THERMO-ELASTIC-PLASTIC-CREEP FINITE ELEMENT ANALYSES OF ANNULAR NUCLEAR FUELS

2012 ◽  
Vol 06 ◽  
pp. 379-384
Author(s):  
Y. D. KWON ◽  
S. B. KWON ◽  
K. T. RHO ◽  
M.S. KIM ◽  
H. J. SONG
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Fuel System ◽  
Finite Element Analyses ◽  
Nuclear Fuels ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program ◽  
Pros And Cons ◽  
Plastic Creep

In this study, we tried to examine the pros and cons of the annular type of fuel concerning mainly with the temperatures and stresses of pellet and cladding. The inner and outer gaps between pellet and cladding may play an important role on the temperature distribution and stress distribution of fuel system. Thus, we tested several inner and outer gap cases, and we evaluated the effect of gaps on fuel systems. We conducted thermo-elastic-plastic-creep analyses using an in-house thermo-elastic-plastic-creep finite element program that adopted the 'effective-stress-function' algorithm. Most analyses were conducted until the gaps disappeared; however, certain analyses lasted for 1582 days, after which the fuels were replaced. Further study on the optimal gaps sizes for annular nuclear fuel systems is still required.

scholarly journals Finite Element Analysis of Structural Engineering Problems Using a Viscoplastic Model Incorporating Two Back Stresses

1995 ◽  
Vol 117 (2) ◽  
pp. 377-383 ◽  
Author(s):  
V. K. Arya ◽  
G. R. Halford
Keyword(s):  
Finite Element ◽  
Structural Engineering ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Finite Element Program ◽  
Viscoplastic Model ◽  
Engineering Problems ◽  
Element Program ◽  
Viscoplastic Models

The feasibility of a viscoplastic model incorporating two back stresses and a drag strength is investigated for performing nonlinear finite element analyses of structural engineering problems. The model has recently been put forth by Freed and Walker. The feasibility of the viscoplastic model is demonstrated for nonlinear structural analyses by implementing the model into a finite element program and performing nonlinear finite element analyses for several uniaxial and multiaxial problems. Good agreement is shown to exist between the results obtained using the finite element implementation and those obtained experimentally. The advantages of using advanced viscoplastic models for performing nonlinear finite element analyses of structural components are indicated.

Elastic-Plastic Line-Spring Finite Elements for Surface-Cracked Plates and Shells

1982 ◽  
Vol 104 (4) ◽  
pp. 287-292 ◽  
Author(s):  
D. M. Parks ◽  
C. S. White
Keyword(s):  
Finite Element ◽  
Finite Element Program ◽  
Elastic Line ◽  
Shell Elements ◽  
Elastic Plastic ◽  
Cracked Plates ◽  
Spring Element ◽  
Element Program ◽  
Virtual Crack Extension Method ◽  
Pressurized Cylinder

The elastic line-spring finite element of Parks, et al. [1], which was incorporated into the ABAQUS© finite element program, is extended to include elastic-plastic response for approximate evaluation of the J-integral in surface-cracked plates or shells. J-analysis of a long axial crack in a pressurized cylinder is performed both with the virtual crack extension method and with a single elastic-plastic line-spring element attached to a 180-deg ring of shell elements constrained to (axial) plane strain. Agreement of the two models is generally good, both in the elastic range (as was noted earlier by Buchalet and Bamford) and in the plastic range. An axially cracked, internally pressurized cylinder containing a semi-elliptical flaw of aspect ratio a/c = 1/3, and of varying maximum relative depths a/t has also been analyzed.

scholarly journals Influence of Brick Walls on the Temperature Distribution in Steel Columns in Fire

10.14311/1077 ◽  
2009 ◽  
Vol 49 (1) ◽  
Author(s):  
António J. P. Moura Correia ◽  
Joao Paulo C. Rodrigues ◽  
Valdir Pignatta e Silvac
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Fire Resistance ◽  
Experimental Models ◽  
Finite Element Program ◽  
Steel Columns ◽  
Element Program ◽  
The University ◽  
In Fire ◽  
Resistance Tests

This paper reports on a study of steel columns embedded in walls in fire. Several fire resistance tests were carried out at the Laboratory of Testing Materials and Structures of the University of Coimbra, in Portugal. The temperatures registered in several points of the experimental models are compared with those obtained in numerical simulations carried out with the SUPERTEMPCALC finite element program. 

Study of beam–soil interaction using finite element and centrifugal models

1982 ◽  
Vol 19 (3) ◽  
pp. 345-359 ◽  
Author(s):  
D. Leshchinsky ◽  
S. Frydman ◽  
R. Baker
Keyword(s):  
Finite Element ◽  
Load Transfer ◽  
Finite Element Analyses ◽  
Finite Element Program ◽  
Buried Structures ◽  
Centrifuge Models ◽  
Element Program ◽  
Principal Directions ◽  
Centrifugal Model ◽  
Nonlinear Elastic

A comparison is presented between the results of centrifugal model tests and finite element analyses for the problem of load transfer to a rigid tie beam buried in sand. The finite element program utilized a nonlinear elastic (hyperbolic) soil constitutive relation, obtained from tests in simple shear. It was found that, for this particular type of problem, the finite element solution may reasonably represent the interaction between the beam and the surrounding soil. It is pointed out that this agreement does not ensure that the use of such finite element analyses would be justified in problems involving rotation of principal directions, and local unloading.The effect of compaction of the fill was investigated, and it was found that compaction leads to an increase in load transferred to the beam above that which is due to density effects alone.Key words: finite elements, centrifuge, models, soil–structure interaction, buried structures.

scholarly journals Comparison of the Characteristics of Solid Type and Annular Type Nuclear Fuels Using Thermoelastic-Plastic-Creep FEM

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Young-Doo Kwon ◽  
Dae-Suep Lee ◽  
Tae-Hyeok Yun
Keyword(s):  
Finite Element ◽  
Nuclear Power ◽  
Power Plants ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Finite Element Program ◽  
Thermomechanical Characteristics ◽  
Element Program ◽  
Plastic Creep ◽  
Thermoelastic Plastic

The purpose of this study is to compare the characteristics of two types of nuclear fuel using the finite element program of thermoelastic-plastic-creep analysis. The analyzed fuel rods are of two types, solid and annular ones, and their thermomechanical characteristics are compared. Thermoelastic-plastic-creep analyses were made using an in-house finite element analysis program that adopts the “effective-stress-function” algorithm. The temperature-dependent material properties, which were obtained from the experiments for actual nuclear reactors, are adopted. The effects of type of fuel systems are revealed in both stresses and temperature distributions. The maximum tensile and compressive hoop stress of pellet and cladding are monitored to evaluate the mechanical behavior, and the maximum temperature is used to evaluate the thermal behavior. Although the annular type of fuel has certain disadvantage, it would be used very effectively or safely in future nuclear power plants.

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