Dynamic structural analysis and fatigue assessment of wind turbine towers

Resumo

The wind energy has been very promising because it is inexhaustible energy of low environmental
impact. Based on the increasing demand on renewable and clean energy, the wind turbine design has advanced
significantly in terms of its size and type. In Brazil, considering this advance, the conventional conical steel
tower is a predominant type of supporting structure. Proper consideration of all the aspects before mentioned
pointed out our team to develop an analysis methodology with emphasis to evaluate the stresses through a
dynamic structural analysis of a typical wind turbine supporting steel tower, including the nondeterministic wind
actions. Thus, this research works aims to study the dynamic non-deterministic structural response and evaluate
the service life of a steel tower to be used as a support for a wind turbine model type MM-92 from Repower. In
this investigation, the numerical model developed for the structural analysis of the tower adopted the usual mesh
refinement techniques present in Finite Element Method (FEM) simulations and implemented in the ANSYS
program. The analysis of the non-deterministic dynamic response of the tower is performed for several wind
velocities, having in mind a critical evaluation about the maximum values obtained for the Von Mises's stresses
and the service life of the investigated structure. Finally, the results obtained along this study are evaluated and
compared with the limit values recommended by international design codes and recommendations.