A dynamic model of an overhung rotor with ball bearings

2011 ◽  
Vol 225 (4) ◽  
pp. 310-321 ◽  
Author(s):  
O Cakmak ◽  
K Y Sanliturk
Keyword(s):  
Ball Bearing ◽  
Element Model ◽  
Contact Dynamics ◽  
Ball Bearings ◽  
Cage Structure ◽  
Order Tracking ◽  
Rolling Elements ◽  
Localized Defects ◽  
Gyroscopic Effects ◽  
Multi Body

A ball bearing comprising rolling elements, inner and outer rings, and a cage structure can be described as a multi-body system (MBS). In order to predict the dynamic behaviour and resonance characteristics of a rotor–ball bearing system, it can be modelled and analysed as a MBS with flexible and rigid parts. In this study, a ball bearing is modelled with MBS approach using MSC ADAMS commercial software. The Hertzian theory is used for modelling the contact dynamics between the balls and the rings. The ball bearing model is then assembled with the rotor model which comprised a shaft and a disc positioned at the free end of the shaft. The ball bearing model is used with both flexible and rigid shaft assumptions in order to highlight the differences between the two cases. For the flexible shaft case, the MBS model also included a finite element model of the shaft. As expected, it is necessary to include the flexibility of the shaft in the model in order to to predict the changes in the modal characteristics of the system as a function of the rotor speed. Furthermore, including the gyroscopic effects leads to observe the forward and backward travelling modes with different natural frequencies. The effects of the bearing diametral clearance and localized defects on the inner and outer rings are modelled and analysed using the model developed. Also, the effects of the rotor unbalance on the vibration level of the whole system are examined. A test rig – consisting of two ball bearings, a shaft, and a disc – is also designed and developed so as to validate the theoretical model using experimental data. Order tracking and modal analyses are carried out and Campbell diagrams are obtained. Finally, the theoretical and the experimental results are compared and a refined MBS model is obtained for further analyses.

Modelling and Validation of a Rotor System With Ball Bearings

2010 ◽  
Author(s):  
Onur Cakmak ◽  
Kenan Y. Sanliturk
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Ball Bearing ◽  
Ball Bearings ◽  
Test Rig ◽  
Transform Method ◽  
Order Tracking ◽  
Bearing Defects ◽  
Gyroscopic Effects ◽  
Short Time

In this paper, a dynamic model of a rotor-ball bearing system is developed in Msc. ADAMS commercial software. Contacts between the balls and the rings are modelled according to Hertzian theory. The bearing model is capable of representing the effects of bearing defects and internal clearances. When they are coupled with the rotor structures, bearings without any defect can also cause excessive vibrations due to the resonance characteristics of the system. In order to demonstrate these characteristics the rotor itself is modelled as a flexible shaft and a disc positioned at the free end of the shaft. The rotor-ball bearing model developed here is capable of representing the gyroscopic effects and the behaviour of the system under different unbalance conditions. Various case studies are performed and Campbell diagrams are obtained by using short-time Fourier transform method. A test rig consisting of two ball bearings, a shaft and a disc is also designed and developed so as to validate the theoretical model using experimental data. The test rig is developed in such a way that all of the elements are easy to assemble/disassamble, allowing quick observation of the system’s dynamic behaviour for different parameters including imbalance, internal clearance and bearing defects. Modal analysis and order tracking analysis were carried out using the test rig. Both the modal results and Campbell diagrams obtained using experimental data are compared with their theoretical counterparts. In the light of the experimental data, the theoretical model is validated for the purpose of further analyses and research.

Finite Element Modeling and Analysis of Rolling Bearing Based on Explicit Dynamics

2013 ◽  
Vol 397-400 ◽  
pp. 589-592 ◽  
Author(s):  
Jing Cui ◽  
Hua Qing Wang ◽  
Fei Xiao ◽  
Zuo Yi Dong
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Rolling Bearing ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Body Contact ◽  
Explicit Dynamics ◽  
Deep Groove ◽  
Rolling Elements ◽  
Multi Body

A finite element model of a rolling bearing with ANSYS/LS-DYNA is bulit , considering pressure, speed, multi-body contact effects and constraints under friction. The movement process of the rolling bearing based on explicit dynamics is simulated successfully. Several relevant parameters of 6205 deep groove ball bearing are calculated and determined. The results show that rotational speeds of cage and rolling elements which get from finite element analysis are consistent with the theoretical calculated values and stress situations are the same as Hertz analysis solutions. It proves that the proposed model is effective, which lays a foundation for subsequent analysis and diagnosis for defected bearings.

Hysteretic Resonances and Intermittency Chaos in Ball Bearings

2018 ◽  
Author(s):  
Zhiyong Zhang ◽  
Xiaoting Rui ◽  
Yushu Chen ◽  
Wenkai Dong ◽  
Lei Li
Keyword(s):  
Ball Bearing ◽  
Harmonic Balance Method ◽  
Rolling Bearing ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Rotor Systems ◽  
Revolute Joints ◽  
Rolling Elements ◽  
Varying Compliance

Ball bearings are essential parts of mechanical systems to support the rotors or constitute the revolute joints. The time-varying compliance (VC), bearing clearance and the Hertzian contact between the rolling elements and raceways are three fundamental nonlinear factors in a ball bearing, hence the ball bearing can be considered as a nonlinear system. The hysteresis and jumps induced by the nonlinearities of rolling bearings are typical phenomena of nonlinear vibrations in the rolling bearing-rotor systems. And the corresponding hysteretic impacts have direct effects on the cleavage derivative and fatigue life of the system components. Therefore, the behaviors of hysteresis and jumps are given full attentions and continued studies in the theoretical and engineering fields. Besides, many researchers have done a lot of calculations to depict the various characteristics of bifurcations and chaos in the rolling bearings and their rotor systems, but few researches have been addressed on the inherent mechanism of the typical intermittency vibrations in rolling bearings. With the aid of the HB-AFT (the harmonic balance method and the alternating frequency/time domain technique) method and Floquet theory, this paper will investigate deeply the resonant hysteresis and intermittency chaos in ball bearings.

Analysis of Roller/Ball Bearing Vibrations

1979 ◽  
Vol 101 (1) ◽  
pp. 118-125 ◽  
Author(s):  
S. Braun ◽  
B. Datner
Keyword(s):  
Spectral Analysis ◽  
Diagnostic Method ◽  
Search Strategy ◽  
Ball Bearing ◽  
Ball Bearings ◽  
Periodic Functions ◽  
Localized Defects

Described is a vibration based diagnostic method aimed at detecting localized defects developing in roller/ball bearings. The signature is decomposed into generalized periodic functions and a search strategy for the various components developed and implemented. The method is shown to be applicable for cases where spectral analysis fails to give results.

Application of Vibration Analysis in Ball Bearing Fault Detection

2005 ◽  
Author(s):  
F. Bakhtiary-Nejad ◽  
A. H. Nayeb ◽  
S. E. Yeganeh
Keyword(s):  
Fault Detection ◽  
Computer Program ◽  
Time Domain ◽  
Vibration Analysis ◽  
Ball Bearing ◽  
Detection Method ◽  
Ball Bearings ◽  
Test Results ◽  
Localized Defects ◽  
Set Up

In this paper, existence of localized defects in a ball bearing has been diagnosed using vibration analysis. First, different kinds of faults which occur in ball bearings have been investigated. Then an analytical model has been proposed for determining the damaged ball bearing vibrations due to a localized defect. Also various methods of fault detection have been evaluated. Next, in order to examine the ball bearings, a testing set-up has been designed and constructed. Then by preparing a computer program, which calculates defect frequencies, some ball bearings have been tested. The test results were originally derived in time-domain. Then by using vibration analysis of healthy and damaged ball bearings in frequency-domain, a fault detection method for ball bearings has been proposed.

scholarly journals Thermo-dynamical modelisation of the degradation of a ball bearing in variables use conditions

2020 ◽  
Vol 21 (6) ◽  
pp. 608
Author(s):  
Dalila Belmiloud ◽  
Mohammed Lachi ◽  
Hervé Pron ◽  
Fabrice Bolaers ◽  
Jean-Paul Dron ◽  
...  
Keyword(s):  
Thermal Model ◽  
Ball Bearing ◽  
Ball Bearings ◽  
Thermal Heating ◽  
Nodal Method ◽  
Rotating Machine ◽  
Rolling Elements ◽  
Many Sources ◽  
Different Parts ◽  
Over Time

Many sources of heat can emanate from the operation of a rotating machine, and one of which is the friction among the different parts of the ball bearings. Over time, these frictions may lead to a tearing of matter of the rings or on the rolling elements that cause some type of degradation by flaking. Flaking, in turn, produces a repetitive shock as a new source of thermal energy. This work proposes a physical model for the study of the thermal heating of a ball bearing during operation. The resolution of the energy balance is achieved by the Nodal method where both the heating due to friction and the heat induced by the passage of the balls on defect are taken into account. The proposed thermal model is validated through an experimental thermal analysis. The obtained results show that the temperature increases in the position of defect ball ring with increasing rotational speed. The same results are obtained for the influence of radial load.

Nonlinear Excitation Model of Ball Bearing Waviness in a Rigid Rotor Supported by Two or More Ball Bearings Considering Five Degrees of Freedom

2001 ◽  
Vol 124 (1) ◽  
pp. 82-90 ◽  
Author(s):  
G. H. Jang ◽  
S. W. Jeong
Keyword(s):  
Degrees Of Freedom ◽  
Ball Bearing ◽  
Angular Displacement ◽  
Equations Of Motion ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Rigid Rotor ◽  
Nonlinear Load ◽  
Rolling Elements ◽  
Nonlinear Equations Of Motion

This research presents a nonlinear model to analyze the ball bearing vibration due to the waviness in a rigid rotor supported by two or more ball bearings. The waviness of a ball and each races is modeled by the superposition of sinusoidal function, and the position vectors of inner and outer groove radius center are defined with respect to the mass center of the rotor in order to consider five degrees of freedom of a general rotor-bearing system. The waviness of a ball bearing is introduced to these position vectors to use the Hertzian contact theory in order to calculate the elastic deflection and nonlinear contact force resulting from the waviness while the rotor has translational and angular motion. They can be determined by solving the nonlinear equations of motion with five degrees of freedom by using the Runge-Kutta-Fehlberg algorithm. Numerical results of this research are validated with those of prior researchers. The proposed model can calculate the translational displacement as well as the angular displacement of the rotor supported by two or more ball bearings with waviness. It also characterizes the vibration frequencies resulting from the various kinds of waviness in rolling elements, the harmonic frequencies resulting from the nonlinear load-deflection characteristics of ball bearing, and the sideband frequencies resulting from nonlinearity of the waviness interaction.

An Analytic Model for Ball Bearing Vibrations to Predict Vibration Response to Distributed Defects

1980 ◽  
Vol 102 (2) ◽  
pp. 205-210 ◽  
Author(s):  
L. D. Meyer ◽  
F. F. Ahlgren ◽  
B. Weichbrodt
Keyword(s):  
Ball Bearing ◽  
Analytic Method ◽  
Time Varying ◽  
Ball Bearings ◽  
Spectral Character ◽  
Rotating System ◽  
Operating Modes ◽  
Lagrangian Equations ◽  
Rolling Elements ◽  
Bearing Race

An analytic method for predicting the spectral character of vibrations generated by an important class of defects in ball bearings is described. This family of bearing problems comprises those operating modes in which the magnitude of the ball-race contact force varies continuously and periodically as the bearing rotates. Defects of this type include race misalignment and off-sized rolling elements. The analytic technique is based on solving Lagrangian equations for the time-varying displacement of the bearing race in response to the rotating system of ball forces.

Temperature Rise Prediction of Oil-Air Lubricated Angular Contact Ball Bearings Using Artificial Neural Network

2019 ◽  
Vol 12 (3) ◽  
pp. 248-261
Author(s):  
Baomin Wang ◽  
Xiao Chang
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Temperature Rise ◽  
High Speed ◽  
Ball Bearing ◽  
Influence Factors ◽  
Ball Bearings ◽  
Ann Model ◽  
Angular Contact Ball Bearing ◽  
Artificial Neural

Background: Angular contact ball bearing is an important component of many high-speed rotating mechanical systems. Oil-air lubrication makes it possible for angular contact ball bearing to operate at high speed. So the lubrication state of angular contact ball bearing directly affects the performance of the mechanical systems. However, as bearing rotation speed increases, the temperature rise is still the dominant limiting factor for improving the performance and service life of angular contact ball bearings. Therefore, it is very necessary to predict the temperature rise of angular contact ball bearings lubricated with oil-air. Objective: The purpose of this study is to provide an overview of temperature calculation of bearing from many studies and patents, and propose a new prediction method for temperature rise of angular contact ball bearing. Methods: Based on the artificial neural network and genetic algorithm, a new prediction methodology for bearings temperature rise was proposed which capitalizes on the notion that the temperature rise of oil-air lubricated angular contact ball bearing is generally coupling. The influence factors of temperature rise in high-speed angular contact ball bearings were analyzed through grey relational analysis, and the key influence factors are determined. Combined with Genetic Algorithm (GA), the Artificial Neural Network (ANN) model based on these key influence factors was built up, two groups of experimental data were used to train and validate the ANN model. Results: Compared with the ANN model, the ANN-GA model has shorter training time, higher accuracy and better stability, the output of ANN-GA model shows a good agreement with the experimental data, above 92% of bearing temperature rise under varying conditions can be predicted using the ANNGA model. Conclusion: A new method was proposed to predict the temperature rise of oil-air lubricated angular contact ball bearings based on the artificial neural network and genetic algorithm. The results show that the prediction model has good accuracy, stability and robustness.

Friction Tests of Ball Bearings with Comparison of Lubricants

2017 ◽  
Vol 866 ◽  
pp. 375-378
Author(s):  
Sathitbunanan Sumate ◽  
Wirote Ritthong
Keyword(s):  
Energy Efficiency ◽  
Electric Power ◽  
Ball Bearing ◽  
Maximum Load ◽  
Engine Oil ◽  
Ball Bearings ◽  
Hydraulic Oil ◽  
Proper Size ◽  
Transmission Fluid ◽  
Moving Parts

The ball bearings are the rotating components which are widely spread to moving parts for all machinery operation in general industry. This paper presents the ball bearing resistance tool which has a proper size and can handle the maximum load of 300 kg by using an electric power. The ball bearing resistance tool was used to test the bearings No. 6011 cm. The series of tests was performed in the ball bearings lubricated; engine oil SAE 10W/40, auto transmission fluid Dexron, and hydraulic oil. The rotational speeds for testing were vary; 500, 600 and 700 rpm respectively. At each speed, there were various weight; 50, 70, 90,110,130,150, and 170 kg respectively. The results show that the hydraulic oil generated the smallest coefficients of friction and energy efficiency for ball bearing operation.

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