Dynamic Response Prediction And Fatigue Reliability Analysis Of Speed-increase Gearbox For Wind Turbine

As the key component of the wind turbine,the comprehensive performance of speed-increase gearbox directly affects the reliability of the whole wind turbine.The speed-increase gearbox for wind turbine has a high failure rate owing to the working condition of irregular random load and transient impact load.Consequently,higher requirements for the dynamic characteristics and running stability of the gearbox are put forward.The research of dynamic characteristics and fatigue reliability is of great theoretical significance and engineering application value to improve the comprehensive performance of the speed-increase gearbox.The paper takes the speed-increase gearbox for wind turbine as research object,dynamic transmission error analysis,vibration response prediction,fatigue life calculation and fatigue reliability analysis are carried out.The main research work of this paper can be summarized as follows:(1)On the basis of calculating the bearing stiffness,time-varying mesh stiffness,and the static transmission error of the gear pair,the bending torsion coupled vibration dynamic model of the gear transmission system for the wind turbine is established,and the vibration response of the components is obtained by solving the vibration differential equation of the transmission system,then the dynamic transmission error and dynamic meshing force of each gear pair are calculated.(2)The coupling dynamic model of the speed-increase gearbox is established by using the ANSYS software,the modal analysis is carried out to obtain its natural frequencies and mode shapes.On this basis,dynamic meshing force is applied and the modal superposition method is used to predict the dynamic response of the speed-increase gearbox,and the vibration response of each evaluation point is obtained.Then the vibration test is carried out on the dynamic performance test bench of the speed-increase gearbox to verify the accuracy of the simulation results.(3)A double parameter rain-flow counting method is used to compile the fatigue load spectrum of the measured load time series of the speed-increase gearbox,taking the output gear pair and the planet frame as the research object,the S-N curve of the material is calculated according to the GL standard,and then based on the Palmgren-Miner theory,the fatigue of each component is calculated by the FE-SAFE software.Then the influence of surface roughness and load on fatigue life is studied.(4)Based on the stress-strength interference theory,the reliability of the bending fatigue and contact fatigue of each gear pair in the transmission system is calculated by using the second moment method,and the sensitivity of the reliability to the basic variables is analyzed.Then the reliability of the static strength of the planetary frames is calculated by using the Monte Carlo method.On this basis,the fatigue reliability analysis model of the transmission system is established,and the fatigue reliability of the transmission system is analyzed.