• 한국재료학회지
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• 제29권1호
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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.

• 한국재료학회지
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• 제27권7호
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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.

• International Journal of Precision Engineering and Manufacturing
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• 제8권4호
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• pp.38-44
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• 2007

Combat vehicles are frequently maneuvered in battlefields when the lives of combatants are being threatened. These vehicles are important elements that influence the consequences of a battle. Their armor must be lightweight and provide excellent protection to ensure successful operations. Ceramic composite armor has recently been developed by many countries to fulfill these requirements. We reviewed previous research to determine an effective armor design, and then fabricated a composite armor structure using $Al_2O_3$ and glass fiber-reinforced polymer. Specimens were manufactured under controlled conditions using different backing plate thicknesses and bonding methods for the ceramic layer and the backing plate. The penetration of an armor-piercing bullet was evaluated from ballistic protection tests. The bonding method between the ceramic layer and the fiber-reinforced polymer influenced the ballistic protection performance. A bonding layer using rubber provided the best protection.

• 복식
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• 제60권5호
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• pp.35-50
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• 2010

The purpose of this study was to know how helmet and armor was reinterpreted in historical play by considering general concept and type of old helmet and armor from the aspect of costume history and comparing the helmet and armor types of TV historical plays, Yeongaesomun and Taewangsasingi, whose historical backgrounds were based on the age of Goguryeo. The helmet and armor type shown in Yeongaesomun was reinterpreted as the one, which is close to historical investigation, by reappearing lamellar armor and jongjangpanju(helmet made of slim, long plate) shown in Goguryeo wall painting. The helmet and armor type shown in Taewangsasingi expresses fantastic helmet and armor by adding fantastic factor regardless of historical investigation. The study result reveals that there are several common characteristic factors between the helmet and armors of two historical plays. First, there was a classification in the display of character and story. The helmet and armor type shown in Yeongaesomun classified color and detail design depending on lamellar armor or character. In Taewangsasingi, the helmet and armor was manufactured depending on character's nature and the chain armors, which are lighter than existing helmet and armors, were usual. Second, they escaped from the historical investigation about traditional helmet and armor. In Yeongaesomun, myeonggwangae(a type of armor), which might be popular, was not expressed and Taewangsasingi is free from an imperative idea of historical investigation by manufacturing helmet and armor referring to that of ancient Rome age. The modern sense was reflected to increase dramatic effect. The helmet and armor of Yeongaesomun provides modern feeling by using stainless steel material and modern color arrangement and that of Taewangsasingi is designed in modern, splendid way as it aimed at game development from the planning step.

• 한국의상디자인학회지
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• 제9권1호
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• pp.71-87
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• 2007

Main role to expand the fashion in the middle age was played by aristocracy and knight. They contributed to the fashion of the middle age regardless of aesthetic sense. First, in any age, there was a self-display design using splendid decoration or material in the costume of high-class people. Aristocracy, especially, knight in the middle age classified themselves from others by wearing the costume suitable for their statuses. Second, the Crusade knight appearing all over the cinema gathered various peoples and caused acute optic angle about specialty of costume. Therefore the trend preferring foreign costumes was changed to new fashion while it was connected to desire searching for a change. Third, although armor of knight was created because of protection in the war, in the 13th century, its character of motion and defense was emphasized and it became splendid style. More over, the costume of knight was developed to more emphasize masculine beauty with heavy upper body and light lower body so it caused sexual difference of costume in the middle age. Fourth, As knight searched effective defensive weapon, chain mail was relegated by plate armor. The order of armor that the hight wore in 1350 was as follows. First, he wears adhesive shirts, braies, hose and wears metal protector on arm and leg. He wears padded undercoat called gambeson, hauberk, plate armor and surcoat on them.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1051-1057
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• 2010

Database for the damage reference by armor piercing bullet test was established for both tube and plate specimens having a range of thickness. As the inclined angles of hit are increasing, it has been found that penetration damage diameter tends to increases accordingly in both specimen of the tube and plate, and such penetration damage diameter on the rear side becomes bigger than those on the front side. The tube specimen showed that the damage becomes bigger when central areas rather than the peripheral were hit. Through the plate test, it also has been found that the penetration ballistic limit for Al alloy is about 25.4mm and that of stainless steel about 12.7mm. From the fatigue analysis results using the database for damage reference, it has been identified whether the safety requirements of military aircraft could be met.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.111-118
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• 2004

For the precise analysis of high velocity impact problem though FEM with element erosive method, the adequate mesh size and critical equivalent plastic strain(EQPS) is chosen prior to the simulation. In this research, it is strongly required from a standpoint that critical EQPS is used to decide whether perforation occurs or not. The optimization of dual armor plate consisting of 4340 steel and 2024 aluminium against a die steel sphere with high-velocity has been suggested using Lagrangian explicit time-integration code, NET2D. The response surface method based on the design of experiment is utilized for the size optimization. The optimized thickness of each layer, in which perforation does not occur, the strength of multi-layer is maximized and total weight is minimized, is obtained at a constant velocity of a pellet with a designated total thickness.

• 헤리티지:역사와 과학
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• 제44권3호
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• pp.178-199
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• 2011

부산 복천동고분군은 4~5세기를 중심연대로 하는 삼국시대 무덤으로 종장판갑이 다량 출토한 고분군으로 널리 알려져 있다. 2006년 복천동 고분 구릉의 동쪽 사면 말단부에 축조된 164 165호분에서 종장판갑 2령이 추가로 조사되었다. 본고에서는 보존처리가 완료된 종장판갑 2령의 내용을 정리하고, 기존 종장판갑 부장 유구와의 비교검토를 통해 4세기대 종장판갑 부장양상에 대해 살펴보았다. 164 165호에서 출토된 종장판갑은 제작기술 속성을 기준으로 IIa형식(型式)인 경주 울산식 판갑으로 분류되며, 종장판갑편년 3단계 중 II단계의 이른 시점으로 편년된다. 부장양상을 살펴보면, 동단계에 속하는 구릉 정상부의 대형분에서는 종장판갑이 2령 이상 복수로 부장되지만, 164 165호에서는 1령씩 단수 부장된다. 따라서 복천동에서 경주 울산식 판갑(I IIa식)이 부장되는 단계에는 분묘의 규모에 따라 부장되는 종장판갑의 수량에 격차가 있음을 알 수 있다. 종장판갑은 지금까지 복천동 고분 구릉 정상부에 위치한 대형무덤에 부장되고 있어 상위계층의 전유물로 생각되어 왔지만, 164 165호분과 같이 무덤의 입지, 규모, 부장유물의 양과 질적인 면에서 중소형분에 속하는 분묘에서도 종장판갑이 부장된 사실이 확인되었다. 164호분은 장단축비가 1:3 이상인 세장방형 목곽묘로 갑옷 및 유구의 형태, 부장유물의 배치 상태 등에서 경주 구정동 3호분, 사라리 55호분 등과 같은 소위 경주식 목곽묘로 볼 수 있다. 반면 부장 토기의 양상은 소위 금관가야식 토기라 불리는 김해지역 토기와 공통되는 점이 주목된다. 4세기대 복천동고분군에서는 분묘의 입지, 규모, 종장판갑의 부장 수량 등에서 분묘간의 격차가 확인된다. 하지만 종장판갑의 부장유무만으로 분묘간의 계층성을 논하기 어려우며, 종장판갑의 부장이 곧 군사력의 장악을 상징하는 것으로 해석하기는 곤란하다. 164호분의 양상에서는 판갑 부장의 지역성, 복천동 분묘의 계층성에 대해 유추해 볼 수 있다.

• 한국전산구조공학회논문집
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• 제36권5호
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• pp.331-338
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• 2023

현대의 방탄 장갑은 우수한 관통 저항성을 갖추어야할 뿐만 아니라 군인과 군용차량의 기동성이 확보되어야 하기 때문에 경량화가 중요한 개발 요소가 되었다. 이종 적층 평판 구조의 방탄 장갑의 방탄 성능은 동일 중량 대비 구성 재료의 배열에 따라 달라진다. 본 논문에서는 케블라, 초고분자량 폴리에틸렌 그리고 에바 폼으로 구성된 방탄 장갑의 적층 배열에 따른 방탄 성능을 분석한다. 구성 재료의 두께가 5mm와 6.5mm인 두 가지 경우에서 6가지 적층 배열에 대하여 7.62 × 51mm NATO 탄환의 M80 탄을 856m/s의 속도로 충돌시키는 피탄 해석을 수행하였다. 방탄 성능을 평가하기 위해 이종 적층 평판을 관통한 발사체의 잔류 속도와 잔류 에너지를 측정하였다. 시뮬레이션 결과를 통해 케블라, 초고분자량 폴리에틸렌, 에바 폼의 배열 순서를 갖는 적층 구조가 동일 중량에 대해 가장 우수한 방탄 성능을 가짐을 확인하였다.

• Steel and Composite Structures
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• 제14권4호
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• pp.313-333
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• 2013

The web-encased steel-concrete composite (WESCC) beam is a new developed steel-concrete composite beam. Experiments of six simply supported WESCC beam specimens were conducted. The effects of the shear-span ratio and steel section type were all investigated on the static behaviors such as failure modes, failure mechanism and bearing capacity. The experimental results denoted that all specimens failed in bending mode and the degree of combination between the bottom armor plate of steel shape and concrete were very well without any evident slippage, which demonstrated that the function of bottom armor plate and web were fully exerted in the WESCC beams. It could be concluded the WESCC beams have high stiffness, high load carrying capacity and advanced ductility. The design methods are proposed which mainly consist the bearing capacity calculation of bending and flexural rigidity. The calculation results of the bearing capacity and deflection which take the shear deflection into account are in agreement with the experimental results. The design methods are useful for design and application of the innovative composite beams.