Dynamics Analysis And Crack Diagnosis On Rotor System With Multi Faults

Rotating machinery is used widely in various fields of industrial production.The study on dynamic characteristics and vibration response of rotor system as the main working part of rotating machinery is very important for fault diagnosis,identification and control.Based on crack stiffness model,rub-impact force and classical short bearing theory,dynamic models of rotor system with rigid support and oil-film support are established in this paper.Runge-Kutta method is utilized to solve differential equations of the system,and dynamic response of different rotor systems are analyzed,which provides theoretical basis for the diagnosis of crack fault in the rotor system.The experimental study on the cracked rotor systems with rigid support and oil-film support are carried out,which validate the theoretical simulation results.The main achievements are obtained in this paper as follows.1.Taking the uncracked rotor system and cracked rotor system with rigid support as the research objects,the nonlinear dynamics behaviors of the rotor system under different parameters are studied by using Runge-Kutta method,and the morphological changes of whirl orbits are compared and analyzed in the uncracked rotor system and cracked rotor system.2.Based on rub-impact forces and crack stiffness model,the dynamic model of the Jeffcott rotor system with crack and rub-impact multi-fault is established,the fourth-order Runge-Kutta method is adopted to solve and simulate.In the Jeffcott rotor system with rub-impact and the Jeffcott rotor system with crack and rub-impact multi-fault,the bifurcation diagram,time waveform,frequency spectra and the whirl orbits near the 1/2 critical speed are compared and analyzed.3.Considering the coupling of crack,rub-impact and nonlinear oil-film forces,dynamic models of the cracked rotor system and multi-fault rotor system with crack and rub-impact supported by nonlinear oil-film forces are established.Bifurcation diagrams and whirl orbits near 1/2 critical speed are compared and analyzed.The dynamics characteristics of the bearing-rotor systems with crack and coupling fault are studied.4.The experimental study on rotor systems with crack fault is carried out.Experimental contents consist of the research on the rotor system with rigid support and the rotor system with oil-film support.The effect of crack fault on the response in the rotor systems is analyzed.The corresponding theoretical simulation results are verified by experimental study.The conclusion provides reference for the diagnosis of crack fault and multi-fault in rotor system.