Three methods for studying coupled vibration in a multi flexible disk rotor system

2017 ◽  
Vol 31 (11) ◽  
pp. 5219-5229 ◽  
Author(s):  
Yi-Jui Chiu ◽  
Xiao-Yun Li ◽  
Yi-Cheng Chen ◽  
Sheng-Rui Jian ◽  
Chia-Hao Yang ◽  
...  
Keyword(s):  
Rotor System ◽  
Coupled Vibration ◽  
Flexible Disk

Transient Vibration of High-Speed, Lightweight Rotors Due to Sudden Imbalance

1983 ◽  
Vol 105 (3) ◽  
pp. 480-486 ◽  
Author(s):  
M. Sakata ◽  
T. Aiba ◽  
H. Ohnabe
Keyword(s):  
Transient Response ◽  
High Speed ◽  
Rotor System ◽  
Response Analysis ◽  
Transient Vibration ◽  
Flexible Shaft ◽  
Shaft System ◽  
Transient Response Analysis ◽  
Flexible Disk ◽  
Blade Loss

In the field of rotor dynamics, increased attention is being given to the transient response analysis of the rotor, since the effects of impact loading and vibrations of the rotor arising from blade loss can be studied by a time transient solution of the rotor system. As recent trends in rotating machinery have been directed towards lightweight, high-speed flexible rotors, the effect of flexibility on transient response analysis is becoming of increasing importance. In the present paper, a transient vibration analysis is carried out on a flexible-disk/flexible-shaft system or rigid-disk flexible-shaft system subjected to a sudden imbalance that is assumed to represent the effect of blade loss. To solve the basic equation governing a rotating flexible disk the Galerkin’s method is used, and the equation of motion of the rotor system is numerically solved by employing the Runge-Kutta-Gill’s method. Experiments were conducted on a model rotor having a blade loss simulator; the shaft vibrations were also measured. The validity of the anaytical results was demonstrated by comparison with the experimental results.

Method of Coupled Vibration Control for Dual Rotor System With Inter-Shaft Bearing

2021 ◽  
Author(s):  
Yanhong Ma ◽  
Chenglong Shi ◽  
Bo Sun ◽  
Jie Hong
Keyword(s):  
Vibration Control ◽  
Mode Coupling ◽  
Weight Ratio ◽  
Low Pressure ◽  
Rotor System ◽  
Coupled Vibration ◽  
Coupling Vibration ◽  
Rotor Systems ◽  
Modal Coupling ◽  
Coupling Characteristics

Abstract Structural layout scheme of dual rotor system with inter-shaft bearing plays an important role in reducing the bearing frame and structure weight of areo-engine. This kind of scheme is often used in the design of high thrust-weight ratio turbofan engine. However, the inter-shaft bearing will cause the direct interaction of the force and displacement between the high and low pressure rotor systems, contributing to the coupling of the dynamic characteristics of two rotor systems. The coupling may eventually lead to the failure of the rotor displacement control, loss of the robustness of the connection structure or excessive dynamic load of the bearing. The main purpose of this paper is to, firstly study and quantitatively evaluate the coupling characteristics of the dual rotor system, secondly obtain the correlation between the structural feature parameters such as the position of the inter-shaft bearing and the coupling vibration or interactive excitation characteristics of the system, finally propose the coupling vibration control method of dual rotor system. The dynamic model of dual rotor system with inter-shaft bearing is established. The modal frequencies and modes of dual rotor system with or without coupling are analyzed and compared. The results illustrate the complexity of coupled vibration of high pressure and low pressure rotors. Then modal coupling characteristics evaluation parameter of dual rotor system based on energy distribution relationship is proposed. Using the coupling factor defined, the correlation between the inter-shaft bearing support feature and the modal coupling characteristics is discussed. The results show that, placing the inter-shaft bearing near the mass center of low pressure turbine can effectively restrain the mode coupling, meanwhile the proportion of bearing strain energy can also reflect the mode coupling characteristics of dual rotor system to a certain extent. Then a method of controlling the response coupled vibration of dual rotor system with inter-shaft bearing, based on the principle of mode superposition, is proposed. An example verifies the method can control the response coupling vibration of dual rotor system in wide speed range and under complex excitation conditions.

scholarly journals A Study of the Influence of Rubbing on the Dynamics of a Flexible Disk Rotor System

1993 ◽  
Author(s):  
Fangsheng Wu ◽  
George T. Flowers
Keyword(s):  
Harmonic Balance ◽  
Dynamical Behavior ◽  
Harmonic Balance Method ◽  
Rotor System ◽  
Governing Equations ◽  
System A ◽  
Jeffcott Rotor ◽  
Inertial Moment ◽  
Flexible Disk ◽  
Rotor Model

This study is concerned with investigating the influence of lateral disk flexibility on the dynamics of a rotor system experiencing rub. A rotating, flexible continuous disk/shaft model was developed and the dynamical behavior of this system with and without rubbing was studied. The model developed in this study is similar to the Jeffcott rotor model except that the disk is treated as a laterally flexible continuous circular plate. The motion of the disk was transformed from physical coordinates to a set of generalized coordinates under which the generalized motion was uncoupled and the responses were calculated. Then the inertial moment acting on the shaft was computed and introduced into the governing equations of the shaft motion. Direct integration and the harmonic balance method were used to study the steady state motion of the system. A number of parameter variation studies were performed for varied rub clearances and disk mass influence ratios. The system responses to the rub, its occurrence and development, and the global stability of the observed responses were studied. The results show that rub can be classified into two types: light rub and heavy rub, and the light rub has the forms of forward, backward, or mixed whirling motion. The results also show that the disk flexibility may alter the critical speed to some degree and may also significantly affect the amplitude and stability of the rotor vibration.

Roll-Yaw Coupled Vibration of the Rotor System With Breathing Crack and Unbalance Mass

2015 ◽  
Author(s):  
J. Zhao ◽  
H. A. DeSmidt ◽  
M. Peng ◽  
W. Yao
Keyword(s):  
Coupling Effect ◽  
Rotor System ◽  
Crack Model ◽  
Clear Understanding ◽  
Coupled Vibration ◽  
Breathing Crack ◽  
Energy Concept ◽  
Vibration Responses ◽  
Rolling Rate ◽  
Rotor Model

This paper develops a new finite element rotor model with consideration of the coupling effect of rolling and yawing motion. The crack model is built using released strain energy concept in fracture mechanics. The nonlinear breathing behavior of cracks on the rotor shaft is simulated through Zero Stress Intensity Factor (SIF) method. The vibration responses of rotor system are solved by Newmark Integration method for both nominal and damaged system. With the yawing motion, the additional force will be induced for beam element and center disk. Incorporated with breathing crack model, the breathing behavior of crack is comprehensively studied in terms of the rolling rate, yawing rate and yawing acceleration. The clear understanding of crack breathing behavior is beneficial for the damage detection and health monitoring of the rotor system.

scholarly journals Effects of Surface Waviness on the Nonlinear Vibration of Gas Lubricated Bearing-Rotor System

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Jian Li ◽  
Shaoqi Yang ◽  
Xiaoming Li ◽  
Qing Li
Keyword(s):  
Nonlinear Dynamic ◽  
Dynamic Performance ◽  
Engineering Application ◽  
Axial Direction ◽  
Rotor System ◽  
Circumferential Direction ◽  
Coupled Vibration ◽  
Surface Waviness ◽  
The Stability ◽  
Gas Bearing

This paper presents the effects of the surface waviness on the nonlinear dynamic performance of a gas bearing-rotor system. The coupled vibration with the elastomer is taken into consideration to fit the actual engineering application. The effects of the directions, the amplitudes, and the numbers of waves to the nonlinear dynamic performance are investigated. The results show that the existence of the surface waviness in the circumferential direction can improve the stability of the system obviously. But the surface waviness in the axial direction is damage to the system. The nonlinear dynamic performance of the system is insensitive to the number of surface waviness. The increase of the amplitude of the waviness in circumferential direction can improve the stability of the system.

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