scholarly journals Effects of operation temperature on thermal expansion and main parameters of radial ball bearings

2015 ◽  
Vol 19 (5) ◽  
pp. 1835-1844 ◽  
Author(s):  
Radivoje Mitrovic ◽  
Ivana Atanasovska ◽  
Natasa Soldat ◽  
Dejan Momcilovic
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Ball Bearing ◽  
Load Capacity ◽  
Radial Clearance ◽  
Contact Period ◽  
Ball Bearings ◽  
Finite Element Analyses ◽  
Main Bearing ◽  
Operation Temperature

The research of influence of operation temperature on the thermal expansion and main parameters of radial ball bearings is presented in this paper. The main bearing parameters are identified in accordance with the increasing requests concerning stability and load capacity. A series of Finite Element Analyses is performed for quasi-static analysis of all identified bearing parameters during contact period in referent temperature. Then, the dependence of bearing material characteristics on the operation temperature is discussed. Few series of Finite Element Analyses are performed for a particular radial ball bearing type, with characteristics in accordance with manufacturer specifications, for several operation temperatures. These two problems analyses include consideration of relation between the initial radial clearance, thermal expansion strains and contact deformations of the parts of the bearing assembly. The results for radial ball bearing parameters are monitored during a ball contact period for different temperatures and the appropriate discussion and conclusions are given. The conclusions about the contribution of developed procedure in defining the optimum operation temperature range are shown.

Modeling of Flexible Coupling to Connect Misaligned Flexible Rotors Supported on Ball Bearings

2014 ◽  
Author(s):  
T. C. Gupta ◽  
K. Gupta
Keyword(s):  
Dynamic Response ◽  
Stiffness Matrix ◽  
Ball Bearing ◽  
Radial Clearance ◽  
Fe Model ◽  
Ball Bearings ◽  
Flexible Coupling ◽  
Flexible Rotors ◽  
Deep Groove ◽  
Coupling Stiffness

Parallel or/and angular misalignment between rotors connected by flexible coupling causes deformation of coupling elements and rotor shafts both. The forces and moments from flexible coupling act on driver and driven rotors simultaneously and depend upon dynamic response of coupled rotor system. The authors’ aim in the present work is to propose a methodology to incorporate the coupling stiffness matrix and coupling loads into the finite element model of flexibly coupled flexible rotors supported on deep groove ball bearings. The coefficients of coupling stiffness matrix and coupling loads are nonlinear and depend upon the amount of parallel and angular misalignments. To segregate the effect of nonlinear stiffness of coupling on the dynamic response of the system, the stiffness of ball bearing is initially considered to be linear. Thereafter, ball bearing nonlinearities arising from radial clearance, Hertzian deformation of balls and races, and varying compliance effect are included into the FE model of the system. Considering different types of misalignments in succession and combination, the dynamic response is characterized by the presence of 1N, 2N and other super or sub harmonics. The misalignment in one plane is found to affect the dynamic response in both the orthogonal planes. Comparing to the stiffness of flexible coupling, the stiffness of ball bearing is of higher order and therefore, nonlinear coupling forces and moments have dominant influence on the dynamic response of the system.

Straightener Settings for Under-Straight Residual Curvature of Reel Laid Pipeline

2014 ◽  
Author(s):  
Alan Roy ◽  
Venu Rao ◽  
Carlos Charnaux ◽  
P. Ragupathy ◽  
T. Sriskandarajah
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Residual Strain ◽  
Axial Strain ◽  
Cost Effective ◽  
Pipe Material ◽  
Finite Element Analyses ◽  
Field Development ◽  
Cost Effective Method ◽  
Residual Curvature

The pipeline inplace buckling design by residual curvature method for controlled thermal expansion during operation is a novel and cost effective method for initiating multiple expansion loops for a reel-laid pipeline. The controlled thermal expansion will be initiated and managed by planned buckle sites at regular intervals of say, 1km spacing with residual curvature corresponding to 0.20%–0.25% residual strain. The pipelines installed by the reel Lay process are required to be straightened by a reverse curvature process which results in pipeline with nominally zero curvature and axial strain. In order to achieve a residual strain of 0.20%–0.25%, two options are available either to over-straight or under-straight the pipelines. This paper discusses the methodology used laying of pipeline with 0.20%–0.25% residual strain at pre-determined intervals by an under-straightening process with a combination of a central 40m under straight section with a residual strain of 0.2%–0.25% and a 15m transition section on either side of the central section, at 1km intervals. The paper presents the methodology used to determine the settings for the top straightener module of reel lay vessel using finite element analyses, as the equipment settings for under or over straight pipes are not readily available from analytical methods. The optimum settings were obtained after substantial number of FEA simulations allowing for the statistical range in pipe material properties from “strong” to “weak” and these settings are used in reeling trials to make necessary adjustments. The residual strain, out-of-straightness and axial force distributions in pipe sections for straight, under-straight and transition sections are discussed. The paper discusses how these settings were used on-board the vessel and the modifications and adjustments required to select the final settings for the under-straight curvature for the field development of Statoil Skuld project as a case study. This paper briefly discusses the vessel equipment specific features and limitations that may need to be taken into consideration in finite element analyses to optimise the straightener settings for residual strain.

scholarly journals Behaviour of Bi-Adhesive in Double-Strap Joint with Embedded Patch Subjected to Bending

2015 ◽  
Vol 45 (3) ◽  
pp. 83-96 ◽  
Author(s):  
Şemsettin Temiz ◽  
Hamit Adin ◽  
Ismail Yasin Sülü
Keyword(s):  
Finite Element ◽  
Joint Strength ◽  
Load Capacity ◽  
Finite Element Analyses ◽  
The Finite Element Method ◽  
Middle Portion ◽  
Stress Concentrations ◽  
Linear Finite Element ◽  
Failure Loads ◽  
Study Behaviour

Abstract In this study, behaviour of bi-adhesive used in the repair of damaged parts was analyzed, using the finite element method. In a double-strap joint with an embedded patch, patch is embedded into the adherents for structural requirements. In addition, to increase the strength of the joint, two adhesives are used to bond the adherents. This approach reduces stress concentration at the overlap ends, increases the load capacity and delays the failure. These effects give rise to higher joint strength. For this purpose, a stiff adhesive, FM73 produced by Cytec Fiberite, was applied in the middle portion of the overlap, while a softer adhesive, SBT9244 from 3M, was applied towards the edges, prone to stress concentrations. Non-linear finite element analyses were carried out to predict the failure loads, to assist with the geometric design and to identify effective ratios of sizes to maximize joint strength.

An Investigation of the Characteristics of Electromagnetic Bearings Using the Finite Element Method

1994 ◽  
Vol 116 (4) ◽  
pp. 710-719 ◽  
Author(s):  
Foam-Zone Hsiao ◽  
An-Chen Lee
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Load Capacity ◽  
Nonlinear Behavior ◽  
Ball Bearings ◽  
The Finite Element Method ◽  
Nonlinear Characteristics ◽  
Nonlinear Relation ◽  
Flux Leakage ◽  
Element Method

The load capacity of EMBs with a restricted air gap is usually small in comparison with that of traditional ball bearings. One possible way to overcome this limitation is to increase the operation field strength of EMBs; however, this approach unavoidably involves nonlinear characteristics of EMBs. This paper investigates the nonlinear behavior of two commonly used types of EMBs by using the finite element method, in which the nonlinear relation of the B-H curve, the flux leakage, and the fringing effect are taken into account. The behavior of the EMBs under different bias currents and gap lengths is investigated, as are the effects of geometric parameters on the bearing characteristics. The results of the paper provide a useful guide for designing EMBs when using their nonlinear characteristics.

A New Dynamic Model of Ball-Bearing Rotor Systems Based on Rigid Body Element

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Hongrui Cao ◽  
Yamin Li ◽  
Xuefeng Chen
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Ball Bearing ◽  
Rotor System ◽  
Radial Clearance ◽  
Fe Model ◽  
Ball Bearings ◽  
Rolling Ball ◽  
Rotor Systems ◽  
Body Element

Ball-bearing rotor systems are key components of rotating machinery. In this work, a new dynamic modeling method for ball-bearing rotor systems is proposed based on rigid body element (RBE). First, the concept of RBE is given, and then the rotor is divided into several discrete RBEs. Every two adjacent RBEs are connected by imaginary springs, whose stiffness is calculated according to properties of the RBEs. Second, all the parts of rolling ball bearings (i.e., outer ring, inner ring, ball, and cage) are considered as RBEs, and Gupta's model is employed to model bearings which include radial clearance, waviness, pedestal effect, etc. Finally, the rotor and all the rolling ball bearings are coupled to develop a dynamic model of the ball-bearing rotor system. The vibration responses of the ball-bearing rotor system can be calculated by solving dynamic equations of each RBE. The proposed method is verified with both simulation and experiment. The RBE model of the rotor is compared with its finite element (FE) model first, and numerical simulation shows the validity of the RBE model. Then, experiments are conducted on a rotor test rig which is supported with two rolling ball bearings as well. Good agreements between measurement and simulation show the ability of the model to predict the dynamic behavior of ball-bearing rotor systems.

Experimental and Numerical Studies on Nonlinear Dynamic Behavior of Rotor System Supported by Ball Bearings

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Changqing Bai ◽  
Hongyan Zhang ◽  
Qingyu Xu
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Ball Bearing ◽  
Rotor System ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Flexible Rotor ◽  
Nonlinear Dynamic Behavior

Ball bearings are important mechanical components in high-speed turbomachinery that is liable for severe vibration and noise due to the inherent nonlinearity of ball bearings. Using experiments and the numerical approach, the nonlinear dynamic behavior of a flexible rotor supported by ball bearings is investigated in this paper. An experimental ball bearing-rotor test rig is presented in order to investigate the nonlinear dynamic performance of the rotor systems, as the speed is beyond the first synchroresonance frequency. The finite element method and two-degree-of-freedom dynamic model of a ball bearing are employed for modeling the flexible rotor system. The discrete model of a shaft is built with the aid of the finite element technique, and the ball bearing model includes the nonlinear effects of the Hertzian contact force, bearing internal clearance, and so on. The nonlinear unbalance response is observed by experimental and numerical analysis. All of the predicted results are in good agreement with experimental data, thus validating the proposed model. Numerical and experimental results show that the resonance frequency is provoked when the speed is about twice the synchroresonance frequency, while the subharmonic resonance occurs due to the nonlinearity of ball bearings and causes severe vibration and strong noise. The results show that the effect of a ball bearing on the dynamic behavior is noticeable in optimum design and failure diagnosis of high-speed turbomachinery.

Bearing Capacity of a Skirted Foundation Under VMH Loading

2003 ◽  
Author(s):  
Susan Gourvenec ◽  
Mark Randolph
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Load Capacity ◽  
Limit State ◽  
Design Guidelines ◽  
Shallow Foundation ◽  
Combined Loading ◽  
Ultimate Limit State ◽  
Finite Element Analyses ◽  
Offshore Industry

This paper presents results from a series of three-dimensional finite element analyses investigating the ultimate limit state of a circular skirted shallow foundation over a comprehensive range of combined vertical, moment and horizontal loading. Failure loci in V:M:H load space derived from the finite element analyses are compared with limit state predictions from the offshore industry design guidelines [1]. The comparison highlights considerable conservatism of the current design method largely due to poor representation of the response to fully combined loading and neglect of the tensile capacity achieved with foundation skirts. These shortcomings are particularly significant with respect to foundations for offshore conditions and result in an oversight of considerable potential load capacity in design.

Nonlinear Dynamic Analysis of an Asymmetric Ball Bearing Rotor System

2019 ◽  
Author(s):  
Doğancan Bahan ◽  
Ender Ciğeroğlu
Keyword(s):  
Ball Bearing ◽  
Nonlinear Dynamic Analysis ◽  
Harmonic Balance Method ◽  
Beam Theory ◽  
Hertzian Contact ◽  
Radial Clearance ◽  
Ball Bearings ◽  
Algebraic Equations ◽  
Rotor Systems ◽  
Nonlinear Algebraic Equations

Abstract Performance of ball bearing–rotor systems are highly dependent on and often limited by characteristics of ball bearings. Several studies are available in the literature, investigating varying compliance and subharmonic resonances of ball bearings. Most of the studies are carried out with rigid rotors to focus on modelling of the bearings. There exist few studies which take flexibility of rotors into account. Furthermore, even if the rotor flexibility is modelled, most of the time symmetrical rotors are considered. However, rotors are rarely symmetric in realistic applications due to different locations of bearings and different weights of rotor components (compressors, turbines etc.). In this study, an asymmetric, balanced, flexible rotor supported by ball bearings considering Hertzian contact and radial clearance is investigated. Rotor shaft is modelled with Nelson finite rotor elements using Timoshenko beam theory and disks are considered as rigid masses. Harmonic Balance Method (HBM) is used to obtain nonlinear algebraic equations in the frequency domain and Alternating Frequency Time (AFT) method is utilized to find Fourier coefficients of nonlinear bearing forces. In order to decrease the number of nonlinear equations to be solved, Receptance Method (RM) is applied. Resulting set of nonlinear algebraic equations is solved by using Newton’s method with arclength continuation. Several case studies are performed and effects of asymmetry on nonlinear periodic vibration response of rotors are studied.

scholarly journals Investigation of Static, Modal and Harmonic vibration analyses of Single Row SKF6205 Deep Groove Ball Bearing for thermal applications

2021 ◽  
Vol 309 ◽  
pp. 01096
Author(s):  
M. Raju ◽  
S. Thiagarajan ◽  
D. Peter Pushpanathan ◽  
S. Selvarasu ◽  
S. Thirumavalavan ◽  
...  
Keyword(s):  
Finite Element ◽  
Ball Bearing ◽  
Research Work ◽  
Finite Element Analyses ◽  
Stress Variation ◽  
Single Row ◽  
Stochastic Conditions ◽  
Deep Groove ◽  
Deep Groove Ball Bearing ◽  
Mechanical Element

It is the necessary to predict the endurance capability of the mechanical element with its increased application and complexity. The present research work estimates the stress variation and displacement characteristics using finite element analyses of Single Row SKF6205 Deep Groove Ball Bearing under radial and axial loadings. The vibration analyses are evaluated in three aspects; static, modal, and harmonic analysis. The simulations show the variation of stress levels of the bearing in different loads. These results are used to predict the fatigue life, wear rate, and productivity of the ball bearing at various stochastic conditions.

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