Dynamic Analysis of an Offshore Wind Turbine: Wind-Waves Nonlinear Interaction

An offshore wind turbine can be considered as a relatively complex structural system since several environmental factors (e.g. wind and waves) affect its dynamic behavior by generating both an active load and a resistant force to the structure's deformation induced by simultaneous actions. Besides the stochastic nature, also their mutual interaction should be considered as nonlinear phenomena could be crucial for optimal and cost-effective design. Another element of complexity lies in the presence of different parts, each one with its peculiar features, whose mutual interaction determines the overall dynamic response to non-stationary environmental and service loads. These are the reasons why a proper and safe approach to the analysis and design of offshore wind turbines requires a suitable technique for carrying out a structural and performances decomposition along with the adoption of advanced computation tools. In this work a finite element model for coupled wind-waves analysis is presented and the results of the dynamic behavior of a monopiletype support structure for offshore wind turbine are shown. © 2010 ASCE.