scholarly journals Vibration characteristics of a rotor-bearing system caused due to coupling misalignment – a review

2021 ◽  
Vol 39 ◽  
pp. 1-10
Author(s):  
Ashutosh Kumar ◽  
Prabhakar Sathujoda ◽  
Vinayak Ranjan
Keyword(s):  
Vibration Characteristics ◽  
Rotor Bearing ◽  
Bearing System

Nonlinear vibration characteristics of the rotor bearing system with bolted flange joints

2019 ◽  
Vol 233 (4) ◽  
pp. 910-930
Author(s):  
Yifu Zhou ◽  
Zhong Luo ◽  
Zifang Bian ◽  
Fei Wang
Keyword(s):  
Nonlinear Vibration ◽  
Time Domain ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Rolling Bearing ◽  
Vibration Characteristics ◽  
Rotor System ◽  
Rotor Bearing ◽  
Bolted Flange ◽  
Bearing System

As sophisticated mechanical equipment, the rotor system of aero-engine is assembled by various parts; bolted flange joints are one of the essential ways of joints. Aiming at the analysis of the nonlinear vibration characteristics of the rotor-bearing system with bolted flange joints, in this paper, a finite element modeling method for a rotor-bearing system with bolted flange joints is proposed, and an incremental harmonic balance method combined with arc length continuation is proposed to solve the dynamic solution of the rotor system. In order to solve the rotor system with rolling bearing nonlinearity, the alternating frequency/time-domain process of the rolling bearing element is deduced. Compared with the conventional harmonic balance method and the time-domain method, this method has the characteristics of fast convergence and high computational efficiency; solving the rotor system with nonlinear bearing force; overcome the shortcoming that the frequency–response curve of the system is too sharp to continue solving. By using this method, the influence of bearing clearance and stiffness on vibration characteristics of the rotor system with bolted flange joints is studied. The evolution law of the state of the rotor system with bolt flange is investigated through numerical simulation and experimental data. The results indicated that the modeling and solving method proposed in this paper could accurately solve the rotor-bearing system with bolted flange joints and analyze its vibration characteristics.

Experimental and Numerical Studies on Spherical Roller Bearings Using Multivariable Regression Analysis

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
R. G. Desavale ◽  
R. Venkatachalam ◽  
S. P. Chavan
Keyword(s):  
Regression Analysis ◽  
Sugar Cane ◽  
High Speed ◽  
Roller Bearing ◽  
Vibration Characteristics ◽  
Multivariable Regression Analysis ◽  
Rotor Bearing ◽  
Multivariable Regression ◽  
Bearing Structure ◽  
Bearing System

Many industries make wide use of rotor bearing systems such as high speed turbines and generators. However, the vibration of antifriction rotor–bearings is a key factor in reducing the life of the bearings; thus significantly influencing the performance and working life of the whole power plant. In earlier research on the vibration characteristics of high speed rotor–bearing systems, such as in induced draft (ID) fans, an application used in sugar cane factories, the supporting antifriction bearings were simplified as a particle on a shaft with radial stiffness and damping coefficient. However, such simplification neglects the effects of the bearing structure on the vibration performance of the rotor–bearing system. This paper demonstrates the benefits of a more holistic approach and establishes a numerical model of the stiffness of the spherical roller bearing through Buckingham's π theorem (BPT). On the basis of this model, we argue for the benefits of a new dimensional analysis (DA) technique for rotor–bearing systems. Our new DA also considers the influences of the bearing structure parameters on the vibration of rotor–bearing systems. We demonstrate the effectiveness of our approach by conducting a comparative BPT study using an ID fan, a rotor–bearing system in use in sugar cane factories. We first analyzed an ID fan using the simplified model to obtain the defect frequencies and vibration amplitude responses of the ID fan system. Subsequently the same ID fan rotor was also analyzed using our new multivariable regression analysis (MVRA) approach to verify the validity of our new and holistic BPT. The results indicate that the new method we propose in this paper for the calculation of vibration characteristics of a high speed rotor–bearing (ID fan) is credible and will save time and costs by the accurate detection of imminent bearing failure.

A novel method to determine the coupling scaling laws of vibration characteristics for rotor-bearing systems

2020 ◽  
pp. 107754632096402
Author(s):  
Wendi Zhang ◽  
Zhong Luo ◽  
Yuqi Li ◽  
Yunpeng Zhu
Keyword(s):  
Iteration Method ◽  
Scaling Laws ◽  
Vibration Characteristics ◽  
Scaled Model ◽  
Geometric Scaling ◽  
Rotor Bearing ◽  
Novel Method ◽  
Scaled Models ◽  
Distorted Model ◽  
Bearing System

The purpose of this article is to study the coupling effects of support stiffness on geometric scaling factor powers of the rotor-bearing system and predict vibration characteristics of a prototype by scaled models accurately. Associated to the least-squares–based similitude method, the discrete iteration method proposed evaluates the estimated scaling laws under variable (instable) powers and further broadens the restriction of boundary conditions in scaling laws, which is the main finding in this article. The discrete iteration method does not need to establish a physical model but directly uses input and output parameters to establish output scaling laws. The complete scaled model and geometric distorted model are selected as study cases to prove the effectiveness and accuracy of the discrete iteration method. The vibration characteristics of the rotor-bearing system are obtained by the finite element method with validation by experimental test for the natural characteristics. The comparison between the prediction results and those without the discrete iteration method shows that discrete iteration method can significantly improve the accuracy for predicting the prototype.

Experimental Research on Nonlinear Vibration Characteristics of Rotor Bearing System With Coupling Fault of Rub-Impact and Oil Whirl

2005 ◽  
Author(s):  
Changli Liu ◽  
Yimin Zhang ◽  
Qing Kai Han ◽  
Bangchun Wen
Keyword(s):  
Nonlinear Vibration ◽  
Experimental Research ◽  
Vibration Characteristics ◽  
Rotor System ◽  
Harmonic Vibration ◽  
Oil Film ◽  
Oil Whirl ◽  
Rotor Bearing ◽  
Coupling Fault ◽  
Bearing System

An experimental rotor rig was developed to investigate nonlinear vibration characteristics of rotor bearing system with coupling fault of rub-impact and oil whirl. It was found that when the effect of oil film force on a rub-impact rotor system is comparatively weak, the rotor/stator rub-impact will cause the system to give rise to sub- and super-harmonic vibration components. In a rub-impact rotor system with oil whirl fault, super-harmonic vibration components were excited, when rotor/stator rub-impact happens before oil film whirl because of small rotor/stator clearance. When the rotor/stator clearance is comparatively large, the rub-impact happens after oil film whirl, and the effect of rub-impact on the rotor system will be very weak.

Effects of Coupling Misalignment on the Vibration Characteristics of a Two Stage Turbine Rotor

1995 ◽  
Author(s):  
P. Arumugam ◽  
S. Swarnamani ◽  
B. S. Prabhu
Keyword(s):  
Turbine Rotor ◽  
Vibration Characteristics ◽  
Periodic Excitation ◽  
Two Stage ◽  
Flexible Element ◽  
Rotor Bearing ◽  
Reaction Forces ◽  
Rotating Shafts ◽  
Flexible Mechanisms ◽  
Bearing System

Abstract Misalignment between driving and driven machines is unavoidable. Flexible couplings are used to accommodate the misalignment. The flexible mechanisms in the coupling impose moments on the rotors connected. The reaction forces developed due to the imposed moments act as periodic excitation forces on the rotating shafts. In the present work the effect of these reaction forces on the vibration characteristics of a two-stage turbine rotor-bearing system has been studied considering flexible element coupling.

Experimental Investigation of Pedestal Looseness in a Rotor-Bearing System

2009 ◽  
Vol 413-414 ◽  
pp. 599-605 ◽  
Author(s):  
Wen Xiu Lu ◽  
Fu Lei Chu
Keyword(s):  
Experimental Investigation ◽  
Nonlinear Vibration ◽  
Nonlinear Response ◽  
Harmonic Component ◽  
Vibration Characteristics ◽  
Experimental Setup ◽  
Rotor Bearing ◽  
Harmonic Components ◽  
Bearing System

An experimental setup of rotor-bearing system is installed and vibration characteristics of the system with pedestal looseness are investigated. The pretightening bolt between the bearing house and pedestal is adjusted to simulate the pedestal looseness fault. The vibration waveforms, spectra and orbits are used to analyze the nonlinear response of the system with pedestal looseness. Different parameters, including speed, looseness gap, imbalance mass and disk position are changed to observe the nonlinear vibration characteristics. The experiments show that the system motion generally contains the 1/2X fractional harmonic component and multiple harmonic components such as 2X, 3X, etc. Under some special conditions, the pedestal looseness occurs intermittently, that is, occurs in some periods and doesn’t in other periods.

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