• Title/Summary/Keyword: aramid fiber

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Study on the Mechanical Properties of Rubber Composite Materials Contained PBO, Aramid Chopped Fiber (PBO, Aramid Chopped Fiber가 함유된 고무복합재료의 기계적 물성연구)

  • Lee, Jun Hee;Lee, Kwang-Woo
    • Textile Coloration and Finishing
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    • v.33 no.4
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    • pp.327-337
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    • 2021
  • The uniformly dispersed Aramid and Poly (phenylene benzobisoxazole) (PBO) in a variety of rubber was investigated. The mechanical properties of rubber were characterized by hardness, tensile strength, elongation at break, heat resistance, oil resistance, cold resistance, ozone resistance measurements. The 3mm Aramid chopped fiber better tensile strength than the other Chopped fiber. The Aramid of 3mm chopped fiber showed excellent reinforcing in rubber composite because of homogeneous dispersion. Consequently, the best 3mm Aramid chopped fiber and rubber improved the tensile strength and elongation at break of the composite. Also, 3mm Aramid chopped fiber improved the oil-resistant, ozone resistant and cold resistant.

A Study on the Fatigue Behavior of ARALL and Manufacturing of ARALL Materials (ARALL재의 개발과 이의 파괴거동에 관한 연구)

  • 손세원;이두성;장정원;홍성희
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.908-912
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    • 1996
  • FRMLs consist of thin sheets of high strength metal, which are laminated using a structural adhesive and high strength fibers. ARALL(Aramid-fiber Reinforced Aluminum alloy Laminates) of FRMLs is a new class of hybrid material. HERALL(Heracron Reinforced Aluminum Laminate) i.e. domestic ARALL is made of homemade aramid fibers, adhesives and adhesive technique. Domestic aramid fiber is Heracron manufactured by KOLON and domestic adhesive is epoxy resin manufactured by Han Kuk Fiber. In this study, Fatigue crack propagation behavior was examined in a 2024-T3 aluminum alloy/aramid-fiber epoxy 3/2 laminated composites, HERALL and ARAL $L^{ⓡ}$-2 LAMINATE comparing with 2024-T3 aluminum alloy. The extrinsic toughening mechanisms in HERALL and ARALL were examined, the crack bridging behavior of fibers was analyzed by new algorithm, which measures crack bridging stress, and the crack bridging zone length was measured.

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The Effects of Temperature and Water Absorption on Failure Behaviors of Carbon / Aramid Fiber Composites (온도 및 수분이 탄소/아라미드 섬유 복합재의 파손거동에 미치는 영향)

  • Kwon, Woo Deok;Kwon, Oh Heon;Park, Woo Rim
    • Journal of the Korean Society of Safety
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    • v.37 no.4
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    • pp.11-19
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    • 2022
  • This paper presents the effects of high temperature and water absorption on the mechanical behaviors of carbon-aramid fiber composites, specifically their strength, elastic modulus, and fracture. These composites are used in industrial structures because of their high specific strength and toughness. Carbon fiber composites are vulnerable to the impact force of external objects despite their excellent properties. Aramid fibers have high elongation and impact absorption capabilities. Accordingly, a hybrid composite with the complementary properties and capabilities of carbon and aramid fibers is fabricated. However, the exposure of aramid fiber to water or heat typically deteriorates its mechanical properties. In view of this, tensile and flexural tests were conducted on a twill woven carbon-aramid fiber hybrid composite to investigate the effects of high temperature and water absorption. Moreover, a multiscale analysis of the stress behavior of the composite's microstructure was implemented. The results show that the elastic modulus of composites subjected to high temperature and water absorption treatments decreased by approximately 22% and 34%, respectively, compared with that of the composite under normal conditions. The crack behavior of the composites was well identified under the specimen conditions.

Estimation of Fatigue Characteristics Using Weibull Statistical Analysis with Aramid Fiber on LNGC Secondary Barrier (LNGC 2차 방벽에 적용된 Aramid 섬유의 Weibull 통계 분석을 이용한 피로특성 평가)

  • Park, Jin Hyeong;Oh, Dong Jin;Kim, Min Gyu;Kim, Myung Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.5
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    • pp.415-420
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    • 2017
  • Insulation systems in Liquefied Natural Gas Carriers (LNGC) are vulnerable to sloshing impact and fatigue loads because of waves. If gas leaks into the primary barrier, the Flexible Secondary Barrier (FSB) prevents the leakage of gas in this system. Fatigue strength of the FSB largely depends on the behavior of composite materials. In this study, a new system is applied to the FSB using aramid fiber to improve the fatigue strength of the secondary barrier, with the intention of replacing conventional E-glass fibers. The manufacturing method involved varying the ratio of the aramid fiber to the E-glass fiber for optimum design of the FSB. The fatigue tests results of the secondary barrier using aramid fiber were superior to that using E-glass fiber. The statistical analysis is performed to obtain the fatigue test results and estimate the probability of failure as well as the design guideline of LNGC secondary barriers.

Dyeing Properties of Easily Dyeable m-Aramid Knit Fabric (염색이 용이한 메타 아라미드 편성물의 염색성에 관한 연구)

  • Lee, Bum Hoon
    • Textile Coloration and Finishing
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    • v.32 no.3
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    • pp.128-134
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    • 2020
  • Heat and flame protecting cloth is usually made of meta aramid fiber because of its own properties. But the high inter molecular hydrogen bonding and high Tg is the reason of the difficulty to dye meta aramid fiber. Recently, it was commercialized that the easily dyeable meta aramid fiber(AMD) for improving dyeability. In this study, the dyeing properties of AMD dyed with cationic dyes were investigated. The K/S values of AMD were 5~10% higher than these of general meta aramid fiber(AM) in the case of 1%owf caused by the lower crystallinity of AMD. The difference between K/S values of AMD and AM was increased as increasing dyeing concentration. The washing and rubbing fastness grade of AM and AMD were similar and good to very good.

Torsional behaviour of reinforced concrete beams retrofitted with aramid fiber

  • Kandekar, Sachin B.;Talikoti, Rajashekhar S.
    • Advances in concrete construction
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    • v.9 no.1
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    • pp.1-7
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    • 2020
  • Retrofitting is an alteration of existing member or component of the structure. In civil engineering point of view, it is called strengthening of the old structure. Deterioration of structures may be due to aging, corrosion, failure of joints, earthquake forces, increase in service loads, etc. Such structures need urgent repair, retrofitting and strengthening to avoid collapse, cracking and loss in strength or deflection. Advanced techniques are required to be developed for the repair of structural components to replace conventional techniques. This paper focuses exclusively on torsional behaviour of Reinforced Concrete (RC) beams and retrofitted RC beams wrapped with aramid fiber. Beams were retrofitted with aramid fiber by full wrapping and in the form of 150 mm wide strips at a spacing of 100 mm, 150 mm, 200 mm respectively using epoxy resin and hardener. A total 15 numbers of RC beams of 150 mm×300 mm×1300 mm in size were cast, 3 beams are tested as control specimens, and 12 beams are tested for torsion up to the failure and then retrofitted with aramid fiber. Experimental results are validated with the help of data obtained by finite element analysis using ANSYS. The full wrapping configuration of aramid fiber regains 105% strength after retrofitting. With the increase in spacing of fabric material, torsional strength reduces to 82% with about 45% saving in material.

Study on the Mechanical Properties of Compounding Chopped Fiber and Rubber (슈퍼섬유 Chopped fiber와 고무와의 Compound에 따른 기계적 물성연구)

  • Lee, Jun Hee;Lee, Kwang-Woo;Byon, Young-Hoo
    • Textile Coloration and Finishing
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    • v.28 no.3
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    • pp.183-188
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    • 2016
  • The uniformly dispersed p-Aramid chopped fiber in a variety of rubber was investigated. The cross section and surface properties in a variety of rubber were characterized by scanning electron microscopy(SEM), weight, tensile strength, cold resistance measurements. The 1mm p-Aramid chopped fiber better uniformly dispersed than the other p-Aramid chopped fiber. The p-Aramid of lmm chopped fiber showed excellent adhesion in rubber composite because of homogeneous dispersion. Consequently, the best 1mm chopped fiber and rubber improved the strength of the composite.

Surface Modification Effect and Mechanical Property of para-aramid Fiber by Low-temperature Plasma Treatment (저온 플라즈마 처리를 이용한 파라 아라미드 섬유의 표면 개질 효과 및 역학적 특성(2))

  • Park, Sung-Min;Son, Hyun-Sik;Sim, Ji-Hyun;Kim, Joo-Young;Kim, Taekyeong;Bae, Jin-Seok
    • Textile Coloration and Finishing
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    • v.27 no.1
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    • pp.18-26
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    • 2015
  • para-aramid fibers were treated by atmosphere air plasma to improve the interfacial adhesion. The wettability of plasma-treated aramid fiber was observed by means of dynamic contact angle surface free energy measurement. Surface roughness were investigated with the help of scanning electron microscopy and atomic force microscopy. The tensile test of aramid fiber roving was carried out to determine the effect of plasma surface treatments on the mechanical properties of the fibers. A pull-out force test was carried out to observe the interfacial adhesion effect with matrix material. It was found that surface modification and a chemical component ratio of the aramid fibers improved wettability and adhesion characterization. After oxygen plasma, it was indicated that modified the surface roughness of aramid fiber increased mechanical interlocking between the fiber surface and vinylester resin. Consequently the oxygen plasma treatment is able to improve fiber-matrix adhesion through excited functional group and etching effect on fiber surface.

Mode-I fracture toughness of carbon fiber/epoxy composites interleaved by aramid nonwoven veils

  • Beylergil, Bertan;Tanoglu, Metin;Aktas, Engin
    • Steel and Composite Structures
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    • v.31 no.2
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    • pp.113-123
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    • 2019
  • In this study, carbon fiber/epoxy (CF/EP) composites were interleaved with aramid nonwoven veils with an areal weight density of $8.5g/m^2$ to improve their Mode-I fracture toughness. The control and aramid interleaved CF/EP composite laminates were manufactured by VARTM in a [0]4 configuration. Tensile, three-point bending, compression, interlaminar shear, Charpy impact and Mode-I (DCB) fracture toughness values were determined to evaluate the effects of aramid nonwoven fabrics on the mechanical performance of the CF/EP composites. Thermomechanical behavior of the specimens was investigated by Dynamic Mechanical Analysis (DMA). The results showed that the propagation Mode-I fracture toughness values of CF/EP composites can be significantly improved (by about 72%) using aramid nonwoven fabrics. It was found that the main extrinsic toughening mechanism is aramid microfiber bridging acting behind the crack-tip. The incorporation of these nonwovens also increased interlaminar shear and Charpy impact strength by 10 and 16.5%, respectively. Moreover, it was revealed that the damping ability of the composites increased with the incorporation of aramid nonwoven fabrics in the interlaminar region of composites. On the other hand, they caused a reduction in in-plane mechanical properties due to the reduced carbon fiber volume fraction, increased thickness and void formation in the composites.

Flexural Behavior of Reinforced Concrete Beams Strengthened with Aramid Fiber-Reinforced Sheet (Aramid섬유시트를 사용한 철근콘크리트보의 보수.보강)

  • 김진수;박재만
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.840-845
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    • 1999
  • In this study, it was experimentally investigated the effectiveness of repair and strengthening methods for RC beams deteriorated under severs enviromental conditions. Polymer cement were employed to restore the sectional loss and aramid fiber-reinforced sheet was used to reinforce the surface subject to tension. Repaired and strengthened reinforced-concrete samples were subjected to loading tests. The tests revealed that the sectional restoration enhanced the loading capability of the sample structures. Additional strengthening with one aramid fiber-reinforced sheet improved 18% of yielding load and 30% of ultimate load of the structure. Reinforcing with two aramid fiber-reinforced sheets brought about an enhancement of 22% of yielding loading and 49% of ultimate load.

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