Ultimate Load Analysis and Design of the Jacket-Type Offshore Wind Turbine under Extreme Environmental Conditions

Abstract

Since there is high risk of typhoons for structural damage in Taiwan the offshore site design conditions shall include the occurrence of typhoons The objective of this thesis was to carry out ultimate load analysis and optimum design of a jacket-type support structure of an offshore wind turbine under extreme environmental conditions To study the environmental characteristics of the offshore wind turbine site we chose the environmental data measured at Hsinchu buoy station and Waipu tide station as the basis of preliminary analysis The external conditions and the design load cases to be considered in this study were based on the requirements of IEC 61400-3 or GL Tropical Cyclone Technical Note In the calculation of aerodynamic loads TurbSim and FAST v8 software provided by National Renewable Energy Laboratory (NREL) were used to simulate stochastic inflow turbulence and to analyze the dynamic response of the NREL 5-MW offshore wind turbine respectively For hydrodynamic loads the Morison’s equation was used to calculate the wave and current induced loads on the support structure where fluid particle velocity and acceleration were obtained by using the stream function wave theory and the second-order kinematics model After the finite element analysis the results of the ultimate loads acting on the support structure for each design load case were discussed Finally we conducted the optimum design of the jacket-type support structure for evaluating total design steel weights by using the API RP 2A-LRFD standard and the results may be used as the basis of construction cost estimation Note that the computer programs developed by the research team of Shen-Haw Ju are open and free to use

Date of Award	2017 Jun 15
Original language	English
Supervisor	Shen-Haw Ju (Supervisor)