• Title/Summary/Keyword: Crimp

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A Study of Carbon NCF Prepreg Manufacturing and Stacking Pattern Optimal Design Using Structure Analysis (CFRP 적용을 위한 Carbon NCF Prepreg 제작 및 구조해석을 활용한 적층패턴 최적설계 연구)

  • Kim, S.;Shin, H.C.;Ha, Sung Kyu
    • Composites Research
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    • v.33 no.1
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    • pp.13-18
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    • 2020
  • Recently, the fire rescue truck in problem proceed research it for the fast works action and for pass the small road. So we were research for weight reduction. In this study, the (NO. 5) fifth boom of the fire rescue truck have 288 mm(W) × 299 mm(D) × 3,691 mm(L) with a maximum load of 876 kg and the thickness of 3 mm of the Steel Boom. This changing of Steel (STRENX960) to CFRP was weave Carbon Fiber NCF (±45°, 2axis) and then it make the NCF Prepreg. This process was designed based on structural analysis, the effects of NCF Prepreg (±45°) on torsion were identified, and the optimal design was made with Stacking Pattern (b). Stack patterns were optimized for levels equal or higher than existing Steel Boom and CFRP Boom stacked in the UD direction, and finally, the lightening effect on weight of approximately 49.6% of the steel was identified.

The Mechanical Properties and Hand of Cotton Fabrics with the Variation of Weft Density (면직물의 위사밀도 변화에 따른 역학특성 및 태)

  • Bae Jin-Hwa;Park Jung-Whan;An Seung-Kook
    • Science of Emotion and Sensibility
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    • v.8 no.4
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    • pp.345-354
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    • 2005
  • In this study, the mechanical properties and hand characteristics have been analyze4 according to fabric structural parameters such as the weft density and weave stricture of cotton fabric. KES-FB system was used to measure hand characteristics and mechanical properties of fabric. The weft density made an effect on bending and shear properties but not on tensile , compression, and surface properties. In case of wearing property, B/w, 2HG/G, 2HB/B, 2HB/W, $\sqrt[3]{B/W}$, $\sqrt{2HB/W}$, W/T, WC/W were affected tv the weft density. The crimp was highly correlated with the tightness, hand, wearing an4 mechanical properties, specially tensile linearity, bending, shear, and compression properties. The weft crimp influenced the bending, shear, compression resilience, surface roughness, hand, and wearing properties. The tightness has an effect on tile bending, shear, compression, surface friction, hand, and wearing properties.

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Image Analysis of Luster Images of Woven Fabrics and Yarn Bundle Simulation in the Weave - Cotton, Silk, and Velvet Fabrics -

  • Kim, Jong-Jun
    • Journal of Fashion Business
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    • v.6 no.6
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    • pp.1-11
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    • 2002
  • The attractiveness of the textile fabrics are generally judged by visual or tactile evaluation methods. Since the surface of the textile materials are so diverse that the visual factors such as optical properties or luster of the fabrics are not easily measurable. While most of the cotton fabrics are not so much lustrous, calendering process could impart the cotton fabric better luster. Also, the general grade silk-like polyester fabrics resemble silk fabric with some limit in terms of luster properties. One of the interesting fabrics showing subdued luster is the velvet fabrics with dark shade. In this study, the luster related properties are examined using some image analysis methods. Yarn models based on the fabric weave types were developed to further investigate the effect of fabric crimp shapes due to weave on the optical properties or luster of the fabrics.

Bending Characteristics of Carbon Fabric/Polymeric Foam for Sandwich Structures (직조 탄소섬유 발포 고분자 샌드위치 구조의 굽힘특성)

  • Chang Seung Hwan;Jang Tae Seong;Choi Jin Ho;Cheon Seong Sik
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.10a
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    • pp.131-134
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    • 2004
  • In this paper, a representative unit volume (RUV) model was employed to simulate thermoforming process of carbon fabric-polymeric foam sandwich structures. Thermoforming simulations, which capture crimp angles and amplitude changes of carbon fabric with respect to different types of foams under the operating pressure were conducted with the help of RUV model. Changed shapes of tow structure after thermoforming were reflected in the two dimensional to determine mechanical properties of skin parts, i.e_ carbon fabric composites after thermoforming. Bending simulations with respect to different foam systems as well as different moduli of carbon fabric composites were successfully carried out by using properties obtained from two-dimensional analyses.

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FE Analyses of the Compressive Characteristics of Carbon Fabric/Polymeric Foam for Sandwich Structure (유한요소해석을 이용한 직조 탄소섬유 발포 고분자 샌드위치 구조의 압축특성)

  • Chang Seung Hwan;Cheon Seong Sik
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.194-197
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    • 2004
  • In this paper, compressive characteristics of carbon fabric skin with polymeric foam core sandwich structure were investigated by FE analyses and compressive tests of polyurethane foam were also conducted with respect to temperature changes, which were determined by curing processes of epoxy or polyester resin to obtain mechanical behaviour of polyurethane foam. FE analyses indicated variation of parameters with respect to manufacturing pressure, which have comparatively massive effect upon mechanical properties of sandwich structures, i.e. wavelength as well as crimp angle of carbon fabric

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Variation of Tow Geometry for Polymer Foam-Composite Sandwich Structures during Forming (플리머 포움-복합재료 샌드위치 구조의 성형 중 토우 구조의 변화)

  • Woo Jong Won;Kim Yong Soo;Chang Seung Hwan
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.04a
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    • pp.198-201
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    • 2004
  • This paper aims to investigate the micro-mechanical behaviour of tow geometry with forming pressures and densities of foams during the curing process of plain weave carbon fibre fabric prepregs onto polymer foams. In order to find out and compare deformation patterns between different forming conditions, tow parameters such as amplitude and crimp angle etc. are investigated. From the observation results, geometric difference in the tow architecture with respect to forming conditions and foam characteristics were found. To observe the micro-deformation of the fabric structure, appropriate specimens from carbon fibre-foam sandwich structures are sectioned and observed under the microscope.

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A Stereo Vision-based Algorithm for the 3-Dimensional Inspection of a Crimped Terminal (압착단자의 3차원 검사를 위한 스테레오 비젼 알고리즘)

  • Lee, Moon-Kyu;Jang, Sang-Won
    • IE interfaces
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    • v.11 no.2
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    • pp.93-106
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    • 1998
  • This paper suggests a stereo vision-based algorithm for the 3-dimensional inspection of a crimped terminal. The crimped terminal is one of wire harness assemblies which transmit current or signals between a pair of electrical or electronic assemblies. Four types of nonconformities considered includes terminal rolling, band up/down, twist, and crimp height. To obtain stereo image correspondence, an algorithm using Hough transform is proposed. Coordinate transform is then applied to evaluate the degree of 3-dimensional nonconformities. The algorithm has been successfully tested on a number of real specimens collected from a wire harness factory. The test results show the feasibility of the proposed algorithm.

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MICROSCOPIC OBSERVATION OF DRAPED COMPOSITE MATERIALS : Bias Extension and Biaxial Tests (직물 복합재료의 드레이핑 미소 거동 관찰 : 일방향 편향 인장실험과 이축 인장실험)

  • 장승환
    • Composites Research
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    • v.17 no.1
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    • pp.38-46
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    • 2004
  • This paper aims to correlate the micro-mechanical behaviour of tow geometry with applied in-plane forces during deformation of dry woven carbon-fibre fabric. These in-plane forces lead to differences in tow reorganisation during deformation and so changes in the way in which 'lock-up' occurs. In this paper, deformation of micro-mechanical parameters such as tow interval, crimp angle, change in tow amplitude and wavelength are investigated. To observe the micro-deformation of the fabric structure, appropriate specimens from bias extension and biaxial tests are sectioned and observed under the microscope. It was found that different loading conditions cause geometric deferences in the tow architecture. The variation in deformed tow geometry with shear angle is fitted using a simple parametric model.

Changes in Physical Properties of Paper by Solvent-Bonding between Cellulose Fibers Using Aqueous Solution of N-Methylmorpholine N-Oxide (N-Methylmorpholine N-Oxide 수용액을 이용한 셀룰로오스 섬유들간의 용제접착에 의한 종이의 물성 변화)

  • 이양헌;박찬헌;이현진;이선희
    • Textile Coloration and Finishing
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    • v.11 no.1
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    • pp.34-41
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    • 1999
  • To examine the increase of paper strength by solvent-bonding using N-methylmorpholine N-oxide (NMMO), a paper was treated with aqueous solutions of NMMO, concentrated at $90^\circ{C}$ for selected periods of time, and pressed for 5 seconds followed by washing and drying. The effect of the increasing NMMO concentration on bonding state and some important properties of samples were mainly investigated. With increasing concentration of NMMO, the degree of bonding between fibers was increased, the fiber cross-sectional shape was changed from 'thin ribbonlike' to 'round rodlike' by swelling with solvent, and the longitudinal waves (crimp) were introduced to fibers, hence the shrinkage, weight per unit area, and thickness of paper were increased. Consequently, the tensile strength and elongation, under standard and wet conditions, and the stiffness were increased, and the water absorption was decreased generally with increasing concentration of NMMO. The moisture regain of treated samples was lower than that of the untreated sample, because of the reduction of space between fibers. But the moisture regain was increased a little with increasing concentration of NMMO due to the fiber swelling with NMMO followed by structural relaxation.

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Physical Properties of Recycled Polyester Yarns According to Recycling Methods (재생 방법에 따른 재생 폴리에스터사의 물성 변화)

  • Lee, Sun-Young;Won, Jong-Sung;Yoo, Jae-Jung;Hahm, Wan-Gyu;Lee, Seung-Goo
    • Textile Coloration and Finishing
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    • v.24 no.1
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    • pp.91-96
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    • 2012
  • The physical properties of recycled polyester yarns according to recycling methods were investigated. Virgin polyester draw texturized yarn(DTY), material-recycled(MR) polyester DTY and chemical-recycled(CR) polyester DTY were prepared. Surface morphology, thermal property, micro-structure and mechanical property of recycled polyester yarns were estimated. SEM-EDS analysis showed that the CR PET yarn had better crimp and more stable structure than MR PET yarn. Tm of the MR PET yarn was higher than that of the CR PET yarn. The intensity of the crystallization peak of the CR PET yarn was a little higher than that of the MR PET yarn. Tensile strength of the MR PET yarn was slightly higher than that of the CR PET yarn. Breaking elongation of the CR PET yarn was slightly higher than that of the MR PET yarn.