Numerical Investigation of Soil-Structure Interaction for Onshore Wind Turbines Grounded on a Layered Soil

The present thesis aims to model and evaluate Soil-Structure Interaction (SSI) issues for the dynamic response of onshore wind turbines grounded on a layered soil. The recent growth of wind energy installations has provoked a rapid expansion into regions where the soil conditions may be complex and the seismic risk high. Numerical simulations are of crucial importance for predicting unfavorable effects due to the interaction between the wind turbine, its foundation and the underlying layered soil. This investigation focuses on a 3-blade wind turbine grounded on a stratified half space. In the first part, the harmonic response of the structure-soil system is analyzed with the accurate coupling between the Finite-Element and the Boundary-Element Method (FEM/BEM). The second part presents the transient response of a 5-MW reference turbine subjected to aerodynamic and seismic loads, considering SSI effects. Here, Lumped Parameter Models (LPM) for the foundation-soil system are implemented as a simplified alternative. The suitability of the LPM is proved by means of comparisons with the FEM/BEM approach. The influence of several parameters is evaluated, in order to provide a range of values for which the SSI has to be accounted for. The final purpose of this study is to gain a deeper understanding of SSI effects for layered soils in seismic areas, thus contributing to a more reliable performance assessment and cost estimation.      «

The present thesis aims to model and evaluate Soil-Structure Interaction (SSI) issues for the dynamic response of onshore wind turbines grounded on a layered soil. The recent growth of wind energy installations has provoked a rapid expansion into regions where the soil conditions may be complex and the seismic risk high. Numerical simulations are of crucial importance for predicting unfavorable effects due to the interaction between the wind turbine, its foundation and the underlying layered soi...     »