Nonlinear dynamics of a wind turbine tower

The recent diffusion of wind turbines has evidenced problems about their vulnerability in different site conditions, as shown by recent collapse of wind towers after severe actions. The analysis of structures subjected to variable actions can be carried out by means of several methods with different levels of accuracy, among which the nonlinear dynamics is generally recognized as the most reliable one. This paper develops a numerical procedure to obtain approximate solutions for rigid-plastic response of structures subjected to base harmonic pulse. The model is applied to a wind turbine tower subjected to inertia forces generated by an harmonic ground acceleration, in which the failure is assumed depending on the formation of shear hinges. The approach presents the advantages of rigid-plastic procedures, in particular an efficient representation of the post-elastic behaviour of the structure, low computational competence and limited number of mechanical parameters.