Reliability Analysis In Foundation-tower-blade And The Whole Risk Evaluation Of Offshore Floating Wind Turbine

Wind energy is one of the cheapest and cleanest energy sources.Especially in the last two years,the research of offshore floating wind turbine has developed rapidly.Because the strong wind and frequent sea waves that offshore wind turbines may encounter more serious problems,conditions lead to the survival performance of floating offshore wind turbine has been reduced,which may lead to more trouble.In this study,NREL OC4 semi-submersible floating wind turbine is used as the research object and the risk of reliability evaluation is done.A comprehensive analysis of the structure reliability of floating offshore wind turbine tower-based systems,fixed type turbine,ordinary floating wind turbine and piezoelectric intelligent plate blade system is accomplished.The details are: the aerodynamic load calculation and motion response of wind turbine are cauculated by using FAST software,put the time domain result ANSYS software,the calculation results with the existing database and related literature combined with random load model,calculate failure probability and the Dirlik formula of rain flow counting method.The dynamic fault tree analysis program is written in MATLAB language to calculate the failure probability and the importance of different risk events during the life cycle.Risk analysis of floating offshore wind turbine is divided into four subsystems,namely the base tower system,blade system,transmission system and control system.FMECA methods are adopted to evaluate failure analysis.According to the working environment and fault characteristics of them,the qualitative and semi quantitative analysis of the hazard matrix and the risk priority number(RPN)are completed.The study found that floating offshore wind turbine tower-based system failure probability is low,the structure risk is becoming increasingly obvious during its life;for the blade system,floating ones is higher than the fixed ones,floating ones are more dangerous in the cut-out wind speed,and the fixed ones are more dangerous in extreme wind conditions,in the use of smart piezoelectric materials,the root stress,the fatigue failure probability and failure probability of system are all decreased,but with the increase of the modulus of elasticity of the piezoelectric material,the decline of the stress level gradually decrease.