Abstract
Stochastic dynamic analysis of an offshore wind turbine (OWT) structure plays an important role in the structural safety evaluation and reliability assessment of the structure. In this paper, the OWT structure is simplified as a linear single-degree-of-freedom (SDOF) system and the corresponding joint probability density function (PDF) of the dynamic response is calculated by the implementation of the path integration (PI) method. Filtered Gaussian white noise, which is obtained from the utilization of a second-order filter, is considered as horizontal wind excitation and used to excite the SDOF system. Thus, the SDOF model and the second-order linear filter model constitute a four-dimensional dynamic system. Further, a detailed three-dimensional finite element model is applied to obtain the natural frequency of the OWT and the efficient PI method, which is modified based on the fast Fourier transform (FFT) convolution method, is also utilized to reduce the execution time to obtain the PDF of the response. Two important parameters of wind conditions, i.e., horizontal mean wind speed and turbulence standard deviation, are investigated to highlight the influences on the PDF of the dynamic response and the reliability of the OWT.
Highlights
Wind energy has been playing an increasingly important role lately regarding the successful transition from fossil fuels to renewable energy [1]
offshore wind turbine (OWT) subjected to horizontal stochastic wind excitation, which can be defined with respect to the during the discussion, while the parameters of wind conditions change according to specific cases
An effective and accurate path integration (PI) method, based on Markov properties and fast Fourier transform (FFT) convolution, was implemented to study the stochastic dynamic response of an offshore wind turbine (OWT) structure supported by a bucket foundation under horizontal stochastic wind excitation
Summary
Wind energy has been playing an increasingly important role lately regarding the successful transition from fossil fuels to renewable energy [1]. As in the ocean environment, an offshore wind turbine (OWT) structure is always excited by various random excitations, such as wind, waves, and currents, which all pose a great threat to the structure. Code-based designs such as IEC [12], DNVGL [13], and CCS [14] utilize deterministic methods to predict the structural dynamic response. In this regard, the stochastic dynamic response of the OWT can be obtained by one or several deterministic loads or excitations. In many practical structures, a perfect deterministic behavior cannot be guaranteed, because of unpredictable excitation, and because of various uncertainties in Energies 2019, 12, 3051; doi:10.3390/en12163051 www.mdpi.com/journal/energies
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call