Auxiliary Bearing System Optimization for AMB Supported Rotors Based on Rotor Drop Analysis: Part I — Rotor Drop Analysis Method

2016 ◽  
Author(s):  
Jianming Cao ◽  
Paul Allaire ◽  
Timothy Dimond ◽  
Saeid Dousti
Keyword(s):  
Ball Bearing ◽  
System Optimization ◽  
American Petroleum Institute ◽  
Operating Conditions ◽  
Rolling Element Bearing ◽  
Hertzian Contact ◽  
Analysis Method ◽  
Contact Loads ◽  
Auxiliary Bearing ◽  
Bearing System

For rotors supported with active magnetic bearings (AMBs), the auxiliary bearing system or backup bearing system is needed to avoid serious potential internal damaging in the event of AMB loss of power or overload. The evolution of auxiliary systems has been made a priority by the American Petroleum Institute using analytical or experimental methods. In part I of this paper, a detailed rotor drop nonlinear transient analysis method including flexible shaft, rolling element bearing components including inner/outer races and balls, as well as flexible/damped supporting structures is given. A finite element based 6-DOF flexible rotor model is used to indicate shaft motion before the drop (operating conditions) and during the rotor drop event. Un-lubricated Hertzian contact models are used between the shaft and inner/outer races, between balls and races. To avoid heavy calculating time, two different methods to calculate ball bearing contact loads are discussed and the simulation results are compared. These models are applied to predict shaft-race-ball displacements and angular speeds, contact loads and ball bearing stresses during the drop for angular contact auxiliary bearings. This method also can be used to design and optimize the auxiliary bearing system as presented in the 2nd part of this paper.

Auxiliary Bearing System Optimization for AMB Supported Rotors Based on Rotor Drop Analysis: Part II — Optimization for Example Vertical and Horizontal Machines

2016 ◽  
Author(s):  
Jianming Cao ◽  
Paul Allaire ◽  
Timothy Dimond ◽  
Saeid Dousti
Keyword(s):  
Ball Bearing ◽  
System Optimization ◽  
Analysis Method ◽  
Design And Optimization ◽  
Size Number ◽  
Auxiliary Bearing ◽  
Bearing Design ◽  
Bearing Stress ◽  
Bearing Damage ◽  
Bearing System

This paper forms Part II of the rotor drop analysis, focusing on the auxiliary bearing system design and optimization based on the rotor drop analysis methods, as introduced in Part I. Optimization focuses on shaft orbit, maximum ball bearing stress, and how to avoid possible ball bearing damage due to impact loading during rotor drop by optimizing auxiliary design including bearing selection, preload method, radial and axial damping element, and flexible bearing support. Using the detailed rotor drop model and time transient method, a variety of simulations are presented for 1) an energy storage vertical flywheel system, and 2) an 8-stage horizontal centrifugal compressor, are conducted to investigate the effects of auxiliary bearing design and to optimize the auxiliary system. Axial drops, radial drops and combination of radial/axial drops are all evaluated considering angular contact auxiliary bearing size, number of rows, preload, and flexible damped bearing supports in the axial and radial directions. The rotor drop analysis method introduced in this paper may be used as a design toolbox for the auxiliary bearing system.

The Non-Uniform Preloading Effect on Stiffness Behaviour of Angular Contact Ball Bearings

2012 ◽  
Author(s):  
Wenwu Wu ◽  
Jun Hong ◽  
Xiaohu Li ◽  
Yang Li ◽  
Baotong Li
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Structural Performance ◽  
Angular Contact Ball Bearing ◽  
Actual Operating ◽  
Bearing Life ◽  
Bearing Stiffness ◽  
Increasing Demand ◽  
Bearing System

With the increasing demand of higher operating speed for bearing system, more challenges have been exposed on the maintaining of the bearing performance. Preloading is an effective method to handle these challenges. Traditionally, the preloading of bearing system has been applied by uniform approaches such as rigid preload and constant preload. However, this treatment may hardly deal with the optimization of preloading problem due to the non-uniformity of the bearing stiffness becomes more apparent under high-speed operating conditions. A novel and practical approach is therefore presented in this paper to incorporate the non-uniformity effect to improve the structural performance of bearing under actual operating conditions. Firstly, the critical relationship between the stiffness behaviour and the non-uniform preload is evaluated for bearing system. The stiffness problem of angular contact ball bearing system is then formulated analytically by Jones’ model. With this approach, boundary conditions are achieved to solve the local contact deformation and predict the bearing life under non-uniform preload. Finally, both the uniform preload and the non-uniform preload cases for bearing system are simulated under various operating conditions. Comparing with traditional methods, the proposed method can provide a better solution in both stiffness and life that will enable a designer to obtain a deep insight on the optimization of bearing system.

scholarly journals Experimental investigation of ball bearing lubrication conditions by shock pulse method

2019 ◽  
Vol 36 (1−2) ◽  
Author(s):  
Ratnesh Kumar Gupta ◽  
Vikas Rastogi ◽  
R C Singh ◽  
N Tandon
Keyword(s):  
Ball Bearing ◽  
Pulse Method ◽  
Operating Conditions ◽  
Condition Based Maintenance ◽  
Ball Bearings ◽  
Shock Pulse ◽  
Optimum Conditions ◽  
Wear And Tear ◽  
Lubrication Conditions ◽  
Bearing System

Lubricant (grease) is a vital requirement of ball bearing system. Grease not only protects ball bearing from wear and tear but performs various other functions that are essential for proper functioning of ball bearings. The lubricant (grease) under different conditions attains different properties which in turn affect the performance of the ball bearings. The effect of the condition of the lubricants on the performance of the ball bearings is well documented. the work reports about the investigation of ball bearing using shock pulse method by using two different instruments (Tester T2000 Model and Shock Pulse Meter 43A) of different operating conditions of ball bearing the condition such as used the quantity of grease as different percentage (0%, 25%, 50%, 75%, 100%) and bad quality grease (burn grease) at different rpm at a fixed load (10kg) and compare the normalized shock pulse value (dB) at different operating conditions. This method uses a piezo-electric accelerometer superimposed electrically as well as mechanically to about 32 kHz of resonant frequency. The result will help in bearing related to quantity as well as quality condition based maintenance choosing the optimum conditions for detecting the lubricant problem in ball bearing.

An Analytical Model of Four-Point Contact Rolling Element Ball Bearings

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Jacob D. Halpin ◽  
Anh N. Tran
Keyword(s):  
Analytical Model ◽  
Ball Bearing ◽  
Minimum Energy ◽  
Point Contact ◽  
Contact Angles ◽  
State Theory ◽  
Operating Conditions ◽  
Rolling Element Bearing ◽  
Design Guideline ◽  
Rolling Element

The purpose of this work is to establish an analytical model and standard way to predict the performance characteristics of a four-point contact, or gothic arch type, rolling element ball bearing. Classical rolling element bearing theory, as developed by Jones, has been extended to include the complex kinematics of the four-point contact bearing; thereby providing complete elementwise attitude and internal load distribution of the bearing under operating conditions. Standard performance parameters, such as element contact stresses, contact angles, inner ring deflections, nonlinear stiffness's, torque, and L10 life, are solved explicitly via standard Newton–Raphson techniques. Race control theory is replaced with a minimum energy state theory to allow both spin and slip to occur at the ball-to-raceway contact. The developed four-point model was programed within the orbis software program. Various test cases are analyzed and key analytical results are compared with the Jones four-point contact ball bearing analysis program, the Wind Turbine Design Guideline, DG03, and traditional two-point (angular contact) analysis codes. Model results for the internal distribution of ball loads and contact angles match the Jones program extremely well for all cases considered. Some differences are found with the DG03 analysis methods, and it is found that modeling a four-point contact bearing by overlaying two opposed angular contact bearings can result in gross errors.

Study on dynamic characteristics of angular ball bearing with non-linear vibration of rotor system

2008 ◽  
Vol 222 (9) ◽  
pp. 1811-1819 ◽  
Author(s):  
L-Q Wang ◽  
L Cui ◽  
L Gu ◽  
D-Z Zheng
Keyword(s):  
Dynamic Characteristics ◽  
Ball Bearing ◽  
Linear Equations ◽  
Rotor System ◽  
Hertzian Contact ◽  
Initial Contact ◽  
Linear Vibration ◽  
Non Linear ◽  
Linear Behaviour ◽  
Bearing System

A rotor system supported by an angular ball bearing displays very complicated non-linear behaviour due to non-linear Hertzian contact force. The non-linear force and moment caused by the ball bearing are calculated on the basis of the relationship between deflection, and five-degree-of-freedom dynamic equations of the rotor ball bearing system are established. The Newmark-β method and the Newton—Raphson method are used to solve the non-linear equations. The dynamic characteristics of angular ball bearings are computed, considering the non-linear vibration of the rotor system. Taking angular ball bearing QJS208ACQ4C1/HNP4 as an example, the effects of the vibration of the rotor system on bearing dynamic characteristics are analysed. The results show that the spin-to-roll ratio of balls, the slide ratio of the cage, and stiffness of the bearing all vary obviously with the non-periodic vibration range of the rotor; initial contact angle and axial load of the ball bearing change the non-linear dynamic nature of the rotor system and dynamic characteristics of the bearing. The rotor ball bearing system can work stably by choosing the structural and operation parameters reasonably.

Nonlinear Vibration Analysis of an Unbalanced Flexible Rotor Supported by Ball Bearings With Radial Internal Clearance

2008 ◽  
Author(s):  
T. C. Gupta ◽  
K. Gupta ◽  
D. K. Sehgal
Keyword(s):  
Ball Bearing ◽  
Natural Frequencies ◽  
Power Spectra ◽  
Hertzian Contact ◽  
Phase Portraits ◽  
Integration Scheme ◽  
Flexible Rotor ◽  
Deep Groove ◽  
Varying Compliance ◽  
Bearing System

In the present work, the nonlinear dynamic response of an unbalanced horizontal flexible rotor supported by deep groove ball bearing is studied. Nonlinearity effects in rolling element bearings arise from Hertzian contact force deformation relationship and clearance between rolling elements and races. The system is bi-periodically excited due to varying compliance of ball bearing and rotating unbalance. The flexible rotor bearing system is modeled by finite element method, taking into account the gyroscopic moments, rotary inertia, shear deformation, proportional damping, nonlinear stiffness and radial internal clearance of ball bearing. The implicit type numerical time integration scheme Newmark-β and Newton-Raphson methods are used to numerically solve the nonlinear equations of motion. The mathematical model is validated for the natural frequencies of the flexible shaft and whirl frequencies. On account of variation in the ball bearing stiffness, the variation in natural frequencies of the rotor ball bearing system is estimated. The influence of ball bearing nonlinearity on dynamic behavior is analyzed by time histories of steady state response, phase portraits and power spectra. Effect of radial internal clearance and varying compliance on the unbalance response of flexible rotor is studied in detail.

scholarly journals Non-Newtonian mixed thermo-elastohydrodynamics of hypoid gear pairs

2017 ◽  
Vol 232 (9) ◽  
pp. 1105-1125 ◽  
Author(s):  
M Mohammadpour ◽  
S Theodossiades ◽  
H Rahnejat ◽  
D Dowson
Keyword(s):  
Fuel Efficiency ◽  
Transmission Efficiency ◽  
Operating Conditions ◽  
Predictive Analysis ◽  
Hypoid Gear ◽  
Shear Rates ◽  
Contact Loads ◽  
Harmful Emissions ◽  
Vehicle Fuel Efficiency ◽  
Hypoid Gear Pairs

Transmission efficiency is the main objective in the development of vehicular differential systems, comprising hypoid gear pairs. The overall aim is to contribute to improved vehicle fuel efficiency and thus levels of harmful emissions for modern desired eco-drive axles. Detailed predictive analysis plays an important role in this quest, particularly under realistic operating conditions, comprising high contact loads and shear rates. Under these conditions, the hypoid gear pairs are subject to mixed non-Newtonian thermo-elastohydrodynamic conditions, which is the approach undertaken in this paper. Such an approach for hypoid gear pair has not hitherto been reported in the literature.

Applications of vibro-acoustic measurement and analysis in conjunction with tribological parameters to assess surface fatigue wear developed in the roller-bearing system

2021 ◽  
pp. 135065012098246
Author(s):  
Shashikant Pandey ◽  
Muniyappa Amarnath
Keyword(s):  
Roller Bearing ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Stribeck Curve ◽  
Fatigue Wear ◽  
Surface Fatigue ◽  
Rolling Element ◽  
Measurement And Analysis ◽  
Contact Surfaces ◽  
Bearing System

Rolling-element bearings are the most commonly used components in all rotating machinery. The variations in the operating conditions such as an increase in the number of operating cycles, load, speed, service temperature, and lubricant degradation result in the development of various defects such as pitting, spalling, scuffing, scoring, etc. The defects that appeared on rolling contact surfaces cause surface deterioration and change in the vibration and sound levels of the bearing system. The present experimental investigations are aimed at assessing the surface fatigue wear that appears on the contact surfaces of roller bearings. The studies considered the estimation of specific film thickness, analysis of surface fatigue wear developed on the rolling-element surfaces, surface roughness analysis, grease degradation analysis using Fourier transform infrared radiation, and vibration and sound signal measurement and analysis. The results obtained from the experimental investigation provide a good correlation between surface wear, vibration, and sound signals with a transition in the lubrication regimes in the Stribeck curve.

A fuzzy logic neural network algorithm for compressor crankshaft-rolling bearing system optimization

2021 ◽  
pp. 1-7
Author(s):  
Zheng Zhang ◽  
Jianrong Zheng
Keyword(s):  
Neural Network ◽  
Fuzzy Logic ◽  
Dynamic Analysis ◽  
Weighted Average ◽  
Rolling Bearing ◽  
System Optimization ◽  
Simulation Software ◽  
Network Algorithm ◽  
Neural Network Algorithm ◽  
Bearing System

Taking the crankshaft-rolling bearing system in a certain type of compressor as the research objective, dynamic analysis software is used to conduct detailed dynamic analysis and optimal design under the rated power of the compressor. Using Hertz mathematical formula and the analysis method of the superstatic orientation problem, the relationship expression between the bearing force and deformation of the rolling bearing is solved, and the dynamic analysis model of the elastic crankshaft-rolling bearing system is constructed in the simulation software ADAMS. The weighted average amplitude of the center of the neck between the main bearings is used as the target, and the center line of the compressor cylinder is selected as the design variable. Finally, an example analysis shows that by introducing the fuzzy logic neural network algorithm into the compressor crankshaft-rolling bearing system design, the optimal solution between the design variables and the objective function can be obtained, which is of great significance to the subsequent compressor dynamic design.

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