• Title/Summary/Keyword: Load characteristics design

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A Study on the Stratum Thickness Arrangement and Roof Bolt Support Design using Robust Design (강건설계를 이용한 층서두께 배열과 루프볼트 지보설계에 관한 연구)

  • Jang, Myoung Hwan
    • Tunnel and Underground Space
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    • v.28 no.2
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    • pp.142-155
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    • 2018
  • The ${\bigcirc}{\bigcirc}$ mine has irregularly developed stratum around the ore body. The purpose of this study is to array irregular stratum thickness systematically for effective roof bolting and to implement a supporting system corresponding to it. The number of 81 cases combined with stratum thicknesses was limited to 9 cases by robust design. For each case, the load height which can act as a roof load was determined by the characteristics of stratum and RMR. The load range due to the load height is calculated assuming block shaped and arch shape. The support load of the roof bolt was considered as the average load of the two methods. Numerical analysis results of the support design showed that the cable bolt was more effective for the roof supporting fully grouted than the anchoring type. As a result of the construction, it was possible to control the roof, but all of the roof was gradually sinking downward due to the deformation of the side wall of the mine tunnel.

Low-Load/Low-Eccentricity Performance Improvement Designs for Hydro Power Application of Cylindrical Turbine Guide Bearings - Introduction of Pad Leading-Edge Tapers (수력 원통형 터빈 가이드 베어링의 저부하/저편심 성능향상 설계 - 패드 선단 테이퍼의 도입)

  • Lee, An Sung;Jang, Sun-Yong
    • Tribology and Lubricants
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    • v.33 no.2
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    • pp.65-70
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    • 2017
  • In vertical hydro/hydraulic power turbine-generator applications, traditionally, cylindrical turbine guide bearings (TGBs) are widely used to provide turbine runner shafts with smooth rotation guides and supports. All existing cylindrical TGBs with simple plain pads have drawbacks such as having no pressure generation and film stiffness at the no-load condition and in addition, at the low-load/low-eccentricity condition, having very low film stiffness values and lacking design credibility in the stiffness values themselves. In this paper, in order to fundamentally improve the low-load/low-eccentricity performance of conventional cylindrical TGBs and thus enhance their design-application availability and usefulness, we propose to introduce a rotation-directional leading-edge taper to each partitioned pad, i.e., a pad leading-edge taper. We perform a design analysis of lubrication performance on $4-Pad{\times}4-Row$ cylindrical TGBs to verify an engineering/technical usefulness of the proposed pad leading-edge taper. Analysis results show that by introducing the leading-edge taper to each pad of the cylindrical TGB one can expect a constant high average direct stiffness with a high degree of design credibility, regardless of load value, even at the low-load/low-eccentricity condition and also control the average direct stiffness value by exploring the taper height as a design parameter. Therefore, we conclude that the proposed pad leading-edge tapers are greatly effective in more accurately predicting and controlling rotordynamic characteristics of vertical hydro-power turbine-generator rotor-bearing systems to which cylindrical TGBs are applied.

The Design and Computer Simulation of the Rotating type of Superconducting Power Supply (회전형 초전도 Power Supply의 설계 및 컴퓨터 시뮬레이션)

  • Bae, Joon-Han;Oh, Yun-Sang;Song, Myung-Kon;Ji, Chang-Seop;Kim, Ho-Min;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.187-189
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    • 1996
  • In this paper, we have studied several operating characteristics through the analysis of system. First, we have constituted the equivalent circuit to analyze the operating characteristics of rotating type of superconducting power supply and have induced the optimal design parameter. The computer simulation have showed that the pumping current is in proportion to the area of the pole and rotor speed, and is inverse proportion to the magnitude of load. Therefore, to acquire maximum pumping current we must design the power supply system with maximum area of the pole and minimum inductance of the load.

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Wear Loss Presumption of Motorcycle Disk Brake Using Design of Experiment (실험계획법에 의한 이륜자동차 브레이크 디스크의 마멸량 예측)

  • Park, Gyu-Jung;Park, Heung-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.4
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    • pp.15-21
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    • 2007
  • The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a disk-on-pad type friction tester. Such parameters conditions have an effect on the frictional factor such as number of ventilated disk hole, applied load, sliding speed, and sliding distance. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 4 elements were investigated for an optimal condition for the best motorcycle break system employing regression analysis method. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.

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Probabilistic Analysis of Lifetime Extreme Live Loads in Office Buildings (사무실의 사용기간 최대 적재하중에 대한 확률론적 분석)

  • 김상효;조형근;배규웅;박흥석
    • Computational Structural Engineering
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    • v.3 no.1
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    • pp.109-116
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    • 1990
  • Live load data in domestic office buildings have been collected in a systematic manner. Based on surveyed data, equivalent uniformly distributed load intensities, which produce the same load effect as the actual spatially varying, live load, have been obtained for various structural members (such as slab, beam, column, etc. ). Influence surface method has been employed to compute load effects under real live load, including beam moment, slab moment as well as axial force in column. The results have been examined to find probabilistic characteristics and relationship between influence area and load intensity (or coefficient of variation). The results were also compared with other survey results and found to be reasonable. Based on the probabilistic load models obtained, the lifetime extreme values have been analyzed and compared with current design loads. Tentative equations applicable to decide more rational design loads are also suggested as functions of influence area.

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A study of the actuator control characteristics of underwater vehicle (수중운동체의 구동장치부 제어특성에 관한 연구)

  • 이정규;백운보;김중완;이만형
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.371-375
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    • 1991
  • The purpose of this paper is the design of a controller of electric actuator for high speed underwater vehicle which is robust against hydro load torque. For this purpose, we design the controller of PD & VSC control schemes. Under proper assumption of the hydro load torque, the tracking performances of these schemes are analyzed through the computer simulation, and the results are presented.

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A Study on the Forming Characteristics of Radial-Forward Extrusion Process (레이디얼-전방압출 공정의 성형특성에 관한 연구)

  • 황승규;이호용;황병복
    • Transactions of Materials Processing
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    • v.11 no.1
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    • pp.84-89
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    • 2002
  • This study is concerned with the analysis of the forming characteristics of radial-forward extrusion. Angle between radial and forward extrusion, gap height, and friction factor are considered as important design factors to affect forming characteristics in radial-forward extrusion. The rigid-plastic finite element method is adopted to analyze the effects of design factors on forming loads. The incremental rates of loads are nearly constant except the deformation zone from radial to forward extrusion. The smaller angle induces lesser force increment, therefore forming load increases as the angle increases. Maximum load also increases as gap-height decreases and friction factor increases.

Overload Characteristics Analysis of Phase Controlled Rectifier for Plasma Application (플라즈마 응용을 위한 위상제어 정류기의 과부하 특성해석)

  • 노의철;정규범;김용진;최정완
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1996.11a
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    • pp.104-108
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    • 1996
  • This paper deals with the design considerations and characteristics analysis of a SCR rectifier in pulsed over load operation. The Pulse repetition rate is one every 150 seconds and each current pulse width is 10 seconds. Therefore the characteristics of the transformer and SCR rectifier which consist the pulsed DC power supply are different from those of the conventional AC/DC power converters having continuous load. The variations of the DC output voltage drop, PF and THD versus the %Z of the transformer is analyzed through simulations and the experimental results thought to be useful in design high power pulsed DC power suppler.

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Bending Collapse Characteristics of Hat Section Beam Filled with Structural Foam (폼 충진 모자단면 빔의 굽힘붕괴 특성)

  • Lee, Il-Seok;Kang, Sung-Jong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.2
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    • pp.92-99
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    • 2006
  • Design capability for high safety vehicle with light weight is crucial to enhancing competitive power in vehicle market. The structural foam can contribute to restraining section distortion in body members undergoing bending collapse at vehicle crash. In this study, first, the validation of analysis model including structural foam model for simulating fracture behavior was discussed, and the bending collapse characteristics of five representative section types were analyzed and compared. Next, with changing the laminate foam shape, load carrying capability and absorbed energy were observed. The results suggests a design strategy of body members filled with laminate foam, leading to effectively elevating bending collapse characteristics with weight increase in the minimum.

A study on the Design on the Tubular Drive Shaft (중공 드라이브 샤프트의 설계에 관한 연구)

  • Kim, Woo-Kang;Go, Jun-Bin;Kim, Hong-Bae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.3
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    • pp.7-12
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    • 2009
  • This study aims to find the friction welding and induction harden conditions, which are obtained by welding conditions, and the friction welding characteristics and induction harden conditions of tubular shaft were investigated with respect to low load test, high load test. Friction welding and induction harden machine have been widely used in manufacturing reflects of metal. The material of solid and tubular shaft selected that is used for parts of automobile steel. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of friction welding conditions makes good and the condition of friction and get the tubular condition. The purpose of this study is to find fatigue test condition and induction harden characteristics design for tubular shaft.

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