Non-linear Vibration And Noise Analysis And Dynamic Optimization Of Speed-increase Gearbox For Wind Turbine

Speed-increase gearbox is an important transmission part of wind turbine. Gearboxrequires high reliability and long service life, because the unit of wind turbine works atsevere natural environment and it is not convenient to repair. The nonlinear vibration ofgear transmission system reflects the comprehensive performance of the gearbox tosome extent. Therefore the research on vibration noise and dynamic optimizationmethod of speed-increase gearbox for wind turbine has important theory significanceand great engineering values on vibration and noise reduction.The topic of this paper is supported by National Key Technology R&D Program ofChina. Using the theories of gear engagement, nonlinear vibration and optimizationdesign method, the nonlinear vibration and noise as well as dynamic responseoptimization of the speed-increase gearbox for wind turbine have been carried out inthis paper. The main research work in this paper can be summarized as follows:①The dynamic finite element analysis model of the speed-increase gearbox forwind turbine is established in the software of ANSYS. Using the method of blockLanczos to analyze the finite element modal of the gearbox, the natural frequency andnormal mode of the speed-increasing gearbox are obtained. Taking the time-varyingmesh stiffness, damping, tooth backlash, transmission error and other non-linear factorsinto consideration, the internal excitation including stiffness excitation, error exactionand meshing impact exaction is calculated by numerical simulation. Nonlinear dynamicresponse of the gear system is analyzed by full method, and then the vibrationdisplacement, velocity and acceleration of the gearbox are obtained.②The frequency domain responses of the nodes on the housing are obtained afterthe Fourier transformation of the time domain response which extracted from based onthe result of dynamic response analysis of the speed-increase gearbox. Taking thefrequency domain responses as boundary conditions, an acoustic boundary elementmodel of the housing is built in SYSNOISE. Using the direct boundary element method,radiation noise is predicted, and the surface acoustic pressure contour on the housingand the radiation noise at determined field points can be obtained.③The dynamic response optimization model of the speed-increase gearbox forwind turbine is established, considering the structure parameters of the speed-increasegearbox housing as design variables, volume as the state variable, and the RMS value of vibration acceleration of the housing as the objective function. The optimal solution ofdesign variables are obtained after the dynamic response optimization of thespeed-increase gearbox with first order optimization method.Then the static strengthand vibration characteristics of the speed-increase gearbox was evaluated after theoptimization design.