Stability of periodic motion on the rotor-bearing system with coupling faults of crack and rub-impact

2007 ◽  
Vol 21 (6) ◽  
pp. 860-864 ◽  
Author(s):  
Yue-Gang Luo ◽  
Zhao-Hui Ren ◽  
Hui Ma ◽  
Tao Yu ◽  
Bang-chun Wen
Keyword(s):  
Periodic Motion ◽  
Coupling Faults ◽  
Rotor Bearing ◽  
Bearing System

scholarly journals Research on Periodic Motion Stability of Rotor-Bearing System with Dual-Unbalances

2011 ◽  
Vol 2-3 ◽  
pp. 728-732
Author(s):  
Chao Feng Li ◽  
Guang Chao Liu ◽  
Qin Liang Li ◽  
Bang Chun Wen
Keyword(s):  
Stability Analysis ◽  
Phase Difference ◽  
Periodic Motion ◽  
Initial Phase ◽  
Shooting Method ◽  
Small Eccentricity ◽  
Rotor Bearing ◽  
Large Eccentricity ◽  
The Stability ◽  
Bearing System

Multiple freedom degrees model of rotor-bearing system taking many factors into account is established, the Newmark-β and shooting method are combined during the stability analysis of periodic motion in such system. The paper focused on the influence law of two eccentric phase difference on the instability speed of rotor-bearing system. The results have shown that the instability speed rises constantly with the eccentric phase difference angle increasing in small eccentricity system. When the two unbalance be in opposite direction, the system reached its maximum instability speed. However, the unstable bifurcation generates mutation phenomenon for large eccentricity system with the eccentric phase difference angle increasing. In summary, the larger initial phase angle can inhibit system instability partly. The conclusions have provided a theoretical reference for vibration control and stability design of the more complex rotor-bearing system.

scholarly journals Nonlinear Dynamic Analysis of Rotor Rub-Impact System

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Youfeng Zhu ◽  
Zibo Wang ◽  
Qiang Wang ◽  
Xinhua Liu ◽  
Hongyu Zang ◽  
...  
Keyword(s):  
Periodic Motion ◽  
Chaotic Motion ◽  
Nonlinear Dynamic Analysis ◽  
Period Doubling ◽  
Time History ◽  
Rotor System ◽  
Quasiperiodic Motion ◽  
Rotor Bearing ◽  
Motion Period ◽  
Bearing System

A dynamic model of a double-disk rub-impact rotor-bearing system with rubbing fault is established. The dynamic differential equation of the system is solved by combining the numerical integration method with MATLAB. And the influence of rotor speed, disc eccentricity, and stator stiffness on the response of the rotor-bearing system is analyzed. In the rotor system, the time history diagram, the axis locus diagram, the phase diagram, and the Poincaré section diagram in different rotational speeds are drawn. The characteristics of the periodic motion, quasiperiodic motion, and chaotic motion of the system in a given speed range are described in detail. The ways of the system entering and leaving chaos are revealed. The transformation and evolution process of the periodic motion, quasiperiodic motion, and chaotic motion are also analyzed. It shows that the rotor system enters chaos by the way of the period-doubling bifurcation. With the increase of the eccentricity, the quasi-periodicity evolution is chaotic. The quasiperiodic motion evolves into the periodic three motion phenomenon. And the increase of the stator stiffness will reduce the chaotic motion period.

Diagnose and Analysis of Coupling Faults on Nonlinear Rotor-Bearing-Seal System Prediction

2009 ◽  
Vol 413-414 ◽  
pp. 553-559
Author(s):  
Shu Lian Liu ◽  
An Li ◽  
Shui Ying Zheng
Keyword(s):  
Numerical Calculation ◽  
Nonlinear Equations ◽  
Integration Method ◽  
Labyrinth Seal ◽  
Numerical Calculations ◽  
Dynamic Equations ◽  
Coupling Analysis ◽  
Coupling Faults ◽  
Rotor Bearing ◽  
Bearing System

The fluid-solid coupling analysis of the nonlinear rotor-bearing system with labyrinth seal was presented. The dynamic equations of rotor-bearing system were built up by combining d’Alemdert principle with Rize way, then the nonlinear oil film forces based on steady short bearing model, unbalanced excitation forces and gas excitation forces calculated by FLUENT could be coupled to system. Such nonlinear equations were numerically solved by Newmark integration method. The dynamics and the representation characteristics were investigated through a lot of numerical calculations, then the occurrence and development mechanism of the different coupling faults revealed based on the results of numerical calculation. The severity and mutation of some faults were also studied.

Bifurcation and Chaos Behavior of Rotor-Bearing System With Crack and Pedestal Looseness Faults

2007 ◽  
Author(s):  
Yuegang Luo ◽  
Songhe Zhang ◽  
Feng Wen ◽  
Bangchun Wen
Keyword(s):  
Critical Speed ◽  
Journal Bearings ◽  
Cracked Rotor ◽  
Bifurcation And Chaos ◽  
Coupling Faults ◽  
Speed Range ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

A dynamic model was set up for the two-span rotor-bearing system with coupling faults of crack and pedestal looseness supported on three plain journal bearings. The nonlinear dynamic behaviors that induced by crack, pedestal looseness and coupling faults are numerically studied. There is quasi-periodic motion appearing in the cracked rotor-bearing system, and it within the sub-critical speed range in the pedestal looseness rotor-bearing system. There is chaotic motion appearing within the supper-critical speed range in the pedestal looseness rotor-bearing system. The pedestal looseness fault is the main influence on the coupling faults system, and there is Period-3 motion appearing in the system. The results may bring up theoretical references for fault diagnoses, dynamic design, and security running to rotor-bearing system.

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