Analysis of the influence of manufacturing error on the modal characteristics of disc-drum combined rotor
In order to explore the influence of manufacturing errors on rotor modal characteristics,the mechanisms of rotor modal localization,mode step,and frequency steering characteristics were described based on rotor dynamics and perturbation theory.According to actual rotor assembly engineering,the manufacturing error forms of typical mating surfaces were characterized by user-defined functions,and point cloud data were generated.The skin model method was used for the first time to introduce manufacturing errors into the rotor finite element model,and the characteristics of manufacturing errors on its frequency steering,mode step,and mode localization were analyzed for this model.The mode displacement localization factor was used to quantify the degree of rotor vibration mode localization caused by manufacturing errors.The results showed that when the manufacturing error was considered to a certain extent,it could induce the rotor detuning,leading to the change of the rotor system stiffness and aggravating the frequency steering characteristics;at the same time,through analysis of the mode confidence criterion diagram,it can be seen that the mode shape had the phenomenon of dislocation step and sequence step;the detuning effect caused by manufacturing error could make the vibration energy gather in some areas of the rotor,so some frequencies falling in the frequency pass band of the ideal model may fall into the frequency band gap after detuning,and the phenomenon of mode shape localization occurred;further quantitative analysis showed that the mode displacement localization factor can effectively characterize the degree of vibration mode localization.The research methods and results can provide a reference for complex rotor assembly technology.
disc-drum combined rotormanufacturing errorfrequency steeringmode steplocalization of vibration modes
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