Study On Rigid-flexible Coupling Modeling And Dynamic Response Of Main Bearings Of Wind Turbine

Wind turbines will start and stop with the change of wind speed during the operation.The dynamic external loads under such conditions will cause great damage to the equipment.As the key supporting component of the drive chain system,the main bearing is susceptible to fatigue failure under the action of variable load impact.Therefore,how to accurately reveal the dynamic response characteristics of the main bearing during operation and the cause of fatigue damage is of great significance for improving the structural design level of the wind turbine.This article takes the 1.5MW wind turbine main bearing as the research object,and carries out the research work on the dynamic response simulation of the main bearing under the typical working conditions.The specific content and the obtained research conclusions are as follows:(1)The load calculation of the main bearing.Using Bates theory and the leaf momentum method,the calculation method of the axial load of the main bearing of the wind turbine was deduced.The axial loads of the main bearing under the rated wind speed and the limit wind speed were calculated to be 44926 N and 160450 N,respectively.On the basis of reasonable simplification of wind turbine model,an equivalent physical model of the main shaft is established,and the radial load of the main bearing is calculated according to the established static balance equation,and the radial load of the bearing is calculated to be 632628 N.The calculation result of the load provides reliable data support for the rigid-flexible coupling simulation analysis of the subsequent main bearing.(2)A rigid-flexible coupled multi-body contact dynamics simulation model of the main bearing was established.Based on the multi-body system dynamics,the rigid-flexible coupling dynamics model of the main bearing was built based on the ADAMS multi-body dynamics analysis platform and the ANSYS finite element analysis platform.In the modeling process,the influence of the main bearing inner ring and cage flexibility and the presence of oil film on the radial contact stiffness and damping of the main bearing are considered.Under the selected operating conditions,the rigid-flexible coupling model of the main bearing and the full-body model of the main bearing were used to simulate and calculate the theoretically calculated values of the main bearing cage and the roller speed.The results show that the coupled model is correct.Compared with the full rigid body model,the simulation results of the coupled model are more accurate and reliable.(3)Simulation analysis of dynamic response of main bearing of wind turbine generator.Using the established rigid-flexible coupling multi-body contact dynamics simulation model of the main bearing,simulation analysis was performed under the selected two typical operating conditions.The results show that the impact of the main bearing roller on the cage and the inner ring is greatest at the initial stage of start-up of the wind turbine.The dangerous positions of the bearing occur at the cage pockets and near the edges of the inner raceways respectively;the cages in the steady operation stage are mainly radial to the rollers.Impact action,at this time the dangerous position of the force occurs on both sides of the inner and outer walls of the cage,and the two phases of the cage are obviously subjected to uneven force.In the gust conditions,the frequency of contact stress between the roller and the cage increases,and the dangerous position of the force is at the pocket hole of the cage.The uneven force of the cage still exists.The contact stress of the roller to the inner ring is abruptly changed.Still concentrated near the edge of the inner raceway.The research work done in this paper has certain reference value for the selection of the main bearing and the optimization of the structure of the wind turbine.