| The rotor system is a mechanical system widely used in the fields of aircraft engines,gear transmissions,large steam turbines,and other areas.As the rotor typically carries high torque during high-speed rotation,any accidents could cause significant economic and personal safety losses.Therefore,strict analysis of the dynamic characteristics is particularly necessary in the design process of the rotor system.However,there are a variety of uncertainties over the life of the rotor system,including parameter uncertainty due to measurement errors and approximations to certain parameters,as well as model uncertainties due to approximation and simplification of some details during modeling.Therefore,uncertainty modeling and dynamic characterization of rotor systems is of great significance to better understand their performance and behavior.Based on the nonparametric method of random matrix theory,this paper combines the Riccati transfer matrix method to carry out uncertain modeling and uncertain dynamic characteristics analysis of rotor system.The main research contents are as follows:(1)To address the issue of model uncertainty in the rotor system,the theory of random matrix and Riccati transfer matrix method were combined to establish the dynamic model of the rotor system with model uncertainty.The critical speed of the rotor system with uncertainties is studied,and the effects of various parameter uncertainties and model uncertainties such as support stiffness,shaft segment length,node mass,and shaft segment diameter on the critical speed of the rotor system were analyzed.The research finds that model uncertainties and parameter uncertainties have significant differences in the critical speed of the rotor system,and the fluctuation ranges of the uncertainties of different parameters also vary.(2)Based on the model uncertainty probability model,a computational analysis method for the stochastic dynamics characteristics and stochastic dynamics response of multi-degreeof-freedom rotor system was proposed.To solve the vibration mode and unbalanced response problems in the dynamic response of the rotor system,the accuracy of the deterministic model calculation results was verified using finite element software.The variation range and magnitude of the mode shape at the first two orders of forward precession natural frequencies and unbalanced response at the double disc of the cantilever double-disc rotor system were calculated under given divergence parameters of the nonparametric kinetic mode of 0.03,0.06,0.09,0.12,and 0.15.(3)A method for identifying the divergence parameter of nonparametric dynamic models for uncertain rotor systems was proposed.With the calculated vibration mode of the deterministic rotor system and the measured vibration mode of the actual rotor system,the divergence parameter of the actual rotor system can be identified using the measured data.The rationality of the nonparametric model’s dynamic response calculation method and divergence parameter identification is verified through experiments. |
