Study On Coupling Vibration Characteristics Of Shaft-Disc-Blade Covered Ring Rotor

With the development of industrial technology and the advancement of technology,the rotor system plays a very vital role in the national economy.Due to the increase in rotor operating speed and accuracy requirements in recent years,the coupling dynamic characteristics between the various component structures have also become an important factor affecting the reliability of the rotating structure.How to predict the coupled vibration characteristics of the rotor to avoid accidents is the key to the safety and reliability of the turbine engine.In view of the above problems,this paper studies the coupled vibration characteristics of lower speed turbine rotors:The energy structures of the sub-structures of the shaft-disc-blade-ring rotor are discretized on the basis of the assumed mode method.The Lagrangian theorem is used to derive the equation of motion of a rotor with ring.Only the effects of axial torsional deformation,lateral bending deformation of the blade,and bending and torsion deformation of the ring are considered in the rotor.The deformation of the rigid disk is not considered.The natural frequency and mode shape of the rotor with ring are obtained by using MATLAB software.Two new coupled vibration modes are defined:the shaft-blade-ring(SBR)mode and the blade-ring(BR)mode.Based on the finite element modal analysis theory of the rotor,the finite element model of the rigid disk without shroud and the rotor with shroud is established.The rotor is modeled and modal analyzed by ANSYS Workbench software to obtain its natural frequency and vibration type.Comparing the no-ring rotor with the shrouded rotor coupled vibration mode,the shroud affects the coupled vibration in a single rigid disc rotor.Not only is the rotor coupling mode changed,but its modal order is also changed.For the single-disc with ring rotor that disk is rigid,the mode shape obtained by the assumed mode method and the numerical simulation method is consistent,and the difference between the natural frequency values is small.In addition,in numerical simulation,the ring are simulated using solid and shell elements,respectively.Comparing the results with the assumed mode method results,the results of using solid ring are closer and more in line with the actual situation.On this basis,the influence of the number of blades and the thickness of the ring on the coupled vibration of the rotor is further discussed.The experimental vibration test is carried out on the flexible single-disc six-blade rotor.The test system is mainly composed of two parts:the rotor simulation test platform and the signal acquisition system.The vibration acceleration and displacement signals are obtained by conducting rotor vibration tests at different speeds.The vibration signal data is collected and analyzed to obtain the time domain map,the spectrum map and the shaft trajectory map of the rotor.Thereby the vibration characteristics of the rotor at different rotational speeds are further analyzed.The coupled vibration of the shaft-disk-blade-ring rotor was analyzed by the research in this paper.This provides a reference for further research on the dynamic characteristics and fault diagnosis of turbine engine rotors,and provides a research basis for the design and optimization of turbine engines.