Investigation of Soil–Structure Interaction Effects on Seismic Response of a 5 MW Wind Turbine

This paper investigates the seismic behavior of a wind turbine, including soil–structure interaction (SSI). A full-system finite-element model is introduced for dynamic analysis, including SSI. The model is based on the NREL 5 MW reference wind turbine that consists of a rotor blade system with three rotating blades, nacelle, and tower connected to a soil–foundation system. The proposed model is validated using the full-system natural frequencies of the reference wind turbine. In the soil foundation system, the foundation is modeled as a rigid gravity-based foundation with two DOFs and the SSI effect is considered using a cone model. Dynamic analyses are developed in frequency and time domains, and the model is subjected to earthquake excitation and wind loading for different soil types for parked and operational conditions. Transfer functions are obtained, and the modal frequencies of the soil foundation structure system are estimated. Results show that SSI plays an important role in the response of the wind turbine. We can conclude that for a parked wind turbine, the effect of SSI is beneficial while considering that SSI has a detrimental effect in the operational conditions of wind turbine. The participation of different input loads in total response of an operational wind turbine is also presented.