• Title/Summary/Keyword: Fabric Stiffness

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Qualitative Research on Actual Wearing Conditions and Satisfaction of Rifle Shooting Clothing (소총 사격복 착용실태 및 만족도에 관한 질적연구)

  • Lee, Ah Lam;Park, Soozin;Kim, Na Yun;Nam, Yun Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.4
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    • pp.517-528
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    • 2015
  • This study investigates actual wearing conditions and satisfaction based on qualitative research for rifle shooting clothing. The survey was conducted in two ways: in-depth interviews of 4 rifle shooting experts and subjective questionnaires for 18 active rifle shooters. They agreed on the importance of rifle shooting wear to minimize body sway and contribute to a balanced body posture. Most rifle shooters purchase made-to-measure rifle shooting clothing at a domestic store, but the clothing often needs extra adjustments due to an uncomfortable fit. Current fabric for rifle shooting clothing consists of a cotton canvas with a polyester mix; however, rifle shooters are unsatisfied with its stiffness in hot and wet conditions. Due to the specific fabric features, rifle shooting clothing should not be washed despite year-round use that represents another point of dissatisfaction. Rifle shooters always wear specially designed underclothes to improve shooting skills and comfort sensation. In conclusion, it is necessary to develop well fitted and comfort rifle shooting clothing that could improve shooters skills based upon this study.

Graft Copolymerization of MMN4-Vinylpyridine onto Cotton Fiber (면섬유(綿纖維)에의 MMA/4-Vinylpyridine의 공(共)그라프트 중합(重合))

  • Bae, Hyun-Sook;Kim, Sung-Reon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.17 no.3
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    • pp.347-358
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    • 1993
  • Graft copolymerization of MMN4-VP onto cotton fiber using Ce(IV) salt as an initiator and triton X-100 as an emulsifier was performed under various polymerization conditions. In cograft polymerization, the polymeization behavior according to variation of 4-VP feed composition and the characteristics of MMA/4-VP graft polymer such as affinity for acid dye owing to cationization of cotton, antibacterial activity and thermal behavior were investigated. The results of this study were as follows : 1. While in copolymerization of MMA and 4-VP, 4-VP content in copolymer was more than that of monomer feed composition. 2. Increasing 4-VP content, graft yield was decreased, but graft efficiency was increased. In case of MMA/4-VP graft polymerization, the highest graft yield was obtained at higher CAN concentration than in MMA graft polymerization, the reason is that the behavior of 4-VP was disturbed by Ce(IV) sail 3. Elevation of temperature resulted in increase of graft yield and the apparent activation energy of MMA/4-VP graft polymerization was higher than that of MMA graft polymerization. 4. MMA/4-VP grafted cotton fiber showed affinity for acid dye, antibacterial activity and higher moisture regain than MMA grafted cotton fiber. MMA/4-VP grafted cotton fabric showed improvement of wrinkle recovery up to 40~50% graft yield and decreased thereafter. MMA/4-VP and MMA grafted cotton fabric did not showed significant difference in wrinkle recovery and stiffness.

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A Study on the Mechanical and Hand Properties of the Lining Fabrics (의복 안감의 역학적 특성 및 태 평가)

  • Kim, Myung-Ok;Uh, Mi-Kyung;Park, Myung-Ja
    • Fashion & Textile Research Journal
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    • v.8 no.3
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    • pp.357-362
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    • 2006
  • This study is to evaluate the objective sensibility of the commercial lining fabrics. Five kinds of the linings were collected by adding taffetas with four kinds of fibers (polyester, nylon, rayon, and acetate) to one polyester stretch fabric. The six basic mechanical and hand properties were studied by using KES-FB system (Kawabata Evaluation System). The result of measuring the mechanical properties shows that polyester has high bending rigidity (B), that polyester-stretch has a high value of linearity of load-extension curve (LT), tensile energy (WT), tensile resilience (RT), and coefficient of friction (MIU) and a low value of bending rigidity(B), shear property, and geometrical roughness (SMD). The nylon has a high value of bending rigidity (B), shear property, and compression resilience (RC). The rayon has a high value of coefficient of friction (MIU) and linearity of compression-thickness curve (LC) and a low value of shear property, and the acetate has a low value of shear property. The result of hand value shows that polyester, nylon, and acetate are a high value of KOSHI (stiffness), NUMERI (smoothness), and FUKURAM (fullness & softness), and they feel stiff and massive, that rayon has a low value of NUMERI and FUKURAMI. The total result of hand value shows that polyester taffeta and polyester stretch fabric are about the same as the best material for the lining of a woman's dress for spring and summer, and the next thing is acetate, but nylon and rayon are somewhat inferior materials. This provides a fundamental data for the comfortable clothing production of a higher value-added product through the study on the mechanical and hand properties of the lining as well as the right side of fabrics.

A Study on the Mechanical Properties of Fabrics for Korean Folk Clothes (Part 2) On the Women's Fall & Winter Fabrics (한복지의 역학적 특성에 관한 연구 (제2보) 여자용 추동한복지)

  • Sung Su-Kwang;Kouh Jae-Oon;Kwon Oh-Kyung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.12 no.2 s.27
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    • pp.169-179
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    • 1988
  • In the part 1, relations were found between fundmental mechanical properties and primary hand values, performance of Korean women's summer fabrics. In this paper, in order to investigate the hand values and mechanical properties such as tensile, shearing, bending, compression, surface and thickness & weight of the women's fall & winter fabrics were measured by KES-F system. Sorts of 90 commercial fabrics for women's fall & winter clothes were classfied into 39 silk and 51 polyester fabrics according to meterials. The experimental results were analysed statistically to relate the hand values and the mechanical properties and concerning to formation of weared clothes and transformation behavior were investigated. Furthermore, there mechanical properties as well as their hand values were discussed in comparison with those values for kimono fabrics. The main results are summarized as follows; 1. The shape of silk fabrics in formation for weared clothes show a box-shaped silhouette. Polyester fabrics has a easy to shape-less and make a silhouette which goes along with the body. 2. Silk fabrics for Korean women's fall & winter clothes have ${\pm}1\sigma$ range of bending, shearing, surface properties and thickness as compared with kimono fabrics. 3. A wrinkle recovery and drapability of silk fabrics for Korean women's fall & winter clothes are inferior to kimono fabrics. On the other hand, the fabrics for Korean women's fall & winter clothes have conical-shaped silhouette based on higher bending rigidity. 4. Except for flexibility with soft feeling, a primary factor of mechanical properties contributes to the hand values of fabrics for Korean women's fall & winter clothes having no concern with materials were same as the women's summer fabrics. 5. As for the hand values of fabrics for Korean folk clothes, stiffness, anti-drape stiffness are larger than those of kimono fabric and stiffness, anti-drape stiffness, crispness of fabrics for Korean women's fall & winter clothes have smaller values as compared with Korean women's summer fabrics.

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Drape Simulation Estimation for Non-Linear Stiffness Model (비선형 강성 모델을 위한 드레이프 시뮬레이션 결과 추정)

  • Eungjune Shim;Eunjung Ju;Myung Geol Choi
    • Journal of the Korea Computer Graphics Society
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    • v.29 no.3
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    • pp.117-125
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    • 2023
  • In the development of clothing design through virtual simulation, it is essential to minimize the differences between the virtual and the real world as much as possible. The most critical task to enhance the similarity between virtual and real garments is to find simulation parameters that can closely emulate the physical properties of the actual fabric in use. The simulation parameter optimization process requires manual tuning by experts, demanding high expertise and a significant amount of time. Especially, considerable time is consumed in repeatedly running simulations to check the results of applying the tuned simulation parameters. Recently, to tackle this issue, artificial neural network learning models have been proposed that swiftly estimate the results of drape test simulations, which are predominantly used for parameter tuning. In these earlier studies, relatively simple linear stiffness models were used, and instead of estimating the entirety of the drape mesh, they estimated only a portion of the mesh and interpolated the rest. However, there is still a scarcity of research on non-linear stiffness models, which are commonly used in actual garment design. In this paper, we propose a learning model for estimating the results of drape simulations for non-linear stiffness models. Our learning model estimates the full high-resolution mesh model of drape. To validate the performance of the proposed method, experiments were conducted using three different drape test methods, demonstrating high accuracy in estimation.

Elastic-plastic Micromechanics Modeling of Cross-anisotropic Granular Soils: II. Micromechanics Analysis (직교 이방적 사질토의 미시역학적 탄소성 모델링: II. 미시역학적 해석)

  • Jung, Young-Hoon;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
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    • v.23 no.3
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    • pp.89-100
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    • 2007
  • In the companion paper, we provided the novel elastic-plastic constitutive model based on the micromechanics theory. Herein, the elastic and elastic-plastic deformation of granular soils is meticulously analyzed. To guarantee high accuracy of the microscopic parameter, the systematic procedure to evaluate the parameters is provided. The analysis of the elastic response during the isotropic and triaxial compression shows that the stress-level dependency of cross-anisotropic elastic moduli is induced by the power relationship of the contact force in the normal contact stiffness, while the evolution of fabric anisotropy is more pronounced during triaxial compression. The micromechanical analysis indicates that the plastic strains are likely to occur at very small strains. The plastic deformation of tangential contacts has an important role in the reduction of soil stiffness during axial loading.

A Study on Structural Test and Derivation of Standard Finite Element Model for Composite Vehicle Structures of Automated People Mover (자동무인경전철 복합재 차체 구조물의 구조 시험 및 해석적 검증에 의한 유한요소 모델 도출 연구)

  • Ko, Hee-Young;Shin, Kwang-Bok;Kim, Dae-Hwan
    • Composites Research
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    • v.22 no.5
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    • pp.1-7
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    • 2009
  • The vehicle structure of Automated People Mover(APM) made of aluminum honeycomb sandwich with WR580INF4000 glass-fabric epoxy laminate facesheets was evaluated by structural test and finite element analysis. The test of the vehicle structure was conducted according to JIS E 7105. The structural integrity of vehicle structure was evaluated by stress, deflection and natural frequency obtained from dial-gauge and acceleration sensor. And the proposed finite element models were compared with the results of structural test. The results of finite element analysis showed good agreement with those of structural test. Also, in order to improve the stiffness of vehicle structure, the modified underframe model with reinforced side sill was proposed in design stage. The composite vehicle structures with modified underframe model had the improved structural stiffness about 44%.

Site response analysis using true coupled constitutive models for liquefaction triggering

  • Cristhian C. Mendoza-Bolanos;Andres Salas-Montoya;Oscar H. Moreno-Torres;Arturo I. Villegas-Andrade
    • Earthquakes and Structures
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    • v.25 no.1
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    • pp.27-41
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    • 2023
  • This study focused on nonlinear effective stress site response analysis using two coupled constitutive models, that is, the DM model (Dafalias and Manzari 2004), which incorporated a simple plasticity sand model accounting for fabric change effects, and the PMDY03 model (Khosravifar et al. 2018), that is, a 3D model for earthquake-induced liquefaction triggering and postliquefaction response. A detailed parametric study was conducted to validate the effectiveness of nonlinear site response analysis and porewater pressure (PWP) generation through a true coupled formulation for assessing the initiation of liquefaction at ground level. The coupled models demonstrated accurate prediction of liquefaction triggering, which was in line with established empirical liquefaction triggering relations in published databases. Several limitations were identified in the evaluation of liquefaction using the cyclic stress method, despite its widespread implementation for calculating liquefaction triggering. Variations in shear stiffness, represented by changes in shear wave velocity (Vs1), exerted the most significant influence on site response. The study further indicated that substantial differences in response spectra between nonlinear total stress and nonlinear effective stress analyses primarily occurred when liquefaction was triggered or on the verge of being triggered, as shown by excess PWP ratios approaching unity. These differences diminished when liquefaction occurred towards the later stages of intense shaking. The soil response was predominantly influenced by the higher stiffness values present prior to liquefaction. A key contribution of this study was to validate the criteria used to assess the triggering of level-ground liquefaction using true coupled effective-stress constitutive models, while also confirming the reliability of numerical approximations including the PDMY03 and DM models. These models effectively captured the principal characteristics of liquefaction observed in field tests and laboratory experiments.

A Study on Enzymatic Degummings of Raw Silk and Silk Fabric (견의 효소 정련에 관한 연구)

  • Lee, Yong-U;Song, Gi-Won;Jeong, In-Mo
    • Journal of Sericultural and Entomological Science
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    • v.28 no.1
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    • pp.66-71
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    • 1986
  • The studies were carried out to screen the optimum conditions for enzymatic degumming of raw silk yarn and silk fabric by use of Alkalase, a protease produced by Bacteria, comparing with Papain and Trypsin representing natural proteolytic enzymes. 1. The optimum temperature and acidity of degumming solution were 70$^{\circ}C$, pH 5-6 for Papain degumming, 40$^{\circ}C$, pH 8 for Trypsin and 50-60$^{\circ}C$ pH 8-9 for Alkalase. 2. By increasing the Alkalase concentration in the range of 0.6 to 1.0 gram per liter, the time for enzymatic degumming of silk yarn could be reduced by 40 minutes. 3. In degumming of silk yarn by Alkalase, the pretreatment of 95$^{\circ}C$, 10 minutes at 0.1% sodium bicarbonate solution or posttreatent of 80$^{\circ}C$, 20 minutes at 2% (o.w.f.) sodium silicate solution improved the efficiency of enzymatic degumming, as compared to that of nontreatment. 4. The breaking strength, elongation and Lousiness results of enzymatically degummed silk yarn were apt to be improved more than those of soap-degummed one. 5. When the pretreatment of alkaline solution was done with over 20% of degumming ratio, the enzymatic degumming efficiency of both Havutae and Crepe de chine could be reached to the same level with those of soap-soda degummed. 6. As the pretreated silk fabric with 20% of degumming ratio was under action of three proteases, respectively, the deumming efficiency of Havutae and Crepe de chine were completed by Alkalase more than by Papain or Trpysin. 7. The stiffness of enzymatically degummed Crepe de chine was not only reduced by 17% more than that of soap-soda degummed one but also the Drape coefficient was decreased in enzymatically degummed fabrics, which was closely related with the soft touch of degummed fabrics.

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Silk Finishing with Polyurethane Resin used for the Linen-like Finishing (의마가공용 폴리우레탄 수지를 이용한 견직물의 가공)

  • Lee, Jung-Soon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.27 no.12
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    • pp.1368-1373
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    • 2003
  • 본 연구에서는 견직물에 강경한 촉감을 부여하여 한복지 뿐만 아니라 현대의 패션경향에도 부합되는 소재를 개발하고자 하였다. 견직물에 강경성을 부여하기 위하여 의마가공용 폴리우레탄 수지를 이용하여 수지농도와 큐어링온도에 따른 수지부착율을 조사하였고, 여기에 수반되는 물리적 특성의 변화를 살펴보았다. 또한 가공된 견직물의 세탁에 대한 내구성도 살펴보아 동시에 실용가능성도 검토하였다. 이상의 연구를 통해 다음과 같은 결과를 얻었다. 1. 의마가공용 폴리우레탄 수지를 견직물에 처리할 경우 수지 농도가 증가할수록 수지 부착량이 증가하였다. 2. 열처리온도를 변화시켜 수지부착량의 변화를 살펴본 결과 열처리 온도가 증가할수록 수지의 부착량이 감소하여 본 실험에 사용된 수지의 적정 열처리 온도가 160-18$0^{\circ}C$인 것을 고려해 볼 때 견직물의 경우 17$0^{\circ}C$의 열처리 온도가 적절한 것으로 나타났다. 3. 수지 처리된 견직물의 역학적 특성치의 변화를 살펴본 결과 RT, EM, MIU값은 감소하는 경향을 가지며, LT, B, 2HB, G, 2HG, 2HG5값은 증가하는 경향을 나타내어 폴리우레탄 수지처리로 의마가공 효과를 갖는 견직물을 얻을 수 있었다. 4. 수지 처리된 견직물의 역학적 특성치는 물세탁 후에도 크게 변화가 없어 세탁에 대한 내구성을 지니고 있는 것으로 나타났다.