• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.253-259
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• 1997

씨일의 마모에 따른 터빈펌프의 동적거동을 고찰하기 위해서 10단 터빈펌프를 대상으로 유한요소법에 의한 동특성 해석을 수행하였다. 베어링과 씨일의 동적계수를 회전속도의 하수로 계산하였으며, 이를 동적거동해석에 적용하였다. 해석결과 씨일들은 그 간극이 커질수록 강성 및 감쇠계수가 크게 떨어지고 누설량이 급격히 늘어남을 확인하였다. 따라서 1차 위험속도(1st Critical Speed) 이하에서 충분한 분리여유(Seperation Margine)를 가지고 정상운전되도록 설계된 터빈펌프라 할지라도 장기적 사용시 마모가 진전됨에 따라 계의 1차 위험속도가 변하여 운전속도에 접근할 수 있으며, 아울러 이 때 씨일의 감쇠가 크게 줄어들어 급격한 진동의 증가를 가져올 수 있음을 보였다.

• 소성∙가공
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• 제9권6호
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• pp.638-643
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• 2000

This study Is concerned with the development of design support program for deep drawing process. The present support program is designed to generate the layout drawings by utilizing the following key functions: analysis of product shape, generation of key stages by pattern database, determination of layout generation method, generation of layout. furthermore, from the results by process design program input data for simulation Is automatically generated with appropriate process parameters and connected seamlessly to carry out the finite element analysis so that the design can be checked for the possible problems in real manufacturing process. The designer can generate layout drawings and test the design by simulation quickly and conveniently In these system designer can verify and optimize the design. We tested this system for various type of product shape md found that the generated layout is in good agreement with the real cases.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.845-862
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• 2009

Recently, Tunnel in soil has been designed frequently because Mountain Tunnel has been increased rapidly due to straight of horizontal curve and residents' complaints, tunnel portal has been planned at closed to surface for minimization of environmental damage. To excavate tunnel in soil, where displacement and crushing occur in tunnel face and crown because of unstable ground condition, appropriate reinforcement method needed. On this paper, through design and construction of the soil tunnel, consider application of reinforcement method, economical efficiency and stability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.307-308
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• 2007

At present, there are unnecessary electrical consumes and a lot of fuel-losses by the vaporized gas due to the rising of fuel temperature because the fuel pump of the fuel supply system rotates regularly regardless to the driving condition. In this paper, we designed the multi-step controller for controlling fuel pump to supply fuel according to RPM of each moment by measuring the real time RPM of the engine at ECU of the vehicle. Also, it can judge the existence or nonexistence of disorder by measuring the pressure of the fuel supply line, in case of abnormal state, it can supply the fuel intelligently by changing the mode to self-compensation mode.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.636-641
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• 2010

고성능 로켓엔진에 사용되는 다단연소싸이클의 주요 부품인 예연소기 개발 과정에서 브레이징 접합부를 모사하는 시편에 대한 강도 시험을 수행하고 유한 요소 해석 결과와 비교하였다. 용광로 브레이징되는 헤드의 산화제 분사기 및 진공 가압 브레이징되는 냉각채널 접합부를 모사할 수 있는 시편을 설계 및 제작하고 스트레인 게이지를 붙여 파단 시험을 수행하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.656-661
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• 2003

Modem reciprocating air compressors have tendency to a multi-stage W-type or V-type cylinder arrangement for the purpose of high outlet pressure, compactness and low vibration and noise. A valid counter weight calculation method using the complex expression is proposed for reducing the inertia forces of the compressor. Counter weight removes only 1st forward whirl component. Counter weight formulations are applied to the six various compressor structures which are (a) 1 cylinder single-throw crank shaft, (b) 2 cylinder single-throw crank shaft (c) 2 cylinder double-throw clank shaft, (d) 3 cylinder single-throw crank shaft, (e) 4 cylinder single-throw crank shaft and (f) 4 cylinder double-throw crank shaft. The improvement of performance is verified through available vibration test.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권2호
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• pp.85-91
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• 2002

A novel multi-section power divider configuration is Proposed to obtain wide-band frequency performance up to microwave frequency region. Design procedures for the proposed microwave broadband power divider are composed of a Planar multi-section three-Ports hybrid and a waveguide transformer design procedures. The multi∼section power divider is based on design theory of the optimum quarter- wave transformer Furthermore, in order to obtain the broadband isolation performance between the two adjacent output ports, the odd mode equivalent circuit should be matched by using the lossy element such as resistor. The derived design formula for calculating these odd mode∼matching elements is based on the singly terminated filter design theory. The waveguide transformer section is designed to suppress the propagation of the higher order modes such as waveguide modes due to employing the metallic electric wall. Simulation and experiment show excellent performance of multi section power divider.

• 소성∙가공
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• 제21권4호
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• pp.265-270
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• 2012

In this study, a process design method for the multi-pass shape drawing is proposed with consideration of the drawing stress. First, the shape drawing load was calculated to evaluate the shape drawing stress, and the intermediate die shape was determined by using an electric field analysis and the average reduction ratio. In order to evaluate whether material yielding occurs at the die exit, the drawing stress was determined by using the calculated shape drawing load. Finally, FE-analysis and shape drawing experiments were conducted to validate the design of the multi-pass shape drawing process. From the results of the FE-analysis and shape drawing experiments, it was possible to produce a sound shape drawn product with the designed process. The dimensional tolerances of the product were within the allowable tolerances.

• 한국정밀공학회지
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• 제7권2호
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• pp.95-104
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• 1990

This paper descirbes some research of Computer-aided Design of multi-stage cold forging die of rotationally symmetric parts produced by the press or former. An approach to the system is based on knowledge based system. Knowledges for tool design are extracted from the plasticity theory, handbooks, relevent references and empirical know-how of experts in cold forging companies. The deveoped system is composed of three main modules such as die design module, punch design module, tool elements design module which are sued independently or in all. Using this system, design parameters (types of dies, geometric shapes and dimensions of dies, types of punches, geometric shapes and dimensions of punches, geometric shapes and dimensions of tool elements) in each operation are determined and the output is generated in graphic form. The develpoed system, aids designer, provides powerful capability for designing dies, punches and tool elements.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.296-297
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• 2010

본 연구는 자전거의 속도를 이용하여 자동으로 기어변속을 하는 시스템 개발에 관한 연구이다. 본 논문은 자전거의 기어변속 메커니즘을 활용하여 기어 변속기를 개선함으로써 진행속도에 맞추어 자동으로 기어 변속을 수행하는 시스템의 설계 및 개발에 관하여 서술하였다. 상세하게는 뒷바퀴에 속도 측정장치를 설치하여 회전수에 따라 자전거의 진행하는 속도를 감지하며, 기존 자전거의 변속기에 개발된 전자제어장치를 탑재하여 운행자의 진행속도에 맞추어 자동변속을 구현한다.