• Title/Summary/Keyword: Counter Force

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Longitudinal Force Analysis of CWR on High Speed Rail Bridges (고속철도 교량상의 장대레일 축력 해석)

  • 이지하;양신추;이종득
    • Proceedings of the KSR Conference
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    • 1998.05a
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    • pp.556-563
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    • 1998
  • Railway bridges have a significant effect on the stress and displacement of continuous welded rail(CWR). Longitudinal compression force at high temperature, combined breaking or acceleration forces can introduce track buckling. On the other hand, longitudinal tensile forces, associated with low temperatures, in combination with breaking forces may break rail. Therefore, it is very important to work out thorough counter measures for those problems, specially in high speed rail which high safety is required. The exact evaluation of longitudinal force of rail has the key to the solution. The main aim of the present paper is to examine whether the longitudinal force of CWR's on Kyung-Bu-HSR satisfy the criteria to be fulfilled in the design of railway bridge. The analyses are carried out by using "CWRAP" program which was developed by our research group. The ballast resistance and breaking force effects on the longitudinal force of CWR are investigated.

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Crank Angles Design to Reduce the Excitation Forces in 4-stroke Diesel Engine (4행정 기관의 기진력 감소를 위한 크랭크 각 설계)

  • 서영수;박정근;정의봉
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.11a
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    • pp.108-114
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    • 2000
  • The excitation forces from the periodical firing pressure in cylinder and the rotating crank mechanism cause lots of vibration problems in diesel engine. In this paper, the theoretical formulas for excitation forces are introduced and computational program for the optimization of crank angle is also developed to reduce the free moments in diesel engine. The computational results of 4-stroke in-line engine are applied to verify the reliability of the program.

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Effects of Blankholding force and Vee-ring on the Blanking characteristics in Fine-Blanking Die (정밀전단금형에서 판누름압력과 삼각돌기가 전단특성에 미치는 영향)

  • 이종구
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.5 no.3
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    • pp.50-57
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    • 1996
  • This study was performed the blankholding force and Vee-ring effects on blanking characteristics, such as maximum blanking force, burnish, dish-shape, hardness. etc. in fine-blanking die by the experimental method. Two types of aluminum (Al.1050-O, Al, 5052-H) Such as annealed and unannealed materials were used for the experiment. In order to get a hydrostatic pressure effect, the clearance was set to 0.5% of the thickness of strip, and the counter punch and stripper plate with Vee-ring was set-up. While this experiment was carry8ing out, the average blanking velocity was constant (37.5mm/sec). As a result of this study, we got a good surface roughness and a dimensions, the good squareness and the reduction of dish-shape could be obtained, and also the additional results obtained were such that the hardness of shear plane was increased and the maximum blanking force was reduce in the condition of Vee-ring height of 1.0~1.5mm, and blankholding force of 1200kg.

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Effects of Deposition Method of Thermally Decomposed Platinum Counter Electrodes on the Performance of Dye-Sensitized Solar Cells (염료 감응형 태양전지 효율에 미치는 백금 상대 전극 제조공정의 영향)

  • SEO, HYUN WOO;BAEK, HYUN DUK;KIM, DONG MIN
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.1
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    • pp.63-69
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    • 2017
  • In this work, two different platinum (Pt) counter electrodes have been prepared by spin coating a Pt solution and screen printing a Pt paste on fluorine doped tin oxide (FTO) glass substrate followed by sintering at $380^{\circ}C$ for 30 min. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) analyses of the Pt electrodes showed that the spin coated electrode was catalytically more active than the screen printed electrode. The above result agrees well with the surface morphology of the electrodes studied by atomic force microscopy (AFM) and the photovoltaic performance of the dye-sensitized solar cells (DSSCs) fabricated with the Pt electrodes. Moreover, calculation of current density-voltage (j-V) curves according to diode model with the parameters obtained from the experimental j-V curves and the EIS data of the DSSCs provided a quantitative insight about how the catalytic activity of the counter electrodes affected the photovoltaic performance of the cells. Even though the experimental situations involved in this work are trivial, the method of analyses outlined here gives a strong insight about how the catalytic activity of a counter electrode affects the photovoltaic performance of a DSSC. This work, also, demonstrates how the photovoltaic performance of DSSCs can be improved by tuning the performance of counter electrode materials.

A Study on the Effect of Wind Force and Moment Acting on T/S HANNARA (실습선 한나라호에 작용하는 풍압력 및 풍압모우멘트 영향에 관한 연구)

  • Lee, Yun-Sok
    • Journal of Navigation and Port Research
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    • v.31 no.3 s.119
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    • pp.223-228
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    • 2007
  • In recent trends of the enlargement and specialization, container ship, LNCG, PCC and passenger ship which have relatively large hull and superstructure above the water line, are already being operated in the world It is very important information for the safety operation of these vessels to estimate the ship's performance under the specific wind condition while berthing, unberthing or low-speed sailing. In this paper, the effect of wind force and moment acting on the training ship HANNARA is investigated by using the numerical calculations. The results of drift angle and counter rudder angle with the relative wind direction and force, the critical wind velocity with the ratio of wind velocity and ship's speed and maximum heeling angle with the wind velocity are shown The presented results can be applied directly to T/S HANNARA in berthing maneuver and avoiding typhoons, and utilized as an educational materials.

A study on the lift-generation mechanism of an insect with tandem wing configuration (두 쌍의 날개를 가지는 곤충의 양력 발생 메커니즘에 대한 연구)

  • Kweon, Ji-Hoon;Choi, Hae-Cheon;Chang, Jo-Won
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.389-394
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    • 2007
  • Numerical simulations are conducted to investigate the mechanism for force generation of an insect with tandem wing configuration. Various stroke amplitudes, stroke plane angles and phase difference between the fore- and hind-wings are considered. The Reynolds number is 150 based on the chord length and maximum translation velocity of the wing. When an insect requires high lift such as takeoff, it flaps its wings in parallel at a lower stroke plane angle and a bigger stroke amplitude than those in the hovering. With wings in counter-stroke, the lift fluctuations decrease, and moreover mean lift force decreases. Interactions among the fore-wing, hind-wing and vortices are examined to explain the force variations

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An Experimental Study on Balancing Stabilization of a Service Robot by Using Sliding Mechanism (슬라이딩 메커니즘을 이용한 서비스 로봇의 밸런싱 자세의 안정화에 대한 실험연구)

  • Lee, Seungjun;Jung, Seul
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.3
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    • pp.233-239
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    • 2013
  • This paper presents the analysis and control of the position of the COG (Center of Gravity) for a two-wheel balancing robot. The two-wheel balancing robot is required to maintain balance by driving two wheels only. Since the robot is not exactly symmetrical and its dynamics is changing with respect to moving parts, robust balancing control is difficult. Balancing performance becomes difficult when two arms hold a heavy object since the center of gravity is shifted out of the wheel axis. Novel design of a sliding waist mechanism allows the robot to react against the shift of the COG by moving the whole upper body to compensate for the imbalance of the mass as a counter balancer. To relocate the COG position accurately, the COG is analyzed by force data measured from two force sensors. Then the sliding COG mechanism is utilized to control the sliding waist position. Experimental studies are conducted to confirm the proposed design and method.

Agitation Performance Study of 2-shafts Agitator Rotate Directio in the Mud Tank Based on CFD (CFD를 이용한 머드 탱크 2축 교반기의 회전방향에 따른 교반성능 연구)

  • Im, Hyo-Nam;Lee, Hee-Woong;Lee, In-Su;Choi, Jae-Woong
    • Journal of Ocean Engineering and Technology
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    • v.28 no.2
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    • pp.111-118
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    • 2014
  • In drilling process of oil wells, the drilling fluid such as mud keeps the drill bit cool and clean during drilling, with suspending drill cuttings and lubricating a drill bit. In this paper, a commercial CFD package(ANSYS Fluent 15.0) was used to solve the hydrodynamic force and evaluate mud mixing time in the mud mixing tank on offshore drilling platforms. Prediction of power consumption in co-rotating and counter-rotating models has been compared with results of Nagata's correlation equation. This research shows the hydrodynamic effect inside the two phase mud mixing tank according to rotating directions(co-rotating and counter-rotating). These results, we can conclude that the co-rotating direction of the two shafts with mixing blade in the mud mixing tank can be a preferable in power consumption and mixing time reduction.

Development of High Precision Plate Holder in Automotive Seat Recliner by Mechanical Press(I) : Application of FCF Method (기계식 프레스에 의한 자동차 시트 리클라이너의 고정밀 플레이트 홀더 개발(I) : FCF 공법 적용)

  • Kim, Byung-Min;Choi, Hong-Seok;Chang, Myung-Jin;Bae, Jae-Ho;Lee, Seon-Bong;Ko, Dae-Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.7
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    • pp.55-63
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    • 2008
  • Fine blanking is a process of press shearing which makes it possible to produce the thick sheet metal of the finished surface and the close dimensional accuracy over the whole material thickness in the single blanking operation. In this paper, a plate holder of automotive seat recliner is manufactured by FCF(Flow Control Forming) method using the conventional mechanical press instead of the fine blanking press. Main processes for manufacturing of the plate holder by FCF method are embossing, half blanking and trimming processes. Optimal clearance, stripper force and counter force to increase the dimensional accuracy of the plate holder have been investigated by FE-analysis. As a result of FE-analysis, the clearance for both embossing and half blanking processes was -2%t and the forces of stripper and counter were 25ton and 15ton, respectively. After manufacturing the plate holder by FCF method, the measured dimensional characteristics have been compared with the required specifications as the final product. Although the dimensional accuracy of the plate holder manufactured by FCF method was a little inferior to that by fine blanking process, it was satisfactory in a general sense.

Heat Source Identification Technique of Aircraft and Flare using 2-color Detectable Infrared Sensors (복수 대역 감지 적외선 센서를 이용한 항공기와 플레어의 열원 식별 기술)

  • Lee, Dong-Si;Lee, Kee-Keun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.7
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    • pp.1031-1039
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    • 2015
  • Present guided missiles are equipped with infrared seeker to find the infrared sources radiating from target plane and then chase, which results in an improvement of the hitting success rate when in striking target objects. To interrupt the chases from the guided missile, the target plane spreads the flare, avoiding the missile attracts. Our research is to develop a 2-color infrared identification technique to discern the flare and real thermal source from target plane. Considering flare radiation properties and EM atmosphere transmission rates, two channels were selected, in which main channel (MC) was in a range of 3.7 μm∼4.8 μm and auxiliary channel (AC) in 1.7 μm∼2.3 μm. A 2500K heat source was used for an artificial flare source, while a 570K heat source was utilized for airplane infrared source in experimental testing. Two infrared sensors detectable only at each chanel were employed in order to measure the voltage ratio from two channels, identifying the flare and real target plane via comparison the voltage ratio. Several experimental conditions were imported in order to prove that our proposed 2-color infrared identification technique is very efficient way to discern heat sources from aircraft and flare, demonstrating that our proposed technique is very promising means for our force’s InfraRed Counter Counter Measure (IRCCM) in order to countermeasure opposite force’s InfraRed Counter Measures (IRCM).