Passive Contra-Magnetized Parallel-Airgap Serial Flux Magnetic Bearings

2010 ◽  
Vol 224 (11) ◽  
pp. 2515-2524
Author(s):  
K Kalita ◽  
W K S Khoo ◽  
S D Garvey ◽  
R J Hill-Cottingham ◽  
D Rodger ◽  
...  
Keyword(s):  
Load Capacity ◽  
Three Dimensional ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Two Dimensional ◽  
Specific Load ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Automatic Mesh

Conventional magnetic bearings accomplish a specific load capacity, defined as the ratio of maximum sustainable weight to the total self-weight, of up to 35:1. In this paper, the authors introduce a class of passive magnetic bearings that comprise a large number of parallel airgaps and discs and can deliver specific load capacities substantially higher than 35:1. Two-dimensional planar, two-dimensional axi-symmetric, and three-dimensional finite-element analysis (FEA) have been undertaken to predict the force capability of the bearings. An unoptimized prototype passive magnetic bearing is constructed to demonstrate the concept and its force-carrying capacity. The experimental results are then compared with those obtained from the FEA. Further optimization of the bearings is done across the whole design space comprising tens of thousands of models using an automatic mesh generator in conjunction with solving the FE models in nested loops.

THREE DIMENSIONAL FINITE ELEMENT SIMULATION OF THE FRETTING WEAR PROBLEMS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3890-3895 ◽  
Author(s):  
CHOON YEOL LEE ◽  
JOON WOO BAE ◽  
BYUNG SUN CHOI ◽  
YOUNG SUCK CHAI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Fretting Wear ◽  
Symmetric Model ◽  
Two Dimensional ◽  
Element Analysis ◽  
Inconel 690 ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The structural integrity of steam generators in nuclear power plants is very much dependent upon the fretting wear characteristics of Inconel 690 U-tubes. In this study, a finite element analysis was used to investigate fretting wear on the secondary side of the steam generator, which arises from flow-induced vibrations (FIV) between the U-tubes and supports or foreign objects. Two-dimensional and three-dimensional finite element analyses were adopted to investigate the fretting wear problems. The purpose of the two-dimensional analysis, which simulated the contact between a punch and a plate, was to demonstrate the validity of using finite element analysis to analyze fretting wear problems. This was achieved by controlling the value of the wear constant and the number of cycles. The two-dimensional solutions obtained from this study were in good agreement with previous results reported by Strömberg. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate tubes contacting at right angles. The results of the analyses showed donut-shaped wear along the contacting boundary, which is a typical feature of fretting wear.

On the Three-Dimensional Finite Element Analysis of Dovetail Attachments

2003 ◽  
Vol 125 (2) ◽  
pp. 372-379 ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair
Keyword(s):  
Boundary Conditions ◽  
Dimensional Analysis ◽  
High Stress ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Element Analysis ◽  
Computational Costs ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The stress analysis of dovetail attachments presents some challenges. These stem from the high stress gradients at the edges of contact. They also stem from the nonlinearities accompanying conforming contact. Even with two-dimensional analysis, obtaining converged peak stresses is not trivial. With three-dimensional analysis, convergence can be expected to be more difficult to achieve because of the added computational costs of refinement in three dimensions. To meet these challenges, this paper describes a submodeling procedure with finite elements. The submodeling approach features bicubic surface fits to displacements for submodel boundary conditions. The approach also features a means of verifying these boundary conditions have converged; this is crucial to obtaining accurate converged peak stresses. The approach is applied to a three-dimensional test piece used to simulate a dovetail attachment. This application leads to converged three-dimensional stresses. These stresses serve to quantify the sort of increases in contact stresses in attachments due to three-dimensional effects.

scholarly journals A Numerical Study of the effect of Bolt Thread Geometry on the Load Distribution of Continuous Threads

2021 ◽  
Author(s):  
Abdulla Sherif Mahmoud Fathalla ◽  
◽  
Ali Akhavan Farid ◽  
Reza Moezzi ◽  
Seyed Saeid Rahimian Koloor ◽  
...  
Keyword(s):  
Load Distribution ◽  
Numerical Study ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Reliable Performance ◽  
Dimensional Simulation ◽  
Three Dimensional Finite Element ◽  
Distribution Behaviour

Load distribution has been studied extensively for ISO thread, but the load distribution on power screw threads, specifically ACME and Square threads, has not been studied yet. In this article, axisymmetric two-dimensional and three-dimensional Finite Element Analysis have been conducted on bolts with different sizes and thread geometries to examine the effect of the thread geometry on the load distribution. The thread geometries were studied with ISO, ACME, and Square threads attention. The sizes used are from the ISO coarse series. In order to investigate on the effect of bolt thread geometry, several simulations have been performed. The two-dimensional simulation results have shown reliable performance in determining the load distribution behaviour when the thread geometry is modified. Moreover, the results agreed with the three-dimensional simulation outcomes regarding the load distribution behaviour when the size is varied.

scholarly journals Two - Dimensional Finite Element Analysis of Composite Patch Repairs Using Shell Laminate Elements

2003 ◽  
Vol 12 (2) ◽  
pp. 096369350301200
Author(s):  
George J Tsamasphyros ◽  
George N Kanderakis ◽  
Nikos K Furnarakis ◽  
Zaira P Marioli-Riga
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Element Analysis ◽  
Composite Patch ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Patch Repairs ◽  
Three Dimensional Finite Element

A host of one and two-sided composite patch reinforcements of metallic structures with different patch thickness were considered, in order to compare two-dimensional finite element analysis using shell laminate elements with three-dimensional finite element analysis. In order to verify the accuracy of this approach a parametric study has been performed and the 2D results were compared to the outcome of the corresponding three-dimensional finite element analysis, which accuracy has been experimentally verified in previous works. It was found that for the case of two-sided reinforcement the results obtained by the two methods were in very good agreement. For the case of one-sided reinforcement some deviation of the results of two-dimensional analysis has been observed, which was due to the tendency of the structure for out-of-plane bending, resulting from the bonding of a reinforcing patch to only one face of the structure. According to the results of this parametric study and since most aircraft structures are constrained against local out-of-plane bending (e.g. aircraft skins through stringers) two-dimensional finite elements analysis using shell laminate elements is proposed as an accurate and easy to use analysis tool for the design of both one and two-sided composite patch repairs of relatively simple structures.

On the Three-Dimensional Finite Element Analysis of Dovetail Attachments

2002 ◽  
Author(s):  
J. R. Beisheim ◽  
G. B. Sinclair
Keyword(s):  
Boundary Conditions ◽  
Dimensional Analysis ◽  
High Stress ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Element Analysis ◽  
Computational Costs ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The stress analysis of dovetail attachments presents some challenges. These stem from the high stress gradients at the edges of contact. They also stem from the nonlinearities accompanying conforming contact. Even with two-dimensional analysis, obtaining converged peak stresses is not trivial. With three-dimensional analysis, convergence can be expected to be more difficult to achieve because of the added computational costs of refinement in three dimensions. To meet these challenges, this paper describes a submodeling procedure with finite elements. The submodeling approach features bicubic surface fits to displacements for submodel boundary conditions. The approach also features a means of verifying these boundary conditions have converged: This is crucial to obtaining accurate converged peak stresses. The approach is applied to a three-dimensional test piece used to simulate a dovetail attachment. This application leads to converged three-dimensional stresses. These stresses serve to quantify the sort of increases in contact stresses in attachments due to three-dimensional effects.

Study on Stability of High Embankment with Strong Weathering Filling under Complicated Stress Conditions

2011 ◽  
Vol 97-98 ◽  
pp. 78-84
Author(s):  
Sheng Chuan Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Strength Reduction ◽  
Slope Instability ◽  
Instability Criterion ◽  
Two Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Strength reduction elasto-plastic finite element analysis defines the reduction factor when slope has been destroyed as the slope stability factor of safety, which combines with strength reduction technique, the limit equilibrium theory and the principle of elastic-plastic finite element. Three-dimensional finite element analysis should be used in stability analysis of slope because it can overcome the short advantages of two-dimensional finite element and can simulate the complex topographic and geological conditions. Based on the large-scale triaxial shear test, the modified Duncan-Chang model is established. Based on strength reduction elasto-plastic finite element, stability of high fill embankment was studied with three-dimensional finite element method considering the complex terrain conditions. Study results suggest that plastic strain and displacement mutant of slip surface node can be a sign of slope instability as a whole. At the same time calculation of three-dimensional finite element also does not converge. Therefore, it can be slope instability criterion calculate whether the finite element static analysis converges or not. On the other hand, stability safety factor of high fill embankment under three-dimensional conditions is larger than that of two-dimensional conditions, which shows that boundary conditions of high fill embankment enhance its stability.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Sign in / Sign up

Export Citation Format

Share Document