Open AccessAnalytical Solution for Monopile Supported Offshore Wind Turbines Considering Soil-Pile-Water Interaction
Author(s) -
Piguang Wang,
Yifu Chang,
Mi Zhao,
Renqiang Xi,
Chao Zhang
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/719/4/042015
Subject(s) - substructure , vibration , natural frequency , structural engineering , pile , soil structure interaction , added mass , offshore wind power , oscillation (cell signaling) , geotechnical engineering , seismic loading , coupling (piping) , geology , engineering , physics , wind power , finite element method , acoustics , mechanical engineering , electrical engineering , biology , genetics
Offshore wind turbines (OWTs) are dynamically sensitive systems and vulnerable to external excitations such as aerodynamic and hydrodynamic loadings. These loadings may lead to excessive oscillation for the support structure of OWTs. Therefore, it is essential to evaluate the natural frequencies of the system to keep them away from excitation frequencies of external vibration sources. This paper investigates the natural frequencies and seismic responses of the OWT system. The soil-structure interaction (SSI) is modelled by three coupled springs and fluid-structure interaction (FSI) is simulated by the added mass. Then a closed-form solution of the natural frequencies is derived to consider the variation of cross-section. Furtherly, seismic responses of the system are obtained by mode superposition method. Effects of SSI, substructure mass and axial loading are finally investigated. The results indicate that substructure mass can significantly decrease the frequencies of the structure while axial loading plays only a small part in the process. SSI has an important effect on the seismic responses of OWTs. It is essential to consider the cross-coupling spring to analyze the seismic responses for accuracy.