Offshore wind turbine nonlinear wave loads and their statistics
Name
1117714042-MIT.pdf
Size
9.11 MB
Format
Adobe PDF
Checksum (MD5)
1f4d064d8e1ca23fda34ebc301662d5e
Author(s)
Zhang, Yu,Ph.D.Massachusetts Institute of Technology. Department of Mechanical Engineering.
Advisor(s)
Paul D. Sclavounos.
Date Issued
2019
Publisher
Massachusetts Institute of Technology
Abstract
Due to the large influence of lateral flexible vibrations on offshore wind turbine foundations and the higher natural frequencies of the offshore wind turbine foundation relative to the dominant frequencies of the linear wave load model, the modeling of the dynamic behavior of the foundation under nonlinear wave loads and analysis of their statistical characteristics have become an important issue for offshore wind turbine design. This thesis derives an approximate model of the nonlinear wave loads in the time domain by Fluid Impulse Theory, verifies it with a boundary element method software WAMIT and validates it with experimental measurements. The load level crossing rates and the load power spectral density is obtained in multiple sea states. The simulated nonlinear wave loads are applied as the forcing mechanism on the offshore wind turbine and its foundation, and the mudline bending moments are computed and compared with experimental measurements. The system identification is conducted by fitting the model with the experimental data using linear regression method. The analytical extreme and fatigue prediction of the offshore wind turbine system are derived and evaluated in waters of finite depth and in multiple seastates. Key words: Nonlinear wave loads, nonlinear wave loads statistics, system identification, extremes and fatigue
Description
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 83-86).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
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