Challenges for tower structures of multi-megawatt class wind turbines
Abstract eng: Wind energy is already significant and will become even more important among the renewable energies in the future. The development of multi-megawatt class wind turbines provides new challenges for the tower and foundation structures. Typical tower heights of modern wind turbines are between 100 m and 160 m. The towers are usually made of steel. However, hybrid towers consisting of a prestressed concrete part with a steel segment on top are also common due to the high tower heights. For these towers and foundations, the fatigue behavior may become decisive for the design. This paper gives, firstly, a short overview on typical design guidelines for wind turbines and focuses on special requirements for the tower design. Then, steel and hybrid tower concepts of modern wind turbines are presented. The paper particularly focuses on the influence of the fatigue behavior. 1 Design of wind turbine towers Wind energy plays already a significant role among the renewable energies. To continue the significant and sustainable contribution to the energy market, the technical development of wind turbines and the economic aspects are even more important in future. The tower heights of modern wind turbines are usually between 100 m and 160 m and tubular steel towers are most commonly used. In recent times hybrid towers made of a prestressed concrete part with a steel segment on top occur more often to enable higher towers up to 160 m. With these tower heights in combination with bigger rotor diameter profitable wind energy projects can be realized not only in coastal regions but also at low-wind sites in the inland. Due to the large tower heights the realization of wind energy projects represents a new challenge and requires new concepts for tower constructions since these large wind turbines are particularly susceptible to vibrations by design. Wind turbines are designed for a service life time of 20 to 25 years and the whole turbine including tower and foundation has to withstand high dynamic loads. To guarantee the operation of wind turbines the tower design shall be focused on extreme loads as well as on fatigue and dynamic behavior. Compared to other structures wind turbines are exposed to high cycle fatigue loads and high number of load cycles, see Table 1. The number of load cycles is usually in the range of 108 to 109 over the service
Contributors:
Publisher:
Taylor and Francis Group, London, UK
Conference Title:
Conference Title:
Sixth International Conference on Structural Engineering, Mechanics and Computation
Conference Venue:
Cape Town, South Africa
Conference Dates:
2016-09-05 / 2016-09-07
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.
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Record created 2016-09-20, last modified 2016-09-20
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