Analysis Of Vibration Response And Structure Noise Of Speed-up Gearbox For High-power Wind Turbine

Along with the development of economy in our country, the amount of energydemands more and more，and in the tight supply situation，wind energy as animportant forms of renewable energy obtains more and more attention and the scopesof its applications are enlarged increasingly，so the wind power technology isenforced to develop quickly．The transmission system of speed-increasing gearbox isone of the important components of wind generator，and its main function is totransfer wind power from blades to increase the speed of wind generator．Therefore，the system of wind gearbox has a high requirement against its reliability and stability．Wind-turbine gearbox is developing in the direction of high power．Because itruns at high speed，suffers from large load and works in the harsh environment，factors like this have a big impact on vibration and noise of the gearbox．So it is veryimportant to study the vibration characteristics and noise of the gearbox system．The subject is sponsored by National Supporting Plan Project．Based on thehigh-power split wind-turbine gearbox， and considering the internal dynamicexcitation，the dynamic characteristics and noise of the gearbox are completelyanalyzed with finite element method．The main work in this thesis is listed as follows：①The solid model and coupled FEM model of the whole gearbox system areestablished. The system consists of two planetary gear systems and one parallel axistransmission system．The transmission ratio of the system and the support stiffness ofbearings under the actual load are calculated．②The internal dynamic excitation of spur gear and helical gear which containsthe time-varying meshing stiffness excitation，the error excitation and the meshimpact excitation are calculated by programming on MATLAB software andsimulated by the finite element method．③The natural characteristics of the gearbox system and the gearbox housingare calculated and analyzed fully by the block Lanczos method in ABAQUS software，the first20orders of natural frequency and mode shape of both are obtained．④Only considering the internal dynamic excitation，with the superpositionmethod of mode of vibration，the dynamic characteristics of the system are computedby numerical simulation． Consequently， the time domain curves of vibrationdisplacement，velocity and acceleration of related nodes are attained,and which are transformed to the frequency response curves by means of fast fourier transform(FFT), and the vibration severity of the gearbox is evaluated．⑤Based on the frequency response curve of acceleration，the structure noise ofthe gearbox is calculated and analyzed according to1/3octave principle．...