Modal Parameter Identification And Projections Of Extreme Vibration Response On Offshore Wind Power Structures

With the rapid development of offshore wind power industry, wind turbinecapacity and size increasing day by day, thus structural vibration issues are alsoincreasingly prominent. Meanwhile, because of the complexity of the environment, awide range of loads, nonlinear coupling and random characteristics of the differentloads and etc., at present, the study on dynamic characteristic of the offshore windturbine structure in the problem is still inadequate. In addition, wind power structuralaccidents have occurred, so the wind turbine structural safety assessment is necessary.It is very significant for the safety assessment of offshore wind turbine structures tostudy on its the dynamic characteristics and analyze the structural dynamic responseunder extreme conditions, but also it has important reference value and engineeringsignificance to guide the design of the structure.This paper, takes the Qidong prototype of offshore wind power structure forstudy, based on the measured vibration signal of multiple shutdown conditions andtyphoon conditions, combines dynamic signal processing technology, programmingcalculations with finite element numerical simulation, researches into vibration issuesof offshore wind power structure. First, use RDT method combined with ITD methodto NExT method combined with ERA based on singular entropy fixing orderdetermination to realize the wind turbine structural modal parameters accuratelyidentify and analyze the dynamic characteristics. Secondly, the3-D finite elementmodel is constructed based on real engineering and an analytical modal analysis isperformed to generate modal parameters to verify the accuracy of modal parameteridentification though the numerical model. Then considering wind loads, wave loadsand coupling effects were simulated using the harmonic superposition methodfluctuating wind, wave superposition method for modeling linear wave loads imposedon the model to analyze the dynamic response of wind power structure, accuratevibration prediction model. Finally, the prediction model structures for offshore windextrapolated extreme vibration response. Then considering wind loads, wave loadsand coupling effects were simulated using the harmonic superposition methodfluctuating wind, wave superposition method for modeling linear wave loads imposedon the model to analyze the dynamic response of wind power structure, to obtainaccurate vibration prediction model. Finally, the prediction model structures foroffshore wind extrapolated extreme vibration response. Through this computational analysis and projections, get offshore windfoundation and tower structure stress is in good condition and the whole structure issafety under extreme conditions. The method of measured data combined with finiteelement simulation can better assess security of offshore wind power structures.