• Title/Summary/Keyword: Kevlar

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Changes of Physical and Mechanical Properties of Firefighter Protective Clothing After Radiant Heat Exposure (노출시간과 열강도에 따른 복사열 노출후의 소방보호복의 물리적 특성과 역학적 특성변화)

  • ;N.Pan;G.Sun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.6
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    • pp.853-863
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    • 1999
  • the change of physical properties (thickness, weight, air permeability) and mechanical properties(abrasion resistance breaking load and displacement) of samples were determined after heat exposure by a RPP tester. The effect of exposure time and heat flux intensity on the changes and the relationship between physical properties and mechanical properties were investigated. FR treated cotton Kevlar/PBI and Nomex with different structureal characteristics were chosen for specimens. The changes of physical properties and mechanical properties were calculated based on their initial values before heat exposure. The longer exposure time and the high heat flux intensity the more changes of those properties. Heat flux intensity was more effective on the changes, The showed to be affected by an interplay of shrinkage and pyrolysis products loss. The changes of thickness and abrasion resistance showed to be higher for plain weave fabric and those of air permeabiliyt and breaking load and displacement for twill weave fabric. While FR treated cotton which have high RPP value experienced serious and detrimental changes after heat exposure Kevlar/PBI which has low RPP value showed no high changes. In conclusion it could be confirmed that when total performance of a protective clothing is estimated retention capability of physical and mechanical properties after heat exposure as well as RPP value must be considered.

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A Study on NDE technique using Acoustic Reflection Microscope (반사형 음향 현미경을 이용한 비파괴 검사 기술에 관한 연구)

  • Moon, Geon;Ko, Dae-Sik;Kim, Jang-Gwon;Jun, Gye-Seok
    • The Journal of the Acoustical Society of Korea
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    • v.6 no.3
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    • pp.23-30
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    • 1987
  • In this paper, the characteristic response of reflected signals of acoustic reflection microscope, V(z) phenomenon, has been studied and a new type of NDE technique has been presented. 10 Won coin, aluminium, IC component, and kevlar-epoxy samples have been used for the experiment of NDE and the acoustic microscope operating at a center frequency of 3 MHz has been used in the focused or defocused mode of operation. In experiment, it has been shown that the acoustic microscope has the resolution of $500\mu m$ and the defects present on the surface and near surface of samples have been detected by acoustic transducer and imaged on a monitor, and the variation of the contrast of image for samples has been in good agreement with V(z) phenomenon.

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A Numerical Study of the High-Velocity Impact Response of a Composite Laminate Using LS-DYNA

  • Ahn, Jeoung-Hee;Nguyen, Khanh-Hung;Park, Yong-Bin;Kweon, Jin-Hwe;Choi, Jin-Ho
    • International Journal of Aeronautical and Space Sciences
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    • v.11 no.3
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    • pp.221-226
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    • 2010
  • The failure of a Kevlar29/Phenolic composite plate under high-velocity impact from an fragment simulation projectile was investigated using the nonlinear explicit finite element code, LS-DYNA. The composite laminate and the impactor were idealized by solid elements, and the interface between the laminas was modeled as a tiebreak type in LS-DYNA. The interaction between the impactor and laminate was simulated using a surface-to-surface eroding contact algorithm. When the stress level meets the given failure criteria, the layer in the element is eroded. Numerical results were verified through existing test results and showed good agreement.

Development of All-in-one Case Insulation for the End-burning Solid Rocket Motor (End-burning 고체추진기관 적용 일체형 연소관 내열재 개발)

  • Kim, Jinyong;Lee, Sunjae;Choi, Jiyong;Park, Jaebeom;Lee, Sangyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.1045-1047
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    • 2017
  • In this study, we focused on development of the all-in-one case insulation for end-burning solid rocket motors. Material of insulation used unvulcanized rubber based on EPDM/kevlar. In case of boots insulation, preforms was made by using hot press molding, and then the tape was inserted between two preforms for all-in-one curing in the case. Finally bladder method was applied for curing of insulation.

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A Study on the mechanical Characteristics of Kevlar Plain Weft Knitted Fabrics Reinforced Composites for Development of Intrusion Beam of Car Side Door Application (자동차 사이드 도어용 인트루젼 비임 개발을 위한 케블라섬유강화 복합재료의 기계적 특성에 관한 연구)

  • 이동기
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.89-98
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    • 2000
  • Using conventional textile techniques such as weaving braiding knitting and stitching it is possible to produce a wide range two and three dimensional fiber preforms, however so far only a limited attention has been given to knitted fabrics in composite industry. This is mainly due to the opinion that knitted fabric reinforced composites posses low mechanical properties owing to their looped fiber architecture. But it is possible to obtain desired mechanical properties by selecting proper knitted fabric structure, In this paper mechanical characteristics of kevlar plain weft knitted fabrics reinforced plastics(KFRP) are evaluated for th development of intrusion beam of car side door. Tensile bending impact properties of KFRP are measured experimentally and crush demands of Americal Federal Motor Vehicle Safety Standard No.214(FMVSS 214) compared with the bending load and displacement of KFRP by quasi-static test method. The applicability and limitation of bending load and displacement of KFRP according to specimen size has been discussed.

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Reliability Based on Robust Design Optimization of Tension Mooring Unit Considered Marine Circumstance Condition (해양 환경조건을 고려한 긴장계류장치의 신뢰성 기반 강건설계 최적화)

  • Oh, Young-Cheol;Kang, Byoung-Mo;Ko, Jae-Yong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.06a
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    • pp.120-121
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    • 2013
  • Recently, our country is to be diversification a leisure activity and tourism form by income level rise and traffic circumstance improvement. But Basic facilities expropriated these leisure activities have built an insufficient condition. Also, Building a facility, Introduced tools and materials import the whole quantity. Therefore, In this paper, it builds a tension mooring unit to use EPDM and Kevlar R29 and it develops a domestic marine circumstance through reliability based on robust design. It contributes to marine leisure culture activation and industry development.

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