Novel materials and modelling for large wind turbine blades

Abstract

Commercial wind turbines have developed incrementally in size over the last 30 years such that the largest wind turbine up to the end of 2005 had a rated output of 5 MW, a rotor diameter of 124 m, and an individual blade weight of 18 ton. The question therefore arises as to what the ultimate limits on the turbine size might be. Potential design limiting factors in wind turbine design include: static and fatigue strength; overall rotor mass (which has implications for tower head mass, tower structure, and foundations); blade stiffness (required to ensure clearance between the blade tip and the wind turbine tower); blade and tower transportability. The article presents work carried out within the EPSRC SUPERGEN Wind consortium on the potential use of novel materials in wind turbine blades and the resulting consequences on blade strength and integrity. A generalized, parametric finite-element wind turbine blade model has been developed and applied to a ‘baseline’ blade design. Results are presented on static and fatigue strength for new fibre materials and how they can be incorporated into the blade model to demonstrate the likely impact on blade stiffness, strength, and weight. Possible future developments in blade structural design will be discussed in the context of other potential material innovations and ‘smart’ control concepts.