Research on Rubbing Fault in a Dual-Disc Overhung Rotor-Bearing System

2007 ◽  
Vol 353-358 ◽  
pp. 977-980
Author(s):  
Zhao Hui Ren ◽  
Tao Yu ◽  
Yue Gang Luo ◽  
Nai Hui Song ◽  
Bang Chun Wen
Keyword(s):  
Dynamic Characteristics ◽  
Mechanical Model ◽  
Reference Value ◽  
Rotating Machinery ◽  
Force Model ◽  
Nonlinear Dynamic Characteristics ◽  
Rotor Bearing ◽  
Simulation Results ◽  
Set Up ◽  
Bearing System

Mechanical model and rubbing force model of a dual-disc overhung rotor-bearing system are set up respectively. By using an experiment rig to simulate rubbing fault, the nonlinear dynamic characteristics of rubbing rotor system are investigated and the dynamic characteristics of mid-disc and overhung disc are analyzed respectively. The numerical simulation results coincide with the experiment results and the research in this paper has practical reference value to the safe and stable run of the practical rotating machinery.

Nonlinear Characteristics of Two-Span Rotor-Bearing System with Three-Coupling Faults

2011 ◽  
Vol 52-54 ◽  
pp. 303-307
Author(s):  
Yue Gang Luo ◽  
Song He Zhang ◽  
Zhao Hui Ren ◽  
Bang Chun Wen
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Nonlinear Characteristics ◽  
Coupling Faults ◽  
Comprehensive Method ◽  
Nonlinear Dynamic Characteristics ◽  
Speed Range ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System

The dynamic model of two-span rotor-bearing system with three-coupling faults of rub-impact, crack and pedestal looseness faults was set up, and the influences of faults to nonlinear dynamic characteristics of the system were studied by mapping and continuation comprehensive method. There are many harmonic elements of 1/3, 1/2, 2/3, 1, 3/2 and 2 et al within the sub-critical rotate speed range. But the 3/2 and 2-harmonic elements decrease within the super-critical rotate speed range. It may the main characteristics of the system with three-coupling faults of rub-impact, crack and pedestal looseness. It should notice to diagnosis the three-coupling faults of the system when running within the super-critical rotate speed range.

Nonlinear dynamic characteristics of a three-dimensional rod-fastening rotor bearing system

2014 ◽  
Vol 229 (5) ◽  
pp. 882-894 ◽  
Author(s):  
Yi Liu ◽  
Heng Liu ◽  
Xin Wang ◽  
Minqing Jing
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Three Dimensional ◽  
Dynamic Features ◽  
Stability Margins ◽  
Mass Eccentricity ◽  
Nonlinear Dynamic Characteristics ◽  
Rotor Bearing ◽  
Rod Fastening Rotor ◽  
Bearing System

The nonlinear dynamic characteristics of three-dimensional rod-fastening rotor bearing system are investigated in this paper. The rod-fastening rotor includes discontinuous shaft, rotating disks, circumferentially distributed rods, and macrointerfaces between disks. The first three parts are discretized by three dimensional elements, and the macrointerfaces are connected by some springs whose stiffness is determined by a proposed linear partition method. For comparison, the three-dimensional dynamic model of a corresponding complete rotor bearing system is also built. After the rod-fastening and complete rotor bearing system are reduced by a component mode synthesis, periodic motions and stability margins are calculated by using the shooting method and path-following technique, and the local stability of system is obtained by using the Floquet theory. Comparative results show the both systems have a resemblance in the bifurcation features when mass eccentricity and rotating speed are changed. The vibration response has the identical frequency components when typical bifurcations occur. The dynamic stress is obtained by regarding the displacements of all nodes as load. Moreover, the unbalanced and insufficient of the pre-tightening forces lead to obvious disadvantageous influence on the stability and vibration of the both systems. Generally, this paper considers the interfacial effect of the rod-fastening rotor bearing system and the relative nonlinear dynamic features are obtained.

Nonlinear Response Analysis of Three-Span Rotor-Bearing System with Three Cracks in Shafts

2013 ◽  
Vol 753-755 ◽  
pp. 1093-1097
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Hong Ying Hu
Keyword(s):  
Numerical Simulation ◽  
Dynamic Characteristics ◽  
Nonlinear Response ◽  
Crack Depth ◽  
Response Analysis ◽  
Sliding Bearings ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The model of three-span rotor-bearing system with three cracks in shaft supporting on the six sliding bearings was set up. The influences of crack faults to the responses of the rotor system were studied on numerical simulation. Along with the increase of the crack depth in first span, the main influence to the dynamic characteristics of the system is in the first span. Along with the increase of the crack depth in second span, the main influences to the response of first and third spans are in the region of critical rotate speed, and it to the second span is in the regions of critical and supercritical rotate speed. Along with the increase of the crack depth in third span, the main influences to the response of the three spans are in the region of critical rotate speed.

Nonlinear dynamic characteristics of marine rotor-bearing system under coupled heave and pitch ship motions

2020 ◽  
pp. 095440622097756
Author(s):  
Wenzhuo Zhang ◽  
Ming Li
Keyword(s):  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Ship Motions ◽  
Analytical Mechanics ◽  
Periodic State ◽  
Head Waves ◽  
Nonlinear Dynamic Characteristics ◽  
Rotor Bearing ◽  
The Stability ◽  
Bearing System

The coupled heave and pitch motions of a ship sailing in head waves affect the stability of the marine rotor-bearing system. Based on the theory of analytical mechanics, this study establishes a dynamic model of the rotor-bearing system subjected to the coupled motions of heave and pitch, considering nonlinear oil film moments produced by the tilting of the rotor in the bearings. The nonlinear dynamic behaviours of the system are analysed using numerical methods to obtain Poincaré sections, bifurcation diagrams, and the largest Lyapunov exponents. The results show that dynamic bifurcation characteristics reveal complex quasi-periodic motion of upper and lower branches after the initial instability of the system, and the speed of second instability increase markedly. At high speeds, the amplitude of the rotor system increases sharply, which can cause the rotor to touch the inner wall of the bearings in the quasi-periodic state and a failure to transition to the chaotic state. Additionally, the effects of heave and pitch amplitude variations on the dynamic characteristics of the system are also discussed.

Dynamic Characteristics of Nonlinear Elastics Rotor-Bearing System With Coupling Faults of Pedestal Looseness and Rub-Impact

2009 ◽  
Author(s):  
Yuegang Luo ◽  
Songhe Zhang ◽  
Zhaohui Ren ◽  
Bangchun Wen
Keyword(s):  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Critical Speed ◽  
Dynamic Design ◽  
Coupling Faults ◽  
Nonlinear Motion ◽  
Speed Range ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System

A dynamic model of the nonlinear elastics rotor-bearing system with coupling faults of pedestal looseness and rub-impact was set up, taking the linearity and cube item as the physics nonlinear factors. The complex characteristics of the rotor-bearing system were numerically studied. There exists complex nonlinear motion of periodic, quasi-periodic and chaotic in the response of the system. The main motions of the rotor-bearing system with rub-impact fault are periodic-2, periodic-4 and quasi-periodic within the super-critical speed range, but it with coupling faults of pedestal looseness and rub-impact are periodic-3 and chaotic. The influence of oil-film force to the rotor system is weakened by the pedestal looseness fault. The results may bring up theoretical references for fault diagnoses, dynamic design, and security running to rotor-bearing system.

Effects of Two Cracks in Shafts on Dynamic Characteristics of Two-Span Rotor-Bearing System

2012 ◽  
Vol 271-272 ◽  
pp. 1270-1274 ◽  
Author(s):  
Yue Gang Luo ◽  
Song He Zhang ◽  
Bin Wu ◽  
Hong Ying Hu
Keyword(s):  
Dynamic Characteristics ◽  
Crack Depth ◽  
Frequency Doubling ◽  
Frequency Division ◽  
Periodic Motions ◽  
Nonlinear Dynamic Model ◽  
Speed Range ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System

The nonlinear dynamic model of two-span rotor-bearing system with two cracks in shafts is set up, and the effects of two cracks in shafts on dynamic characteristics of the rotor-bearing system are analyzed. Along with the increase of the crack depth in first span, the chaotic and periodic motions increase, and the quasi-periodic motion decrease in the supercritical rotate speed. There are harmonic elements of 1/4, 1/2 and 3/4 frequency division within the sub-critical speed range at different crack depths. There appears the frequency doubling resonance obviously when the crack depths are larger. Along with the increase of the crack depth in second span, the main influences to the responses of system are in the second span. The chaotic regions increase and then decrease and the periodic motions region increase in the sub-critical rotate speed range.

Dynamic Behavior Analysis of Three-Span Rotor-Bearing System with Rub-Impact Fault

2012 ◽  
Vol 460 ◽  
pp. 160-164 ◽  
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Behavior Analysis ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Rotor System ◽  
System Response ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The dynamic model of the three-span rotor-bearing system with rub-impact fault was set up. The influence to nonlinear dynamics behaviors of the rotor-bearing system that induced by rub-impact of one disc, two discs and three discs were numerically studied. The main influence of the rotor system response by the rub-impact faults are in the supercritical rotate speed. There are mutations of amplitudes in the responses of second and third spans in supercritical rotate speed when rub-impact with one disc, and there are chaotic windows in the response of first span, and jumping changes in second and third spans when rub-impact with two or three discs.

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