Vibration Characteristics Analysis And Structural Topology Optimization Of Wind Turbine Gearbox

The wind turbine gearbox is the core part of the wind turbine.It is arranged between the main shaft and the generator of the fan.Its comprehensive performance is an important standard to measure the performance of the whole wind turbine.Because of the narrow space of the fan cabin,the gearbox has high power to weight ratio requirements,and the wind turbine gearbox is subjected to random variable wind load and instantaneous strong wind impact load all year round,which puts forward more stringent requirements for its dynamic performance.Therefore,the research on Vibration Characteristics Analysis and structural topology optimization of wind power gearbox is of great theoretical and practical significance to realize gearbox lightweight and improve the dynamic performance of gearbox.In this paper,the time-varying wind speed characterization and wind load excitation simulation,internal excitation and dynamic meshing force calculation,vibration response prediction and topology optimization of gearbox are carried out.The main research work of this paper is as follows(1)Considering the coherence of wind speed between the blade and the tower,a20 particle tower blade model is established.Based on the harmonic superposition method,the fluctuating wind speed and power spectral density at each point of the fan are obtained.Combined with the wind speed disturbance caused by the tower shadow effect of wind shear,the comprehensive input wind speed at the hub center point is calculated and substituted into the segmented expression of the spindle torque,and the time-varying torque is used as the wind power gear Input external excitation of the box.(2)Using ROMAX software to solve the bearing support stiffness,combined with the static transmission error and time-varying meshing stiffness of each gear pair,a 54 degree of freedom lumped parameter model including translation torsion of transmission system was established,and the system dynamic differential equation was derived.Through solving the dynamic meshing force of each gear pair under rated condition and time-varying wind load condition,the meshing force after introducing external time-varying wind load excitation was obtained The mean value of resultant force decreases while the fluctuation increases.(3)ANSYS software is used to build the dynamic finite element model of the wind turbine gearbox.Based on the modal analysis,the natural frequencies and vibration modes of the gearbox are obtained.The modal superposition method is used to solve the vibration response of each evaluation point under the rated condition and time-varying wind load condition.The simulation results show that the vibration of each evaluation point increases significantly when the random wind load is considered.Then the vibration response of the wind turbine gearbox under the rated condition is measured The simulation results are in good agreement with the experimental results.(4)Based on the theory of elastic mechanics,the mathematical model of continuum topology optimization is derived The optimization model of gearbox box is established by WORKBENCH software,and the topology optimization is carried out with the minimum structural flexibility as the objective.According to the optimization results,the structure of the gearbox box is modified,and the vibration response of the wind power gearbox after weight reduction is analyzed.It is concluded that the vibration of each evaluation point of the gearbox box after optimization is reduced.