• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.257-268
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• 2018

We have studied the damage mechanism of a metallic thin plate by the highly energetic fragments generated from high explosive(HE) warhead. The penetration process has presumed that the velocity of a fragment is in the range of 350 m/s to 3353 m/s, the thickness of Aluminum 2024 target plate is in the range of 1 mm~6.3 mm thick. The mass of fragment with hemisphere nose shape is in the range of 0.32 g to 16 g. The analytical solution for penetration process has been derived by using the report of the project THOR. The results of analysis implied that the closed forms by an exponentially decay function well fit the change of the ballistic limit velocity, loss velocity and loss mass of fragment as the mass of fragment and the thickness of target plate increase.

• Journal of the Korean Institute of Gas
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• v.4 no.1 s.9
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• pp.33-39
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• 2000

Stress intensity factor after penetration was discussed experimentally using long surface pre-cracked specimens of aluminum alloy 5083. The propagation behavior evaluation of long surface crack by equation proposed at penetration of short surface crack could be need modification to evaluate precisely because the error was high as aspect ratio is little. The modification of stress intensity factor with consideration of aspect ratio at penetration of long surface crack can be analyzed the behavior of crack penetration quantitatively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1095-1101
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• 2008

In this paper, seismic analysis of LNG storage tank is performed. The analysis models are both pipe and pipe, wall and guide of LNG tank. And equivalent static analysis and response spectrum analysis are applied to these two models, respectively. From the analysis, deflections and equivalent stresses are compared. Results show that response spectrum analysis is more accurate than equivalent static analysis for LNG storage tank.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.411-418
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• 2012

In this study, behavior of unpatched and patched cylindrical shells with through-wall cracks has been estimated using numerical experiments, and patching effect of them has been investigated according to various patching parameters. To show credibility of numerical models considered, two ways such as h- and p-methods have been adopted. Also, domain integral method and virtual crack extension method have been considered to calculate energy release rates based on linear elastic fracture mechanics. For examples, the unpatched cylindrical shells with circumferential cracks under remote tension have firstly been analyzed to show the validity of finite element modeling with h-method or p-method, and then the results have been compared with literature values published. Next, the sensitive analysis of patch repaired problems in terms of thickness of patch and adhesive, shear modulus of adhesive, composite material type of patch, crack length, etc. has been carried out.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.51-57
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• 2012

In this study, numerical analysis was carried out for both partially penetrated SCP(sand compaction pile) and fully penetrated SCP constructed into the ground. Midas GTS was used as a FEM analysis program, which is widely used in geotechnical engineering. For the analysis, ground displacement, effective stress and pore water pressure at the time both just after embankment on the ground and 365days later were compared and analyzed. As the results, the effect regarding partially penetrated SCP was similar to the effect regarding fully penetrated SCP under the bottom of the center of embankment when considering the safety towards shear failure.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.109-116
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• 2018

In order to destroy the hard target, it is essential to develop a penetration warhead with high penetration performance. To design a penetration warhead, this paper discusses the effect of nose shape factors such that nose shape, nose length, nose tip diameter, on the penetration performance of the penetrator. AUTODYN-2D has been used to conduct the computational analysis. The experimental result of Forrestal, and a simulation result have been compared to verify the reliability of computational analysis. Computational results show that the nose length have more influence on the penetration performance than the nose shape. Furthermore, simulation results show that the penetration performance can be improved by increasing the nose tip diameter to a specific value, when the nose length of the penetrator is uniform.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.80-90
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• 1993

Radiation streaming through penetrations has been of great concern in radiation shielding design and analysis. This study developed a Monte Carlo method and constructed a data library of results calculated by the Monte Carlo method for radiation streaming through a straight cylindrical duct in concrete walls of a broad, mono-directional, mono-energetic gamma-ray beam of unit intensity. It was demonstrated that average dose rate due to an isotropic point source at arbitrary positions can be well approximated using the library with acceptable error. Thus, the library can be used for efficient analysis of radiation streaming due to arbitrary distributions of gamma-ray sources.

• Composites Research
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• v.25 no.6
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• pp.191-197
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• 2012

In this paper, the penetration behavior of carbon/epoxy composite laminates subjected to high velocity projectile impact was studied by numerical simulation. The composite laminates made of carbon/epoxy with $[45/0/-45/90]_{ns}$ stacking sequence and the spherical steel impactor were three-dimensionally modeled. The ply numbers of 16 and 24 and the impact velocities in the range of 140-250 m/s were considered. The analysis was performed using an explicit finite element code LS-DYNA. The residual velocity and the amount of damage were predicted and compared to the experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.1-9
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• 2021

A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and prevent flame diffusion in fire accidents. In case that the A60 piece is newly developed or its initial design is revised, it is important to verify the fire resistance performance using a fire test procedure (FTP) code. In this paper, transient heat transfer analysis was carried out to evaluate the fire resistance design compatibility of the newly devised A60 piece. The analysis results were verified via a fire test. The heat transfer characteristics were also investigated by comparing design specifications, such as diameter, internal configuration, and material type. The analysis was performed using ABAQUS/Implicit, and the fire test was performed according to the FTP code. The fire resistance performance of the A60 pieces satisfied the safety of life at sea convention regulation. The material type was the most important design specification for the A60 piece. Based on the maximum test temperature, the measured temperature of SUS316L material was 25% lower than that of S45C on average. The differences between thermal conductivity and specific heat of each material were 17% and 58%, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1083-1091
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• 2013

The design of missile require extremely small warheads that must be highly efficient and lethal. The penetration characteristics of each penetrator and the total number of penetrators on the warhead are obvious key factors that influence warhead lethality. The design of the penetrator shape and size are directly related to the space and weight of the warhead. The design of the penetrator L/D was directly related to the space and weight of the warhead. L and D are the length and the diameter of the projectile, respectively. The AUTODYN-3D code was used to study the effect of penetrator penetration. The objective of numerical analysis was to determine the penetration characteristics of penetrator produced by hypervelocity impacts under different initial conditions such as initial velocity, obliquity angle and L/D of penetrator. The residual velocity and residual mass were decreased with increasing initial impact velocity under $L/D{\leq}4$.