• Title/Summary/Keyword: 안내 질량

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Free Vibration of Beams with a Guided Mass and an Elastic Spring Support (안내질량을 갖는 탄성지지된 보의 자유진동)

  • Ryu, Bong-Jo;Lee, Gyu-Seop;Lee, Jong-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.2
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    • pp.176-184
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    • 1996
  • The paper describes the vibration characteristics of the mechanical system consisting of a uniform Timoshenko beam with a guided mass and an elastic spring support. The free end of the beam does not rotate and the spring attatched to the guided mass is elastically restrained against translation. The guided mass is assumed to be a rigid body having a finite size, but not a mass point as it has been assumed so far. The effect of magnitudes, rotary inertia and the size of the guided mass on the vibration characteristics is fully investigated by the numerical simulation using FEM and experiment. In order to verify the eigenvalue sensitivity for considered system, comparison exact solutions with FEM is conducted, and a good agreement between two solutions is also highlighted.

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Random Vibration and Harmonic Response Analyses of Upper Guide Structure Assembly to Flow Induced Loads (유체유발하중을 받는 상부안내구조물의 랜덤진동 및 조화응답해석)

  • 지용관;이영신
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.1
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    • pp.59-68
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    • 2002
  • The cylindrical Upper Guide Structure assembly of the reactor intervals wish the Core Support Barrel and the Inner Barrel Assembly is subjected to flow induced loads horizontally which include random pressure fluctuation due to turbulent flow and pump pulsation pressures. The purpose of this papers is to perform random vibration and harmonic response analyses fort flow induced loads. The dynamic response characteristics due to random turbulence and pump pulsation loads were evaluated using the lumped mass beam model. Especially the model considered the annulus effects due to water gaps existing between cylindrical structures such as the Upper Guide Structure Barrel, the Core Support Barrel, and the Inner Barrel Assembly. The effect of the Inner Barrel Assembly inside the Upper Guide Structure assembly was studied. The peak dynamic responses lot each loading condition due to the addition of IBA were affected by the natural frequencies of the structures. Therefore the peak dynamic responses of the structures should be conservatively obtained from evaluation of dynamic analysis for various loading conditions.

Design and Analysis of a Radial Turbine for Ocean Thermal Energy Conversion (해양온도차발전용 반경류 터빈의 설계 및 해석)

  • Nguyen, Van Hap;Lee, Geun Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.3
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    • pp.207-214
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    • 2015
  • The preliminary design of a radial inflow turbine using R134a as the working fluid at 5 kW of power for application to ocean thermal energy conversion (OTEC) is performed to obtain the trends for the efficiency and geometrical dimensions of the turbine. Using input conditions that included a turbine inlet temperature of $25^{\circ}C$, an outlet static pressure of 4.9 bar, and a mass flow rate of 1.16 kg/s, the results of a mean flow analysis show the major dimensions of the turbine, along with an angular velocity of 12,820 rpm. Based on these results, a three-dimensional turbine model is constructed for a computational fluid dynamics (CFD) analysis. The flow characteristics inside the turbine, including the volute and nozzle, are investigated using the CFD software ANSYS CFX. For a pertinent number of nozzle guide vanes, ranging from 10 to 15, the turbine efficiency was higher than 80%, with the highest efficiency shown by a nozzle with 15 guide vanes.

Vibration Characteristics of a Cantilevercd Beam with a Guided Mass and an Elastic Spring Supports (안내질량을 갖는 탄성지지된 외팔보의 진동 특성)

  • 류봉조;이규섭;이종원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.408-413
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    • 1994
  • The paper describes the vibration characteristics of the mechanical system consisting of a uniform cantilevered Timoshenko beam with a guided mass and an elastic spring supports. The free end of the beam does not rotate and the spring attatched to the guided mass is elastically restained against translation. The effect of magnitudes, rotary inertia and the size of the guided mass on the vibration characteristics is fully investigated by the numerical simulation using FEM and experiment. In order to verify the eigenvalue sensitivity for considered system, comparison exact solutions with FEM are conducted, and a good agreement between two solutions is also highlighted.

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Study on a Center of Gravity of Polygon as an Enriched Learning Topic for the Gifted in Mathematics (수학 영재의 심화학습을 위한 다각형의 무게중심 연구)

  • Kim, Sun-Hee;Kim, Ki-Yeon
    • Journal of Educational Research in Mathematics
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    • v.15 no.3
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    • pp.335-352
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    • 2005
  • In this paper, we consider a center of gravity of convex polygon which could be an enriched topic for the gifted in mathematics(7th grades) and suggested a case that the gifted experienced a center of gravity. Based on properties of Archimedes' center of mass, we define it as a point which make a polygon be in counterpoised with its area and explain how to find that point through using integral calculus or internal division. Then we consider that the gifted would experience various kinds of mathematical thinking and apply diverse ways of problem solving 3s searching for this topic. As this research, the teacher would be able to conduct the gifted with penetration into center of gravity and to let them participate in advanced learning courses which value ma-thematical thinking while they undergo similar experiences such as mathematicians.

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A Study on the Fuel Assembly Stress Analysis for Seismic and Blowdown Events (지진 및 냉각재상실사고시의 핵연료집합체 응력해석에 관한 연구)

  • Kim, Il-Kon
    • Nuclear Engineering and Technology
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    • v.25 no.4
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    • pp.552-560
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    • 1993
  • In this study, the detailed fuel assembly stress analysis model to evaluate the structural integrity for seismic and blowdown accidents is developed. For this purpose, as the first step, the program MAIN which identifies the worst bending mode shaped fuel assembly(FA) in core model is made. And the finite element model for stress calculation of FA components is developed. In the model the fuel rods (FRs) and the guide thimbles are modelled by 3-dimensional beam elements, and the spacer grid spring is modelled by a linear and relational spring. The constraints come from the results of the program MAIN. The stress analysis of the 16$\times$16 type FA under arbitary seismic load is performed using the developed program and modelling technique as an example. The developed stress model is helpful for the stress calculation of FA components for seismic and blowdown loads to evaluate the structural integrity of FA.

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Development of Transient Behavior Simulation Tool and Analysis of Gas Turbines (발전용 가스터빈 동적 거동 시뮬레이션 Tool 개발 및 해석)

  • Kim, Jeong Ho;Kim, Tong Seop
    • Plant Journal
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    • v.13 no.4
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    • pp.48-50
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    • 2017
  • A program for analyzing the transient behaviors of industrial gas turbines was developed. Each component (compressor, combustor, turbine and ducts)of gas turbine is modeled as a fully module to enhance the expandability of the program. We used object-oriented programing for this purpose. The mass and energy balance equations are solved numerically by Multivariable Newton Raphson method. The characteristic maps for the compressor and turbine were used for predicting the performance of a gas turbine engine. Combustion in the combustor is assumed to be complete combustion. PID control is used to maintain constant rotational speed and turbine exhaust temperature by the control of the fuel flow rate and the changing of the compressor inlet guide vane angle at the same time. It was confirmed that stable control of the gas turbine was possible, even for a rapid load change.

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The Ultra-Centrifuge Rotordynamics (초고속 원심분리기의 회전체동역학 설계)

  • 이안성;김영철;박종권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.319-323
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    • 1996
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