Dynamic Characteristics Analysis Of Functional Graded Material Rotor System

As an important working part of rotating machinery,the application range of rotor system covers many fields such as aerospace,machinery,and computer,which have received extensive attention due to its normal operation of the entire machine.With the development of the rotor system towards high-speed and light-weight,composite materials with good thermo-mechanical properties are gradually applied to the rotor system,in the face of high temperature,high pressure,high speed and other harsh working environments.Aviation engine gear often uses thin webs,thin rims,and multiple weight-reducing holes,which can be simplified into a typical shaft-disk rotor structure with low-stiffness and high-flexibility features.The influence of gear web flexibility on the dynamic characteristics of the gear transmission system cannot be ignored.However,existing modeling methods are not suitable for such gear rotors.Based on these factors,this paper focuses on the dynamic modeling and dynamic characteristics analysis of the gear transmission system with functionally graded material rotor in the temperature field,and carries out the following work:(1)According to the principle of differential quadrature finite element method,a dynamic model of a functionally graded shaft-disk rotor system with flexible shaft and flexible various-thickness disk as components is established to investigate the coupling dynamic behavior of this rotor system in thermal field.Considering the thermophysical properties of the material,the functionally graded material model whose property changes in the form of a power law along the thickness direction and the radius direction is established.Based on the theory of rotor dynamics,the global control differential equation of the coupled rotor system is established.Through comparative analysis with literature results,finite element software calculation results and modal experimental results,the reliability and accuracy of the model are fully verified,and the effects of temperature difference,rotational speed,geometric parameters and material parameters on the thermal-elastic coupled vibration characteristics of the light-weight shaft-disk rotor are discussed in detail,which enriches the existing research data and aid the design work and future research of rotor system.(2)Based on Timoshenko beam theory and medium thick plate theory,a modeling method of functional graded shaft-disk-ring coupled rotor system in temperature field is proposed.According to the gear meshing process,considering the time-varying meshing stiffness,the meshing potential energy of the gear meshing pair is deduced,while the gear meshing element is established.The shaft-disk-ring coupled rotor is used as the gear rotor,connected by meshing elements,so that the dynamic model of functional graded gear meshing pair in the temperature field is established.Through the comparative analysis with the calculation results of finite element software,it is confirmed that the model has high calculation accuracy and calculation efficiency.(3)Dynamic modeling of the three parallel shaft-spur gear transmission system in the aero-engine accessory transmission system is carried out through the above-mentioned modeling method of functional graded gear meshing pair.Taking the finite element calculation results as a reference,the reliability of the numerical models of the transmission shaft,the primary gear transmission system and the secondary gear transmission system is verified step by step.The coupled vibration caused by the meshing of gear teeth is analyzed in detail.Combined with the parametric study of the coupled vibration characteristics and dynamic characteristics of the gear transmission system in the temperature field,the intrinsic relationship is explored.The influence of the relevant parameters of the gear web on the overall characteristics of the gear transmission system is emphatically discussed,which provides some theoretical support for the design of functional graded gear rotor and the accurate prediction of the dynamic vibration response law of the gear transmission system.