• 제목/요약/키워드: Use of force

검색결과 2,228건 처리시간 0.046초

장대레일 철도 교량의 축력 영향인자 분석 (Influence Factors Affecting the Longitudinal Force of Continuous Welded Rail on Railroad Bridges)

  • 김경삼;한상윤;임남형;강영종
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(II)
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    • pp.385-390
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    • 2003
  • Recently, use of Continuous Welded rail(CWR) is increased for structural, economical reason but new problem is caused accordingly and phenomenon that give threat in traveling by ship stability of train is led. According as rail is prolonged, excessive relative displacement and longitudinal force can happen to rail by temperature change and external force. Specially, buckling or fracture of rail can happen in railroad bridges because relative displacement by bridge and properties of matter difference between rail grows and additional axial force happens to rail by behavior of bridge. According to several study, longitudinal force of rail in bridge is influenced with ballast resistance, elongation length, boundary condition, stiffness of framework. Non-linear behavior of ballast acts by the most important factor in interaction between rail and bridge. Therefore, must consider stiffness of bridge construction with non-linear characteristic of ballast and stiffness of base for accuracy with longitudinal force calculation and analyze. In this study, perform material non-linear analysis for longitudinal force of CWR and three dimensional buckling analysis to decide buckling force.

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모발의 나노 트라이볼러지 특성해명을 위한 원자현미경(Atomic Force Microscopy) 프로브의 개발 (A New Design of AFM Probe for Nanotribological Characterizations Measurement of Human Hair)

  • 권현규;고언위
    • 반도체디스플레이기술학회지
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    • 제14권4호
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    • pp.1-7
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    • 2015
  • People are always pursuing the aesthetic feeling relentlessly. But some people have such problems with their hairs like alopecia, cancer chemotherapy, burns, and scalp injury. So the synthetic hair has played a very important role to make up for these deficiencies. But long term use can lead to adverse reactions or uncomfortable feeling. This is primarily caused by its properties differ with human hair. In particular, nanotribological characterizations (roughness, friction force and adhesive force) of synthetic hair surface are dissatisfy with the needs of normal hairs. This paper presents the experiments on nanotribological characterizations measurements of human hairs (coloring hair, permed hair and common hair) in shampooing condition or without shampooing condition. Using atomic force microscopy (AFM) to find out a range of synthetic hair nanotribological characterizations which can correspond with natural hair. The measurements of nanotribological characterizations focus on surface roughness, friction force and adhesive force, and a new design of AFM probe was used for measuring the nanotribological characterizations.

슬라이딩 모드 제어기를 이용한 밀링공정의 절삭력 제어 (Cutting Force Regulation in Milling Process Using Sliding Mode Control)

  • 이상조;이용석;고정한
    • 대한기계학회논문집A
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    • 제25권8호
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    • pp.1173-1182
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    • 2001
  • Recent noticeable advances of CNC machine tools have considerably improved productivity and precision in manufacturing processes. However, in the respect of productivity some defects still remain because selection of machining conditions entirely depends on the experiences of programmers. Usually, machining conditions such as feed rate and spindle speed have been selected conservatively by considering the worst cases, and it has brought the loss of machining efficiency. Thus, the improvement of cutting force controller has been done to regulate cutting force constantly and to maximize feedrate simultaneously in case that machining conditions change variously. In this study, sliding mode control with boundary layer is applied to milling process for cutting force regulation and in a commercial CNC machining center data transfer between PC and PMC (programmable machine controller) of CNC machine is done using a standard interface method. And in the cutting force measurement, an indirect cutting force measuring system using current signal of AC servo is adopted in order not to use high-priced equipment like tool dynamometer. The purpose of this study is to maximize the productivity in milling process, thus its results can be applied to cases such as rough cutting process.

Module Phase Set Shift를 이용한 선형 동기 전동기의 추력 리플 저감 설계 (Design of Linear Synchronous Motor for Thrust Force Ripple Reduction using Module Phase Set Shift)

  • 유광현;이형우;조수연;오세영;함상환;임종빈;안한웅;이주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2011년도 제42회 하계학술대회
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    • pp.848-849
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    • 2011
  • Rotating machines are using gears to change the rotary motion into the linear motion, on the other hand, linear motors have a accurate position control and excellent dynamic characteristics because of generating a thrust force directly. But the important problem, one of the linear motor is a high thrust force ripple. Thrust force ripple has a bad effect on the position accuracy and the dynamic characteristics, so it is necessary to reduce the thrust force ripple. Cogging is one of the cause that affect thrust force ripple. Cogging has some connection with the GCD between pole pitch and teeth pitch It is proposed method to reduce a thrust ripple of the linear motor that chamfering, skew, and so on. In this paper, the module phase set shift(MPSS) is used to reduce a thrust force ripple that has a similar effect to skew. And propose a method that reduce a thrust force ripple more by use of chamfering.

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횡방향 영구지반변형 발생시 관$\cdot$지반 상호작용력의 산정에 관한 연구 (Study on The Estimation of Pipeline\ulcornerSoil Interaction Force during Transverse Permanent Ground Deformation)

  • 김태욱;임윤묵;김문겸;장성희
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2003년도 춘계 학술발표회논문집
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    • pp.165-173
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    • 2003
  • In this study, the applicability of currently used pipeline.soil interaction force and previously proposed analytical relationship for the response analysis of buried pipeline subjected to transverse permanent ground deformation (PGD) due to liquefaction is evaluated. Based on meaningful contemplation, the improvement of interaction force and proposition of analytical relationship is made. Improved interaction force includes various patterns of PGD or spatial distributions of interaction force caused by the decrease of soil stiffness, and proposed relationship based on improved formula is applicable without regard to the width of PGD. Through the comparison of numerical results by use of commercial FEM program, the rational applicability of proposed relationship is objectively confirmed.

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전자기력을 이용한 3 자유도 정밀 위치결정기구에 관한 연구 (A Study on Three Degree-of-Freedom Fine Positioning Device Based on Electromagnetic Force)

  • 이기하;최기봉;박기환;김수현;곽윤근
    • 한국정밀공학회지
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    • 제15권11호
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    • pp.199-207
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    • 1998
  • This paper presents the design and the control of three degree-of-freedom(DOF) fine positioning device based on an electro-magnetic force. The device is designed by use of a magnetic circuit theory and it is capable of fine motion due to the electro-magnetic force. The device consists of permanent magnets, yokes and coils. The magnetic fluxes generated from the permanent magnets constitute magnetic paths through steel, whereas the coils are arranged into the gap between two surfaces of the yokes. Therefore, by supplying current to the coils, the coils are capable of some motions due to Lorentz forces. For the optimal design of the actuating system, the system parameters are defined and investigated under the given constraints. From the system modeling in small displacement, three decoupled equations of motion are obtained. To get better performance of the system, a PID controller is implemented. Experimental results are presented in terms of time response and accuracy.

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선삭가공에서 절삭분력을 이용한 공구의 마멸검출에 관한 연구 (A Study on the Detection of Tool Wear by Use of Cutting Force Component in Orthogonal Cutting)

  • 김기중;현청남
    • 한국정밀공학회지
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    • 제3권4호
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    • pp.30-42
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    • 1986
  • On the analysis of cutting mechanics in orthogonal cutting, each cutting force component can be predicted. By adding the flank face wear term to the prediction equation for cutting force components, complete equations are obtained. Using these equations, it is shown that cutting force components are increased linearly as flank face wear land is developed, in theory and experiment. By making non-dimensional term ie. Fv/Fc, the width of variation of output signal Fv/Fc is greately decreased compared with each cutting force component as cutting condition is varied. Among these conditions, the variation of chip width in the range of more than 1mm and that of cutting velocity have little effect on the output signal Fv/Fc, that of Flank face werr land can be detected without difficulty.

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스트럿 타이 모델개발을 위한 시각화 도구 개발 (Development of Visual Tools for Strut-Tie Model)

  • 김남희;홍성걸;여득현
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2008년도 정기 학술대회
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    • pp.596-601
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    • 2008
  • This paper presents how to develop visual design tools for construction of strut-and-tie models(S (STM). STMs have shown internal force flows for dimensioning and proportioning of D-regions of reinforced concrete structures. In order to select an appropriate strut-and-tie model some interactive graphic tools are necessary to help designers compare alternatives by changing the geometry of initial STM. This study proposes to use force polygons representing the equilibrium state of STM. The change of STM dynamically shows change of force magnitudes by force polygon. Once the geometry of STM is determined the detailing design process is required in the next procedure.

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공구마멸에 따른 절삭력의 RMS특성 (The RMS Characteristics of Cutting Force Depending on the Tool Wear)

  • 권용기;오석형;김동현
    • 대한기계학회논문집
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    • 제17권9호
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    • pp.2214-2222
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    • 1993
  • With the use of the NC machine tool, the unmanned production system has been growing recently in the manufacturing field. This there are problems with monitoring adequate tool fracture during the cutting process efficiently. This study was planned and carried out to discover a way of monitoring tool condition in NO-LINE systems during the cutting process. The acquisition of data in cutting force and tool wear has been made in the section examined, to extract the RMS value of the cutting force as specific factors in the cutting process. The fluctuation of the RMS characteristics. From the results, it has been shown that the fluctuation of the RMS values for the cutting force has a close relation to flank wear.

다축 힘/모멘트센서의 불확도평가 및 응용에 관한 연구 (Uncertainty Evaluation of a Multi-axis Force/Moment Sensor and Its Application)

  • 김갑순
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.177-180
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    • 2001
  • This paper describes the calibration method and the evaluation method of relative expanded uncertainty for a multi-axis force/moment sensor. This sensor should be calibrated to be use in the industry. Now, the confidence of the calibration result is expressed with interference error. But it is no inaccurate, because an interference error, besides, a reproducibility error of the sensor, a error of this six-axis force/moment sensor calibrator, and so on. Thus, in order to accurately evaluate the relative expanded uncertainty of it, the concept of the uncertainty should be induced, and these errors must be contained in the relative expanded uncertainty. In this paper, the calibration method is exhibited and the evaluation method of the relative expanded uncertainty is also exhibited. And, a six-axis force/moment sensor was calibrated and the relative expanded uncertainty was evaluated.

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