Dynamic Response Analysis Of Offshore Wind Turbines’ Support Structure With Four Piles

As an initiatives environmentally responsible development, offshore windturbine structural system is accompanied by a growing number of practicalengineering problems. Therefore, dynamic response analysis of offshore wind turbinestructural system under environmental loads has important reference value andengineering significance.Wind loads and wave loads are very important components of complex offshoreenvironmental loads. Once occurred, they will have a great effect on offshore windturbine structural system. Thus it is essential for simulation of the force analysis onoffshore wind turbine structural system to determine rationally forms and sizes ofwind loads and wave loads firstly. After that, in view of the engineering practicalproblems, analysis of offshore wind turbine structural system’s dynamic response willbe done under environmental loads, which represents the completeness of safetyassessment of offshore wind turbine structural system.In this paper, dynamic response analysis of offshore wind turbines’ supportstructure with four piles under wind loads and wave loads based on practicalengineering in sea area of Zhuhai, and the mathematical model of structural system isestablished by measured data and actual working conditions. The main measures areas follows:First of all, five-order Stokes wave theory is applied in this paper. Morisonformula is adopted in simulation of the force on support structural jacket portion fromwave current in the downstream. For different wave height and velocity of sea waves,phase angle for acting on the structure with maximum wave force are calculated. Theresults are used as the input conditions for structure static analysis with ANSYSsoftware. To find the maximum stress parts of the structure and observe the effect ofdifferent phase angel on wave and current loads acting on the supporting structure.Then the paper uses the linear filtering method. A MATLAB program was made based on Davenport spectrum to simulate fluctuating wind load in the actual studyarea, comparing the experimental spectra with target spectra. The instantaneous windspeed result is attained by adding fluctuating wind load time-history and average windspeed.80m support structure Tower is divided into20segments. Then I convert theinstantaneous wind speed time-history to wind loads time-history acting on Towerwith Wind Pressure Formula.Finally the finite element method is used on performance for model analysis onoffshore wind turbines’ support structure with four piles. Nonlinear spring is adoptedto simulate the interaction between foundation and soil; And based on the modalanalysis, ANSYS software is used to analyze the dynamic response of the structureunder wind loads and wave loads alone, and compare node displacement and stress ofsupporting structure under two different loads. Then I analyze the dynamic responseof the support structure under separate loads and combined loads, which is thecombination of wind loads and wave loads.The main purpose of this paper is to find the displacement maximum and stressmaximum through analysis of dynamic response of support structure under windloads and wave loads separately, and compare the results under different loads todetermine the control environment loads on offshore wind support structure in thelocal waters. Then I make analysis of the dynamic response of the structure undercombined loads. It provides evidence for dynamic analysis of support structure undercoupled with environmental loads. And also offers referential analysis conclusions tothe design of the offshore bucket foundation and turbine in the complex marineenvironment.