• Title/Summary/Keyword: Line of Bearing

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A Study on the Parallel Line Pivoted Pad Thrust Bearing (평행선 지지식 추력베어링에 관한 연구)

  • 이경우;김종수;제양규
    • Tribology and Lubricants
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    • v.15 no.1
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    • pp.24-28
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    • 1999
  • This paper describes a new pivoting technique to improve bearing performance in pivoted pad thrust bearings. This new technique adjusts the pivot line in a line pivoted pad thrust bearing to be parallel to the trailing edge of a sector shaped pad. Bearing performance factors such as load carrying capacity, frictional torque and flow rate are numerically investigated for conventional point-pivoted and line-pivoted pads and for the new parallel-line pivoting technique. It is shown that the load carving capacity can be maximized with the new technique.

Dynamic Characteristics of Parallel Line Pivoted Pad Thrust Bearing (평행라인 피봇식 추력베어링의 동특성 해석)

  • 이경우;김종수;제양규
    • Tribology and Lubricants
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    • v.16 no.4
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    • pp.274-281
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    • 2000
  • In this paper, linearized dynamic characteristics of parallel line pivoted pad thrust bearing (here-inafter refer to PLP thrust bearing) was analyzed by perturbation method with inlet pressure. Inlet pressure and excitation frequency influence dynamic characteristics of PLP thrust bearing at all operating conditions, such as angular pivot position, mass of pad. Therefore, the characteristics have to be analyzed with inlet pressure, excitation frequency, mass of pad and thickness of pad. Otherwise, the analysis may be over or under estimate.

Multipath Track Association Technique using Characteristics of Conical Bearing in Horizontal Line Array Sonar (수평 선배열 소나의 원추각 특성 기반 다중경로 트랙 연관 기법)

  • Raegeun Oh
    • Journal of the Korea Institute of Military Science and Technology
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    • v.27 no.2
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    • pp.156-166
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    • 2024
  • This paper conducts a study on methods for associating multipath tracks received by a horizontal line array sonar. The horizontal line array sonar introduces conical bearing ambiguities due to its array-shaped characteristics. Target signals are often subject to multipath propagation in the ocean, resulting in errors in target bearing estimation due to these bearing ambiguities. Recent research efforts have been directed toward using multipath tracks to estimate the positions of targets. However, there has been a lack of research dedicated to identifying multipath tracks from the measurements of a horizontal line array sonar. Therefore, this study identifies the conical bearing characteristics of multipath signals based on the result of experiment and establishes criteria for associating multipath tracks. Additionally, Simulations are performed to determine the ability to associate multipath tracks.

Estimation of bearing error of line array sonar system caused by bottom bounced path (해저면 반사신호의 선 배열 소나 방위 오차 해석)

  • Oh, Raegeun;Gu, Bon-Sung;Kim, Sunhyo;Song, Taek-Lyul;Choi, Jee Woong;Son, Su-Uk;Kim, Won-Ki;Bae, Ho Seuk
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.6
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    • pp.412-421
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    • 2018
  • The Line array sonar consisting of several hydrophones increases array gain and improves the performance for detecting the direction of the target compared to single hydrophone. However, line array sonar produces the bearing error that makes it difficult to determine the bearing of incoming source signal due to the relation between bearing angle of target and vertical angle of multipath signals. Vertical angles of multipath are varied with the geometry of receiver and target and various underwater environments, therefore it is necessary to consider the bearing error to estimate accurately the bearing of the target. In this study, acoustic modelling was performed to understand the effect of multipath signals on the target signal. The errors of bearing angle estimated from the bottom bounced signals are calculated with several environment. In addition, the expected bearing line, as a function of source-receiver range, compensated for the bearing error is predicted from the estimated bearing angle.

Dynamic Characteristics of Parallel tine Pivoted Pad Thrust Bearing (평행라인 피봇식 추력베어링의 동특성 해석)

  • 이경우;김종수;제양규
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.06a
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    • pp.111-118
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    • 1999
  • In this paper, linearized dynamic characteristics of parallel line pivoted pad thrust bearing(hereinafter refer to PLP thrust bearing) was analyzed by perturbation method with inlet pressure. Inlet pressure and excitation frequency irfluence dynamic characteristics of PLP thrust bearing at all operating condition, such as angular pivot position, mass of pad. Therefore, the characteristics is have to analyzed with inlet pressure, excitation frequency, mass of pad and thickness of pad. Otherwise, the analysis is able to estimate the characteristics over or under.

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Behavior of Bridge Bearings for Railway Bridges under Running Vehicle

  • Choi, Eun-Soo;Yu, Wan-Dong;Kim, Jin-Ho;Park, Sun-Hee
    • International Journal of Railway
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    • v.5 no.1
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    • pp.10-21
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    • 2012
  • Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.

Effect of a two bearing lines deck on the bridge substructure

  • Shaker, Fatemeh;Rahai, Alireza
    • Structural Engineering and Mechanics
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    • v.81 no.2
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    • pp.117-129
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    • 2022
  • This research evaluated the different types of deck to pier connections effects (one or two elastomeric bearing lines and rigid) on a concrete bridges. Three-dimensional bridge models behavior with different deck to pier connections and different distances of two bearing lines were studied under the service load. Also, the detailed connection system with two elastomeric bearing lines was modeled to evaluate the effect of changing distance between two-lines. Results indicated that the proper location of elastomeric bearings has a major impact on the transferring forces to the substructure. Double elastomeric bearing lines have a behavior between one line and rigid connections. Transferring bending moment to the substructure in two-lines is more than the corresponding value of the one line. Moreover, an increase in the distance of two-lines lead to a significant increase in the rotational stiffness of the connection, and an analytical solution was investigated for their relation. In fact, the semi-rigidity effect of this connection and its change due to the distance of bearings should be considered in the design process.

Left/Right Bearing Discrimination with Adaptive Cardioid Beamforming (적응 카디오이드 빔 형성을 이용한 좌/우 방위 분리 기법)

  • 손윤준;천승용;김기만
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.6
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    • pp.489-495
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    • 2003
  • Single towed line array receiver contains an ambiguity on conjugate bearings because of lacking aperture in transverse direction. To solve the left/right bearing ambiguity of line array receiver this paper proposed using single line array with fixed cardioid beam. Fixed cardioid beam has problem about back beam gain exists for steering beam inherent. Back beam is makes form on direction that is different from actually source so that reduced the performance of left/right bearing discrimination. In this paper, line way with adaptive cardioid beam for resolve problem of back beam gain is proposed. So the proposed method has more improved left/right bearing discrimination than fixed cardioid beam, Simulation results show the performance of the proposed method.

Study on Bearing and Frequency Target Motion Analysis for Passive Line Array SONAR Using Accumulative Batch Estimation (누적 일괄추정 기법을 이용한 수동 선배열 소나 방위 주파수 - 표적기동분석 연구)

  • Kim, In-Soo
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.10
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    • pp.788-796
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    • 2016
  • Bearing and frequency measurements of TMA (Target Motion Analysis) in passive line array SONAR have lower bearing rate and frequency doppler, and are not detected or tracked continuously because of various ocean environments. This is a main reason to effect the TMA performance and it takes a long time to get TMA solutions. We propose the bearing and frequency TMA(BFTMA) using accumulative batch estimation to solve the TMA problem of line array passive SONAR. The accumulative batch estimation structure is based on MLE (Maximum Likelihood Estimation) but used accumulative measurements. The accumulative batch estimation is applied for the BFTMA with nonlinear Kalman filter to estimate the target range, speed and course. Simulation and sea data analysis were carried out to verify the performance and applicability of the proposed techniques.

Comparison of the Performance of Pivoted Pad Thrust Bearings (피봇식 패드 추력베어링의 성능 비교)

  • 김종수
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.3
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    • pp.337-342
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    • 1998
  • In this paper the lubrication performances of line pivoted pad thrust bearing and point pivoted pad thrust bearing are studied by a numerical analysis. The running characteristic parameters such as nondimensional load carrying capacity nondimensional friciton power loss nondimensional flow rate and film thickness ratios are calculated for various circumferential pivot positions. The results provide a usdful data for the selection of pivot position in a pivoted and thrust bearing.

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