Community Research and Development Information Service - CORDIS

Development of advanced blades for wind turbines

A wide ranging study of advanced blade components for wind turbines has generated a significant amount of important data that will improve the design and manufacture of wind turbine blades. This, in turn, will help increase the competitiveness of the European wind turbine industry in the world market. The consortium of 14 partners investigated five discrete research topics. These were: improved structural design of wingblades; advanced wing blade manufacturing; exploitation of wood composites for wingblades; exploitation of glassfibre/epoxy composites for large wing blades; and, guidelines and norms for design of wing blades. Five working groups, each comprising an industrial partner and several research partners, were established to conduct research on each topic. Four working groups were led by leading blade manufacturers in Europe, so tasks were defined, focused and of direct industrial interest. The response of materials and structures to fluctuating loads is the key to the structural design of blades. Four aspects were therefore considered in-depth: durability under different types of loading; creep/fatigue in wood composites; degradation under repeated loading; and, data analysis and development of design guidelines. All materials under test were characteristic of those used in existing or proposed blade designs. Three blade components (steel studs in glass and wood composites and a carbon composite blade) were extensively tested for degradation and modes of failure during loading. The varied construction of the blade root, a critical structural part of a rotor blade, was also reviewed. Results from the fatigue testing of the materials have enabled "stiffness controlled fatigue curves" for glass fibre composites and glass/carbon fibre composites to be established, allowing designers to make better choices between materials. Results of component testing showed that degradation was difficult to detect in the studs and blade, until the loads became much higher than the design loads. Results from the blade tests were used to improve an earlier prototype blade, whilst the blade root review showed the most cost effective construction to be the "post-bonding" stud concept. Finally, the project proposed a methodology to allow turbine manufacturers to conform with the European Union machinery directive and label turbines with the CE mark.

Reported by

Risø National Laboratory
4000 Roskilde
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