Analysis on the Dynamic Buckling Behavior of the Spacer Grid Structure

2018 ◽  
Author(s):  
Yan Guo ◽  
Chenglong Gu ◽  
Wei Tian ◽  
Weicai Li
Keyword(s):  
Cell Size ◽  
Dynamic Stiffness ◽  
Time History ◽  
Dynamic Buckling ◽  
Grid Structure ◽  
Analysis Model ◽  
Spacer Grid ◽  
Pressurized Water ◽  
Analytical Results ◽  
The Impact

The spacer grid is a key element of the fuel assembly used in the Pressurized water reactor. Due to its structural complexity, the analysis and the design of the spacer grid structure is difficult. This paper discusses the 5 × 5 cell size partial grid analysis including the detailed grid structural elements, through which, the impact force, the rebound velocity and the time history of acceleration and as well as other mechanical properties of grid under different initial impact velocity were obtained. This paper carried out the dynamic buckling criterion studies, and determined the dynamic buckling load of the 5 × 5 cell size partial spacer grid. Based on assuming the impact process is simple harmonic vibration, the method to determine the dynamic stiffness of the spacer grid was proposed. The experiments were also performed for the comparison with the analytical results. It is found that the analytical results are in good agreement with the experimental results. As a result, we can conclude that the analysis model including detailed grid elements is able to yield accurate analytical results.

An Estimation of the Dynamic Buckling Load for the Spacer Grid of Pressurized Water Reactor Fuel Assembly

2006 ◽  
Vol 326-328 ◽  
pp. 1603-1606 ◽  
Author(s):  
Sang Youn Jeon ◽  
Young Shin Lee
Keyword(s):  
Fuel Assembly ◽  
Dynamic Buckling ◽  
Buckling Load ◽  
Estimation Methods ◽  
Pressurized Water Reactor ◽  
Spacer Grid ◽  
Pressurized Water ◽  
Water Reactor ◽  
Spacer Grids ◽  
The Impact

This study contains an estimation of the dynamic buckling load for the spacer grid of fuel assembly in pressurized water reactor. Three different estimation methods were proposed for the calculation of the dynamic buckling loads of spacer grid. The dynamic impact tests and analyses were performed to evaluate the impact characteristics of the spacer grids and to predict the dynamic buckling load of the full size spacer grid. The estimation results were compared with the test results for the verification of the estimation methods.

Experimental Studies on the Impact Buckling of Bars and the Effect of Stress Wave

2006 ◽  
Vol 326-328 ◽  
pp. 1621-1624
Author(s):  
Rui Wang ◽  
Zhi Jun Han ◽  
Shan Yuan Zhang
Keyword(s):  
Stress Wave ◽  
Axial Stress ◽  
Axial Strain ◽  
Experimental Studies ◽  
Time History ◽  
Dynamic Buckling ◽  
Buckling Load ◽  
Quantitative Relation ◽  
Lateral Velocity ◽  
The Impact

The experimental studies on the dynamic buckling of the perfect bars with three kinds of lengths under impulsive axial compression were completed and the boundary condition of clamped-fixed was realized firstly in present studies. The time-history curves of axial strain of bars under different impact velocity were recorded. According to the magnitudes of the axial strain and bifurcate time, the quantitative relation of dynamic buckling load and critical bifurcate length are achieved; according to the curves recorded, the lateral velocity of bars are computed also. The experimental results show that the dynamic buckling load of the bar is distinctly greater than the static one, the front of stress wave can be regarded as fixed and the effect of the axial stress wave in the dynamic buckling of bar must be considered.

scholarly journals Dynamic Performance of Partially Orifice Porous Aerostatic Thrust Bearing

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 989
Author(s):  
Muhammad Punhal Sahto ◽  
Wei Wang ◽  
Ali Nawaz Sanjrani ◽  
Cheng Xu Xu Hao ◽  
Sadiq Ali Shah
Keyword(s):  
Thrust Bearing ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Research Work ◽  
Analysis Model ◽  
Thrust Bearings ◽  
Damping Characteristics ◽  
Fluent Software ◽  
Perturbation Frequency ◽  
The Impact

The aerostatic thrust bearing’s performance under vibration brings certain changes in stiffness and stability, especially in the range of 100 to 10,000 Hz, and it is accompanied by significant increase in fluctuations due to the changes in frequency, and the size of the gas film damping. In this research work, an analysis is carried out to evaluate the impact of throttling characteristics of small size orifice on stiffness and stability optimization of aerostatic thrust bearings. There are two types of thrust bearing orifices such as: partial porous multiple orifice and porous thrust bearings and their effects on variations in damping and dynamic stiffness are evaluated. A simulation based analysis is carried out with the help of the perturbation analysis model of an aerostatic thrust bearing simulation by using FLUENT software (CFD). Therefore, two models of aerostatic thrust bearings—one with the porous and other with partial porous orifice are developed—are simulated to evaluate the effects of perturbation frequencies on the damping and dynamic stiffness. The results reveal a decrease in the amplitude of dynamics capacity with an increase in its frequency, as well as a decrease in the damping of partial porous aerostatic thrust bearings with an increase in the number of orifices. It also reveals an increase in the radius of an orifice with an increment of damping of bearing at the same perturbation frequency and, with an increase in orifice height, a corresponding decrease in the damping characteristics of bearings and in the dynamic stiffness and coefficient of damping of bearing film in the frequency range less than 100 Hz.

Fire Durations of Concern for a Modern Legal Weight Truck Cask

2006 ◽  
Author(s):  
Neelima Mallidi ◽  
Miles Greiner ◽  
Venkata V. R. Venigalla
Keyword(s):  
Thermal Protection ◽  
Three Dimensional ◽  
Time History ◽  
Element Analysis ◽  
Pressurized Water ◽  
Dimensional Finite Element ◽  
Term Creep ◽  
Three Dimensional Finite Element ◽  
The Impact ◽  
Containment Integrity

The response of a truck package designed to transport four pressurized water reactor fuel assemblies to a simplified radiation fire model is simulated for a range of fire durations using three-dimensional finite element analysis. A model is developed to determine the cumulative seal degradation from its temperature versus time history. This model is used to determine the minimum fire duration that causes the seal to lose containment integrity. The fire durations that cause the maximum cladding temperature to reach its long term creep deformation and burst rupture temperatures are determined and found to be longer than the duration that cause the seal to lose containment integrity. These simulations are repeated for package models without the compliant regions of the impact limiters, and for a package with the impact limiter completely removed. These simulations quantify the level of thermal protection the impact limiters provide to the seals and cladding during simulated fires.

Dynamic Response Analysis under the Metro-Vibration Loading of Xi'an Bell Tower Timber Structure

2012 ◽  
Vol 170-173 ◽  
pp. 1361-1366 ◽  
Author(s):  
Zhao Bo Meng ◽  
Teng Fei Zhao ◽  
Shi Cai Cui ◽  
Jie Jin
Keyword(s):  
Dynamic Response ◽  
Technical Specification ◽  
Time History ◽  
Response Analysis ◽  
Winkler Foundation ◽  
Analysis Model ◽  
Time Dynamic ◽  
Bell Tower ◽  
Vibration Loading ◽  
The Impact

Taking Xi’an Bell Tower and metro line 2 as research background, at first, according to the theory of Euler-Bernoulli beam in Winkler foundation, the analysis model of train-track-foundation system was established, and then, time-history curve of metro-induced loading acts on tunnel structure is obtained by using Matlab produce platform. Secondly, two-dimensional finite element model of the structure-soil-tunnel interaction model was established using ANSYS. Taken loading time delay into consideration for the first time, dynamic response law of the bell tower under the metro-vibration loading is obtained. Finally, the impact of metro line 2 on Xi’an Bell Tower was evaluated according to the Technical specification for protection of historic buildings against man-made vibration.

Dynamic Response Analysis of Xi'an Bell Tower Timber Structure under the Metro-Vibration Loading of Line 2 and 6

2013 ◽  
Vol 353-356 ◽  
pp. 1732-1738
Author(s):  
Zhao Bo Meng ◽  
Teng Fei Zhao ◽  
Jie Jin ◽  
Xi Feng Li
Keyword(s):  
Technical Specification ◽  
Interaction Model ◽  
Time History ◽  
Element Model ◽  
Response Analysis ◽  
Winkler Foundation ◽  
Analysis Model ◽  
Bell Tower ◽  
Dimensional Finite Element ◽  
The Impact

The effects of metro line 2 and line 6 on Xi'an Bell Tower was studied by numerical analysis in this paper. At first, according to the theory of Euler-Bernoulli beam in Winkler foundation, the analysis model of train-track-foundation system was established, and then, time-history curve of metro-induced loading acts on tunnel structure is obtained by using Matlab produce platform. Secondly, two-dimensional finite element model of the structure-soil-tunnel interaction model was established using ANSYS. Finally, the impact of metro line 2 and 6 and ground transportation on Xi’an Bell Tower was evaluated according to the Technical specification for protection of historic buildings against man-made vibration. The construction of Metro Line 2 and Line 6 will affect the safety of Xi'an Bell Tower.

Dynamic Response Analysis of Xi'an Bell Tower Timber Structure under the Metro-Vibration Load of Line 6

2013 ◽  
Vol 353-356 ◽  
pp. 1718-1723
Author(s):  
Teng Fei Zhao ◽  
Zhao Bo Meng ◽  
Jie Jin ◽  
Xi Feng Li
Keyword(s):  
Dynamic Response ◽  
Technical Specification ◽  
Time History ◽  
Timber Structure ◽  
Response Analysis ◽  
Winkler Foundation ◽  
Analysis Model ◽  
Time Dynamic ◽  
Bell Tower ◽  
The Impact

Taking Xian Bell Tower and metro line 6 as research background, at first, according to the theory of Euler-Bernoulli beam in Winkler foundation, the analysis model of train-track-foundation system was established, and then, time-history curve of metro-induced loading acts on tunnel structure is obtained by using Matlab software. Two-dimensional finite element model of the structure-soil-tunnel interaction model was established using software Ansys,. Taken loading time delay into consideration for the first time, dynamic response law of the bell tower under the metro-vibration loading is obtained. Finally, the impact of metro line 6 on Xian Bell Tower was evaluated according to the Technical specification for protection of historic buildings against man-made vibration. Xi'an Bell Tower timber structure is safe when two trains running of the line 6.

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.

scholarly journals Experimental Verification of Analysis Model of Seismic Isolation With High-Static-Low-Dynamic Stiffness

2021 ◽  
Author(s):  
Kou Miyamoto ◽  
Jun Iba ◽  
Koichi Watanabe ◽  
Ken Ishii ◽  
Masaru Kikuchi
Keyword(s):  
Seismic Isolation ◽  
Dynamic Stiffness ◽  
Time History ◽  
Analysis Model ◽  
Restoring Force ◽  
Maximum Displacement ◽  
Natural Period ◽  
Absolute Acceleration ◽  
Seismic Force ◽  
Allowable Range

Abstract This paper verifies the model of high-static-low-dynamic stiffness (HSLDS) for seismic isolation based on an experiment. Seismic isolation is widely used in several countries. Moreover, the number of seismically isolated buildings has rapidly increased in these few decades. Seismic isolation extends a natural period of a building and decreases the absolute acceleration to re-duce a seismic force. However, as there is a trade-off between displacement and absolute acceleration, it might result in the maximum displacement be-yond an allowable range. HSLDS is nonlinear, and its restoring force can be approximated cube of a displacement. Thus, HSLDS applies a large restoring force for significant displacement, and the force is small for small perturbation around an equilibrium position. To improve the control performance of seismic isolation for displacement, we apply HSLDS for seismic isolation. This paper conducts an experiment and compares the results with a time-history analysis to verify a numerical model of HSLDS

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