• Title/Summary/Keyword: aramid

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Research of the Composite Spun Yarn Manufacturing Process using Silicon Carbide and Para Aramid Fiber (SiC/p-Aramid 복합방적사 제조기술 연구)

  • Kim, Booksung;Ryu, Huijun
    • Textile Coloration and Finishing
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    • v.33 no.4
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    • pp.309-316
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    • 2021
  • Due to the rigid nature of the silicon carbide fiber(SiC), fiber damage occurs from the friction during the carding process. This damage not only lowers the spun yarn yield, but also lowers the heat resistance of the spun yarn, so that ultra-high heat resistant yarn cannot be manufactured. Therefore, in the carding process where the most friction between fiber and machine(wire, etc.) occurs, some factors were modified and tested, and as a result of measuring the change in physical properties, fiber damage decreased due to the wire angle or wire density, resulting in improved yield. The test method used to measure the yield of SiC fiber was the carbonization method, and the content of SiC fibers was calculated using the remaining amount after carbonization. Carbonization test was performed at air condition, 700℃, and for 2 hours. Analysis by SEM-EDX showed that the carbide was consistent with the composition of the SiC fiber.

Performance Evaluation of Steel Frame and Steel Damper Reinforced in RC frame (RC 골조에 보강된 강재프레임과 강재댐퍼의 성능 평가)

  • Lee, Hyun-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.1
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    • pp.77-84
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    • 2023
  • In this study, the performance evaluation of the RC frame specimen (RV2) which was strengthened by a steel frame and a steel damper with the lateral deformation prevention details proceeded. The comparison objects are bare frame specimen (BF), RV2 and AWD, where AWD is a specimen reinforced with steel damper and aramid fiber sheets. In the evaluation of envelope curve, stiffness degradation, and energy dissipation capacity, RV2 was evaluated to have excellent capacity as a whole. To evaluate the strengthening effect of the steel frame based on the maximum strength and energy dissipation capacity, it was evaluated to have a 38% of the RV2's capacity.

An Experimental Study on Uniaxial Compressive Behavior of RC Circular Columns Laterally Confined with Prestressing Aramid Fiber Strap (아라미드 스트랩으로 프리스트레싱 횡구속된 RC 원형기둥의 일축압축거동에 관한 실험적 연구)

  • Han, Sang-Hoon;Hong, Ki-Nam;Lee, Jae-Bum
    • Journal of the Korea Concrete Institute
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    • v.21 no.2
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    • pp.159-168
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    • 2009
  • In this study, strength, stiffness and confinement effect with stress-strain and stress-volumetric strain curves for improved uniaxial compressive behavior of RC circular columns laterally confined with prestressing aramid fiber strap were experimentally investigated. The test variables were the specimens with or without axial reinforcing bar and the number and spacing of strap, prestressing level, the types of reinforcing fiber (CFS, GFS). As a result, the failure type of the columns was very stable and strength increase rate was about 73% comparison with the general RC columns. Moreover, the strain increase rate is very small and the axial displacement confinement effect was very effective compared with existry methods (CFS, GFS), the initial and final lateral confinement effect was excellent.

The Delamination and Fatigue Crack Propagation Behavior in A15052/AFRP Laminates Under Cyclic Bending Moment (반복-굽힘 모멘트의 진폭에 따른 A15052/AFRP 적층재의 층간분리 영역과 피로균열진전 거동)

  • Song, Sam-Hong;Kim, Cheol-Ung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.8
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    • pp.1277-1286
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    • 2001
  • Aluminum 5052/Aramid Fiber Reinforced Plastic(Al5052/AFRP) laminates are applied to the fuselage-wing intersection. The Al5052/AFRP laminates suffer from the cyclic bending moment of variable amplitude during the service. Therefore, the influence of cyclic bending moment on the delamination and the fatigue crack propagation behavior in Al5052/AFRP laminate was investigated in this study. Al5052/AFRP laminate composite consists of three thin sheets of Al5052 and two layers of unidirectional aramid fibers. The cyclic bending moment fatigue tests were performed with five different levels of bending moment. The shape and size of the delamination zone formed along the fatigue crack between Al5052 sheet and aramid fiber-adhesive layer were measured by an ultrasonic C-scan. The relationships between da/dN and ΔK, between the cyclic bending moment and the delamination zone size, and between the fiber bridging mechanism and the delamination zone were studied. Fiber failures were not observed in the delamination zone in this study. It represents that the fiber bridging modification factor should turn out to increase and that the fatigue crack growth rate should decrease. The shape of delamination zone turns out to be semi-elliptic with the contour decreased non-linearly toward the crack tip.