Dynamic behavior of operational wind turbines considering aerodynamic and seismic load interaction
"With the advancements in the wind energy production industry, the demand for a cost effective and safe design of wind turbine structures is growing rapidly. The wide deployment of wind turbines in locations with high seismic hazard has lead engineers to take into account a more comprehensive seismic design of such structures. In response to the need for a computational tool that can perform coupled simulations of wind and seismic loads, a seismic module has been developed for the publicly available National Renewable Energy Laboratory (NREL) code, FAST, at the first step of this research. This achievement allows engineers working in this industry to directly consider interaction between seismic and other environmental loads for turbines with a freely available simulation tool. The first paper details the practical application and theory of these enhancements and provides examples for the use of different capabilities. The platform is then used to show the suitable earthquake and operational load combination with the implicit consideration of aerodynamic damping by estimating appropriate load factors. In the next step, the developed platform is used to evaluate the effects of aerodynamic and seismic load coupling on the power generation and structural dynamics behavior of wind turbines. Various turbine operation scenarios such as (i) normal operational condition, (ii) idling, and (iii) earthquake induced emergency shutdown are simulated to show the differences in generated power and dynamic response of wind turbine structures. The effects of aerodynamic damping and pitch control system are presented which show reduction in the resulting design demand loads. In the last step, a finite element model of the turbine which is calibrated with the previously implemented code is used to evaluate the fragility of wind turbines under seismic and wind excitation. This is obtained by the assessment of nonlinear dynamic behavior of a 5-MW NREL wind turbine considering different earthquake and wind intensities using the finite element model. Engineering Demand Parameters (EDP) and Intensity Measures (IM) are then obtained from Incremental Dynamic Analysis (IDA) and used to assess the probability of exceeding different Damage States (DS) using fragility curves."--Abstract, page iv.
Aerodynamic and Seismic Load Interaction, Buckling and Fragility Analysis, Finite Element Method and Nonlinear Dynamic Analysis, Structural Dynamics and Seismic Response, Civil Engineering, Sustainability
Missouri University of Science and Technology
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