Iterative dynamic condensation method of finite element model for rotor-bearing system

2021 ◽  
Author(s):  
Xun Sun ◽  
Jiwen Cui ◽  
Yue Chen ◽  
Kunpeng Feng ◽  
Hong Dang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Condensation Method ◽  
Dynamic Condensation ◽  
Rotor Bearing ◽  
Bearing System

Online Identification of the Bearing Dynamic Parameters for Rotor-Bearing Systems

2011 ◽  
Vol 141 ◽  
pp. 397-402
Author(s):  
Chang Li Liu ◽  
Shao Ping Zhou ◽  
Yuan Di ◽  
Peng Ru Xie
Keyword(s):  
Finite Element ◽  
Fault Diagnosis ◽  
Finite Element Model ◽  
Element Model ◽  
Identification Algorithm ◽  
Dynamic Parameters ◽  
Online Identification ◽  
Rotor Bearing ◽  
On Line ◽  
Bearing System

A finite element model of rotor-bearing system with two disks was derived. Based on the vibration of journals, the online identification algorithm of the bearing dynamic parameters was studied. The identification of the bearing dynamic parameters of the rotor was validated by numerical simulations. The results will contribute to on-line fault diagnosis based on model.

Finite Element Modelling of a Generic Rotor-Bearing System and Experimental Validation

2015 ◽  
Author(s):  
A. Rehman ◽  
K. S. Ahmed ◽  
F. A. Umrani ◽  
B. Munir ◽  
A. Mehboob ◽  
...  
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Finite Element Model ◽  
Element Model ◽  
Mode Shapes ◽  
Efficient Operation ◽  
Critical Speeds ◽  
Rotor Bearing ◽  
The Impact ◽  
Bearing System

The design and development of the rotating machinery require a precise identification of its dynamic response for efficient operation and failure prevention. Determination of critical speeds and mode shapes is crucial in this regard. In this paper, a finite element model (FEM) based on the Euler beam theory is developed for investigating the dynamic behavior of flexible rotors. In-house code in Scilab environment, an open source platform, is developed to solve the matrix equation of motion of the rotor-bearing system. The finite element model is validated by the impact hammer test and the dynamic testing performed on the rotors supported on a purpose-built experimental setup. Bearing stiffness is approximated by using the Hertzian contact theory. Obtaining the critical speeds and mode shapes further improves the understanding of dynamic response of rotors. This study paves way towards advanced research in rotordynamics in Faculty of Mechanical Engineering, GIK Institute.

Transient Analysis of an Asymmetric Rotor-Bearing System During Acceleration

1992 ◽  
Vol 114 (4) ◽  
pp. 465-475 ◽  
Author(s):  
An-Chen Lee ◽  
Yuan Kang ◽  
Kun-Lung Tsai ◽  
Kuo-Mo Hsiao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Transient Analysis ◽  
Element Model ◽  
Dynamic Equations ◽  
Critical Speeds ◽  
Rotor Bearing ◽  
Asymmetric Rotor ◽  
The Finite Element Model ◽  
Bearing System

This paper deals with the transient vibration of asymmetric rotor systems during acceleration passing through several critical speeds at which synchronous or super-harmonic resonance occurs. The dynamic equations of the rotor-bearing system are formulated by the finite element model and the resulting dynamic equations are time-varying due to the effects of acceleration and asymmetry. In the formulation, a Timoshenko beam element is employed to simulate the rotating shaft and Eulerian angles are used to describe the orientations of the shaft element and disk. The numerical integration scheme for transient analysis is generated from the finite element model. Numerical examples are presented to illustrate (1) the effects of acceleration on peak amplitude and speed at which the peak occurs as the system passes through critical speeds, (2) the optimal acceleration process, which can be obtained by minimizing the peak response and the period of acceleration, (3) the speed regions where the transient instability exists.

Study on Looseness and Impact - Rub Coupling Faults of a Vertical Dual-Disk Cantilever Rotor- Bearing System

2007 ◽  
Vol 353-358 ◽  
pp. 2479-2482
Author(s):  
Yan Jun Lu ◽  
Zhao Hui Ren ◽  
Hong Chen ◽  
Nai Hui Song ◽  
Bang Chun Wen
Keyword(s):  
Finite Element ◽  
Low Frequency ◽  
Element Model ◽  
Coupling Faults ◽  
Mechanics Model ◽  
Low Frequency Vibration ◽  
Rotor Bearing ◽  
Impact And Rubbing ◽  
The Impact ◽  
Bearing System

Because of wrong setting or long-term running of rotating machinery, the looseness may ouur in the bearing seats or bases. And also bring impact and rubbing of rotor-stator, That is the looseness and rub-impact coupling fault. In the paper,a mechanics model and a finite element model of a vertical dual-disk cantilever rotor- bearing system with coupling faults of looseness and rub-impact are set up. Based on the nonlinear finite element method and contact theory, the dynamical characteristices of the system under the influence of the looseness rigidity and impact-rub clearance is studied. The results show that the impact-rub of rotor-stator can reduce the low frequency vibration caused by looseness, and the impact-rub caused by looseness has obvious orientation. Also, the conclusion of diagnosing the looseness and rub-impact coupling faults is given in the end of the paper.

Modeling and Analyzing of Vibration in Working Crankshaft with Cracks

2005 ◽  
Vol 293-294 ◽  
pp. 401-408
Author(s):  
Xuan Yang Lei ◽  
Gui Cai Zhang ◽  
Xi Geng Song ◽  
Jin Chen ◽  
Guang Ming Dong
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
The Other ◽  
Lumped Mass ◽  
Beam Elements ◽  
System A ◽  
Nonlinear Motion ◽  
Simplified Finite Element Model ◽  
Bearing System

In this paper, a simplified finite element model of the cracked crankshaft is proposed, and a new method for simulating the nonlinear vibration of operating crankshaft with several cracks is presented. For crankshaft, cracks occur frequently in the parts of crankpin-web fillet region and the edge of oil aperture because of fatigue or damage. According to the characteristic of those cracks, the cracked parts are modeled by the corresponding cracked spatial finite elements respectively, and two cracked elements are discussed in this study. The other, un-cracked, crankshaft parts are modeled by spatial Timoshenko beam elements. Flywheel and front pulley are simplified as lumped mass elements, and main bearings are simulated by equivalent linear springs and dashpots. In order to find the dynamic response of crankshaft-bearing system, a right-handed rotating coordinate system attached to crankshaft is applied. Based on the proposed finite element model, the breathing behavior of cracks in operating crankshaft is studied, and the nonlinear motion equation with variational stiffness is formed. Finally, a four-in-line crankshaft is taken as an example, and its vibration response corresponding to different kinds of crack are calculated and analyzed. Some conclusions are drawn, and a foundation is laid for diagnosing crack fault of crankshaft.

Finite element model of asymmetrical rotor-bearing systems

KSME Journal ◽  
1988 ◽  
Vol 2 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Yang -Gyu Jei ◽  
Chong -Won Lee
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Rotor Bearing

Whirl Speeds and Unbalance Response of Rotor-Bearing Systems Using Finite Dynamic Elements

1997 ◽  
Author(s):  
Bo-Suk Yang ◽  
Hyung-Sub Hwang ◽  
Sae-Kyoo Oh
Keyword(s):  
Finite Element ◽  
Shape Function ◽  
Element Model ◽  
Rotor Dynamics ◽  
Shape Functions ◽  
Unbalance Response ◽  
Rotor Bearing ◽  
Dynamics Problems ◽  
Dynamic Element ◽  
Bearing System

Abstract The conventional finite element model for rotor-bearing system are formed using shape functions which are based on static displacements, and can lead some errors in analysis of general rotor dynamics problems. A procedure is presented for dynamic modeling of rotor-bearing system which consist of finite dynamic shaft elements, rigid disk, and bearing element. A finite dynamic element model including the effects of rotary inertia, gyroscopic moments, axial force, and axial torque is developed using the frequency dependent shape function. The natural whirl speeds, stability, and unbalance response of rotor system are calculated on several cases and compared with the conventional finite elements.

A Numerical Study on Vibrations of a Roller Bearing With a Surface Crack in the Races

2017 ◽  
Author(s):  
Jing Liu ◽  
Zhifeng Shi ◽  
Yimin Shao ◽  
Boyang Shi ◽  
Zhongjian Tian ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Surface Crack ◽  
Roller Bearing ◽  
Element Model ◽  
Dynamic Finite Element ◽  
Roller Bearings ◽  
Slant Surface ◽  
Explicit Dynamic ◽  
Bearing System

Vibrations of roller bearings will be affected when a surface crack is caused in the bearing system. Thus, it is very helpful to study relationships between the sizes of the surface crack and vibrations of the bearings for detecting and diagnosing the surface crack in the bearing systems. In this study, a dynamic finite element model for a roller bearing with a vertical or slant surface crack on its outer race is presented using an explicit dynamic finite element software package. All components of the roller bearing are formulated as elastic bodies in the finite element model, which can consider the elastic deformations in the bearing system. Effects of the depth and slope angle of the surface crack on the contact forces between the roller and races of the bearing are studied, as well as the vibrations of the bearing. The simulation results show that the explicit dynamic finite element analysis method can be applied for studying the vibration characteristics produced by a vertical or slant surface crack in roller bearings.

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