Multihazard Assessment of Wind Turbine Towers under Simultaneous Application of Wind, Operation, and Seismic Loads

Wind turbines are widely recognized as a renewable energy resource and as such, their safety and reliability must be ensured. Many studies have been completed on the blade rotor and nacelle components of wind turbines under wind and operation loads. While several studies have focused on idealized wind turbine models of the towers, significant advancements on the local behavior and global performance of these models under seismic loads in combination with other loads has been lacking. In this study, realistic numerical models are developed and used to evaluate the performance of wind turbines with various height under wind, operation, and seismic loads. Global performance parameters include drift ratios, normalized base shear, and turbine stability during operation. Localized behavior focuses on the welded connection at the base of the turbine and includes assessment of yielding at the tower base as well as the potential for the development of low-cycle fatigue failures. Several analyses indicated yielding at the turbine base and resonant conditions. The results from these analyses identify several critical issues within the wind turbine design and operation protocol and can aid in the design of future wind turbines.