• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2015.11a
• /
• pp.130-131
• /
• 2015

이 논문은 패널의 각 단층 구성 재료에 고인장, 경량화, 부착성능, 내화성능 등을 향상시켜 단층 각각의 개별적인 특수 성능과 복합패널 구성물로서의 방호방폭 성능을 극대화 할 수 있는 섬유복합패널 외피와 충전재(나노복합소재) 및 접착제에 대한 기초 연구를 수행하였다.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.25 no.9
• /
• pp.1661-1668
• /
• 2001

본고는 지뢰 방호복을 개발, 국산화하기 위해 먼저 방탄소재 구성방법에 관하여 실험한 결과이다. 기존의 여러 겹의 파라-아라미드(Para-aramid)나 단순히 파라-아라미드와 폴리 에틸렌 필름(Polyethlene film)을 조합한 소재구성과는 달리 케블라 파이버(Kevlar fiber)로 만들어진 펠트(felt)를 첨가하여 방탄원리 및 특성을 고려한 구성으로 방호복의 중량을 줄이면서 착용자로 하여금 유연성과 동작성을 향상시켜 임무수행과 안전성을 높일 수 있는 방호복을 개발하고자 하였다. 1) Para-aramid(내 충격열) + Flex-felt(충격 에너지 흡수) + Para-aramid(backface Polyethylene film(에너지 분산 극대)+Para-aramid(내 마찰열, backface순으로 소재를 배열함으로써 기존의 Para-aramed 36겹에 대하여 Para-aramid13겹, Polyethylene film 13겹, 그리고 펠트 1겹으로 동일한 방호성능을 얻었다. 2) 새로운 소재 구성 방법 에 의 한 방탄소재는 동일한 방호성능을 갖는 기존의 소재 구성 방법 에 따른 방탄소재 보다 중량에서 34-l9% ,더 가벼운 것으로 나타나 방호복 구성시 유연성이나 동작성에 유리 할 것으로 사료된다. 3) NIJ-STD-0101.03에서 의 Armor type II에 해당하는 시편 I의 방호한계속도로 구한 운동 에너지량은 154.4J Armor type III-A에 해 당하는 시편II의 방호한계속도로 구한 운동 에너지 량은 183.0J로 나타나 두 시편 모두 5m의 거리에서 M16Al지뢰의 0.032~0.044g사이 의 파편에 대해서 50%의 관통확률을 갖는 것으로 나타났다.

• Journal of Korean Society of Steel Construction
• /
• v.27 no.4
• /
• pp.359-370
• /
• 2015

This paper presents the experimental results for the interfacial bond behaviour between AFRP strip and steel members. The objective of this paper is to examine the interfacial behavior and to evaluate the interfacial bond stress between Aramid FRP strips and steel plates. The test variables were bond length and AFRP thickness. 18 specimens were fabricated and one-face shear type bond tests were conducted in this study. There were two types of failure mode which were debonding and delamination between AFRP strip and steel plates. From the test, the load was increased with the increasing of bond length and AFRP thickness, which was observed that maximum increase of 63 and 86% were also achieved in load with the increasing of bond length and AFRP thickness, respectively. Finally, bond and slip characteristics had the elastic bond-slip model and it was observed that bond strength and fracture energy were not affected by bond length and AFRP thickness.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2012.03a
• /
• pp.65-65
• /
• 2012

The air texturing공정은 노즐에서 전달되는 초음속 에어기류에 의해 overfeed를 수반하여 yarn속 fiber가 뒤얽혀 loop와 crimp를 발달시키는데, 고강력 고탄성율 고내열성 내절단성 등의 특성을 가지는 아라미드섬유를 에어 가공사로 가공 할 경우 가공 전 필라멘트 상태일 때 보다 표면에 생기는 loop로 인하여 촉감이 좋아지고 또한 타 소재와 접착 시 접착제 담지 성능이 향상 되어 접착력이 상승되고, 이를 통해 보강재로서의 기능이 강화되는 반면 역학물성이 기존의 아라미드 보다 저하되는 약점을 가지고 있어 최근 ATY 공정조건이 ATY 사의 구조와 물성변화에 미치는 영향에 대한 많은 연구결과가 발표되고 있다. 본 연구에서는 Aiki air jet texturing machine에서 $Heracron^{(R)}$ para-aramid(840, 1000d, 1500d)를 사용하여 ATY nozzle의 직경을 0.6, 0.75, 1, 1.2mm로 변화를 주어 12개의 para-aramid ATY 시료를 제조하여 이들의 섬도, 강신도, 초기탄성률, 열수축률 그리고 형태불안정성(instability)등의 물성변화를 분석하여 다음과 같은 결과를 얻었다. 노즐의 직경이 증가함에 따라 사 내의 filament간의 움직임이 자유로워 교락이 증가하고 루프가 형성되어 단위길이 당 mass가 커지므로 섬도가 미세하게 증가하는 것을 볼 수 있다. 또한 직경이 증가할수록 절단강도와 초기탄성률은 감소하고 절단신도가 증가하는 경향을 볼 수 있는데 이는 축 방향으로의 배열이 적어져 하중을 분담하는 portion이 감소하고 사의 loop형성이 많아짐으로서 상대적으로 인장력에 대응하는 fiber의 수가 적어지기 때문으로 사료된다. 이는 현미경 관찰로 확인할 수 있는데 직경이 증가함에 따라 사의 loop의 엉킴이 증가하고 filament가 조밀한 것을 확인할 수 있다. 직경 변화에 따른 건 습열 수축률은 1% 미만의 매우 낮은 값으로 영향을 받지 않는 것을 확인 할 수 있는데 para-aramid의 열적특성의 안정성에 기인하는 것으로 사료되며 ATY의 불안정성은 노즐 직경 증가에 따른 어떤 경향성을 찾아볼 수 없었지만 840d, 1000d, 1500d로 섬도가 증가함에 따라 사의 불안정성이 증가하였다.

• Journal of the Society of Disaster Information
• /
• v.11 no.2
• /
• pp.235-243
• /
• 2015

The methods to improve the protection and explosion-proof performance of concrete structures include the backside reinforcement or concrete material property improvement and the addition of structural members or supports to increase the resistance performance, but they are inefficient in terms of economics and structural characteristics. This study is about the basic study on the fiber composite panel cover, and the nano-composite material and adhesive as the filler, to maximize the specific performance of each layer and the protection and explosion-proof performance as the composite panel component by improving the tensile strength, light weight, adhesion and fire-proof performances. The fiber composite panel cover (aramid-polyester ratios of 6:4 and 6.5:3.5) had a 2,348 MPa maximum tensile strength and a 1.8% maximum elongation. The filler that contained the nano-composite material and adhesive had a 4 MPa maximum tensile shear adhesive strength. In addition, the nano-composite filler was 30% lighter than the normal portland cement

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.3
• /
• pp.149-158
• /
• 2004

In this study, deep beam specimens are designed to have the effective shear span to depth ratio 1.0 and web opening within effective shear region. The purpose of this study is to investigate experimentally the shear strengthening effect between before failure and after failure upon using fiber sheets for RC deep beam with opening in web. The results can be summarized as follows; 1)When deep beams with web opening were failed in shear, their initial diagonal crack load and crack width were not influenced by their types of the arranged steel bars. 2)Deep beam with the horizontal reinforced bar was effective in the ultimate load of deep beam with web opening in shear failure 3)There were the approximate values between the experimental values and the analysis of finite element method. 4)The ultimate failure strengths of the repaired and strengthened specimens were increased about 34.4%~83.8% in comparison with specimens not to be strengthened.

• Composites Research
• /
• v.28 no.4
• /
• pp.176-181
• /
• 2015

In this study, the Z-shape fabric design is proposed as the way to enhance the ballistic performance of fabrics which are used as the intermediate layer of stuffed Whipple shield configurations. The Z-shape fabric employs a different boundary condition from those of conventional configurations of fabrics which include 4 edge fixed. Impact analysis on Z-shape aramid yarns and fabrics using LS-DYNA software was performed and the results were compared with 2 edge fixed and 4 edge fixed fabrics to identify the high velocity impact energy absorption characteristics of the Z-shape fabric. It was revealed that the Z-shape showed different impact behavior and higher energy absorption performance than 2 and 4 edge fixed fabrics.

• Korean Journal of Materials Research
• /
• v.4 no.7
• /
• pp.733-740
• /
• 1994

Oxidized-PAN fiber reinforced composite(OFRP), carbon fiber reinforced composite(CFRP), aramid fiber reinforced composite(AFRP), and glass fiber reinforced composite(GFRP) were fabricated with phenolic resin matrix by hot press molding. We tested the friction coefficient and wear rate varying with fiber weight fraction and observed the effect of fibers according to characteristics of individual reinforcement. When the amount of aramid fiber was 45wt%, average friction coefficient was maximum value of 0.353~0.383, where as, when the amount of pitch based carbon fiber was 45wt%, average friction coefficient was the lowest value of 0.164~0.190. The wear rate of AFRP and CFRP was low, but that of GFRP and OFRP increases drastically in the case of increasing of fiber weight fraction. Wear diagram of OFRP was unstable, but that of CFRP and AFRP was a bit stable. Through very unstable diagram of GFRP, we found that friction stability of GFRP was the lowest.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.4
• /
• pp.206-213
• /
• 2021

Recently, although the size of the LNG Cargo Containment System (CCS) has been increasing, the secondary barrier is reported to remain unchanged, and the conventional Flexible Secondary Barrier (FSB) used in Mark-III type has been pointed out to be vulnerable to failure owing to thermal and cyclic loads. In this respect, a tensile test was carried out to verify the reinforcing effect of FSB using aramid fiber on weft compared to the conventional FSB. In order to consider the LNG leakage situation, a series of tensile tests were conducted from ambient to cryogenic temperature, and mechanical properties were evaluated for each fiber direction on account of anisotropy. Tensile behavior and fracture analyses were performed to confirm the mechanical properties of each material according to temperature. Tensile test results proved that replacing the aramid fiber instead of E-glass fiber used on weft is effective in enhancing the mechanical properties.

• Textile Coloration and Finishing
• /
• v.23 no.4
• /
• pp.298-303
• /
• 2011

Aramid fibers have been widely used as the reinforcement for composites due to their high modulus and strength. Nowadays the safety measures is required to improve the personal protection. The dyeing of aramid fibers is considered to be very difficult and their dyeing mechanism is not well illucidated. Therefore, this study is to establish the dyeing & printing technology for aramid fibers. The effects of swelling agent and neutral salt in the dye bath on the obtained colors were studied. Also dyeing method of aramid fibers depending on dyeing temperature and dye concentration were established. Color fastness of the dyed aramid fabric with cationic dyes were acceptable excluding light fastness.