Mesh Characteristic Analysis And Dynamic Performance Optimization Of Wind Turbine Speed-increase Gear System

Speed-increase gearbox is the key transmission device in wind turbine.Its comprehensive performance will directly affect the reliability and stability of wind turbine.With the development of wind power equipment manufacturing technology,wind turbine speed-increase gearbox is developing towards high power,high precision,lightweight,low noise and high reliability.Therefore,the mesh characteristics analysis and dynamic performance optimization of the wind turbine speed-increase gear system are carried out,which has certain theoretical significance and engineering value for the vibration damping and weight reduction design of the wind turbine speed-increase gearbox.In this thesis,the mesh characteristic simulation,internal excitation simulation,vibration characteristic analysis,modal-response optimization of structural system and dynamic performance optimization of transmission system are carried out for the wind turbine speed-increase gear system.The main research work of this thesis can be summarized as follows:(1)Based on the ANSYS/LS-DYNA software to analyze the mesh characteristic of the gear pair,the dynamic contact force,dynamic stress and transmission error of the gear pair are obtained.The Romax static analysis model of the transmission system is established to obtain the bearing support stiffness.Based on the static and dynamic contact analysis of gear pairs,the internal dynamic excitations such as time-varying mesh stiffness excitation,transmission error excitation and mesh impact excitation of gear pair are obtained.(2)Based on APDL of ANSYS software,the coupling dynamic finite element analysis model of box-gear transmission system is established,the natural frequencies and modes of the system are obtained by constrained modal analysis.The internal excitation is applied to the finite element model of the system,and the vibration response of the system is calculated by modal superposition method,which is in good agreement with the measured vibration response of the speed-increase gearbox.(3)Based on the theory of multi-objective optimization design,aiming at avoiding the characteristic frequency of the system and reducing the vibration acceleration of the evaluation point,taking the size parameters of the box structure as design variables and the volume and static strength of the box as constraints,the modal-response joint optimization model of the wind turbine speed-increase gearbox is constructed by ANSYS software.The multi-objective dynamic performance optimization of the box is carried out,and the static and dynamic performance of the optimized speed-increase gearbox is evaluated.(4)The lumped parameter dynamic model of wind turbine speed-increase transmission system is established,and the analytical solution of vibration response of each component is obtained by solving the dynamic differential equation based on harmonic balance method.The basic parameters of gears are taken as design variables,the total transmission ratio of speed-increase gearbox,the strength of gear teeth and assembly conditions are taken as state variables,and the minimum vibration acceleration and the total mass of components are taken as design objectives,the multi-objective hybrid discretization is constructed.With the MATLAB software,the optimal design program is compiled based on branch and bound algorithm,and the optimal design parameters of transmission system are obtained.The dynamic performance optimization effect is obvious.