Model-based Identification Of Typical Vibration Faults In Aero-engine Rotor Systems

The rotor system of aero-engines has a complex structure,high working speed and harsh operating environment,so faults are inevitable.Among aero-engine rotor system faults,unbalance and misalignment faults are the most common.When an unbalance or misalignment fault occurs,the rotor system vibration will increase.If it is not diagnosed in time,it will affect the normal operation of the aero-engine and seriously threaten the flight safety of the aircraft.To ensure flight safety and reliability,it is of great significance to carry out the identification of unbalance and misalignment fault of aero-engine rotor systems.Fault identification research on the typical aero-engine rotor system vibration faultsunbalance and misalignment faults is completed.The specific research content is as follows:1.A model-based rotor vibration fault identification method is proposed.The rotor vibration fault identification method proposed in this paper divides the identification of unbalance and misalignment faults into two steps.First,the axial positioning of the fault is identified by the harmonic balance method,then the identification of the fault amplitude and phase is completed based on the sensitivity method,therefore the identification of unbalance and misalignment faults is completed.It provides a theoretical basis for the identification of unbalance and misalignment faults in the rotor system.2.Based on a simple multi-span rotor system the research of vibration fault identification method is carried out.Based on a simple multi-span rotor system,the simulation of rotor fault identification of unbalance,misalignment and their coupled faults is carried out.Furthermore,the simulation of unbalance,misalignment coupled faults in a noise environment is carried out.The identification results show that the model-based rotor vibration fault identification method can accurately identify the location,amplitude and phase of unbalance and misalignment faults,and it also has good applicability in noise environments.3.An accurate model of the simulation gas generator rotor is established.Firstly,the solid element model and beam element model of the simulation gas generator rotor are established;then the free mode experiment of the simulation gas generator rotor is conducted.The first fourorder bending mode frequencies of the simulation gas generator rotor are obtained;Finally,taking the experimental modal frequency as the target and the elastic modulus of the curvic couplings connection area as the correction parameter,the solid element model and the beam element model are corrected.4.The research on the vibration fault identification method based on the simulation gas generator rotor is carried out.Firstly,the revised solid element model is used to carry out the simulation of unbalance,misalignment and their coupling faults respectively,and then the noise-containing coupling fault simulation is carried out.Finally,the revised beam element model is used for rotor fault identification.The recognition results show that the rotor fault identification method proposed in this paper can still accurately identify the location,amplitude and phase of the unbalance and misalignment faults even when there is an error between the identification model and the actual model and the measurement response is disturbed by noise.5.The verification experiment of the rotor fault identification method is Carried out.Firstly,relying on the rotor test bench,a single-span double-disk rotor system is built,and its finite element model is established.Then,the rotor unbalance and misalignment fault experiments are carried out.Finally,the unbalance and misalignment fault parameters are identified based on the established finite element model.The identification results show that the rotor vibration fault identification method proposed in this paper can effectively identify the rotor unbalance and misalignment fault parameters.