• Title/Summary/Keyword: shaft model

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A Study on the Reduction of Differential Vibration of FR Passenger Car (후륜구동 승용차의 디퍼렌셜 진동저감에 관한 연구)

  • 최은오
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.10a
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    • pp.316-321
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    • 1997
  • The purpose of this study is to reduce the vibration noise of differential gear by reducing torque fluctuation of drive pinion shaft which causes vibration noise of differential gear in rear wheel drive vehicles. For this we developed multi-degree of freedom analysis model in which mass moment of inertia and torsional spring combined, the validity of the simulation model was checked by the field test and we examined the influence of torsional vibration of driveline elements by performing forced vibration analysis of engine excitation torque. We studied the methods for reducing torsional vibration of driveline according to the design factor of propeller shaft and examined the effects reducing vibration differential gear by applying flexible coupling.

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A Simulation of Arching Earth Pressure Exerted on Vertical Shafts through Centrifuge Tests (원심모형실험에 의한 수직구 아칭토압 모사)

  • Lee, Dae-Soo;Kim, Kyoung-Yul;Hong, Sung-Yun;Kim, Yoo-Suk
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.1073-1080
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    • 2010
  • In this paper, the centrifuge model tests were conducted for the sake of measuring three dimensional arching earth pressure while two step excavation of the vertical shaft. The results of the centrifuge model tests were compared to newly suggested arching earth pressure equation proposed by Kim et al(2009) and two dimension earth pressure(Rankine). As the results, Measured arching earth pressure revealed about 35 percentages of two dimension earth pressure(Rankine) and almost same as that of newly suggested arching earth pressure equation.

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Study of Two Stroke Low Speed Diesel Engine Crankshaft Crack Phenomenon by Torsional Vibration Calculation & Measurement (비틀림 진동 계산 및 측정을 통해 고찰한 선박용 2행정 저속엔진 크랭크축 파단 현상)

  • Moon, Joung-Ha;Kim, Jeong-Ryul
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.6
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    • pp.452-461
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    • 2014
  • Two stroke low speed diesel engines that have many advantages such as high thermal efficiency and durability have been widely used for marine engine. However, it is also true that many problems have occurred due to the high explosion pressure and severe operating environment. Especially problems of shaft damage etc. intensively occurred due to the phenomenon of crankshaft exceeding the allowable stress, including the shaft vibration of the engine model in the early stage. In this study, the crankshaft fracture phenomenon of early engine model was evaluated and analyzed by using up-to-date torsional vibration calculation program and measurement instrument. And this was numerically shown.

Modeling and Validation of RK4 Multi Axis Rotor system (RK4 다축 회전체 시스템의 동역학모델링 및 검증)

  • Kwonn, Ki Beom;Han, Jeong Sam;Jeon, ByungChul;Jung, Joonha;Youn, Byeng D.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.04a
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    • pp.233-237
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    • 2014
  • In this paper, the finite element modeling of the RK4 rotor kit system (RK4) and then frequency analysis and transient analysis, and was compared with the actual experimental results. RK4 manufactured by General Electric for the purpose of education and research. It is composed of two shaft, Two shaft is connected using a flexible coupling, one disk is mounted. The analytical model is modeled by using the ANSYS finite element analysis program commercially available. Based on impact hammer test results, material properties and the stiffness of the bearing and coupling was tuned. Considering the operating conditions and the vibration response of the analytical model were compared with experimental results.

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A Generalized Modal Analysis for Multi-Stepped, Distributed-Parameter Rotor-Bearing Systems (다단 연속 회전체 베어링 계의 일반화된 모드 해석)

  • 박종혁;홍성욱
    • Journal of KSNVE
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    • v.9 no.3
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    • pp.525-534
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    • 1999
  • The present paper proposes a generalized modal analysis procedure for non-uniform, distributed-parameter rotor-bearing systems. An exact element matrix is derived for a Timoshenko shaft model which contains rotary inertia, shear deformation, gyroscopic effect and internal damping. Complex coordinates system is adopted for the convenience in formulation. A generalized orthogonality condition is provided to make the modal decomposition possible. The generalized modal analysis by using a modal decomposition delivers exact and closed form solutions both for frequency and time responses. Two numerical examples are presented for illustrating the proposed method. The numerical study proves that the proposed method is very efficient and useful for the analysis of distributed-parameter rotor-bearing systems.

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TREPAN SHAPE MODIFICATION OF MOTOR BEARING (모터 베어링의 트레판 형상 수정에 관한 연구)

  • 이경원;반재삼;강형선;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.950-953
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    • 2002
  • Trepan prevents wear of an inside part of a bearing when the initial shaft rotates. It continuously contacts with the eccentric part of the shaft in rotation and is loaded repeatedly. Therefore, even if an early crack of a trepan part is small, a crack progresses by a repeated load. If a crack progresses, very small chips come out. This is pill in the rotor and prevents rotation of the compressor. There can be leaks in a microgroove and extreme wear can occur due to lack of oil on the surface contact pan. Therefore, this study was carried out to compare and investigate trepan strength and deflection characteristics between trepan locations and dimension changes using a finite element method and search a motor bearing for a model with bigger stiffness of a trepan part and the same deflection. And then. five different types of the oil groove model were chosen to prevent small crack and considered also machining ability and the analysis was carried out on oil feeding flow.

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A Study on the Vibration Characteristics of HDD Spindle Motor (하드 디스크 구동 스핀들 모터의 진동 특성에 관한 연구)

  • 장건희;한재혁
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.160-166
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    • 1997
  • The spindle motor in a computer hard disk drive can be modeled as a rotor-bearing system supported by the base plate. Ball bearing is the crucial element to determine the stiffness of the spindle motor, and its design parameters and operating conditions determine the dynamic characteristics of the spindle motor. In the analysis of a rotor-bearing system with a short shaft like a spindle motor, the stiffness of the base plate as well as ball bearings must be considered accurately to analyze the dynamic charateristics of a spindle motor. In this paper, the lateral and the axial vibration of the spindle motor were analyzed by the transfer matrix method for the dual-shaft rotor-bearing model and by d.o.f lumped parameter model, respectively. The simulation results had good agreements with the experimental modal testing. The dynamic characteristics were fully investigated for the change of the major design parameters of the spindle motor, i.e. the preload of ball bearings and the rotational speed.

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Estimation of Bearing Capacity for Open-Ended Pile Considering Soil Plugging (폐색정도를 고려한 개단말뚝의 지지력 산정)

  • 백규호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.397-404
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    • 2002
  • The bearing capacity of open-ended piles is affected by the degree of soil plugging, which is quantified by the IFR. There is not at present a design criterion for open-ended piles that explicitly considers the effect of IFR on pile load capacity In order to investigate this effect, model pile load tests using a calibration chamber were conducted on instrumented open-ended piles. The results of these tests show that the IFR increases with increasing relative density and increasing horizontal stress of soils. The unit base and shaft resistances decrease with increasing IFR. Based on the results of the model pile tests, new empirical relations for base load capacity and shaft load capacity of open-ended piles are proposed. In order to check the accuracy of predictions made with the proposed equations, the equations were applied to the full-scale pile load test preformed in this study, Based on the comparisons with the pile load test results, the proposed equations appear to produce satisfactory predictions.

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Study of Dynamic Characteristics of 2.5-MW Wind Turbine Gearbox (2.5MW 풍력발전기 기어박스 동특성 연구)

  • Kimg, Jung-Su;Park, No-Gill;Han, Ki-Bong;Lee, Hyoung-Woo
    • Journal of Ocean Engineering and Technology
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    • v.28 no.4
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    • pp.314-323
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    • 2014
  • In this study, a gearbox and blade were modeled in the MASTA program, and the housing and carrier components were modeled using a finite element method. Using substructure synthesis, all the components were combined and used to establish a vibration model of a 2.5-MW wind turbine gearbox. In addition, the safety displacement factor was evaluated using an AGMA data sheet about bearing's outer race for the input shaft and output shaft. As a result, the bearing's outer race for the input shaft, and the radial and axial responses were satisfied by the $1^{st}$ and $2^{nd}$ planetary gears and the $3^{nd}$ helical gear transmission error(TE), respectively. However, the output shaft support bearing's outer race responses were not satisfied with the radial response by the $2^{nd}$ TE and axial response by the $3^{rd}$ TE. To reduce the vibration, tooth modification was needed. After profile tooth modification, at the outer race of the output shaft support bearing, the radial response was reduced by approximately $20{\mu}m$, and the axial response was reduced by approximately $6{\mu}m$.

NUMERICAL STUDY WITH VENT SHAFT POSITION IN UNDERGROUND STATION (대심도 지하정거장에서 수직구 위치에 따른 수치적 연구)

  • Oh, Hyun-Joo;Shin, Dea-Yong;Lee, Sang-Gun;Kim, Dong-Hyun;Kim, Charn-Jung
    • Journal of computational fluids engineering
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    • v.17 no.1
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    • pp.36-43
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    • 2012
  • When a high-speed train passes an underground station, large pressure waves are generated due to the piston effect. These pressure waves can cause the problems of vibration and noise as well as the ear discomfort of passengers at the underground station. This work numerically analyzed the pressure wave generation and propagation in an high-speed railway underground station, and the optimal location for vent shafts was studied to improve the passenger comfort by reducing the magnitude of the pressure wave and its rate of change. The evolution of pressure field in the underground station was calculated using a CFD(Computational Fluid Dynamics) software(Fluent), where the axis-symmetric two-dimensional model verified by Wu was used. And this study is applied to modelling of the underground station and the tunnel from Daegok station A-line of GTX(Great Train Express). From the result, we can have a conclusion that the role of vent shafts respectively were different according to the position in and out the underground station. Also Vent shaft in the underground station widely reduced pressure magnitude. And vent shaft out underground station reduced initial pressure peak value. Double vent shafts installed at tunnel toward station entrance and inside of the tunnel are the most efficient to reduce pressure. and pressure reduction increases according to the number of vent shaft.