• Title/Summary/Keyword: Hexahedron

Search Result 66, Processing Time 0.028 seconds

A Study on Constructing Plane Section of Regular Tetrahedmn and Regular (바탕문제를 활용한 정사면체와 정육면체의 절단면 작도에 대한 연구)

  • Han, In-Ki;Kim, Moon-Sup
    • The Mathematical Education
    • /
    • v.46 no.3
    • /
    • pp.303-314
    • /
    • 2007
  • In this paper we try to study a method of constructing plane sections of regular tetrahedron and regular hexahedron. In order to construct plane sections of regular tetrahedron and regular hexahedron first of all, we extract some base problems that are used for construction. And we describe construction process using base problems in detail.

  • PDF

Eight-node field-consistent hexahedron element in dynamic problems

  • Rajendran, S.;Prathap, G.
    • Structural Engineering and Mechanics
    • /
    • v.8 no.1
    • /
    • pp.19-26
    • /
    • 1999
  • Superior performance of field consistent eight-node hexahedron element in static bending problems has already been demonstrated in literature. In this paper, its performance in free vibration is investigated. Free vibration frequencies of typical test problems have been computed using this element. The results establish its superior performance in free vibration, particularly in thin plate application and near incompressibility regimes, demonstrating that shear locking, Poisson's stiffening and volumetric locking have been eliminated.

Design of internal dielectric ceramic antennas for IMT-2000 handset (IMT-2000용 단말기 내장형 유전체 세라믹 안테나 설계)

  • 심성훈;강종윤;박용욱;윤석진;윤영중;김현재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.07a
    • /
    • pp.968-971
    • /
    • 2001
  • In this paper, internal antennas for IMT-2000 handset(1.92∼2.17 GHz) were designed to be capable of being mounted on the circuit-board with a CPW(coplanar waveguide) feeding structure. The chip antennas were miniaturized to a greater extent by fabricating multilayer high dielectric ceramic($\varepsilon$$\sub$r/=7.8) hexahedron. The proposed antennas has λ/4 monopole element with helical structure in the multilayer dielectric ceramic hexahedron. The simulated and measured results were invesgated with width, length, and thickness of helical structure in the hexahedron.

  • PDF

Discrete Ordinates Interpolation Method Applied to Irregular Three-Dimensional Geometries (불규칙한 3차원 형상에 응용된 구분종좌표보간법)

  • Cha, Ho-Jin;Song, Tae-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.6
    • /
    • pp.814-821
    • /
    • 2000
  • The Discrete Ordinates Interpolation Method (DOIM) is tested in three-dimensional enclosures. The radiative transfer equation (RTE) is solved for a linear source term and the DOIM is formulated for a gray medium. Several interpolation methods can be applied to the DOIM scheme. Among them, the interpolation method applicable to an unstructured grid system is discussed. In a regular hexahedron enclosure, radiative wall heat fluxes are calculated and compared with exact solutions. The enclosure has an absorbing, emitting and nonscattering medium and a constant temperature distribution. These results are obtained with varying optical depths (xD = 0.1, 1.0, 10.0). Also, the same calculations are performed in an irregular hexahedron enclosure. The DOIM is applied to an unstructured grid system as well as a structured grid system for the same regular hexahedron enclosure. They are compared with the exact solutions and the computational efficiencies are discussed. When compared with the analytic solutions, results of the DOIM are in good agreement for three-dimensional enclosures. Furthermore, the DOIM can be easily applied to the unstructured grid system, which proves the reliability and versatility of the DOIM.

Performance Tests of an Induction Motor with Hexahedron HTS Bulk Bearing (고온초전도 벌크 베어링을 사용한 유도 전동기의 특성 시험)

  • 임형우;이광윤;박명진;차귀수;이지광
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.52 no.6
    • /
    • pp.286-290
    • /
    • 2003
  • The high temperature superconducting bulk can be used as the bearing of induction motors. This paper presents the fabrication and test results of an induction motor with superconducting bearings using HTS bulks. The bearing had eight hexahedron type YBCO bulks. Height, width and thickness of the HTS bulk were 30mm, 30mm and 10mm, respectively. Single phase induction motor was used to drive the shaft made of aluminum and the rotor of a conventional induction motor. To estimate the performance of the HTS bulk magnetic bearing, no load test, load test and Impact test were carried out. Load tests were performed by using air resistance caused by the shaft-mounted thin cylinder with buckets. Impact tests by axial direction and vertical direction impact showed that the vibration of the shaft gradually decayed. The induction motor with HTS bulk magnetic bearing rotated silently and smoothly throughout the tests. According to the test results, conventional bearings can be replaced with superconducting magnetic bearings made of HTS bulks.

The elastic and plastic behaviour of the micro-FE models for vertebral trabecular bones (척추 해면골에 대한 미세 유한요소모델의 탄성 및 소성특성에 관한 연구)

  • 우대곤;김한성;원예연;백명현;탁계래
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2003.06a
    • /
    • pp.1320-1323
    • /
    • 2003
  • In this study, the micro-FE analyses were carried out for the plastic behaviour of vertebral trabecular bones. Many researchers have investigated the elastic behaviour of trabecular bones by using the micro-finite element models based on the micro-CT images. However, there was no micro-FE model to account for the plastic behaviour of trabecular bones. Ulrich et at. reported that best results at coarser model were obtained when using 'compensated hexahedron models' with the same relative density. This study indicates that, for the elastic and plastic analysis, 'the compensated hexahedron FE model' is likely to be limited to about 63$\mu\textrm{m}$ image resolution in the vertebra trabecular bones.

  • PDF

An Efficient Analysis of Unbounded Scattering Field Using Three Dimensional Boundary Element Method (3차원 경계요소법을 이용한 무경계 산란장의 효율적 해석)

  • 박동희;김정기
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.5 no.3
    • /
    • pp.14-21
    • /
    • 1994
  • In this paper, a numerical method to be obtain the radar cross section(RCS) of three- dimensional bodies with arbitrary geometry and material compositions on the electromagnetic field with arbitrary incident angle is described. The RCS is obtained by solving the individual surface integral equation about multilayers scatterer using the three-dimensional bonudary element method(BEM). To show propriety and usefulness as to the three-dimensional BEM in this paper, the choice of a geometry is a multi-regular hexahedron and multi-right-angled hexahedron out of oblique incident electric field, and is considered to apply to every condition with loss sufficiently.

  • PDF

Evaluation of Numerical Model of a Ball Valve used for a Gas Pipeline (가스 파이프라인용 볼 밸브의 수치해석 모델 평가)

  • KIM, CHUL-KYU;LEE, KYOUNG-KEUN;LIM, TAE-GYUN;JANG, CHOON-MAN
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.27 no.6
    • /
    • pp.764-772
    • /
    • 2016
  • This paper presents on the evaluation of numerical analysis model of a ball valve used for a gas pipeline. The ball valve has important role to control the gas flow of the pipeline as well as safety operation to prevent gas explosion at the emergency. For the validation of numerical simulation, the computational domains are introduced three different types: a hexahedron chamber connected to a pipeline outlet without considering the geometry of pressure tubes, a pipeline only considered the geometry of pressure tubes, and a pipeline connected both of the a hexahedron chamber and pressure tubes. The commercial code, SC/Tetra, is introduced to solve the three-dimensional steady-state Reynolds-averaged Navier-Stokes analysis in the present study. The valve flow coefficient and valve loss coefficient with respect to the valve opening rate of 30%, 50%, and 70% are compared with experimental results. Throughout the numerical analysis for the three analysis domains, pressure computed along the pipeline is affected by computational domains. It is noted pressure obtained by the computational model considering both of the a hexahedron chamber and pressure tubes has a relatively good agreement to the experimental data.

Design of a Surface-mounted Chip Dielectric Ceramic Antenna for PCS Phone (PCS용 표면실장형 칩 유전체 세라믹 안테나 설계)

  • 이종환;우종명;김현학;김경용
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.11 no.1
    • /
    • pp.55-62
    • /
    • 2000
  • In this paper, cellularphone antenna was designed to be capable of being mounted on the circuit-board with co-planar feeding method. The designed antenna is fabricated by the following procedure : make the multi-layered dielectric ceramic($\varepsilon_{\tau}$=23) hexahedron($7.5mm\times4.5mm\times0.4mm$) and then produce λ/4 monopole radiation element with helical structure on the surface of the hexahedron. The results are as followings : Returnloss 27.36 dB, -10 dB bandwidth 76 MHz(3.97 %), H-plane average gain -9.43 dBd.

  • PDF

An Effective mesh smoothing technique for the mesh constructed by the mesh compression technique (격자압축을 이용해 구성된 격자의 효과적인 격자유연화 방법)

  • 홍진태;이석렬;양동열
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2003.05a
    • /
    • pp.331-334
    • /
    • 2003
  • In the finite element simulation of hot forging processes using hexahedron, remeshing of a flash is very difficult. The mesh compression method is a remeshing technique to construct an effective hexahedral mesh. However, because mesh is distorted during the compression procedure or the mesh compression method, mesh smoothing is necessary to improve the mesh Qualify. in this study, several geometric mesh smoothing techniques and a matrix norm optimization technique are applied and compared which is more adaptive to the mesh compression method.

  • PDF