Modelling the seismic soil-structure interaction for wind turbines using simple physical models

The dynamic interaction between the structure, the foundation and the underlying soil has a relevant influence on the global dynamic behavior of wind turbines and can affect its functionality. The Soil-Structure Interaction (SSI) effects can be estimated with numerical models. As in many other application of civil engineering, the simulation of tower-like buildings can be conducted by means of idealized one-dimensional dynamic systems. Usually, these structures are modeled as cantilever beam elements, fixed at the base. However, it is important to include the effects of the elastic soil on the dynamic response of wind turbines in the modeling process, keeping the computational time affordable and the model reliable. In this contribution, we present a practical semi-analytical model for the estimation of the SSI response of wind turbines in the frequency domain. We show a validation of the implementation in Matlab through benchmark problems. Finally, we demonstrate its use analyzing the influence of soil stiffness, soil layering, foundation embedment and variations in the seismic input on the seismic response of wind turbines.