Nonlinear seismic performance of a large-scale vertical-axis wind turbine under wind and earthquake action

Vertical-axis wind turbines (VAWTs) are being regarded as a complementary technology to the more commercially used horizontal-axis wind turbines (HAWTs). This paper investigates the dynamic response and the collapse pattern of a 1 MW VAWT under the wind and earthquake action. A refined numerical model of the VAWT with three straight blades is created using the finite element (FE) method, and the combined kinematic-isotropic material hardening model is adopted to describe the material nonlinear behavior of the turbine tower. This FE modeling method is validated against a nonlinear pushover test. Two earthquake sets that contain 20 near- and 20 far-field earthquakes are selected as the inputs, and the aerodynamic loads are also calculated for the turbine under the rated wind speed. Time-history dynamic analyses are conducted to compare the nonlinear seismic performance of the operational turbine under the selected earthquakes. The results show that the average fore-aft and side-side displacements at the tower top excited by the near-field earthquakes are 35.3% and 20.1% larger than those excited by the far-field earthquakes. Additionally, the near-field earthquakes are prone to cause the yielding, buckling and collapse of the operational wind turbine. The collapse analyses indicate that the exact failure locations of the tower cannot be predicted by the 1st-order mode pushover analysis, and the failure height triggered by the near-field earthquakes is usually higher than that by the far-field earthquakes.