as repairs, strain rate effects, variable amplitude loading, complex stress states, Constant Life Diagrams, etc. is reviewed in detail. Subsequently, proposals are made based on the OPTIMAT BLADES results. DNV and its partner Germanischer Lloyd (GL) intend to incorporate these recommendations in their future design guidelines.
