• Title/Summary/Keyword: 내열설계

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The Tensile Characteristics of Carbon and Silica Reinforced Composites Under Elevated Temperature (카본 및 실리카 강화 복합재료의 고온 인장 특성 평가)

  • 김종환;김재훈
    • Composites Research
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    • v.16 no.3
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    • pp.49-57
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    • 2003
  • This paper presents the tensile characteristics for carbon/epoxy, carbon/phenolic and silica/phenolic composites under elevated temperature, which are considered for vehicle structure or thermal protection materials. The tensile test was conducted with servo-hydraulic testing machine and high temperature furnace, and the mechanical properties such as tensile strength, elastic modulus and Poisson's ratio were evaluated by using high temperature strain gages. Also, they were compared each other with respect to fiber orientation and temperature effect. These test results were used for designing and analyzing some airframe structures with these composites.

Photocatalytic Reactivity of Titania Deposited Beads in Continuous Reactor (광촉매 박막증착 비드의 연속식 반응기에서의 광반응성)

  • Park Jaehyeon;Lee Seung Yong;Ha Jin-Wook
    • Proceedings of the KAIS Fall Conference
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    • 2005.05a
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    • pp.274-276
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    • 2005
  • 본 논문에서는 유동층 화학기상증착법(FB CVB; Fluidized Bed Chemical Vapor Deposition)으로 광촉매가 박막증착된 비드를 제조하였고 제조된 광촉매코팅비드의 광반응성을 연속식 반응기에서 아세트알데히드의 분해능력을 측정하여 분석하였다. 광촉매가 박막증착된 비드의 FE-SEM 분석 결과 글라스 비드 위의 티타니아는 비교적 매끄럽게 증착되었고, 실리카 위의 티타니아는 입자의 형태로 증착되었으며 알루미나 위의 티타니아는 결정상을 이루며 증착됨을 확인 할 수 있었다. Acetaldehyde 기체의 광촉매에 의한 분해 실험을 진행하기 위해 연속식 반응기를 설계 제작하였고, 이 반응기를 사용하여 제조된 광촉매 코팅입자의 광반응성을 살펴보았다. 반응기는 가스 주입구와 출구를 갖고 있으며, 중심부에 UV 램프가 설치되었다. 반응기는 내열유리(pyrex)로 제작하였으며, 체적은 100 ml이다. 반응기 내부의 중심부에 UV 램프가 설치되고 UV 램프와 반응기 외부사이에 유동층 화학기상증착법에 의해 티타니아가 박막증착된 광촉매입자가 위치하여 광반응성을 평가하였다. 유량변화에 따른 광반응성을 측정하였으며, 알루미나에 광촉매를 증착시킨 제품의 경우 가스유량 100cc/min에서는 acetaldehyde가 $100\%$ 분해되고, 가스유량 500cc/min에서는 $50\%$정도 분해되는 것을 알 수 있었다.

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A Study on Design of Flexible Gripper for Handling Working of the Forging Process in Heat Resisting Environment (내열환경 단조공정에서 핸들링작업을 위한 유연 아암 그리퍼 설계에 관한 연구)

  • Yang, Jun-Seok;Koo, Young-Mok;Jo, Sang-Young;Won, Jong-Bum;Won, Jong-Dae;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.18 no.4
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    • pp.216-223
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    • 2015
  • Recently Manipulation capability is important for a robot. Interaction between a robot hand and objects can be properly controlled only is suitable sensors are available. Recently the tendency is to create robot hands more compact and high integrated sensors system, in order to increase the grasping capability and in order to reduce cabling through the finger, the palm and the arm. As a matter of fact, miniaturization and cabling harness represents a significant limitation to the design of small sized embedded sensor. Ongoing work is focusing on a flexible manipulation system, which consists of a dual flexible multi-fingered hand-arm system, and a dual active vision system.

Material Trends of Nozzle Extension for Liquid Rocket Engine (액체로켓엔진 노즐확장부 소재기술 동향)

  • Lee, Keum-Oh;Ryu, Chul-Sung;Choi, Hwan-Seok
    • Current Industrial and Technological Trends in Aerospace
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    • v.9 no.1
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    • pp.139-149
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    • 2011
  • The combustion chamber and nozzle of a liquid rocket engine need thermal protection against the high temperature combustion gas. The nozzle extension of a high-altitude engine also has to be compatible with high temperature environment and several kinds of cooling methods including gas film cooling, ablative cooling and radiative cooling are used. Especially for an upper-stage nozzle extension having a large expansion ratio, the weight impact on the launcher performance is crucial and it necessitated the development of light-weight refractory material. The present survey on the nozzle extension materials employed in the liquid rocket engines of USA, Russia and European Union has revealed a trend that the heavier metals like stainless steels and titanium alloys are being substituted with light weight carbon fiber or ceramic matrix composite materials.

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Optimum Design based on Sequential Design of Experiments and Artificial Neural Network for Heat Resistant Characteristics Enhancement in Front Pillar Trim (프런트 필라 트림의 내열특성 향상을 위한 순차적 실험계획법과 인공신경망 기반의 최적설계)

  • Lee, Jung Hwan;Suh, Myung Won
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.10
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    • pp.1079-1086
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    • 2013
  • Optimal mount position of a front pillar trim considering heat resistant characteristics can be determined by two methods. One is conventional approximate optimization method which uses the statistical design of experiments (DOE) and response surface method (RSM). Generally, approximated optimum results are obtained through the iterative process by a trial and error. The quality of results depends seriously on the factors and levels assigned by a designer. The other is a methodology derived from previous work by the authors, which is called sequential design of experiments (SDOE), to reduce a trial and error procedure and to find an appropriate condition for using artificial neural network (ANN) systematically. An appropriate condition is determined from the iterative process based on the analysis of means. With this new technique and ANN, it is possible to find an optimum design accurately and efficiently.

A Study on the sealing Characteristic of Automobile Waterproof Connector (자동차용 방수커넥터의 밀봉특성에 관한 연구)

  • Ko, Young-Bae;Park, Hyung-Pil;Lee, Jeong-Won;Cha, Baeg-Soon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.4
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    • pp.1859-1864
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    • 2014
  • Liquid silicone rubber(LSR) has been applied to various products such as electronic devices owing to its excellent thermal and chemical resistance. Hyperelastic materials, however, have properties distinguished from general metal materials. Hyperelastic materials show elastic behaviors in the range of large deformation in which load has the nonlinear relation with deformation. In addition, they have characteristics of nonlinearity, incompressibility, in large scale. On account of such characteristics, there are many difficulties in design and production using these materials. In this study, the load-deformation relation obtained from tension and compression tests was applied to finite element analysis in order to design waterproof connectors for automobiles. Furthermore, the effectiveness of the finite element analysis was confirmed by comparing the results of analysis with those of performance tests.

Design of Full-Scale Combustion Chamber of Liquid Rocket Engine for Ground Hot Firing Tests (지상연소시험용 실물형 고압 연소기의 설계)

  • Han Yeoungmin;Kim Seunghan;Seo Seonghyeon;Cho Wonkook;Choi Hwanseok;Seol Wooseok;Lee Sooyong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.299-304
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    • 2005
  • The design procedures of full-scale combustion chamber with chamber pressure of 53bara, mass flow rate of 90kg/s, combustion efficiency of $94\%$ and specific impulse at ground of 253sec were described. The details of combustion performance and geometrical parameters were also given. Full-scale combustion chamber consists of the combustor head with injector/baffle and the chamber/nozzle with regenerative cooling channels. The design results of combustion chamber with ablative materials, detachable injector head with SUS baffle or baffle injector and chamber body for ground hot firing tests were given in this paper.

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Development of Liquid Propellant Rocket Engine for KSR-III (KSR-III 액체추진제 로켓 엔진 개발)

  • Choi Hwan-Seok;Seol Woo-Seok;Lee Soo-Yong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.3
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    • pp.75-86
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    • 2004
  • KSR-III is the first Korean sounding rocket propelled by a liquid propellant propulsion system and it has been developed over 5 years using purely domestic technologies. The propulsion system of KSR-III is a 13-ton class see-level thrust liquid rocket engine(LRE) which utilizes liquid oxygen and kerosene for its propellants and employed pressurized propellant feeding and ablative cooling system. The problem of combustion instabilities which has brought the most difficulty in the development was resolved by implementation of a baffle. Through the development of KSR-III LRE, meaningful achievements have been made in the core technologies of LRE such as design of injectors and combustion chambers and test, evaluation, and control of combustion instabilities. The acquired technologies will be applied to the development of higher performance LREs necessary for future space development programs such as Korean Small Launch Vehicles(KSLV) In this paper, the development of KRE-III LRE system is described including its design, analyses. performance tests and evaluation.

Alloy Design and Properties of Ni based Superalloy LESS 1: I. Alloy Design and Phase Stability at High Temperature (Ni기 초내열 합금 LESS 1의 합금설계 및 평가: I. 합금 설계 및 고온 상 안정성 평가)

  • Youn, Jeong Il;Kang, Byung Il;Choi, Bong Jae;Kim, Young Jig
    • Journal of Korea Foundry Society
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    • v.33 no.5
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    • pp.215-225
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    • 2013
  • The alloys required for fossil power plants are altered from stainless steel that has been used below $600^{\circ}C$ to Ni-based alloys that can operate at $700^{\circ}C$ for Hyper Super Critical (HSC) steam turbine. The IN740 alloy (Special Metals Co. USA) is proposed for improved rupture strength and corrosion resistance at high temperature. However, previous studies with experiments and simulations on stable phases at about $700^{\circ}C$ indicated the formation of the eta phase with the wasting of a gamma prime phase, which is the most important reinforced phase in precipitation hardened Ni alloys, and this resulted in the formation of precipitation free zones to decrease the strength. On the basis of thermodynamic calculation, the new Ni-based superalloy named LESS 1 (Low Eta Sigma Superalloy) was designed in this study to improve the strengthening effect and structure stability by depressing the formation of topologically close packed phases, especially sigma and eta phases at high temperature. A thermal exposure test was carried out to determine the microstructure stability of LESS 1 in comparison with IN740 at $800^{\circ}C$ for 300 hrs. The experimental results show that a needle-shaped eta phase was formed in the grin boundary and it grew to intragrain, and a precipitation free zone was also observed in IN740, but these defects were entirely controlled in LESS 1.

A Study on the Effects on Low Cycle Fatigue Life of a High Pressure Turbine Nozzle due to the Perturbation of Crystal Orientation of Grain of DS Materials (일방향 응고 재료의 결정립 성장 방향 섭동이 고압터빈 노즐 저주기 피로 수명에 미치는 영향에 대한 연구)

  • Huh, Jae Sung;Kang, Young Seok;Rhee, Dong Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.7
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    • pp.653-658
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    • 2016
  • High pressure components of a gas turbine engine are generally made of nickel-base superalloys, using precision casting process due to complicated geometries with intricate channels and cooling holes. Turbine components manufactured from directionally solidified and single crystal materials have columnar grains; however, it is found that the crystals do not grow in its preferred direction, although the orientation can be controlled. This anisotropy can lead to the variations of elastic and Hill's parameters in constitutive equations, and they alter stress distributions and the low cycle fatigue life. We aims to evaluate the effects of perturbed crystal orientations on the structural integrity of a directionally solidified nozzle using low cycle fatigue life. We also attempt to show the necessity for the control of allowed manufacturing errors and stochastic analysis. Our approaches included conjugate heat transfer and structural analysis, along with low cycle fatigue life assessment.