Finite Element Analysis Model for Estimating the Dynamic Crush Strength of the Spacer Grid Assembly for PWRs

2006 ◽  
Vol 324-325 ◽  
pp. 1011-1014
Author(s):  
Kee Nam Song ◽  
Kyung Ho Yoon ◽  
Jae Jun Lee ◽  
Kyung Jin Park
Keyword(s):  
Finite Element ◽  
Dynamic Buckling ◽  
Lateral Loads ◽  
Analysis Model ◽  
Spacer Grid ◽  
Element Analysis ◽  
Loss Of Coolant Accident ◽  
Seismic Accelerations ◽  
Buckling Test ◽  
Crush Strength

The spacer grid assembly, which is an interconnected array of slotted grid straps and welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assemblies of a Pressurized light Water Reactor (PWR). The spacer grid assembly is structurally required to have enough crush strength under lateral loads due to lateral seismic accelerations, lateral Loss Of Coolant Accident (LOCA) blowdown forces, and shipping and handling loads so that the fuel rods are maintained within a coolable geometry, and that the control rods are able to be inserted. The ability of the spacer grid assembly to resist the lateral loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired from the relevant tests. In this study, dynamic buckling tests and finite element analyses on spacer grid assembly specimens are carried out. As a result of the comparisons, the analysis results are in good agreement with the test results to within an 8 % difference range. Therefore, we could predict the crush strength of a spacer grid assembly in advance before performing the dynamic buckling test.

Impact Analysis and Test of the Spacer Grid Assembly for PWRs

2006 ◽  
Vol 326-328 ◽  
pp. 1555-1558
Author(s):  
Kee Nam Song ◽  
Kyung Ho Yoon ◽  
Jae Jun Lee ◽  
Kyung Jin Park
Keyword(s):  
Impact Analysis ◽  
Dynamic Buckling ◽  
Test Results ◽  
Lateral Loads ◽  
Spacer Grid ◽  
Nuclear Fuel Assembly ◽  
Fuel Assemblies ◽  
Buckling Test ◽  
Crush Strength ◽  
Good Agreement

The spacer grid assembly, which is an interconnected array of slotted grid straps and welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly of a Pressurized light Water Reactor (PWR). The spacer grid assembly supports and aligns the fuel rods, guides the fuel assemblies past each other during handling and, if needed, sustains lateral seismic loads. The ability of the spacer grid assembly to resist the lateral loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired from tests. In this study, dynamic buckling tests and finite element analyses on spacer grid assembly specimens are carried out. Comparisons show that the analysis results are in good agreement with the test results to within an 8 % difference range. Therefore, we could predict the crush strength of a spacer grid assembly in advance before performing the dynamic buckling test.

Impact Analysis and Test on the Spacer Grid Assembly for PWRs

2005 ◽  
Vol 297-300 ◽  
pp. 1309-1314 ◽  
Author(s):  
Kee Nam Song ◽  
Kyung Ho Yoon ◽  
Heung Seok Kang ◽  
Kang Hee Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fuel Assembly ◽  
Impact Analysis ◽  
Dynamic Buckling ◽  
Failure Behavior ◽  
Spacer Grid ◽  
Element Analysis ◽  
Water Reactors ◽  
Buckling Test

A spacer grid assembly is one of the main structural components of the fuel assemblies of Pressurized light Water Reactors. The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral loads acting on the fuel assembly so as to keep the fuel assembly straight. The structural performance of the spacer grid assembly is characterized in terms of its dynamic crush strength, which is usually acquired from the test. In this study, a dynamic buckling test and a finite element analysis on the KAERI designed spacer grid assembly are carried out. The pendulum-type tester was used in the test. In the finite element analysis, we proposed an analysis methodology that could predict the dynamic failure behavior of the spacer grid assembly using a commercial finite element code ABAQUS/explicit with appropriate boundary conditions. As a result of the comparisons, the analysis result is in good agreement with the test result to within a 10% difference range. Therefore, we could predict the dynamic behaviors of a spacer grid assembly in advance before performing the dynamic buckling test.

Impact Analysis for the Egg-Crate Structure of a Nuclear Fuel Assembly by Using FEM

2007 ◽  
Vol 353-358 ◽  
pp. 2668-2671
Author(s):  
Kee Nam Song ◽  
Sang Hoon Lee ◽  
Jae Yong Kim
Keyword(s):  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Impact Analysis ◽  
Lateral Loads ◽  
Spacer Grid ◽  
Element Analysis ◽  
Nuclear Fuel Assembly ◽  
Buckling Test ◽  
Crush Strength ◽  
Good Agreement

A spacer grid assembly is one of the main structural components of the nuclear fuel assembly of a Pressurized light Water Reactor (PWR). The spacer grid assembly supports and aligns the fuel rods, guides the fuel assemblies past each other during a handling and, if needed, sustains lateral seismic loads. The ability of a spacer grid assembly to resist these lateral loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired from tests. In this study, a finite element analysis on the dynamic crush strength of spacer grid assembly specimens is carried out. Comparisons show that the analysis results are in good agreement with the test results within an 8 % difference range. Therefore, we could predict the crush strength of a spacer grid assembly in advance, before performing the dynamic buckling test. And also a parametric study on the crush strength of a spacer grid assembly is carried out by adjusting the weld penetration depth for a sub-sized spacer grid, which also shows a good agreement between the test and analysis results.

IMPACT ANALYSIS AND TEST FOR THE SPACER GRID ASSEMBLY OF A NUCLEAR FUEL ASSEMBLY

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1228-1234 ◽  
Author(s):  
KEE-NAM SONG ◽  
SANG-HOON LEE ◽  
SOO-BUM LEE
Keyword(s):  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Impact Analysis ◽  
Test Results ◽  
Lateral Loads ◽  
Spacer Grid ◽  
Element Analysis ◽  
Nuclear Fuel Assembly ◽  
Crush Strength ◽  
Good Agreement

A spacer grid assembly is one of the main structural components of the nuclear fuel assembly for a Pressurized light Water Reactor (PWR). The spacer grid assembly supports and aligns the fuel rods, guides the fuel assemblies past each other during a handling and, if needed, sustains lateral seismic loads. The ability of a spacer grid assembly to resist these lateral loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired from tests. In this study, a finite element analysis on the dynamic crush strength of spacer grid assembly specimens is carried out. Comparisons show that the analysis results are in good agreement with the test results to within about a 30 % difference range. Therefore, we could predict the crush strength of a spacer grid assembly in advance, before performing a dynamic crush test. And also a parametric study on the crush strength of a spacer grid assembly is carried out by adjusting the weld penetration depth for a sub-sized spacer grid, which also shows a good agreement between the test and analysis results.

Development of a New Spacer Grid Form to Enhance the Integrity of Fuel Rod Support and the Crush Strength of a Spacer Grid Assembly

2009 ◽  
Author(s):  
Kee-nam Song ◽  
Soo-bum Lee ◽  
Moon-Kyun Shin ◽  
Jae-Jun Lee ◽  
Gyung-Jin Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Area ◽  
Optimization Technique ◽  
Spacer Grid ◽  
Element Analysis ◽  
Fuel Rods ◽  
Fuel Rod ◽  
Design Variables ◽  
Crush Strength

A spacer grid is one of the most important structural components in a LWR fuel assembly. The spacer grid, which supports nuclear fuel rods laterally and vertically with a friction grip, is an interconnected array of slotted grid straps welded at the intersections to form an egg-crate structure. Dimples and springs are stamped into each grid strap to support the fuel rods. The form of grid straps and spring form is known to be closely related with the crush strength of spacer grid assembly and the integrity of fuel rod support, respectively. Zircaloy is prevailing as the material of the spacer grid because of its low neutron absorption characteristic and its successful extensive in-reactor use. The primary considerations are to provide a Zircaloy spacer grid with crush strength sufficient to resist design basis loads especially due to seismic accidents, without significantly increasing pressure drop across the reactor core. Generally, the thickness and height of the Zircaloy grid strap have been the main design variables in order to meet the above considerations. Recently, it was reported that a dimple location is also a design variable that affects the crush strength of a spacer grid assembly. In this study, a new spacer grid form was developed in order to enhance the integrity of the fuel rod support and the crush strength of the spacer grid assembly by using a systematic optimization technique. Finite element analysis and crush strength tests on the developed new spacer grid form were carried out to check the performance enhancement compared to commercial spacer grids. The enhancement of fuel rod support was confirmed by comparisons of contact area, peak stresses, plastic deformation and etc. According to the results, it is estimated that the actual critical load enhancement of the spacer grid assembly is approximately up to 30% and the actual contact area, when a fuel rod inserted into a spacer grid cell, is more than double for the developed new spacer grid form. And also, some design variables that effect the crush strength of a PWR spacer grid assembly were classified and their effects on the crush strength were investigated by a finite element analysis and a crush strength test.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

Finite Element Analysis of Main Stand of Ф140 Pipe Rolling Mill and Split Casting

2013 ◽  
Vol 690-693 ◽  
pp. 2327-2330
Author(s):  
Ming Bo Han ◽  
Li Fei Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rolling Mill ◽  
Analysis Model ◽  
Element Analysis ◽  
Pipe Rolling ◽  
Full Load ◽  
Finite Element Software ◽  
Theoretical Position ◽  
Technical Requirements

By using finite element software, the paper establishes the main stand analysis model of the Ф140 pipe rolling mill and provides the model analysis of main stand in cases of full load. Verify the design of main stand fully comply with the technical requirements .In this paper, it provides the theoretical position of split casting and welding method using electric slag welding.

scholarly journals Biomechanical assessment of different fixation methods in mandibular high sagittal oblique osteotomy using a three-dimensional finite element analysis model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles Savoldelli ◽  
Elodie Ehrmann ◽  
Yannick Tillier
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Fixation Methods ◽  
Oblique Osteotomy ◽  
Von Mises

AbstractWith modern-day technical advances, high sagittal oblique osteotomy (HSOO) of the mandible was recently described as an alternative to bilateral sagittal split osteotomy for the correction of mandibular skeletal deformities. However, neither in vitro nor numerical biomechanical assessments have evaluated the performance of fixation methods in HSOO. The aim of this study was to compare the biomechanical characteristics and stress distribution in bone and osteosynthesis fixations when using different designs and placing configurations, in order to determine a favourable plating method. We established two finite element models of HSOO with advancement (T1) and set-back (T2) movements of the mandible. Six different configurations of fixation of the ramus, progressively loaded by a constant force, were assessed for each model. The von Mises stress distribution in fixations and in bone, and bony segment displacement, were analysed. The lowest mechanical stresses and minimal gradient of displacement between the proximal and distal bony segments were detected in the combined one-third anterior- and posterior-positioned double mini-plate T1 and T2 models. This suggests that the appropriate method to correct mandibular deformities in HSOO surgery is with use of double mini-plates positioned in the anterior one-third and posterior one-third between the bony segments of the ramus.

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