• Earthquakes and Structures
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• 제17권4호
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• pp.411-424
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• 2019

In this study, a numerical model of a shield tunnel with an assembled segmental lining was built. The seismic response of the segmental lining of the section of the shield tunnel in Line 1 of the Chengdu Metro is analyzed as it passes through the interface of sand-cobble and mudstone layers. To do so, the node-stress seismic-motion input method was used to input the seismic motion measured during the 2008 Wenchuan earthquake, and the joint openings and dislocations associated with the earthquake action were obtained. With reference to the Ethylene-Propylene-Diene Monomer (EPDM) sealing gaskets used in the shield tunnels in the Chengdu Metro, numerical simulation was applied to analyze the contact pressure along the seepage paths and the waterproof property under different joint openings and dislocations. A laboratory test on the elastic sealing gasket was also conducted to study its waterproof property. The test results accord well with the numerical results and the occurrence of water seepage in the section of the shield tunnel in Line 1 of the Chengdu Metro during the 2008 Wenchuan earthquake was verified. These research results demonstrate the deformation of segmental joint under earthquake, also demonstrate the relationship between segmental joint deformation and waterproof property.

• 한국의류산업학회지
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• 제2권3호
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• pp.220-226
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• 2000

This study was to determine the characteristics of vapor-permeable waterproof finished fabric by the coating method. 4 different kinds of coating fabrics (A : wet, porous, polyurethane, B : dry, no porous, polyurethane, C : shape memory polyurethane and D : dry, porous polyurethane) were used, which were developed recently With this sample, moisture transport rate ($40^{\circ}C$, 45%RH & $40^{\circ}C$, 95%RH), changes of coating side's shape by washing times, water repellency rate, contracted length, qmax, heat conductivity, heat keeping rate, heat keeping rate with cotton, heat keeping rate on humidity temperature and humidity within clothing etc. were checked. And it was done in a climate chamber under $20{\pm}2^{\circ}C$, $65{\pm}5%RH$. The results of this study were as follow; In the moisture vapor transmission of sample B and C increased on high temperature and high humidity while sample A and D decreased, on this condition. Qmax rate had high relation with ground fabric's surface properties and the order was A>C>D>B. Heat conductivity had high relation with thickness and surface properties. Heat keeping rates on sweat condition showed around half percents of heat keeping rates on normal condition, but had no relation with moisture vapor transport rate. Changes of the fabric's properties by washing times were different in accordance with the construction of fabrics and the coating resin. Sample C had tow heat keeping rate on the high temperature and humidity and high heat keeping rate on the low temperature and humidity Moisture transport rate of vapor-permeable waterproof finished fabrics had high relation with the properties of ground fabrics on low humidity condition, but on the high humidity condition, it was highly related with the properties of coating resin.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.128-129
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• 2017

Concrete properties alone cannot provide satisfactory waterproof performance because concrete can generate cracks due to possible problems in design, construction and curing process, and various environmental factors. Therefore, concrete structures require installing waterproofing layers for concrete protection and various types of construction methods are currently being applied. The purpose of this study is to investigate the concrete strength changes when waterproofing admixtures are mixed into the concrete. The results of flexural strength testing confirmed that the initial strength of concrete specimens with the admixtures was lower than that of the concrete specimen without the admixture based on different curing periods.

• 품질경영학회지
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• 제46권3호
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• pp.425-440
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• 2018

Purpose: This study is aimed at developing of the flex resistance testing process at low temperature with the waterproof fabric to suit the military environment, and is designed to fit for the purpose of the waterproof materials in order to optimize the test method by finding out matters to improve from existing the test method and through previous studies. Methods: The test method, which has been applied to flex resistance of existing water-repellent materials, was improved and consequently, differentiated test results could be obtained according to the test temperature, sample size, and flexing method. Results: The testing of the total of 8 samples revealed that performance of the military requirement could hardly be met just by presenting the materials or 2~3 layers when the quality criteria for high functional water repellent fabrics were applied. PTFE(Polytetrafluoroethylene) is preferred to PU(Polyurethane) to be used in the extremely low-temperature environment, but durability under the low-temperature environment may be varied depending on film thickness or laminating technique even if the materials of waterproof films are identical. Therefore, in addition to the material or texture, the test method capable of reflecting durability under the low-temperature environment shall be suggested, and the newly designed test method proposed in this study was shown to suggest differentiated quality criteria by the material. Conclusion: The water resistance measurement and the test method following flex resistance with expanded range of flex will enable the differentiable test of the samples according to the number of repetition. This study is meaningful in that it suggests a differentiable test method capable of establishing a basis of deciding suitable material when selecting military goods made of water repellent material by properly improving the test method.

• Tribology and Lubricants
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• 제37권6호
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• pp.224-231
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• 2021

Recently, the waterproofing performance of high-voltage connectors in automotive vehicles has attracted increased interest. In this study, an optimal cross-sectional shape was derived to obtain uniform contact pressure and strain by considering stress relaxation problems caused by initial tension when mounting a seal. A high strain of 52.1 was distributed in the round region, owing to excessive initial tension. The finite element method (FEM) analysis indicated that the strain corresponding to the optimal initial tensile was 11. We adopted six design factors to optimize the seal cross-section and three factors as the main design factors. An orthogonal arrangement table was prepared using Minitab. FEM analyses of 16 study models were conducted to determine the optimized model. The contact pressure of the optimization model is the most evenly distributed while satisfying the waterproof performance of 0.47 MPa. Compared to the initial model, the difference in strain decreases from 35.5% to 19.6%. Finally, the derived cross-sectional shape can reduce the strain of the round region by 33.8% and the differences in the contact pressure at the upper and lower surfaces by 42% and 76%, respectively.

• 한국산업융합학회 논문집
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• 제23권3호
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• pp.463-471
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• 2020

Recently, various tries to apply ROV (Remotely Operated Vehicle) into underwater are being developed. However, due to underwater environment uniqueness, the additional problem must be taken into account when designing an ROV for the inspection of the underwater structure. This is because a GPS-based information method cannot be applied, and the obtainable image is also dependent on the turbidity. Also, it is necessary to be able to satisfy waterproof and operating speeds in consideration of most practical application environments. This paper describes the design results of the ROV system for underwater structure inspection considering the above problems. The designed system applied INS / DVL for location recognition and was configured to support 3D mapping and stereo camera-based image information using sonar depending on visibility. To satisfy the waterproof, a pressure vessel using a composite material was applied. And over-actuated system using eight thrusters to maintain a stable posture and operating speed was applied also. The designed system was verified by structural analysis and flow analysis also.

• 복식
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• 제63권7호
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• pp.1-16
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• 2013

The objective of this study is to analyze the characteristic of a functional design for a commercial outdoor brand jacket based on 3 types of functions : windproof, waterproof, and cold proof. To analyze the design and fabric characteristics of outdoor jackets by function, 903 men's and women's outdoor jacket images were selected from the catalogues during S/S 2009 - F/W 2011 of the 6 brands: The North Face, Columbia Sports Wear, Kolon Sports, K2, Arcteryx and Mont-Bell. These brands were selected based on their high market share and brand awareness of the outdoor brands in Korea. In this study, design elements analysis was conducted as following 8 elements: hood/collar height/central front flap/waistline/pocket location/ventilation for the body part/sleeve patterns/cuff for the sleeve part. Fabrics were analyzed by the frequency of fabric types used in the 3 jacket types. According to the result derived from the analysis of the six brands of outdoor wear jacket design trends by year, detachable hood and a co-use of velcro and elastic bands have been mainly designed for all of windproof, waterproof, and cold proof jacket to all in order to respond quickly to changes in the external environment. For reinforced storage function on trekking, the number of pockets has been gradually growing, and a function was being developed to connect an electronic device to a pocket. The method, result, and collateral observations relevant to each of these phases are described. Outdoor jacket design characteristics were investigated for outdoor brands, which can provide data to suggest more accurate functional design, and satisfy functional design needs. In this regard, this research was significant in the sense that it suggested preliminary data to reconsider competitiveness of the brand products.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.215-216
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• 2017

Existing studies highlights the problems about the negative-side waterproofing design of apartment complex underground structures. This study suggests the alternatives for waterproof design construction details of as a solution, and a review on the applicability of this new construction design details through a mock-up construction is provided.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.310-315
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• 2017

자동차용 방수커넥터는 외부로부터 방수가 필요한 전장부품인 와이어 하네스(Wire Harness)에 연결되어 있는 핵심기능부품이며 특히 와이어씰(Wire Seal) 부품은 고온, 다습, 저온, 먼지, 약품 등의 복합적 환경에서도 체결부 기밀성이 확보되어야 한다. 이러한 와이어씰은 최근 기존의 고상실리콘고무(Heat Cure Rubber)대신 친환경 소재이며 기계적 특성이 우수한 액상실리콘고무(LSR)를 적용하고 있다. 그리고 LSR용 와이어씰을 액상사출성형(Liquid Injection Molding)공정으로 제조할 경우 고상실리콘고무를 제조 하긴 위한 압축성형방식에 비해 사이클타임이 10배이상 빠르고 스크랩이 발생하지 않아 재료의 손실이 없으며 가류 및 생산을 위한 전후처리 과정이 필요 없기 때문에 원가 절감효과가 큰 이점이 있다. 하지만, 방수커넥터를 제조하기 위한 LSR 다캐비티 사출성형공정에서는 일정한 품질의 제품을 확보하기 위하여 캐비티간 균일한 경화온도를 유지하는 것이 중요하다. 본 연구에서는 캐비티간 온도 편차를 최소화 하기 위하여 카트리지 히터의 용량을 위치마다 다르게 설계한 후 열전달 해석과 최적화 모듈을 연계하여 최적의 카트리지 히터 용량을 빠르고 효율적으로 도출하였다. 최적화 해석결과 일정한 히터 용량을 적용한 경우에 비하여 캐비티간 온도 편차는 $13.1^{\circ}C$에서 $8.1^{\circ}C$로 감소 시켜 균일 경화를 위한 온도 편차 $10^{\circ}C$ 이내인 설계 기준을 만족시킬 수 있었다.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.1859-1864
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• 2014

본 액화 실리콘 고무는 내열성 및 내화학적 우수성으로 전자 제품 및 다양한 제품에서 활용되고 있다. 하지만 초탄성 재료는 일반 금속재료와 다른 특성을 보인다. 초탄성 재료는 하중과 변형이 비선형 관계를 보이는 대변형 범위에서도 탄성거동을 나타내는 특성을 지니며, 비선형, 비압축성 및 대형의 특성을 지니고 있다. 이러한 특성 때문에 제품을 설계 및 생산 하기위해는 기능적 측면을 고려한 소재의 특성에 대한 물성 확보가 반드시 필요하기 때문에 현장에서 많은 어려움이 있다. 본 논문에서는 자동차용 방수커넥터 설계를 위해 소재의 인장, 압축 시험으로부터 구한 하중-변형관계를 이용하여 이를 유한 요소 해석에 적용한 결과를 비교하였으며, 해석결과와 제품의 성능 테스트 결과를 비교하여 방수커넥터용 씰의 경우 어떠한 소재특성을 적용할 경우 유용한 결과를 도출할 수 있는지를 확인하였으며, 이를 통해 제품 개발에 유용성을 확인하였다.