Design Of Similar Dynamic Model Of Rotor-support System And The Method Study Of Rubbing Fault Representation

The rotor-support system is one of the key components of the rotary machines such as gas turbine,aero-engine and compressor.Its dynamic characteristics determine the work performance and reliability of the rotary machines.During the research of the rotor system,theoretical analysis,numerical simulation and experimental verification are often be used.However,the theoretical analysis needs to accept some assumption.The numerical simulation need to simplify the model,ignore the secondary factors and assume the boundary conditions.So only using the theoretical analysis and numerical simulation cannot solve the practical engineering problems completely.It needs the experimental verification.It is difficult to study the prototype considering the geometry size,space and experiment cost.So it is important to research the design of similar dynamic model of rotor-support system and distortion model updating.The similarity relationships are firstly derived from dynamic equations of rotor system.The finite element model of the rotor-support system is built.Based on the similarity relationships of the shaft,disk and bearing,the model which has the same natural frequencies with the prototype is designed.The relative errors of the natural frequencies of the prototype and model are within 6%.And the model have the same vibration modes with the prototype.The similarity relationship of the natural frequency is verified.But in the similarity design process,some parameters may produce distortion.The damped natural frequency and undamped natural frequency sensitivities with respect to the system parameters.Take the undamped natural frequency for example,when the bearing support stiffness and the disk mass produce distortion,the distortion models are updated and the transition models are got.Through the simulation,the relative errors of the natural frequencies of the transition model and similarity model are acceptable.The results prove the method of distortion model updating based on sensitivity analysis to be right.Experiments have been carried out to study on the rotor system of the model and prototype.Through the experiment,the relationships were verified.The model is designed which have the same unbalance response with the prototype.For the problem of the eccentricity,eccentric mass and so on producing distortion,the unbalance response sensitivities with respect to these parameters based on finite element are deduced and the distortion model are updated.Experiments have been carried out to study on the unbalance response of the model.The finite element method was verified.Finally,for local rubbing fault reproduced of rotor bearing system is researched.The model designed can replace the prototype to fault mechanism research.