Research On Dynamic Characteristics Of Rotor System With Spline Coupling

Known as the jewel of the industrial crown,the aero engine is a complex mechanical device assembled from millions of parts.As a way of connecting the aeroengine coupling structure,the spline coupling structure is connected to the fan shaft and the turbine shaft for transmission,so its performance will affect the vibration characteristics of the rotor system.Nowadays,in order to improve the bearing capacity,the aero-engines are developing towards the high thrust-to-weight ratio and the high bypass ratio.Therefore,the research on the spline coupling structure that plays the role of the coupling shaft has been paid more and more attention.The mechanical properties of the spline coupling structure have an important influence on the vibration characteristics,stability and reliability of the aerodynamic starting rotor system.In this paper,the relevant research on the transmission part and the positioning part of the spline coupling structure is carried out separately.The related work is carried out on the influence of the toothed stiffness characteristics,the positioning surface parameters and the coupling structure on the rotor vibration characteristics of the spline coupling structure,and the failure of the spline coupling structure is analyzed.Form and its influence,the main research contents of the paper are as follows:(1)Analyze the characteristics of the spline joint structure,and establish a set of tooth meshing model to simulate the toothed twist.The formula for calculating the contact stiffness of the sleeve teeth,the comprehensive stiffness of the meshing model and the meshing force are derived.The effects of the misalignment and the transmission torque on the radial meshing force of the inner and outer teeth of the meshing model are studied.The influence of the meshing model tooth number and the tooth width of the tooth on the radial stiffness of the model is analyzed.(2)Based on the Herz contact theory and the GW model,the calculation formulas of the circular plane contact stiffness,the circular plane contact stiffness and the circular plane bending lateral stiffness are derived.Through the numerical solution and simulation verification,the influence of the positioning surface parameters on the lateral stiffness of the joint structure is analyzed.The influence of the positioning surface parameters on the natural frequency of the joint structure is studied by means of finite element simulation software.Through the variation law of the lateral stiffness and natural frequency of the joint structure,the reference for the design of the axial positioning surface roughness and the radial positioning surface interference is provided.(3)Establish a rotor system with spline coupling structure,and solve the influence of the comprehensive stiffness of the spline coupling structure on the inherent characteristics of the rotor system and the time domain response through numerical analysis.The solid model of the rotor system with the spline coupling structure is introduced into the Workbench simulation software to calculate the influence of the parameters of the joint surface of the joint structure on the lateral stiffness of the rotor.The influence of the misalignment of the joint structure on the rotor system is analyzed,and the misalignment features are obtained.The test is verified by experimental tests..Analyze and compare the vibration characteristics of the rotor system with or without the toothed coupling structure.(4)Study the failure modes of the spline coupling structure and its effects.Firstly,based on the gear tooth meshing model,the parallel and misalignment of the inner and outer toothed sleeves of the model are analyzed,and the strain change of each set of teeth is the trend of the maximum strain value of the strain.Then,through the stress distribution of the shaft system of the rotor system with the toothed coupling structure,the possible damage forms of the tooth surface of the sleeve are analyzed.Finally,the research team accepts the bending moment,the stress distribution of the positioning surface and the contact condition.