• Title/Summary/Keyword: 돔 형상

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A Study on Size Optimization for Rocket Motor with a Torispherical Dome (토리구형 돔 형상을 갖는 연소관의 치수 최적화 설계 연구)

  • Choi, Young-Gwi;Shin, Kwang-Bok;Kim, Won-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.5
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    • pp.567-573
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    • 2010
  • In this study, we evaluated the structural integrity and weight of a rocket motor with a torispherical dome by size optimization. Size optimization was achieved by first-order and sub-problem methods, using the Ansys Parametric Design Language (APDL). For rapid design verification, a modified 2D axisymmetric finite-element model was used, and the bolt pre-tension load was expressed as function of the ratio of the cross-sectional area. The thickness of the dome and the cylindrical part of the rocket motor were selected as the design parameters. Our results showed that the weight and structural integrity of the rocket motor at the initial design stage could be determined more rapidly and accurately with the modified 2D axisymmetric finite-element model than with the 3D finite-element model; further, the weight of the rocket motor could be saved to maximum of 17.6% within safety limit.

Efficient Design Procedure of Concrete Dome and Ring Beam in Containment Structures (콘크리트 격납구조물 돔 및 링빔의 효율적인 설계 기법)

  • Jeon, Se-Jin;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.139-140
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    • 2010
  • Combined analysis is required for the concrete dome and ring beam of containment structure due to the interaction in section forces. In this study, an efficient design procedure is proposed that can be used to determine the preliminary sections of the dome and ring beam as well as a proper level of prestress in the ring beam, prior to a detailed design. The procedure applies the membrane theory of the shell of revolution.

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Conceptual Design of Cylindrical Hydrophone Arrays for Stabilization of Receiving Characteristics under Ocean Ambient Noise (해양 배경 소음 하의 수신 특성 안정화를 위한 원통형 하이드로폰 배열의 개념 설계)

  • Noh, Eunghwy;Lee, Hunki;Ohm, Won-Suk;Chang, Woosuk
    • The Journal of the Acoustical Society of Korea
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    • v.34 no.3
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    • pp.200-209
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    • 2015
  • An underwater sound surveillance system detects and tracks enemy ships in real-time using hydrophone arrays, in which seabed-mounted sensor arrays play a pivotal role. In this paper the conceptual design of seabed-mounted, cylindrical hydrophone arrays for use in shallow coastal waters is performed via finite element calculations. To stabilize the receiving characteristics under the ocean ambient noise, a technique for whitening the ambient noise spectrum using a metal baffle is proposed. Optimization of the array configuration is performed to achieve the directivity in the vertical and azimuthal directions. And the effects of the sonar dome shape and material on the structural vibration and sound scattering properties are studied. It is demonstrated that a robust hydrophone array, having a sensitivity deviation less than 4 dB over the frequency range of interest, can be obtained through the whitening of the ambient noise, the optimization of the array configuration, and the design of acoustically transparent sonar domes.

A Study on the Bucking Load Formulae for the Single Layer Latticed Dome (단층 래티스 돔의 좌굴하중 산정식에 관한 연구)

  • Han, Sang-Eul;Yang, Jae-Geun;Lee, Sang-Ju;Lee, Jung-Hyun
    • Journal of Korean Association for Spatial Structures
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    • v.6 no.1 s.19
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    • pp.75-82
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    • 2006
  • The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is organized by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all renditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

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Bird Strike Analysis and Test of Composite Aircraft Radome (항공기 복합재 레이돔에 대한 조류충돌해석 및 시험)

  • Won, Moon-Seob
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.5
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    • pp.319-325
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    • 2019
  • The main purpose of this study is to compare the bird strike analysis result of the radome composed of composite laminate and sandwich structure attached to aircraft with test result. First of all, we generated bird model which has water properties through SPH(Smoothed Particle Hydrodynamics) method. And then bird strike analysis was conducted with initial velocity of bird measured from bird strike test. From analysis result we investigated whether structural failure occurred or not onto the radome and compare maximum displacement of the radome structure with test result. Also reliability of numerical analysis model was confirmed through time-dependent pressure trend on this collision process matched existing research result. Furthermore, we confirmed that failure behavior of the radome can be affected by density of the particles in the bird model.

Stress Distribution Analysis for High Pressure CNG Pressure Vessel Using FEM (유한요소법을 이용한 고압 CNG압력용기 응력분포 해석)

  • Choi, Sang In;Kim, Young Chul;Kim, Myung Soo;Baek, Tae Hyun
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.7 no.2
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    • pp.427-435
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    • 2017
  • Most of the domestic city buses are equipped with the pressure vessels subjected to internal pressure applied by compressed natural gas. Pressure vessels subjected to internal pressure are used in various forms and purposes. Fuel is explosive and has flammable high pressure. The damage of the pressure vessel causes many property damage and loss of life. Safe design for pressure vessel is always necessary. Due to these reasons, many studies using finite element analysis have been conducted. In this paper, the stresses of cylindrical vessel and spherical dome were analyzed using ANSYS, a finite element analysis software. In order to verify the validity of the analysis, a model with a perfectly spherical shape of the dome was designed and observed. Based on the ASME standard in used, stress distribution was also analyzed for models designed with compressed natural gas(CNG). The FEM analysis software agreed with the theory when the dome shape was perfectly spherical. The model designed based on the ASME specification theory, stress concentration occurred in the knuckle part.

Analysis on Change in Electrical Transmission Characteristic about FSS Radome on Flight Scenario (비행 시나리오에 따른 FSS 레이돔의 전파 투과 특성 변화 분석)

  • Kim, Sunhwi;Bae, Hyung Mo;Kim, Jihyuk;Lee, Namkyu;Nam, Juyeong;Park, Sehjin;Cho, Hyung Hee
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.6
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    • pp.11-20
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    • 2019
  • A Radome protects the radar from the external environment, and as a part of the stealth technology, a frequency-selective surface (FSS) was applied to the radome. Our study investigates the changes in the electrical transmission characteristics of the missile's FSS radome due to aerodynamic heating in various flight scenarios. Accordingly, we designed a FSS radome with a Jerusalem-cross(JSC) geometry and referred the missile flight scenario in the precedent research. Subsequently, electrical transmission characteristics affected by aerodynamic heating were numerically analyzed over time according to the position of radome. As a result, we found that the average transmission value maximally varies -14.3 dB compared to the initial bandwidth owing to changes in electrical transmission characteristics in flight scenarios.