• Fire Science and Engineering
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• v.22 no.5
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• pp.83-89
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• 2008

Using the high expansion foam generator of ISO 7203-2 which spray 6 liter at 5 bar, foam generation characteristics was studied. Wind flow rate, foam screen, concentration of foam agent solution and concentration of salt of water were varied to find the effect of the parameters on foam generation. Research result showed that expansion ratio of foam was increased with wind flow rate. The expansion ratio of foam in the perforated type standard screen was higher than the wire mesh screen. Expansion ratio and drainage time were increased with increase of foam solution concentration. But a increase of salt concentration in solution showed the decrease of expansion ratio and drainage time.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.94-101
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• 2010

Composite materials have a higher specific strength and modulus than traditional metallic materials. Additionally, these materials offer new design flexibilities, corrosion and wear resistance, low thermal conductivity and increased fatigue life. These, however, are susceptible to impact damage due to their lack of through-thickness reinforcement and it causes large drops in the load-carrying capacity of a structure. Therefore, the impact damage behavior and subsequently load-carrying capacity of impacted composite materials deserve careful investigation. In this study, the residual strength and impact characteristics of plain-woven CFRP composites with impact damage are investigated under axial tensile test. Impact test was performed using drop weight impact tester. And residual strength behavior by impact was evaluated using the caprino model. Also we evaluated behavior of residual strength by change of mass and size of impactor. Examined change of residual strength by impact energy change through this research and consider impactor diameter in caprino model.

• The Research Journal of the Costume Culture
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• v.10 no.5
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• pp.532-541
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• 2002

An empirical review on silk fabrics of the Chosun period showed that they varied in kind and design according to their uses. Thus the purpose of this study is to classify the fabrics into excavated and temple fabrics according to their uses and collected places and then to examine characteristics of each type. Excavated fabrics were most accounted for by tabby fabric, followed by satin, twill, leno and gauze and union cloth. Tabby fabric was most used throughout the Chosun period, followed by satin. This is supported by many literary records. Concerning excavated dresses of the same period, tabby fabric, especially Ju was the main material, followed by satin. Leno and gauze fabric was much less used than in the Koryo period. Among excavated dresses surveyed in this study, none was made of compound woven fabrics such as Brocade. Other excavation reports said that Brocade had been used for a cuff of coat in few cases, if any. Tabby fabric was widely used for both the right side and lining while twill and satin fabrics were mainly adapted to weave the right side because they had luster higher than the former, smooth sense of touching and unique designs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.367-370
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• 2005

This paper investigated the sound characteristics in an apartment complex. The field measurement was conducted in order to examine the acoustical characteristics of the apartment complex in situ. As a result, it shows that there are around 3 sec. reverberation time and the additional sound reinforcements at the area of high height due to the surrounded buildings. Thus, 1:50 Scale model measurement and Raynoise computer simulation were carried out with insertion of the parapet and the canopy on the balcony. In case of a single building, the parapet was effective to reduce noise level at low floor levels, and the canopy was effective to reduce noise level at high floor levels. But it also shows that both the parapet and the canopy were not effective to reduce noise level at middle floor levels. In case of an apartment complex, the canopy was less effective to reduce noise level at each floor in comparison with case of the single building.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.181-183
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• 2002

The accurate permeability for preform is critical to model and design the impregnation of fluid resin in the composite manufacturing process. In this study, the in-plane and transverse permeability for a woven fabric are predicted numerically through the coupled flow model which combines microscopic with macroscopic flow. The microscopic and macroscopic flow which are flows within the micro-unit and macro-unit cell, respectively, are calculated by using 3-D CVFEM(control volume finite element method). To avoid checker-board pressure field and improve the efficiency on numerical computation, A new interpolation function for velocity is proposed on the basis of analytic solutions. The permeability of plain woven fabric is measured through unidirectional flow experiment and compared with the permeability calculated numerically. Based on the good agreement of the results, the relationships between the permeability and the structures of preform such as the fiber volume fraction and stacking effect can be understood. The reverse and the simple stacking are taken in account. Unlike past literatures, this study is based on more realistic unit cell and the improved prediction of permeability can be achieved. It is observed that in-plane flow is more dominant than transverse flow in the real flow through preform and the stacking effect of multi-layered preform is negligible. Consequently, the proposed coupled flow model can be applied to modeling of real composite materials processing.

• Composites Research
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• v.22 no.1
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• pp.15-21
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• 2009

In this paper, static compressive test and compression-compression fatigue test of carbon/epoxy composites which have different micro-structures were carried out with respect to the bias angle. In order to find out the effect of the micro-structure of the fabric composite on compressive characteristics the specimens made of UD carbon/epoxy composite comprising the same fiber and matrix system as the fabric composite were also prepared. The compressive strength and modulus were measured and these values were used to develop a semi-empirical formula for predicting compressive strength of the fabric composite with bias angles. The fatigue behavior of the fabric composite with respect to the bias angle variation was also investigated.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.83-89
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• 2022

For the purpose of promoting the excellence of Korea's unique traditional hanji around the world, it was intended to promote 'modernization of tradition' by producing and presenting cultural products suitable for modern sensibility using traditional hanji which is widely used in the arts. First of all, using hanji as a material, jumchi hanji was made by jumchi technique. Cut to a certain width according to the cultural products such as laptop case, cell phone case, hat, and bag. Weave the cut jumchi hanji with plaine weave, twill weave, and hexagon depending on the purpose of the cultural products to be made. A cultural products were made by matching the woven jumchi hanji with artificial leather, cotton, and denim.

• Textile Coloration and Finishing
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• v.11 no.2
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• pp.1-8
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• 1999

이 연구에서는 사이징 공정을 포함해서 수세, 전처리 그리고 최종 열처리 둥의 염색.가공 공정에서의 습열 및 건열 처리 온도가 폴리에스테르 직물의 열응력과 염색성에 미치는 영향을 조사하였다. 사용된 폴리에스테르 필라멘트사는 경사가 50d/24f 스파크사이며 위사는 75d/72f semi-dull사이다. 평직물은 션틀직기, 주자직물은 water jet 직기로 제직하였으며, sizing dryer 온도는 $90^\circ{C}$, $125^\circ{C}$, $150^\circ{C}$, 수세공정의 습열처리 온도는 $90^\circ{C}$, $110^\circ{C}$, $120^\circ{C}$, 전처리 공정의 건열처리 온도는 $180^\circ{C}$, $200^\circ{C}$, $220^\circ{C}$, 마지막 세팅 공정의 건열처리 온도는 $170^\circ{C}$, $180^\circ{C}$, $200^\circ{C}$로 변화시켰다. 이들 습열과 건열처리 온도 변화에 따른 직물내의 필라멘트사의 열 수축률과 직물의 겉보기 염색성의 변화를 조사 분석하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.920-928
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• 2006

Fiber-reinforced composites transmitting microwaves of certain frequencies or bands were proposed. These frequency selective fabric composites(FSFCs) are fabricated by weaving carbon fibers and dielectric fibers that build periodic patterns. Design parameters affecting the electromagnetic characteristics of FSFCs were widely discussed, Then the electromagnetic characteristics of a fabricated plain-weave FSEC were investigated with regard to the electrical conductivities of carbon roving, the fiber undulation, and the aperture-to-cell ratio, for the electrical conductivities, its dependence on frequency as well as on the fiber volume fraction of carbon roving was taken into account. Constituent material properties and the fiber undulation had little effect on the EM properties of the fabricated FSFC, while the aperture-to-cell ratio made a profound effect on them.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.74-74
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• 2012

섬유 프리프레그(Prepreg)는 강화섬유를 수지에 함침하여 B-stage로 만든 복합재료의 중간성형재료이다. 최종적으로 프리프레그를 금형에 적층하여 가열 가압하여 수지를 경화함으로써 최종제품이 완성된다. 본 연구에서는 직물형 프리프레그를 사용하였는데, 사용되는 직물형태로는 복합재료 성형공정에서 형태안정성이 우수한 평직물과 능직물이 주로 사용된다. 직물형 프리프레그를 사용한 복합재료는 작업성과 형태안정성이 우수하면서 내충격특성이 우수하여 오토바이용 헬멧, 방탄용 헬멧 등에 주로 사용된다. 프리프레그에 요구되는 주요 특성중 하나는 Tack성으로서, 성형 과정에서 프리프레그를 여러 장 적층할 때 적층된 층 간에 미끄러지지 않으면서 잘 고정되어 적층 작업을 원활하게 하는 역할을 한다. Tack성은 수지의 B-stage 경화 후의 점성 거동에 따라 변화될 수 있는 것으로 표면의 끈끈함의 정도로서 알 수 있다. Tack성은 온도에 민감하여 측정 시에 일정한 온도의 유지가 중요하다. 이러한 온도에 대한 민감성 때문에 프리프레그의 저장시 저온에서 저장하는 것이 원칙인데, 상온에 있을 경우 시간경과에 따른 Tack성 변화가 크게 나타나게 된다. 따라서 본 연구에서는 아라미드 섬유와 열경화성수지를 이용하여 프리프레그를 제조하고 이를 상온상태에서 보관 시 일정시간 경과에 따른 Tack성 변화를 알아보고자 하였다.