• Composites Research
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• v.18 no.6
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• pp.40-47
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• 2005

In this study, we tried to invent ceramic armor material with brilliant ballistic properties by the silica of the high compression-expansion ratio and based on alumina that has the most economical and higher ballistic efficiency. After we choose three compositions, proper sintering temperature for each composition was decided. After physical/mechanical measurement, we measured ballistic properties about KE(Kinetic Energy, L/D=10.7, tungsten heavy alloy) and HEAT(High Explosive Anti-Tank, K215) projectiles. As a result, $46\%\;Al_2O_3\;-\;51\%\;SiO_2$ of three compositions had the highest ballistic efficiency md better properties than alumina.

• Composites Research
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• v.18 no.6
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• pp.48-53
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• 2005

In this study, to improve the ballistic efficiency of very brilliant alumina-silica armor material, forming press and sintering temperature were changed. After physical/mechanical measurement, we measured ballistic properties about KE(Kinetic Energy, L/D=10.7, tungsten heavy alloy) and HEAT(High Explosive Anti-Tank, K215) projectiles and analyzed them. As a result, in $1235^{\circ}C$, it appeared the highest ballistic efficiency about HEAT and it improved $22\%$ ballistic efficiency, better than invented alumina-silica armor material before.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.134-134
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• 2001

요식업소에서 배출되는 불판 세척 폐액 속에는 폐지방탄화물이 다량 포함되어 있다. 이러한 폐지방탄화물은 수생태계 뿐만 아니라 하수처리 공정에도 악영향을 미칠 가능성이 높다고 알려져 있다. 그럼에도 불구하고, 아직 국내에서는 폐지방탄화물의 환경독성학적인 조사가 이루어지지 않은 실정이다. (중략)

• Composites Research
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• v.18 no.6
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• pp.34-39
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• 2005

In this study, we analyzed the relation between physical/mechanical properties and ballistic properties for several engineering ceramics that were expected to use as armor material. After physical/mechanical measurement, we measured ballistic properties about KE(Kinetic Energy, L/D=10.7, tungsten heavy alloy) and HEAT(High Explosive Anti-Tank, K215) projectiles. Increasing Young's modulus/density, hardness/density and flexural strength/density ratios, ballistic properties were generally increased. Especially it appeared that the ballistic property about KE projectile was lineally increased, as HEL/density ratio increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.332-339
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• 2020

This study was a prior study to establish the shelf life of bulletproof helmets, considered the aging factor of bulletproof helmets. To estimate the aging factor of bulletproof helmets, we established a hypothesis that the 'temperature' factor would have the greatest impact on the shelf life of the bulletproof helmet, considering the environmental treatment of the American army's bulletproof helmet's materials. To verify the hypothesis, high temperature acceleration environmental treatment of bulletproof helmets was performed, and the Arrhenius formula was applied to calculate the shelf life. The study result confirmed the negative correlation between bulletproof performance and high temperature, and the influence of temperature as an aging factor was not significant by deriving life by using the Arrhenius model. The limitation of this study is that we couldn't obtain enough samples due to the specificity (miliary supplies) of the test subjects. However, given that the life-related research on bulletproof helmets has not been carried out, this research has great implications and could be used as a reference for improving the Korean Army's bulletproof helmet specifications.

• Composites Research
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• v.20 no.3
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• pp.1-7
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• 2007

Manufacturing process of the shear thickening fluid(STF) and evaluation of the ballistic penetration resistance performance of the Kevlar-STF composites were studied. STF was made from silica and ethylene glycol, and the Kevlar-STF composite was made by impregnating the STF into the Kevlar fabric. Specimens including neat Kevlar woven fabrics and Kevlar-STF composites with two types of silica were prepared and carried out the ballistic tests. From the results STFs represented shear thickening behavior irrespective of the silica type, and Kevlar-STF composite with spherical silica showed best ballistic penetration resistance performance among them. Especially the specimens of Kevlar-STF composites with spherical silica showed radial fiber deformation by the projectile during the tests, that was somewhat different deformation behavior from those of the neat Kevlar fabrics shown fiber pull-out phenomena or fracture.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.5
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• pp.331-338
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• 2023

Modern bulletproof armor must be light and have excellent penetration resistance to ensure the mobility and safety of soldiers and military vehicles. The ballistic performance of heterogeneous structures of laminated flat plates as bulletproof armor depends on the arrangement of constituent materials for the same weight. In this study, we analyze bulletproof performance according to the stacking sequence of laminated bulletproof armor composed of Kevlar, ultra-high molecular weight polyethylene, and ethylene-vinyl-acetate foam. A ballistic analysis was performed by colliding a 7.62 × 51 mm NATO cartridge's M80 bullet at a speed of 856 m/s with six lamination arrangements with constituent materials thicknesses of 5 mm and 6.5 mm. To evaluate the bulletproof performance, the residual speed and residual energy of the projectile that penetrated the heterogeneous laminated flat plates were measured. Simulation results confirmed that the laminated structure with a stacking sequence of Kevlar, ultra-high molecular weight polyethylene, and ethylene-vinyl-acetate foam had the best bulletproof performance for the same weight.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.7-19
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• 2002

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.487-495
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• 2012

In order to prevent the high velocity bullet from penetration, aluminum alloy and RHA(Rolled Homogeneous Armour) steel, which have a high tensile and compressive strength, are usually used as the bullet-proof armor material. Although these materials have a good bullet proof performance, but not an area density which is a weight increasing factor of bullet-proof armor. Therefore, Mg(magnesium) alloy is a promising substitute for the traditional bullet-proof armor material due to the relatively low areal density. The spatial efficiency of Mg alloy, however, is inferior to the traditional material's, which is a volume(thickness) increasing factor of bullet-proof armor. In this study, we select the multi-layered hybrid armor which consist of Ceramic, with a high strength; Mg alloy, with a low areal density; Kevlar, with a high tensile strength-to-weight ratio; in order to make up for the poor spatial efficiency of Mg alloy. By predicting V50 of the multi-layered armor against 9mm FMJ(Full Metal Jarket). we show that the multi-layered armor have the capability in improving bullet-proof performance in the respect of the areal density, but also the spatial efficiency.

• Composites Research
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• v.22 no.4
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• pp.50-53
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• 2009

This paper mainly describes the armor materials, especially the ceramic materials for the personal protection. In the ceramic armor materials, B4C ceramics and SiC ceramics are the most popular materials. The $B_4C$ ceramics which consists of 4 atoms of boron and I atom of carbon is very light and strong. It is usually used to personal protection armor and chair protection in the helicopter. This material must be sintered at very high temperature because it melts at $2400^{\circ}C$. In order to have a good armor property, it must have very high density which is achieved by hot press or subsidiary sintering aid methods such as reducing the particle size of raw materials or mixing the sintering agents to the raw materials.