Wind, wave and earthquake responses of offshore wind turbine on monopile foundation in clay

This paper investigates the dynamic responses of offshore wind turbine (OWT) supported on monopile foundation in clay subjected to wind, wave and earthquake actions. Based on the open-source software platform OpenSees, a three-dimensional finite model of the system is developed. The tower and monopile is modeled using beam element, the pile-soil interface behavior using nonlinear Winkler foundation approach, and the pile-water interface using hydrodynamic added mass. The wind, wave and earthquake actions are applied as loadings on the system. The effects of several parameters, such as wind velocity, induction factor, wave period, peak ground acceleration, and soil parameters on the dynamic responses of the system are studied. The results indicate that it is necessary to consider the combination of wind, wave and earthquake actions in the design of offshore wind turbine.