Failure of a wind turbine tower under extreme dynamic loads

In order to study and compare failure modes of a wind turbine tower under extreme dynamic loads including wind and seismic loads, a series of nonlinear dynamic time history analyses were performed using a precision finite element model of a typical wind turbine tower built with the software ABAQUS and considering soil-structure interaction and blade modelling. Wind fields were generated using the software Turbsim and wind loads were calculated using the software FAST. The typical ground motion records were selected to be suitable for sites of hard soil. Analysis results showed that most plastic hinges occur at its geometric discontinuous points and the tower faces collapse once a local full-section plastic hinge stably appears; under strong wind, wind energy is concentrated in a lower frequency band, the tower is controlled by its fundamental mode and collapse occurs at its bottom; under strong earthquakes, ground motion energy is concentrated in a higher frequency band, the tower is affected by its higher modes; although plastic hinges firstly appear at its bottom, full-section plastic hinge and collapse are located at the tower's middle or upper part, and different natural ground motions may cause different collapse positions. © 2019, Editorial Office of Journal of Vibration and Shock. All right reserved.