• 제목/요약/키워드: transverse forces

검색결과 174건 처리시간 0.026초

철근콘크리트 원형기둥의 전단철근 유효단면적 평가 (Evaluation of Effective Section Area of Shear Steel in Reinforced Concrete Circular Columns)

  • 김장훈
    • 콘크리트학회논문집
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    • 제11권3호
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    • pp.81-88
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    • 1999
  • 원형 철근콘크리트 기둥의 전단보강철근에 의한 저항강도의 평가를 위하여 전단에 의한 사인장 균열 면을 관통하는 원형 전단보강철근의 횡하중 작용방향의 평균 인장력을 산정하였다 이를 위하여 원형 전단보강철근이 이루는 원의 중심선간 직경, 수직 배근간격 및 기둥축 방향에 대한 사인장 균열면을 고려하였으며, 이들 변수들을 이용하여 원형 전단보강철근의 유효단면적을 계산하는 공식을 제안하였다. 연구결과, 원형 전단보강철근의 유효단면적 계산을 위하여 근 10년 간 사용되어 온 상수 계수가 모든 경우에 일률적으로 사용될 수 없음을 보여주고 있다 즉, 기존에 사용되는 원형전단철근 유효단면적은 기둥의 전단저항강도의 계산에 있어서, 전단철근의 배근간격이 비교적 넓은 비내지진 지역에서는 안전 측의 예측을 하게 되어 구조물의 안전상 큰 문제가 없지만, 배근간격이 촘촘하거나 원통형강관을 사용하게 되는 내진 지역에서는 기둥의 전단저항강도를 실제보다 20% 정도 과하게 예측하여 구조물의 안전에 좋지 않은 결과를 낳을 수도 있다.

有限要素法에 의한 推進軸系의 광振動計算에 관한 硏究 (Calculation of Transverse Vibration of Ship`s Propulsion Shaftings by the Finite Element Method)

  • 전효중;김희철
    • Journal of Advanced Marine Engineering and Technology
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    • 제3권1호
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    • pp.2-18
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    • 1979
  • Due to increasing ship dimensions and installed propulsive power, resonance frequencies of the propeller shaft system tend to decrease and they can appear in some cases within the operating range of the shaft revolution. For calculation of transverse shaft vibrations, various methods have been proposed but as they are mainly for approximate calculation, no contented results are obtained. For fairly accurate estimation of resonance frequencies in the design stage, one can use transfer matrix method of the finite element method and former is rather prefered in ordinary cases. In this study, the finite element method which is utilized for calculation of the propulsion shaft alignment, is introduced to derive the vibration equation of the ship's propulsion shaftings. The digital computer program is developed to solve the above equation, and the details of preparing the input data are described. The method presented in the underlying report was applied to the shafting of ship which has a lignumvitae bearing to verify its reliability and the results of calculation and those of the measurements on rotating shaft show a good agreement. Calculating methods of exciting of forces and damping forces are also discussed for future work.

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횡방향 타입 로드헤더의 터널면 절삭공정 고찰 (Operating Process of Transverse Type Roadheader for Tunnel Excavation in Korea)

  • 조민기;조정우;김문규;정재훈;최성현
    • 터널과지하공간
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    • 제33권1호
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    • pp.1-9
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    • 2023
  • 국내 터널현장에 도입된 드럼타입 로드헤더의 작동방식 및 현장 운영 사례를 소개하였다. 축방향 타입과 횡방향 타입의 작동에 따른 절삭력과 반력의 방향을 분석하였다. 텔레스코픽 실린더의 사용 유무에 따른 터널면 형성의 차이점을 설명하였다. 실린더를 사용하지 않는 경우, 오목한 작은 반경의 터널면이 형성되어 터널면을 좌우로 구분하여 굴진하는 것으로 조사되었다. 그리고 국내 경암 터널 굴착환경에서 썸핑과 쉬어링 공정의 적용방안을 도해적으로 설명하고, 굴착공정에 대한 기존 설명자료를 일부 보완하였다.

선박 주기관에 의한 횡진동 저감을 위한 구조보강 연구 (A Study on the Structural Reinforcement for the Reduction of Transverse Vibration by Ship's Main Engine)

  • 신상훈;고대은;임홍일
    • 한국산학기술학회논문지
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    • 제20권8호
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    • pp.279-285
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    • 2019
  • 다양한 형태의 선체 진동 중, 선체 선미 및 거주구의 횡방향 진동은 대부분 주기관의 횡기진력으로부터 유발되는데, 주기관과 연결된 주변 구조물과의 공진이 발생 할 수 있으므로 공진회피 설계가 반드시 필요하다. 공진 회피를 위한 가진 주파수는 주기관 및 프로펠러 사양으로부터 추정 가능하나, 기관실 주변 구조물의 고유 진동수는 형상의 다양성 등에 의해 추정이 쉽지 않고 경험을 위주로 한 방진 설계가 수행되고 있는 현실이며, 이로 인해 시운전 중에 발생하는 진동 문제는 공정지연, 현장 인력의 과다 투입 및 설계의 반복 수행 등 많은 문제점이 발생하고 있다. 본 연구에서는8,600TEU급 컨테이너선을 대상으로 유연한 설계를 위해 선체 구조배치의 변경 없이 주기관만 12기통에서 10기통으로 변경하는 경우에 대해 주기관 횡진동에 의한 공진 문제를 다루었다. 연구 결과로서, 주기관 횡기진력과 기관실 주변 구조와의 공진 회피를 위한 효율적인 구조보강 설계지침을 제시하였으며, 설계 현장의 실제적인 방진설계 지침으로 활용이 기대된다.

자동차 헤드램프 내의 에이밍 볼트의 풀림 해석 및 실험 (Analysis of Self Loosening of Aiming Bolts in Vehicle Head Lamp)

  • 문지승;백홍;박상신;박종명
    • Tribology and Lubricants
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    • 제35권1호
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    • pp.65-70
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    • 2019
  • Self-loosening of bolts owing to external forces occurs in several machines that are clamped by bolts and nuts. This study focuses on the self-loosening of the aiming bolt of the head lamp in a vehicle. It is important to prevent the aiming bolt from self-loosening as it has a decisive effect on the angle of the head lamp. A nut clamped with a bolt, known as a retainer, is made of plastic and has a partial screw thread. In addition, a transverse load has a considerable impact on the self-loosening of a bolt. We concentrate on the self-loosening of a bolt by a transverse load. The aim of this study is to define the limits of the external force that loosen the bolt. Based on the above conditions, we derive a theoretical equation and develop a numerical analysis program that can calculate the limiting forces for self-loosening. To verify the developed program, we design a test device that can measure the self-loosening by applying sliding forces to the aiming bolt. Using this method, we can draw the following conclusions. First, the developed testing device is suitable to prove the theory for calculating the self-loosening force. Second, the equation confirms the relationship of bolt self-loosening between resistance torque and shear force. Finally, the equation obtains the minimum value of the resistance torque required to decrease the change in the angle of the head lamp, thereby improving the possibility of increasing the stability of the head lamp.

Estimation of local ice load by analyzing shear strain data from the IBRV ARAON's 2016 Arctic voyage

  • Jeon, Mincheul;Choi, Kyungsik;Min, Jung Ki;Ha, Jung Seok
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제10권3호
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    • pp.421-425
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    • 2018
  • The icebreaking research vessel ARAON performed ice field tests during her 2016 Arctic voyage. The ship is subjected to ice loads through ice-ship interaction processes. Local ice load acting on ARAON's bow section was measured by using stain gauges installed on the inner hull plates and transverse frames of bow section. In this paper the local ice loads at transverse frames estimated from shear strain data were compared to ice loads from hull plate pressures by using the influence coefficient method. In addition to the analysis of local ice loads, the characteristics of peak ice loads with the ship speed is also discussed. It is recommended that the local ice loads estimated by calculating shear forces acting on transverse frames may be useful in estimating local ice loads on the hull of ship.

회전형 이상 횡자속형 전동기에서 발생하는 자기력 및 토크 해석 (Analysis of the Magnetic Force and Torque of a Rotatory Two-phase Transverse Flux Machine)

  • 박남기;장정환;장건희
    • 한국소음진동공학회논문집
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    • 제17권1호
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    • pp.33-40
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    • 2007
  • Rotatory two-phase transverse flux machine(TFM) is a relatively new type of motor with high power density, high torque, and low speed in comparison to conventional electrical motors. However, it has some shortcomings,.i.e. complex construction and high possibility of the magnetically induced nitration due to its inherent structure. This Paper investigates the characteristics of the magnetic force and the torque in the rotatory two-phase TFM by using the 3-D finite element method and the spectral analysis. This research shows that the average torque decreases and that the torque ripple increases as the phase delay increases. It also shows that the unbalanced magnetic force is one of the dominant excitation forces in this machine. And it proposes a new topology of rotatory two-phase TFM to eliminate the unbalanced magnetic force.

선체 횡단면의 전단흐름 계산 프로그램 개발 (Development of Shear Flow Calculation Program for Ship Hull Transverse Section)

  • 노인식;이정렬;우정재;오영택
    • 대한조선학회논문집
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    • 제53권3호
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    • pp.188-194
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    • 2016
  • Accurate estimation of shear flows in thin-walled beam section is the key issue to evaluate shear stress distribution of ship hull transverse section under the shear forces acting on hull girder. It is regarded that the method using the warping functions obtained by finite element formulation is the state of the art of this field. Recently, however, IACS took effect the new version of CSR in which direct calculation process of shear flow was suggested. In the direct calculation process, shear flow of ship hull section can be obtained by the addition of determinate and indeterminate shear flows calculated respectively. So, in this paper, the shear flow evaluation codes based on the process proposed by IACS CSR and warping function based method were developed respectively. The calculated results of shear flows for the several examples of ship sections were compared with each other and considered in detail.

공극력의 능동적 보상을 통한 횡자속 선형 유도 구동기의 추력과 부상력의 비연성화 (Decoupling of Thrust Force and Levitation Force of Transverse Flux Linear Induction Motor by the Active Compensation of Magnetic force across the Air-Gap)

  • 정광석;백윤수
    • 한국정밀공학회지
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    • 제21권11호
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    • pp.91-98
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    • 2004
  • TFLIM(Transverse Flux Linear Induction Motor), making its closed magnetic path with the direction of the traveling field orthogonal, had been developed to decrease an edge effect of the general induction motor. To control the levitation force and the thrust force on the secondary part of TFLIM independently, the various methodologies have been presented. When we try to achieve the independent control using only the multi-phase inputs assigned in the stator coils as an approach, in which condition we can minimize the coupling effect between two forces\ulcorner In this paper, we show the qualitative influence of a slip frequency, an ac magnitude, a dc offset superposed in the ac power, and a major parameter of TFLIM on the couple through the computer simulation. And to realize the independent motions between levitation and thrust motion without any auxiliary means fur isolation of the secondary part of TFLIM, the decouple compensator is suggested, including the experimental results.

스파이럴 이동자 코어를 가지는 영구자석여자 횡자속 선형전동기의 등가자기회로망법을 이용한 특성해석 (Characteristic Analysis using Equivalent Magnetic Circuit Network Method for Permanent Magnet Excited Transverse Flux Linear Motor with Spiral Core in a Mover)

  • 이지영;김지원;우병철;강도현;호앙트룽키엔;김광운
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2009년도 제40회 하계학술대회
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    • pp.794_795
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    • 2009
  • This paper presents an analysis method for a permanent magnet excited Transverse Flux Linear Motor (TFLM) with spiral core in a mover. The spiral core is used as mover core in order to make 3-dimensional magnetic flux path at the TFLM which has 3-dimensional magnetic flux flow. Magnetic field is analyzed by three-dimensional Equivalent Magnetic Circuit Network (EMCN) method. And an imaginary part, 'flux barrier,' is introduced to consider the spiral core characteristic. The computed thrust forces is compared to the measured results to show the effect of presented analysis method.

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