• Composites Research
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• 제33권1호
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• pp.13-18
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• 2020

기존 소방구조용 작업차에서 문제가 되고 있는 협소도로 진입의 어려움 및 구조를 위한 신속한 작업 전개 한계성을 극복하기 위한 목적으로 소형 구조작업차 연구가 진행되고 있으며 이에 따른 경량화 연구를 진행하였다. 본 연구에서는 소방 구조 작업차 5번 붐은 288 mm(W) × 299 mm(D) × 3,691 mm(L)이며 이에 걸리는 최대 하중은 876 kg이고, Steel Boom의 Thickness는 3 mm이다. Steel (STRENX960)을 CFRP 복합재로 변경하여 제작하기 위해 Carbon Fiber NCF (±45°, 2축)를 직조하고 이를 NCF Prepreg로 제작하였고 경량화와 강성, 강도를 극대화할 수 있는 최적설계 패턴을 제시하였다. 이 과정은 구조해석을 바탕으로 설계하였고, NCF Prepreg의 (±45°)가 비틀림에 미치는 영향을 확인했으며 적층패턴(b)로 최적설계 하였다. 기존 Steel Boom과 UD방향으로 적층한 CFRP Boom과 동등하거나 이상의 수준에 대한 적층패턴을 최적화하였고, 최종적으로 Steel 대비 약 49.6% 무게에 대한 경량화 효과를 확인하였다.

• 감성과학
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• 제8권4호
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• pp.345-354
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• 2005

본 연구는 직물구조인자인 위사밀도와 직물의 조직을 변화시켜 시직한 면직물을 이용하여 역학특성 및 태의 변화를 KES-FB System을 이용하여 측정하였다. 그 결과 위사밀도가 증가할수록 굽힘특성 및 전단특성이 증가하는 것으로 나타났고, 위사밀도의 변화에 따른 역학특성치 중 굽힘 및 전단특성의 값은 평직이 높게 나타났으며, 인장특성, 압축특성 그리고 표면특성의 값은 조직 및 밀도에 크게 영향을 받지 않는 것으로 나타났다. 한편, 위사밀도 변화에 따른 의복착용성능 중 WC/T, MMD/SMD를 제외한 B/W 및 2HG/G, 2HB/B, 2HB/W, W/T, 그리고 WC/W는 위사밀도에 영향을 받는 것으로 나타났다. 위사방향의 직축은 굽힘특성, 전단특성, 압축회복도(RC), 표면거칠기(SMD), 태와 의복착용성능에 높은 상관을 보이는 것으로 나타났다. 그리고 Tightness는 굽힘특성, 전단특성, 압축특성 그리고 표면 마찰계수와 높은 상관을 보였고, 기본태 및 T.H.V., 의복착용성능에도 높은 상관이 있는 것으로 나타났다.

• 패션비즈니스
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• 제6권6호
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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.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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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.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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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

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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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.

• 산업공학
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• 제11권2호
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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.

• Composites Research
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• 제17권1호
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• pp.38-46
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• 2004

본 논문의 목적은 탄소섬유 건직물의 토우 구조의 미소 거동과 변형 중의 평면 하중과의 관계를 규명하는 것이다. 평면 하중은 변형 중에 토우들을 재배치하며, 결국에는 잠김 현상을 유발하게 된다. 본 논문에서는 토우 간격, 주름각등의 미소 변형 변수들을 관찰하기 위해 일방향 편향 인장실험과 이축 인장실험을 겪은 시편들을 전단각에 따라 분류하여 현미경을 이용하여 변형 경향을 관찰하였다. 전단각에 따른 변형된 토우 구조의 변화를 간단한 설계 변수 모델을 이용하여 근사하였다.

• 한국염색가공학회지
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• 제11권1호
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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.

• 한국염색가공학회지
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• 제24권1호
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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.