Vibration Analysis Of A Motor-Flexible Coupling-Rotor System Subject To Misalignment And Unbalance, Part I: Theoretical Model And Analysis

1994 ◽  
Vol 176 (5) ◽  
pp. 663-679 ◽  
Author(s):  
M. Xu ◽  
R.D. Marangoni
Keyword(s):  
Theoretical Model ◽  
Vibration Analysis ◽  
Rotor System ◽  
Flexible Coupling

scholarly journals Vibration Analysis of Rotor - Coupling - Bearing System With Misaligned Shafts

1996 ◽  
Author(s):  
A. Sreenivasa Rao ◽  
A. S. Sekhar
Keyword(s):  
Theoretical Model ◽  
Finite Elements ◽  
Vibration Analysis ◽  
Rotating Machinery ◽  
Value Analysis ◽  
Flexible Coupling ◽  
Eigen Value ◽  
Shaft Misalignment ◽  
Reaction Forces ◽  
Bearing System

The shaft misalignment, even being a common fault in rotating machinery, is not sufficiently studied. The present work addresses effects of misalignment in rotating machinery. An attempt to give a theoretical model for a rotor-coupling-bearing system has been done. The rotor-bearing system including the flexible coupling is modelled using the finite elements. The reaction forces and moments developed due to flexible coupling misalignment both for parallel and angular are derived and introduced in the model. Vibration analyses such as eigen value analysis and unbalance response are carried out for the rotor system with misaligned shafts.

Rotor Instability Due to Coupled Effect of Lateral and Torsional Modes and Improper Bearing Design

1997 ◽  
Author(s):  
Yatao Zhang ◽  
Jari Nyqvist
Keyword(s):  
Theoretical Model ◽  
Torsional Vibration ◽  
Vibration Analysis ◽  
Rotor System ◽  
Squeeze Film ◽  
Vibration Problem ◽  
Coupled Effect ◽  
Bearing Design ◽  
The Stability ◽  
Bending Modes

Abstract This paper deals with a special subsynchronous vibration problem, namely rotor instability caused by partly coupled effect of torsional and bending modes and partly improper bearing design. A theoretical model is presented to investigate such complicated vibration problem. The analysis shows that a single bending or torsional vibration analysis is not enough to predict the stability of a geared rotor system, which includes a turbine, a gear, a generator, several bearings, a squeeze film damper and stators. Either a bearing design, which gives stability in single lateral vibration analysis, cannot guarantee the stability if a torsional vibration mode is involved. This indicates that the bearing design plays much more significant role in a geared rotor system. The theoretical model has been successfully applied to a steam turbine set, which experienced such kind of subsynchronous vibration, by modifying the original bearing design.

scholarly journals Nonlinear Vibration Analysis of Rotor considering Cogging and Harmonic Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shanle Li ◽  
Feng Liu ◽  
Hongyan Wang ◽  
Haijun Song ◽  
Kuilong Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Magnetic Force ◽  
Rotor System ◽  
Kutta Method ◽  
Rotor Vibration ◽  
Motion Equations ◽  
Runge Kutta Method ◽  
Static Eccentricity ◽  
New Formula

This paper aims to investigate nonlinear vibration characteristics of rotor system considering cogging and harmonic effects. Firstly, relative permeance with eccentric was established and then corrected by correction factor caused by the cogging effect. Based on the new formula of relative permeance, the expression of unbalanced magnetic force was obtained, and the coefficient of cogging effect was defined. Motion equations of rotor system were established, and Runge–Kutta method was used to solve the equations. Results showed that errors between finite and analytical results were smaller considering cogging and harmonic effects. When the harmonics were taken into consideration, the vibration of rotor increases sharply. When the cogging and harmonics were taken into consideration simultaneously, the vibration of rotor decreased instead, which means that stator slots have the effect of reducing vibration in rotor system. Rotor vibration was axis symmetry with static eccentricity rather than central symmetry with no eccentricity, and double, four times, and six times supply frequency always existed in the components of main frequency with eccentric.

Vibration Analysis of a Rail Operating Vehicle

2013 ◽  
Vol 662 ◽  
pp. 591-594
Author(s):  
Wei Guo ◽  
Qian Ding
Keyword(s):  
Vibration Analysis ◽  
Reference Value ◽  
Dynamical Model ◽  
Dynamical Response ◽  
Euler Beam ◽  
Bogie Frame ◽  
Dynamic Design ◽  
Flexible Coupling ◽  
Car Body ◽  
Operating Vehicle

A simplified rigid-flexible coupling dynamical model of the rail operating vehicle, including bogie frame and car body, was built. The car body is modeled as a flexible uniform Euler beam. The dynamical response of the vehicle under the irregularity dynamic action between wheel and rail was numerically calculated and analyzed by the fast stability algorithms. Influences of the suspension on vibration and stability of the vehicle are analyzed. The results have a certain reference value on the dynamic design of multi-functional track operating vehicle.

Coupled Bending-Torsional Vibration Analysis of Rotor System with Two Asymmetric Disks

2011 ◽  
Vol 130-134 ◽  
pp. 2335-2339
Author(s):  
Jun Hong Zhang ◽  
Zhen Peng He ◽  
Wen Peng Ma ◽  
Liang Ma ◽  
Gui Chang Zhang
Keyword(s):  
Phase Difference ◽  
Vibration Analysis ◽  
Initial Phase ◽  
Rotor System ◽  
Dynamic Equations ◽  
Force Model ◽  
Torsional Angle ◽  
Kutta Method ◽  
Internal Damping ◽  
Initial Phase Difference

The dynamic equations derived based on the actual rotor system with two asymmetric disks. In the analysis, the eccentric, rubbing fault characteristics and internal damping effects is considered, and all the analysis is established based on nonlinear oil film force model and coupled bending-torsional differential equations. The Rugge-Kutta method is used to solve numerical model, the torsional displacement response, torsion angle and Poincare map are obtained. The results show torsion amplitudes with initial phase difference π / 2 is larger than initial phase difference of π and 0. In order to eliminate the rigid rolling component the relative torsional angle must be considered.

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