scholarly journals Analysis of Spiral-Grooved Gas Journal Bearings by the Narrow-Groove Theory and the Finite Element Method At Large Eccentricities

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Elia Iseli ◽  
Eliott Guenat ◽  
Roger Tresch ◽  
Jürg Schiffmann
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Pressure ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
Pressure Profiles ◽  
Stability Maps ◽  
Time Periodic ◽  
Good Agreement ◽  
Element Method

Abstract A finite groove approach (FGA), based on the finite element method (FEM), is used for analyzing the static and dynamic behavior of spiral-grooved aerodynamic journal bearings at different eccentricities, number of grooves, and compressibility numbers. The results of the FGA are compared with the narrow-groove theory (NGT) solutions. For the rotating-groove case, a novel time-periodic solution method is presented for computing the quasi-steady-state and dynamic pressure profiles. The new method offers the advantage of avoiding time-consuming transient integration, while resolving a finite number of grooves. The static and dynamic solutions of the NGT and FGA approach are compared, and they show good agreement, even at large eccentricities (ε=0.8) and high compressibility numbers (Λ = 40). Stability maps at different eccentricities are presented. At certain operation points, a stability decrease toward larger eccentricities is observed. The largest stability deviations of the NGT from the FGA solutions occur at large groove angle, low number of grooves, and large compressibility numbers.

Elasto-plastic analysis of a rotating model conical turbine disc

1975 ◽  
Vol 10 (3) ◽  
pp. 167-171 ◽  
Author(s):  
F Ginesu ◽  
B Picasso ◽  
P Priolo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Limit Analysis ◽  
Point Of View ◽  
Complete Analysis ◽  
The Finite Element Method ◽  
Computational Simplicity ◽  
Rotating Shell ◽  
Good Agreement ◽  
Element Method

Results on the plastic collapse behaviour of an axisymmetric rotating shell, obtained by Limit Analysis and the Finite Element Method, are in good agreement with experimental data. The Finite Element Method, though computationally rather costly, permits, however, a more complete analysis of elasto-plastic behaviour. For the present case, the Limit Analysis has the advantage of greater computational simplicity and leads to a quite satisfactory forecast of collapse speed from the engineering point of view.

Analysis of Aerodynamic Journal Bearings With Small Number of Herringbone Grooves by Finite Element Method

1994 ◽  
Vol 116 (4) ◽  
pp. 698-704 ◽  
Author(s):  
D. Bonneau ◽  
J. Absi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Study ◽  
Load Capacity ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
Bearing Number ◽  
Comparison Of The Results ◽  
Herringbone Grooves ◽  
Element Method

A numerical study of gas herringbone grooved journal bearings is presented for small number of grooves. The compressible Reynolds equation is solved by use of the Finite Element Method. The nonlinearity of the discretized equations is treated with the Newton-Raphson procedure. A comparison of the results for a smooth bearing with previously published results is made and the domain of validity of the Narrow Groove Theory is analyzed. Load capacity, attitude angle, and stiffness coefficients are given for various configurations: groove angle and thickness of grooves, bearing number, and that for both smooth and grooved member rotating.

scholarly journals Modeling Electric Field and Potential Distribution of an Model of Insulator in Two Dimensions by the Finite Element Method

2018 ◽  
Vol 3 (1) ◽  
pp. 01
Author(s):  
Nassima M ziou ◽  
Hani Benguesmia ◽  
Hilal Rahali
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
Potential Distribution ◽  
Two Dimensions ◽  
Comsol Multiphysics ◽  
The Finite Element Method ◽  
Good Agreement ◽  
Element Method

The electrical effects can be written by two magnitudes the field and the electrostatic potential, for the determination of the distribution of the field and the electric potential along the leakage distance of the polluted insulator, the comsol multiphysics software based on the finite element method will be used. The objective of this paper is the modeling electric field and potential distribution in Two Dimensions by the Finite Element Method on a model of insulator simulating the 1512L outdoor insulator used by the Algerian company of electricity and gas (SONELGAZ). This model is under different conductivity, applied voltage, position of clean layer and width of clean layer. The computer simulations are carried out by using the COMSOL multiphysics software. This paper describes how Comsol Multiphysics have been used for modeling of the insulator using electrostatic 2D simulations in the AC/DC module. Numerical results showed a good agreement.

Study on Hydraulic Deep Drawing of Square Cups

2014 ◽  
Vol 626 ◽  
pp. 334-339
Author(s):  
Te Fu Huang ◽  
Hsin Yi Hsien ◽  
Yan Jia Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deep Drawing ◽  
Thickness Distribution ◽  
The Finite Element Method ◽  
Experimental Apparatus ◽  
Punch Load ◽  
Simulation Results ◽  
Good Agreement ◽  
Element Method

The friction holding effect and the friction reducing effect occurring during Hydraulic Deep Drawing and the pre-bulging resulting in more plastic deformation on products are applied on sheet hydro-forming. For Hydraulic Deep Drawing of a square cup, the thickness distribution and the relation between the height and the pressure of pre-bulging are simulated with SPCC steels as the specimen by the finite element method. An experimental apparatus of sheet hydro-forming has been constructed to carry out the hydraulic deep drawing experiments of square cups. Experimental thickness distribution and punch load are compared with simulation results. Good agreement was found. The flow patterns of the circular and square blanks with the condition of being firmly pressed against the punch observed from the experiments are in agreement with the predicted results.Keywords:Hydraulic Deep Drawing, sheet hydro-forming, finite element method

Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

2020 ◽  
pp. 135065012097911
Author(s):  
Xinglong Chen ◽  
James K Mills ◽  
Kai Shi ◽  
Gang Bao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Film Thickness ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Eccentricity Ratio ◽  
The Finite Element Method ◽  
Area Formula ◽  
Static Performance ◽  
Element Method

In this work, to improve the static behavior of aerostatic journal bearings, we examine the effect of pockets with different shapes, including the square, rectangular 1, rectangular 2, and circular, manufactured on the surface of the aerostatic journal bearing. The effects of the pocket shapes, pocket area [Formula: see text], eccentricity ratio ɛ, orifice diameter df, average gas film thickness h0, and misalignment angles [Formula: see text] and [Formula: see text] on the static performance are investigated using simulations. The Reynolds equation is solved by the finite-element method in this work. Simulations reveal that the pocket area [Formula: see text], eccentricity ratio ɛ, gas film thickness h0, orifice diameter df, and misalignment angles [Formula: see text] and [Formula: see text] have a significant influence on the load force F and the stiffness K. In general, rectangular 2 pocket bearings are found to perform somewhat better than bearings with other pocket shapes, with the pocket depth set to one-half of h0, when the pocket area [Formula: see text] varies from one-twelfth to one. The pocket area [Formula: see text] should be set according to the average gas film thickness h0 and the orifice diameter df to achieve a better static performance for the bearings. For bearings operated with misalignment angles [Formula: see text] and [Formula: see text], different pocket areas [Formula: see text] should be set according to the pocket shapes for the optimal design.

A Transient Thermoelastohydrodynamic Study of Steadily Loaded Plain Journal Bearings Using Finite Element Method Analysis

1999 ◽  
Vol 122 (1) ◽  
pp. 219-226 ◽  
Author(s):  
Bogdan-Radu Kucinschi ◽  
Michel Fillon ◽  
Jean Fre^ne ◽  
Mircea D. Pascovici
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Journal Bearing ◽  
Journal Bearings ◽  
The Finite Element Method ◽  
Thermal Boundary Conditions ◽  
Theoretical Predictions ◽  
Start Ups ◽  
Method Analysis ◽  
Element Method

The present paper proposes an advanced bidimensional model necessary to calculate the temperature field in a journal bearing submitted to both rapid and slow start-ups. The model takes into account realistic thermal boundary conditions at fluid film-solid interfaces. The thermoelastic deformations of both the journal and of the bush are also considered and a special attention is paid to the ruptured zone of the film. The Finite Element Method (with upwind techniques whenever necessary) is employed to solve the equations implied by the model. Finally, the theoretical predictions were validated by comparison with experimental data. [S0742-4787(00)02701-6]

The Stress of Sliding Vanes in a Rotary Compressor

2005 ◽  
Author(s):  
Yuan Mao Huang ◽  
Chien Liang Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
Rotary Compressor ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Good Agreement ◽  
Cover Plates ◽  
Element Method

A rotary sliding vane compressor was redesigned with extended rods on both edges of each vane and guide slots on both cover plates to improve its performance. The governing equations were derived to obtain loads acting on vanes and the stress of vanes. The finite element method is used with a generated computer program to determine the stress of vanes based on the calculated loads and the measured loads acting on the vanes. The results were compared and show good agreement with those obtained by using an existing software IDEAS.

Experimental and Finite Element Characterization of the Crippling Failure of Composite Stiffeners

2006 ◽  
Vol 326-328 ◽  
pp. 1773-1776
Author(s):  
Jin Hwe Kweon ◽  
Sang Min Choi ◽  
Hee Jin Son ◽  
Ji Young Choi ◽  
Jin Ho Choi ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Progressive Failure ◽  
Local Buckling ◽  
Equilibrium Path ◽  
The Finite Element Method ◽  
Progressive Failure Analysis ◽  
Good Agreement ◽  
Element Method

Progressive failure analysis based on the complete unloading method was conducted to investigate the crippling failure of carbon/epoxy composite stiffeners under axial compression. A modified arc-length algorithm was incorporated into a nonlinear finite element method to trace the equilibrium path after local buckling. For the validation of the finite element method, several carbon/epoxy Z-section stiffeners were tested in compression. The finite element results on the buckling and crippling stresses showed good agreement with the experimental results.

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