Calculation of Equilibrium Position and Dynamic Coefficients of a Journal Bearing Using Free Boundary Theory

1999 ◽  
Vol 122 (3) ◽  
pp. 616-621 ◽  
Author(s):  
Tiesheng Zheng ◽  
Norio Hasebe
Keyword(s):  
Finite Element ◽  
Equilibrium Position ◽  
Static Load ◽  
Journal Bearing ◽  
Computing Time ◽  
Oil Film ◽  
Dynamic Coefficients ◽  
Newton Raphson ◽  
Raphson Method ◽  
Oil Film Pressure

A finite element method, which is based on the variational inequality approach, is introduced to calculate the oil film pressure distribution of a journal bearing. The cavitation zone is found by solving a linear complementary problem. By means of this approach a perturbation can be performed directly on the finite element equation and, consequently, the Jacobian matrices of the oil film forces are obtained concisely. The equilibrium position of the bearing at a given static load is found by the Newton-Raphson method and, as byproducts, dynamic coefficients are obtained simultaneously without any extra computing time. Numerical examples show that the method works satisfactorily. [S0742-4787(00)02302-X]

Finite Element Analysis of Dynamically Loaded Flexible Journal Bearings: A Fast Newton-Raphson Method

1989 ◽  
Vol 111 (4) ◽  
pp. 597-604 ◽  
Author(s):  
J. D. C. McIvor ◽  
D. N. Fenner
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computing Time ◽  
Journal Bearings ◽  
Element Analysis ◽  
Dynamically Loaded ◽  
Newton Raphson ◽  
Time Required ◽  
Raphson Method ◽  
Isoparametric Elements

A fast Newton-Raphson method is presented for the finite element analysis of dynamically loaded flexible journal bearings. The method makes use of 8-node isoparametric elements for the lubrication analysis and 20-node isoparametric elements for the structural analysis. Results are presented for the Ruston and Hornsby 6VEB Mk III marine diesel big-end bearing using this method. The computing time required for this analysis is more than two orders of magnitude less than that previously reported for an elastohydrodynamic bearing analysis using a conventional Newton-Raphson method.

MAXIMUM OIL FILM TEMPERATURE OF A 4-LOBE JOURNAL BEARING WITH THE LOBES OF SMALL ANGULAR LENGTH

Tribologia ◽  
2017 ◽  
pp. 87-92
Author(s):  
Stanisław STRZELECKI
Keyword(s):  
Equilibrium Position ◽  
Journal Bearing ◽  
Thermal State ◽  
Iterative Solution ◽  
Journal Bearings ◽  
Maximum Temperature ◽  
Static Characteristics ◽  
Oil Film ◽  
Grinding Machine ◽  
Oil Film Pressure

Multilobed journal bearings with the lobes of small angular length are often applied in the bearing systems of grinding machine spindles, which is the most important assembly in the grinding machine. The safe operations of such bearings at proper oil film temperature can be assured by the knowledge of thermal state of bearing and its maximum temperature. This paper presents the results of the calculations of some static characteristics of a 4-lobe bearing with the lobes of small angular length and particularly its maximum oil film temperature. The oil film pressure, temperature, and viscosity fields were obtained by an iterative solution of the Reynolds', energy, and viscosity equations. Adiabatic, laminar oil film and the static equilibrium position of journal were assumed.

A Ritz Model of Unsteady Oil-Film Forces for Nonlinear Dynamic Rotor-Bearing System

2004 ◽  
Vol 71 (2) ◽  
pp. 219-224 ◽  
Author(s):  
Tiesheng Zheng ◽  
Shuhua Yang ◽  
Zhonghui Xiao ◽  
Wen Zhang
Keyword(s):  
Free Boundary ◽  
Ritz Method ◽  
Computing Time ◽  
Force Model ◽  
The Finite Element Method ◽  
Oil Film ◽  
Great Saving ◽  
Cavitation Region ◽  
The Given ◽  
Oil Film Pressure

Based on the free boundary theory and variational method, this paper presents a Ritz method to compute the instantaneous hydrodynamic forces of a real bearing subject to any perturbed motions of the rotor. The given method manipulates the cavitation region by simply introducing a parameter to match the free boundary condition and, as a result, a very simple approximate formula of oil-film pressure were obtained leading to great saving of computing time. The numerical examples show the high accuracy of the proposed formulas. This oil-film force model is also used to analyze the nonlinear dynamics of a rigid unbalanced rotor with elliptical bearing support. The results well agree with those of the oil-film force model computed by the finite element method and the computing time is saved greatly.

Influence of Transverse Cracks on Ultimate Strength of a Steel Plate Under Compression

2011 ◽  
Author(s):  
Abbas Bayatfar ◽  
Jerome Matagne ◽  
Philippe Rigo
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Transverse Cracks ◽  
Longitudinal Compression ◽  
Initial Imperfections ◽  
Crack Location ◽  
Linear Finite Element ◽  
Newton Raphson ◽  
Raphson Method

This study has been carried out on ultimate compressive strength of a cracked steel plate component, considering the effects of initial imperfections (transverse and longitudinal residual stresses and initial deflection, as well). The main objective of this paper is to numerically investigate the influence of crack location and crack length on ultimate strength of a steel plate under monotonic longitudinal compression. This investigation is performed through non-linear finite element (FE) analysis using ANSYS commercial finite element code in which is employed Newton-Raphson method. The FE results indicate that the length of transverse crack and especially its location can significantly affect the magnitude of ultimate strength where the steel plate is subjected to longitudinal compressive action.

Simulation studies on static thermal behaviour of true elliptical and orthogonally displaced non-circular journal bearing

2016 ◽  
Vol 68 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Amit Singla ◽  
Amit Chauhan
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Current Trend ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Film Pressure ◽  
Content Type ◽  
Oil Film ◽  
Ellipticity Ratio ◽  
Oil Film Pressure

Purpose The current trend of modern industry is to use machineries which rotate at high speed along with the capability of carrying heavy rotor loads. This paper aims at static thermal analysis of two different profiles of non-circular journal bearings – a true elliptical bearing and orthogonal bearing. Design/methodology/approach The Reynolds equation has been solved through finite difference method to compute the oil film pressure. Parabolic temperature profile approximation technique has been used to solve the energy equation and thus used for computation of various bearing performance characteristics such as thermo-hydrodynamic oil film pressure, temperature, load capacity, Sommerfeld number and power loss characteristics across the bearing. The effect of ellipticity ratio on the bearing performance characteristics has also been obtained for both the elliptical and vertical offset bearing using three different commercially available grades of oil (Hydrol 32, 68 and 100). Findings It has been observed that the thermo-hydrodynamic pressure and temperature rise of the oil film is less in orthogonal bearing as compared to the true elliptical bearing for same operating conditions. The effect of ellipticity ratio of non-circularity on bearing performance parameters have been observed to be less in case of elliptical bearing as compared to orthogonal bearing. It has been concluded that though the rise in oil film temperature is high for true elliptical bearing, but still it should be preferred over orthogonal profile under study, as it has comparably good load-carrying capacity. Originality/value The performance parametric analysis will help the designers to select such kind of non-circular journal bearing for various applications.

STATIC CHARACTERISTICS OF OFFSET 8-LOBE JOURNAL BEARINGS

Tribologia ◽  
2021 ◽  
Vol 295 (1) ◽  
pp. 39-51
Author(s):  
Stanisław Strzelecki
Keyword(s):  
Laminar Flow ◽  
Equilibrium Position ◽  
Iterative Procedure ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Diameter Ratio ◽  
Static Characteristics ◽  
Oil Film ◽  
Cooling Conditions ◽  
Grinding Machines

The 8-lobe journal bearings have found application in the bearing systems of spindles of grinding machines. The design of bearings and the large number of lobes and oil grooves assures good cooling conditions of bearing. These bearings can be manufactured as the bearings with cylindrical, non-continuous operating surfaces separated by six lubricating grooves, bearings with the pericycloidal shape of the bearing bore, and as offset journal bearing. This paper presents the results of the computation of static characteristics of an offset 8-lobe journal bearing operating under the conditions of an aligned axis of journal and bush, adiabatic oil film, and at the static equilibrium position of journal. Different values of bearing length to diameter ratio, relative clearance, and lobe relative clearance were assumed. Reynolds' energy and viscosity equations were solved by means of an iterative procedure. Adiabatic oil film, laminar flow in the bearing gap, and aligned orientation of journal in the bearing were considered.

scholarly journals Fuzzy Logic based Model to Predict Maximum Oil-Film Pressure in Journal Bearing

2013 ◽  
Vol 6 (20) ◽  
pp. 3871-3878 ◽  
Author(s):  
Diyar I. Ahmed ◽  
S. Kasolang ◽  
Basim A. Khidhir ◽  
B.F. Yousif
Keyword(s):  
Fuzzy Logic ◽  
Journal Bearing ◽  
Film Pressure ◽  
Oil Film ◽  
Oil Film Pressure

scholarly journals Efficient analysis of welding thermal conduction using the Newton–Raphson method, implicit method, and their combination

2020 ◽  
Vol 111 (7-8) ◽  
pp. 1929-1940 ◽  
Author(s):  
Zhongyuan Feng ◽  
Ninshu Ma ◽  
Wangnan Li ◽  
Kunio Narasaki ◽  
Fenggui Lu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Hybrid Method ◽  
Thermal Conduction ◽  
Computing Time ◽  
Implicit Method ◽  
Heating Process ◽  
Element Analysis ◽  
Heating And Cooling ◽  
Raphson Method

AbstractFinite element analysis is commonly used to investigate the thermal-mechanical phenomena during welding. To improve the computing efficiency of finite element analysis for welding thermal conduction, a novel Newton–Raphson method (NRM) without the computation of inverse matrix and a hybrid method combing the NRM and conventional implicit method (IMP) were developed. Comparison of computing time between the hybrid method implemented in an in-house software JWRIAN and the IMP used in a commercial software ABAQUS indicated that the computing speed of the former was about 4.5 times faster than that of the latter. Additionally, compared to the conventional IMP, the NRM exhibited higher computing efficiency in the analysis of transient thermal conduction during the welding heating process. Meanwhile, a combined hybrid method of the NRM and IMP was verified to be more efficient in analyzing the welding thermal conduction throughout the heating and cooling processes. Moreover, the thermal cycles computed by the hybrid method were consistent with those from experimental measurement, indicating the high accuracy of the hybrid method. Furthermore, the hybrid method was used to predict the temperature field of the corner boxing fillet joint welded by a low transformation temperature weld metal for generation of compressive residual stress.

Experimentally study of dynamic pressure distribution and oil film forces in journal bearing using ElectroMechanical Film sensor array

2019 ◽  
Vol 234 (4) ◽  
pp. 903-913
Author(s):  
Changmin Chen ◽  
Jianping Jing ◽  
Jiqing Cong ◽  
Chao Ji
Keyword(s):  
Pressure Distribution ◽  
Sensor Array ◽  
Journal Bearing ◽  
Dynamic Pressure ◽  
Vertical Direction ◽  
Journal Bearings ◽  
Film Sensor ◽  
Film Pressure ◽  
Oil Film ◽  
Oil Film Pressure

The acquisition of the oil film pressure and forces on the bearing pads through experimentation is crucial to understanding the characteristics of journal bearing. Lots of efforts had been taken in film pressure measurement, and the pressure was obtained at specified position on the bearing pads. However, due to the space and structure constraint, merely very limited number of the point pressure can be obtained with traditional sensors and acquiring the detail pressure field on whole bearing pad surface is still an open challenge. In this paper, a method based on thin-film sensors technique is proposed and employed to measure the pressure distribution and oil film forces of journal bearings. The measurement is conducted on a cylindrical journal bearing with two axial grooves, and ElectroMechanical Film sensor arrays are designed and laid on the surface of the bearing pads. The oil film pressure is acquired at up to 32 measurement points in total along the bearing pads in both circumference and axial directions. The pressure distribution in a wide rotation speed range is obtained successfully by using fitting algorithm. Furthermore, the oil film forces on horizon and vertical direction are obtained through the integration of the measured pressure filed. The test results prove that it is feasible to measure the oil pressure filed of journal bearings using ElectroMechanical Film piezo-film sensor array.

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