Research On The Fatigue Reliability Of Megawatt Wind Turbine Gearbox

Gearbox is a key component in the wind turbines, as the wind turbine capacity has beenbecoming larger and the devices need to work in more complicated environments, it should havehigher reliability to keep the wind turbines operating safely in the design life. Fatigue reliabilitystudy on large power wind turbine gearbox under complex loadings could give technicalsupports to improve the gearbox durability index, this will be an inducement to make technicalbreakthrough for the parts of large wind generators, and significantly, to enhance the engineeringlevel of China’s wind power equipment and promote the development of wind energy industry.In this thesis, strength, fatigue life and fatigue reliability of some key components in a2.5MW wind turbine gearbox was studied, the main contents are as follows:1）According to the wind turbine design standards IEC61400-1and GB/T19073, based onthe linear filter method, the random wind speeds that wind turbine suffered were simulated. Afterthat, the input loads of gearbox were calculated based on the blade aerodynamic theory and thecontrol characters of wind turbine under different levels of random wind speed; Equivalent rigiddynamic model of the gearbox transmission chain was established, loads on the emergencybraking situation that used to do the strength analysis were simulated with the equivalent rigiddynamic model.2）Strength and stiffness of some components in the gearbox were analyzed with FEAmethod, modal characteristics of the output shaft and the principle of load equilibration offlexible pin in the muti-planetary gear transmission were analyzed as well.3）Taking the planet carriers and flexible pins as flexible bodies, a rigid-flexible couplingdynamic model was builded in ADAMS. Load spectrums of components in the gearbox wereobtained after dynamical simulation.With the transient finite element analysis, the dynamic stressand strain of each parts were obtained.4）Using the fatigue analysis software MSC.Fatigue, based on the static and transient FEAresults and Miner linear cumulative law, fatigue life prediction of components in the windturbine gearbox transmission system under different reliabilities was done, and fatigue reliabilityunder the specified design life was calculated for each parts.