• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.15-16
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• 2004

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.19-19
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• 2004

• 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.

• Composites Research
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• v.24 no.2
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• pp.46-50
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• 2011

This paper describes the state of the art for the development of metallic armor materials which are mainly used as armor plates of the combat vehicles. Several important micro-structural features affecting ballistic properties of the metallic armor are discussed. Optimization of the strength and toughness balance of the metallic armor is necessary for the improvement of the ballistic performance resulting from maximizing the resistance to the penetration of the bullet and also to brittle failure of the plates. Understanding and control of the adiabatic shearing phenomenon developed remarkably during high strain rate deformation is needed to prevent brittle failure of the metallic armor materials.

• Conservation Science in Museum
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• v.26
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• pp.35-66
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• 2021

This study conducted scientific analysis and conservation treatment on four suits of armor and two helmets from the collection of the National Museum of Korea. Based on the findings, it identified structural characteristics of armor from the middle and late Joseon Dynasty. Since a suit of armor is made of composite materials consisting of both organic and inorganic elements, conservation treatment was conducted to the extent that the stable condition of each material remained unaffected by the other materials. The process took place in the sequence of investigation and analysis, removal of contamination, stabilization and reinforcement, repair of damaged parts, and storage. The armor and helmets had suffered severe damage, but were safely repaired and partially restored through the conservation treatment. The findings from the conservation treatment revealed the materials used and structural characteristics of the armored skirt from a two-piece set of armor from the middle Joseon period and for the two suits of overcoat-style armor, suit of vest-style armor, and helmets from the late Joseon era. It also allowed the investigation of the production methods of the armor and helmets.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.6
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• pp.762-781
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• 2018

This paper presents the ballistic armor performance examination and thickness estimation for the latest naval ship structure materials in the Republic of Korea. Up to date, research regarding methods of ballistic experiments establishing database on the latest hull structure materials as well as a precise method of estimating required thickness of armor against specific projectiles have been rarely researched. In order to build a database and estimate proper thicknesses of structure materials, this study used four structure materials that have been widely applied in naval ships such as AH36 steel, AL5083, AL5086, and Fiber Reinforced Plastics (FRP). A $7.62{\times}39mm$ mild steel core bullet normally fired by AK-47 gun was considered as a threat due to its representativeness. Tate and Alekseevskii's penetration algorithm was also used to calculate a correction factor (${\alpha}$) and then estimate the armor thickness of naval ship hull structure materials with a given impact velocity. Through live fire experiments, the proposed method performance difference was measured to be 0.6% in AH36, 0.4% in AL5083, 0.0% in AL5086, and 8.0% in FRP compared with the experiment results.

• Korean Journal of Materials Research
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• v.27 no.7
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• pp.359-363
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• 2017

The resistance of metallic materials to ballistic penetration generally depends on a number of parameters related to projectile, impact, and armor plate. Recently, armor materials have been required to have various properties such as hardness, strength, and impact toughness in order to maintain an excellent ballistic resistance even after impact. In the present study, the influence of tempering on the microstructure and mechanical properties of an ARMOX 500T armor steel plate was investigated and then compared with those of S45C and SCM440 steels. As the tempering temperature increased, the hardness and strength gradually decreased, whereas the ductility and impact toughness clearly increased because the hardness, tensile, and impact properties were affected by the microstructural evolution and precipitation occurring during tempering. On the other hand, temper embrittlement appeared at tempering temperatures of 300 to $400^{\circ}C$ for the impact specimens tested at low temperature.

• Conservation Science in Museum
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• v.20
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• pp.61-76
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• 2018

The National Museum of Korea conducted conservation treatmenton the armor in its collection for the purposes of public display and appropriate preservation. This was preceded by a literature study on the types and features of the armor in order to collect basic data for secure and accurate conservation treatment. The literature study found that during the Joseon dynasty, armor was named in reflection of precise details including the color, material, status of the wearer, and even the certain parts of a suit of armor. In general, the name of armor includes the details in the order of color, underlying textile, and scale material (e.g., iron, leather). The former part of the name presents the features of the garment and the latter part refers to the material of the scales or the status of the wearer. The study also found that main materials used in armor include textiles, leather, and metal, and armor can be classified by the materials of the scales-e.g., metal armor (鐵甲), leather armor (皮甲), paper armor (紙甲), paper-and-fabric armor (淹心甲), silk armor (緞甲). Joseon-period armor can also be classified into four types according to its structure and the method of wearing, and overcoat(袍)-style armor was the most widely used in the period following the Japanese Invasion of Joseon (1592-1598) through the late nineteenth~early twentieth century. Overcoat-style armor was commonly worn by infantry, and the four examples of armor with leather scales at the National Museum of Korea belong to this category.

• Smart Structures and Systems
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• v.7 no.3
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• pp.223-228
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• 2011

An understanding of biomaterials' smart properties and how biocomposite materials are manufactured by cells provides not only bio-inspiration for new classes of smart actuators and sensors but also foundational technology for smart materials and their manufacture. In this case study, I examine the unique smart properties of bone, which are evident at multiple length scales and how they provide inspiration for novel classes of mechanoactive materials. I then review potential approaches to engineer and manufacture bioinspired smart materials that can be applied to solve currently intractable problems such as the need for "smart" body armor or decor cum personal safety devices.

• Korean Journal of Materials Research
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• v.29 no.1
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• pp.43-51
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• 2019

Nacre of abalone shell features a "brick-and-mortar" microstructure, in which micro-plates of calcium carbonate are bonded by nanometers-thick layers of chitin and proteins. Due to the microstructure and its unique toughening mechanisms, nacre possesses an excellent combination of specific strength, stiffness and toughness. This study deals with the possibility of using nacre fragments obtained from abalone shell for making a bulletproof armor system. A composite plate laminated with abalone shell fragments is made and compression and bend tests are carried out. In addition, a bulletproof test is performed with hybrid armor systems which are composed of an alumina plate, a composite plate, and aramid woven fabric to verify the ballistic performance of nacre. The compressive strength of the composite plate is around 258.3 MPa. The bend strength and modulus of the composite plate decrease according to the plate thickness and are about 149.2 MPa and 50.3 GPa, respectively, for a 4.85 mm thick plate. The hybrid armor system with a planar density of $45.2kg/m^2$, which is composed of an 8 mm thick alumina plate, a 2.4 mm thick composite plate, and 18 layers of aramid woven fabric, satisfy the NIJ Standard 0101.06 : 2008 Armor Type IV. These results show that a composite plate laminated with abalone shell fragments can be used for a bulletproof armor system as an interlayer between ceramic and fabric to decrease the armor system's weight.