Development of a Simplified PWR Fuel Assembly Nonlinear Model

2022 ◽  
Author(s):  
Namgyu Park ◽  
Youngik Yoo ◽  
Taesoon Kim ◽  
Sangyoun Jeon
Keyword(s):  
Fuel Assembly ◽  
Nonlinear Model ◽  
Element Model ◽  
Test Results ◽  
Unknown Parameters ◽  
Spacer Grids ◽  
Nuclear Fuel Assembly ◽  
Commercial Code ◽  
Nonlinear Finite Element Model ◽  
Skeleton Structure

Abstract This paper proposes a computation technique to develop a simplified nonlinear model for a typical nuclear fuel assembly. Because more than a hundred fuel assemblies are packed in the reactor, simplistic model generation is critical to evaluate the motion during an anticipated event such as earthquake. Two straight beams are introduced to simplify the fuel assembly, and the beam properties are moderately defined to represent the skeleton structure and a bundle of slender fuel rods. Because nonlinearity is caused by the interaction between the rods and the spacer grids in the skeleton structure, the two beams are connected with multilinear joints that characterize the mechanical interaction between them. An equation of motion for the model is provided, and the degree of the freedom of the model can be reduced by using a few major modes of the beams. Significant mechanical parameters must be defined reasonably, so a method is proposed to identify unknown parameters through a deterministic calculation and an optimization process. All the information, including the identified parameters, are utilized to develop a nonlinear finite element model with a commercial code. The performance of the model is compared with the test results.

A Simple Method to Estimate the Vibration Characteristics of a PWR Fuel Assembly

2011 ◽  
Author(s):  
Hyeong Koo Kim ◽  
Kyou Seok Lee ◽  
Jeong Ha Kim ◽  
Sang Youn Jeon ◽  
Sun Tack Hwang
Keyword(s):  
Fuel Assembly ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Test Results ◽  
Simple Method ◽  
Nuclear Fuel Assembly ◽  
Prototype Test ◽  
End Conditions ◽  
General Frequency ◽  
Supporting Condition

The main objective of this study is to establish a simple method making it possible to analyze the dynamic characteristics of the nuclear fuel assembly considering the geometrical configuration and the supporting condition of reactor internals etc. without any prototype test or FE models. In this study, a general frequency expression has been suggested for Bernoulli-Euler beams with generally restrained boundary conditions using Fourier series as a mode function. And using the frequency expression, the natural frequencies and mode shapes of a conventional fuel assembly for OPR1000 plants with reactor end conditions are calculated and compared with the test results in order to figure out its applicability to estimation on vibration characteristics of the fuel assembly. As a result, since the method suggested in present study gives quite a similar one with test result, present method will be useful to perform design evaluation preliminarily on the vibration characteristic of developing new fuel assembly.

Finite Element Model to Simulate the Spacer Grid Buckling Characteristics

2020 ◽  
Author(s):  
Youngik Yoo ◽  
Joongjin Kim ◽  
Kyongbo Eom ◽  
Hyeongkoo Kim
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fuel Assembly ◽  
Nuclear Fuel ◽  
Grid Cell ◽  
Element Model ◽  
Spacer Grid ◽  
Static Compression ◽  
Fuel Rod ◽  
Nuclear Fuel Assembly

Abstract The purpose of this study is to develop a finite element model that accurately describes the buckling behavior of a spacer grid. The spacer grid is the most important component of a nuclear fuel assembly and supports the fuel rod with a structurally sufficient buckling strength. Therefore, the development of a reliable spacer grid model is essential to evaluate the mechanical integrity of a nuclear fuel assembly. To achieve this objective, a three-dimensional finite element model was proposed to simulate the buckling characteristics and mechanical behavior of a PWR spacer grid. To simulate the exact mechanical properties of the spacer grid cell, the parameter values required for the model were determined by conducting a fuel rod drag test and spacer grid spring/dimple stiffness test. Finally, a spacer grid static compression test and dynamic impact test were performed according to the gap size of the spacer grid cell, and the model was verified by comparing the test and analysis results. The results obtained using the developed spacer grid finite element model agreed well with the mechanical test results, and it was confirmed that both the buckling characteristics and mechanical behaviors of the model were accurately simulated by the proposed model.

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.

Experimental and Finite Element Study on Mechanical Behavior of Bolted Joint with Bolt Clearance in Transmission Tower

2012 ◽  
Vol 625 ◽  
pp. 25-29
Author(s):  
Bin Rong Zhu ◽  
Hai Jun Xing ◽  
Jing Bo Yang
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Test Results ◽  
Bolted Joint ◽  
Transmission Tower ◽  
Double Shear ◽  
Nonlinear Finite Element Model ◽  
Relationship Of ◽  
Study Performance ◽  
Good Agreement

To accurately analyze the force and deformation of the transmission tower, it is necessary to study performance of bolted joint in the tower. In the paper single shear and double shear bolted joint with number of bolts changed is tested. Based on the actual data in test, nonlinear finite element model of bolted joint is established with ABAQUS, considering the bolt clearance and preload, and shows good agreement with test results, which is proved correct and applicable. Eventually, through a comparison of FEM and test results, the factors that affect bolt slip and the changing relationship of axial force of bolt and friction force is described.

Research on the Nonlinear Finite Element Analysis of Rubber CVJ Boot

2013 ◽  
Vol 421 ◽  
pp. 177-180 ◽  
Author(s):  
Jian Hua Zhao ◽  
De Bin Zhu ◽  
Rui Bo Zhang
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Material Model ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Test Results ◽  
Element Analysis ◽  
The Common ◽  
Set Up ◽  
Nonlinear Finite Element Model

Rubber CVJ boot is the important part of the car transmission system. Trough crack and surface wear of the CVJ boot are the common failure modes, so the stress distribution simulation of the boot is needed. Acoording to the Mooney-Rivlin model, the definite method of the coefficient for material model was obtained. Based on the software Abaqus, a nonlinear finite element model of CVJ boot was set up. The elements type was hybrid (mixed formulation) C3D4H. The deformation and strength of the boot under working condition were computed. The maximum stress is 11490MPa, located in the first trough and the contact surface of the 3rd and the 2nd crest have more serious wear, which correlate well with the test results. The next work is to optimize boot structure by this simulation model.

scholarly journals Experimental and Numerical Investigation on the Steel Reinforced Grout (SRG) Composite-to-Concrete Bond

2020 ◽  
Vol 4 (4) ◽  
pp. 182
Author(s):  
Luciano Ombres ◽  
Salvatore Verre
Keyword(s):  
Bond Length ◽  
Failure Modes ◽  
Peak Load ◽  
Element Model ◽  
Test Results ◽  
Shear Tests ◽  
Bond Slip ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Inorganic Matrix

In the paper, the bond between a composite strengthening system consisting of steel textiles embedded into an inorganic matrix (steel reinforced grout, SRG) and the concrete substrate, is investigated. An experimental investigation was carried out on medium density SRG specimens; direct shear tests were conducted on 20 specimens to analyze the effect of the bond length, and the age of the composite strip on the SRG-to-concrete bond behavior. In particular, the tests were conducted considering five bond length (100, 200, 250, 330, and 450 mm), and the composite strip’s age 14th, 21st, and 28th day after the bonding. Test results in the form of peak load, failure modes and, bond-slip diagrams were presented and discussed. A finite element model developed through commercial software to replicate the behavior of SRG strips, is also proposed. The effectiveness of the proposed numerical model was validated by the comparison between its predictions and experimental results.

Design of Static Test Model for Three-Tower Cable-Stayed Self-Anchored Suspension Composed Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 1528-1535
Author(s):  
Yu Zhao ◽  
Yong Jun Zhou ◽  
Jing Sun ◽  
Jin Tao Tang ◽  
Xu Li
Keyword(s):  
Complex System ◽  
Finite Element ◽  
Element Model ◽  
Test Model ◽  
Test Results ◽  
Static Test ◽  
Whole Process ◽  
Aesthetic Appearance ◽  
Load Carrying ◽  
Novel Structures

Cable-stayed self-anchored suspension composed bridges have novel structures and aesthetic appearance with complex system and difficulty for design and construction. In order to acquire a better knowledge of the load-carrying capability of this type of bridges, based on a real bridge and the theory of abnormal similarity, a full-bridge scaled down(1:20) test model was built to simulate the whole process of construction. The test results were preferably fit the theoretical calculation value. It can be seen that the design of the bridge was reasonable, and the accuracy of the calculation of finite element model was verified at the same time. The test and the related results can be used as the reference for the test and design of the similar bridges.

System Level Bench Test for Trailing Arm Strength Estimation

2006 ◽  
Author(s):  
Jaychandar Muthu ◽  
Kanak Soundrapandian ◽  
Jyoti Mukherjee
Keyword(s):  
Failure Mode ◽  
Real Life ◽  
Element Model ◽  
Suspension System ◽  
System Level ◽  
Bench Test ◽  
Component Level ◽  
Arm Strength ◽  
Bench Testing ◽  
Nonlinear Finite Element Model

For suspension components, bench testing for strength is mostly accomplished at component level. However, replicating loading and boundary conditions at the component level in order to simulate the suspension system environment may be difficult. Because of this, the component's bench test failure mode may not be similar to its real life failure mode in vehicle environment. A suspension system level bench test eliminates most of the discrepancies between simulated component level and real life vehicle level environments resulting in higher quality bench tests yielding realistic test results. Here, a suspension level bench test to estimate the strength of its trailing arm link is presented. A suspension system level nonlinear finite element model was built and analyzed using ABAQUS software. The strength loading was applied at the wheel end. The analysis results along with the hardware test correlations are presented. The reasons why a system level test is superior to a component level one are also highlighted.

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