• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2805-2816
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• 1994

This paper describes dynamic finite element analyses performed to study the dynamic behaviors of a shipping container under the impact onto rigid target due to the accidental fall from the hight of 9 m. Using two and three dimensional techniques, the shipping container which gave the maximum damage, ten different drop orientations are considered ; at intervals of $5^{\circ}$ from $45^{\circ}$ to $90^{\circ}$ According to the present results, the orientation of the shipping container which gave the maximum damage is $85^{\circ}$ from horizontal for oblique drop in the primary impact. In the optimal design of the shipping container, the impact limiter material must be considered importantly because it's proper selection affects the weight and the manufacturing cost of the shipping container. The analysis of the shipping container in this paper demonstrated that the shipping container is structurally sound relative to the regulatory drop test requirements.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.31-44
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• 2019

This study simulated a control rod assembly (CRA), which is a part of reactor shutdown systems, in immersed and fluid flow conditions. The CRA was inserted into the reactor core within a predetermined time limit under normal and abnormal operating conditions, and the CRA (which consists of complex geometric shapes) drop behavior is numerically modeled for simulation. A full-scale prototype CRA drop test is established under room temperature and water-fluid conditions for verification and validation. This paper describes the details of the numerical modeling and analysis results of the several conditions. Results from the developed numerical simulation code are compared with the test results to verify the numerical model and developed computer code. The developed code is in very good agreement with the test results and this numerical analysis model and method may replace the experimental and CFD method to predict the drop behavior of CRA.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.1
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• pp.43-49
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• 2005

The package used to transport radioactive materials, which is called by the shipping cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than the one for test, the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors, the results depend on how users apply the codes and can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique lot the free drop impact test of the cask and investigated several vulnerable cases. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.2
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• pp.128-135
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• 2004

Generally, heavy electronic products undergo many different types of shocks in transportation from a manufacturer to customers. Cushioning package is used to protect electronic products from severe shock environments. Since the mass distribution of heavy electronic products is usually unbalanced and complex. it is very difficult to design a cushioning package with having high performance by considering only the equivalent stiffness of that. Therefore, when designing the cushioning package for a heavy electronic product, it is necessary to optimize its shape in order to maximize the cushioning performance. In this study, it is focused on designing an optimal shape of cushioning package for a large refrigerator and an efficient design method is suggested by using a dynamic finite element analysis. As the results of this study the optimal shape of cushioning package, which has high cushioning performance and minimized volume, was obtained through the mechanical drop analysis and a optimization process. Through free drop tests of refrigerators, it was identified that the cushioning performance of the cushioning package was improved up by 25% and the its own volume was reduced by 22 ％.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.677-683
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• 2003

Generally, heavy electronic products undergo many different types of shocks in transporting from a manufacturer to customers. Cushioning package materials are used to protect electronic products from severe shock environments. Since the mass distributions of heavy electronic products are usually unbalanced and complex, it is very difficult to design a cushioning package with haying high performance by considering only the equivalent stiffness of that. Therefore, when designing the cushioning material for a heavy electronic product, it is necessary to optimize its shape in order to maximize the cushioning performance. In this study, it is focused on designing an optimal shape of cushioning material for a large-sized refrigerator and an efficient design method is suggested by using a dynamic finite element analysis. As the results of this study, the optimal shape of cushioning material, which has high cushioning performance and minimized volume, was obtained from the drop analysis and a optimization process. From free drop tests of a refrigerator, it was identified that the cushioning performance of the optimal package were improved up to 16 % and the volume of it was reduced in a range of 22 %.

• International Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.16-22
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• 2018

An analysis has been made on the performance variation due to pressure drop change at propellant supply pipes of liquid rocket engine. The objective is to compare the effectiveness of control variables to tune the liquid rocket engine performance. The mode analysis program has been used to estimate the engine performance for different modes which is realized by controlling the flow rate of propellant. The oxidizer of combustion chamber, the fuel of combustion chamber, the oxidizer of gas generator and the fuel of gas generator are the independent variables to control engine thrust, engine mixture ratio and temperature of gas generator product gas. The analysis program is validated by comparing with the powerpack test results. The error range of compared variables is order of 4%. After comparison of tuning effectiveness it is turned out that the pressure drop at oxidizer pipe of gas generator and pressure drop at combustion chamber fuel pipe and the pressure drop at the fuel pipe of gas generator can effectively tune the thrust of engine, mixture ratio of engine and temperature of product gas from gas generator respectively.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.615-621
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• 2023

In this study, flow analysis of single, double, and triple filter systems of cylindrical structures was performed to analyze the flow characteristics of each filter. As a result of the flow analysis of the filter system, the number of filters and the pressure drop rate tend to be proportional to each other. It was found that the area passing through the inside of the filter had almost the same pressure. The maximum pressure drop rate of the triple filter system was about 14.9% for the forward-flow and about 12.4% for the reverse-flow. It was determined that the performance of the filter was stable within 20% of the allowable pressure drop rate of the filter system, which is the standard presented to the Korea Water Technology Certification Institute(KWTCI). In the future, a study on the decompression characteristics of the filter system according to the effect of the arrangement interval and filter density of the triple filter will be conducted.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.687-689
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• 2014

This paper deals with the optimal muffler model by using acoustic analysis and CFD(computational fluid dynamics) analysis. The complicated muffler model could be better noise reduction performance. However, it could be worse affected to back-pressure performance by pressure drop in working fluid. High back-pressure is caused to low system efficiency. Therefore, it is important for the muffler design to consider the pressure drop. The muffler models are changed their partition plate position. Acoustic power transmission loss(TL) and pressure drop of working fluid are calculated by using computational analysis and used to build database for finding their trends. The optimal muffler model in user-interested frequency range could be selected by analyzing this database.

• International Journal of Ocean System Engineering
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• v.2 no.2
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• pp.92-96
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• 2012

This study presents a rockfall impact analysis of a typical roadway. Dynamic finite element analyses using ANSYS AUTODYN are conducted to determine the effect of the drop heights (5 m, 10 m) on the damage to a roadway model. The Rockfall is modeled as a spherical shape with a weight of 400 kg, and each drop height is converted to a corresponding impact velocity to save computational time. The roadway model is comprised of an asphalt layer, base layer, sub-base layer, and sub-grade layer. In this paper, the asphalt is modeled using a linear elastic model. The base layer, sub-base layer, and sub-grade layer are modeled using a Mohr-Coulomb model. From the analyses, the effects of the drop height on the damages and stresses are examined and discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.451-457
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• 2017

The numerical analysis was conducted to evaluate the behavior of slab-column connection subjected to blast loads using LS-DYNA. The typical form of slab-interior column connection for analysis was considered as a reference specimen and the drop panel slab-interior column was designed to verify the effects of drop panel. The slab-column connections, which were composed of interior, edge and corner column, were additionally analyzed to compare their confinement effects of specimens. Analysis results were contained the failure shape of connection, behavior of member and so on. From the results, the blast-resistant capacities of slab-column connection would be enhanced by reinforcing the drop panel. In addition, the performance of connections could be improved, when the confinement effects were enhanced.