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프리캐스트 콘크리트 세그먼트의 합성섬유 보강재 적용에 따른 구조적 성능 평가
이호성,김창용,이승원,김승준,이경진,Lee, Hoseong,Kim, Changyong,Lee, Sean S.,Kim, Seungjun,Lee, Kyeongjin 한국터널지하공간학회 2018 한국터널지하공간학회논문집 Vol.20 No.2
쉴드TBM 터널의 프리캐스트 콘크리트 세그먼트 라이닝의 보강재로 철근이 주로 사용되어 왔으나, 철근 보강량을 줄이기 위하여 섬유보강재를 적용하는 연구가 진행되어 오고 있다. 세계적으로 터널 시공성을 향상시키기 위하여 강섬유보강재를 적용한 연구와 시공이 진행되어 왔으나, 터널 라이닝 방수막에 대한 펀칭, 자체 부식에 의한 내구성 및 미관상의 문제로 인하여 이에 대한 적용이 국내에서는 미뤄지고 있는 실정이며, 이에 대한 대책으로 합성섬유가 강섬유의 대체제로 주목 받고 있다. 이 연구에서는 섬유(강섬유, 합성섬유) 보강재를 사용한 프리캐스트 콘크리트 세그먼트의 파괴시험을 통하여 성능을 분석하여 현장에서의 적용 가능성을 평가하였다. 그 결과 강섬유와 합성섬유의 조합이나 합성섬유의 혼입량에 따라 보조철근의 대체가 가능한 것으로 분석되었다. Steel bars have been widely used as the primary reinforcement for Precast Segmental Concrete Lining for TBM Tunnels. Previously, studies have been carried out to gauge the potential for steel fiber reinforcement to replace the use of steel bar reinforcements in the segmental lining to reduce the amount of the steel bar reinforcement. Steel fiber reinforcements have been investigated and widely applied to SFRC TBM linings to improve the constructability of SFRC TBM linings worldwide. However, the steel fiber reinforcement often caused punctures to the water membranes inside tunnel lining and had long-term durability deterioration issues caused by steel corrosion, as well as cosmetic problems. Therefore, this paper sought to gauge the potential of synthetic fiber reinforcements, which have proven to be very attractive substitutes for steel fiber reinforcements. This study analyzed the performance of both steel and synthetic fiber reinforcements in segmental linings and evaluated the applicability of the fiber reinforcements to the TBM Precast Concrete Segmental Linings of TBM tunnels. As a conclusion, this study demonstrates that the potential use of steel and synthetic fibers in various combination, can substitute the rebar reinforcement in the concrete mix for segmental concrete linings.
하이브리드 차량용 통합 냉각시스템 성능 평가 및 해석적 연구
이호성(Hoseong Lee),원종필(Jongphil Won),김성철(Sungchul Kim),이동혁(Donghyuk Lee),김현철(Hyun Chul Kim),이대웅(Daewoong Lee),권대복(Daebok Kwon) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The aim of this study is to evaluate the performance of integrated engine/motor cooling system and analyze the battery/inverter cooling system for hybrid electric vehicles(HEV). The prototype integrated radiator for engine/motor cooling was fabricated and the performance was evaluated on the optimum test rig with the variation of coolant flow rate and air inlet velocity. Electrical device cooling system, such as motor and controller, needed to be maintained under 50℃ for thermal stability. Under the certain condition, which inlet temperature difference(ITD) between air and coolant is 20℃, optimum coolant flow rate for electrical device cooling radiator was 10 LPM with heat capacity, 4.5㎾ at air inlet velocity 4㎧. The analysis of the battery/inverter cooling system has been peformed by applying the computational fluid dynamics (CFD) code to investigate fluid dynamic behavior characteristics and effectively design air flow rate of the system for hybrid electric vehicles (HEV). As a result, at design operating condition, air flow rate of the battery/inverter cooling system was 218.0 ㎥/h and the corresponding efficiency of the blower motor was predicted about 70.7%. Furthermore, for the battery/inverter cooling system, the average temperature of the battery was about 42.4℃.
내부열교환기 적용에 따른 차량용 냉방시스템 성능 특성 실험적 연구
이호성(Hoseong Lee),원종필(Songphil Won),조중원(Choongwon Cho),정영철(Youngchul Jung) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Internal heat exchanger is being considered as one of the A/C performance improvement methods because the alternative refrigerant for vehicle are conditioning system compared to the existing refrigerant(R-134a) is not supposed to have sufficient performance. Internal heat exchanger typically increases evaporator’s heat capacity by increasing the degree of subcool at the high pressure side(expansion device inlet condition) and also helps a compressor to run steadily by increasing the degree of superheat at the low pressure side(compressor inlet condition). In this study, the performance evaluation in various driving conditions were investigated and analyzed with the application of internal heat exchanger in the vehicle air conditioning system. Experimental results were found that present vehicle A/C system applied in the internal heat exchanger and existing refrigerant had performance improvement in terms of heat capacity by 5%, in terms of coefficient of performance(COP) by 10%. Based on these results, in case of application of the alternative refrigerant, expected performance loss will be able to be compensated by adding the internal heat exchanger in vehicle A/C system.