Dynamic Characteristics Research Based On Load Spectrum Of Megawatt Level Wind Turbine Gearbox

The research subject of the dissertation stems from the projects “The study of Keytechnologies of industrialization for7MW wind turbine gearbox and spindle bearing”(2012BAA01B05) in the National Science and Technology Pillar Program during the12th Five-Year Plan period of China, respectively.Unit capacity and power density of wind power generators is developing towardthe trend of large-scale. Wind turbine gearbox, a key component for the transmissionsystem of wind turbine, is gear transmission equipment with heavy load under workingcondition of random load and transient impact load. Also, it is one of the weaknesses forwind turbine. Currently, in terms of design and manufacturing technology ofhigh-power wind turbine gearbox, most of the domestic manufacturers is still at thestage absorbing the foreign design technology, result in the domestic high power windturbine gearboxes has high failure rate. Therefore, dynamic characteristics research andfatigue life analysis of megawatt level wind turbine gearbox, which will improving thecapacity of independent design and development for high power wind turbine gearboxand reducing the failure rate, plays an important role to promote localization of highpower wind turbine gearbox.The main contents of this dissertation are shown as follows:①The main structure forms and transmission characteristics and transmissionprinciples of wind turbine gearboxes are introduced. A3D model studied in this paper isestablished by using RomaxWIND, and virtual assembly and interference checking aredone.②Statics analysis for the key components of megawatt wind turbine gearbox isdone respectively under extreme working condition and rate working condition, and thestress distribution and the extreme load coefficient of casing and planet carrier areobtained. At the same time, analysis of meshing characteristics of gear pairs is done,contact pattern of gear tooth and load distribution coefficient of planet gears areacquired under extreme working condition and rate working condition.③Internal excitation, for example time-varying stiffness excitation, transmissionerror excitation, as so on, and external excitation are analyzed detailed at a system’sperspective. Then, transmission sub-system “gear-shaft-bearing” and structuralsub-system “housing” are built by using ABAQUS finite element software to study the inherent characteristic and dynamic response caused by internal excitation and externalexcitation based on load spectrum.④The external loads of megawatt wind power gearbox was analyzed and the loadtime distribution(LDD) and equivalent load was calculated. The contact fatigue strengthand bending fatigue strength of all the gear pairs in the gearbox, and the fatigue life ofall the bearing in the gearbox was checked respectively under the above mentioned loadworking condition.⑤The online test system of dynamic characteristics for megawatt wind powergearbox is found, the vibration characteristics of gearbox was researched and thevalidity of the simulation model is validated.