• Title/Summary/Keyword: Dimensional characteristics

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Three Dimensional Silicon Accelerometer for High Temperature Range (고온용 3차원 실리콘 가속도센서)

  • Son, Mi-Jung;Seo, Hee-Don
    • Proceedings of the KIEE Conference
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    • 1998.07g
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    • pp.2504-2508
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    • 1998
  • In this paper, we propose the new detecting method for three dimensional piezoresistive silicon accelerometer. Furthermore the accelerometer is formed to have endurance for high temperature by perfect isolation of the piezoresistors using Silicon On Insulator(SOI) wafer. Sensor size are optimized with analytical formulae and extended with FEM simulation for the more detailed results. The accelerometer was fabricated by bulk micromachining techonology. We measured the temperature characteristics and the output characteristics, and the both characteristics were compared with the simulated results

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THE NUMERICAL STUDY ON THE SUPERSONIC INLET FLOW FIELD WITH A BUMP (Bump가 있는 초음속 흡입구 유동장의 수치적 연구)

  • Kim S. D.;Song D. J.
    • Journal of computational fluids engineering
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    • v.10 no.3 s.30
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    • pp.19-26
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    • 2005
  • The purpose of this paper is the study on the characteristics of an inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. in this study a comprehensive numerical analysis has been performed to understand the three-dimensional flow field including shock/boundary layer interaction and growth of turbulent boundary layer that might occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicate the potential capability of a three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

3 Dimensional Machining System using Focused ion Beam (집속 이온빔에 의한 3차원 가공 시스템)

  • 박철우;이종항
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.490-493
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    • 2004
  • There is great difficulty in machine below 10 micrometers by conventional machining methods, such as micro-EDM. However, ultra micro machining using focused ion beam(FIB) is able to machine to 50 nanometers. Bie & moulds techniques are better than one-to-one machining techniques in regards to production costs in the mass production of ultra size structures. Also, it is advantageous to machine die & moulds to the 10 micrometers level by FIB technique rather than other techniques. It is difficult to machine the three dimensional machining, such as micro lens, using FIB system because of their machining characteristics. In this paper, three dimensional machining techniques were properly introduced, and also experiments showed effectiveness of their techniques.

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Numerical study of Three-Dimensional Viscous Flow and Compression Wave Induced by the High Speed Train Entering into a Tunnel (터널에 진입하는 고속전철 주위의 3차원 점성유동과 압축파 특성에 관한 수치해석적 연구)

  • Shin C. H.;Park W. G.
    • Journal of computational fluids engineering
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    • v.5 no.3
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    • pp.23-31
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    • 2000
  • The three-dimensional unsteady compressible Full Navier-Stokes equation solver with sliding multi-block method has been applied to analyze three dimensional characteristics of the viscous flow field and compression wave around the high speed train which is entering into a tunnel. The numerical scheme of AF + ADI was used to efficiently solve Navier-Stokes equations in the curvilinear coordinate system. The vortex formation owing to the viscous interaction around the train was found and the generation of compression wave due to the blockage effects was observed ahead of the train in the form of plane wave. The three dimensional characteristics of the flow field compared to the analytic results were discussed in detail. The variation of pressure of tunnel wall surface and velocity profile of the train are identified as the train enters into a tunnel. The changes in aerodynamic forces and streamlines of each specific sections are also discussed.

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A 3-dimensional Wheel-rail Contact Analysis of Railway Vehicle with 2-point Contacts (2점 접촉을 고려한 철도차량의 3차원 휠-레일 접촉해석)

  • Kang, Ju-Seok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.43-52
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    • 2010
  • In this study, the shapes of the wheel and rail are represented by using 3-dimensional surface functions with surface parameters and a 3-dimensional wheel-rail contact analysis is presented. A whole numerical solution of wheel-rail contact at tread and flange including 2-point contacts can be achieved with the proposed numerical algorithm. Kinematic characteristics such as variances of vertical displacement and roll angle, and variance of wheel radius difference for arbitrary yaw and lateral displacement of wheelset, are determined for the KTX wheel-rail pair as an example. The condition of yaw and lateral displacement occurring 2-point contacts to analyze derailment are compared between standard and worn wheels. Differences of contact characteristics between curved and straight rails are also analyzed.

Optimal Design of Piezoelectric Cantilever Fan by Three-Dimensional Finite Element Analysis

  • Kim Byoung-Jai;Rho Jong-Seok;Jung Hyung-Kyo
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.1
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    • pp.90-94
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    • 2005
  • As the structure of the piezoelectric bimorph cantilever becomes increasingly more complicated, a more accurate and efficient analysis of piezoelectric media is needed. In this paper, the piezoelectric transducer is analyzed by using the three-dimensional finite element method. The validity of the three-dimensional finite element routine is confirmed by comparing the experimental result. The resonance characteristics, such as resonance frequency and anti-resonance frequency, of the piezoelectric cantilever are calculated by the experimentally verified three dimensional finite element method. Subsequently, the characteristics, such as mechanical displacement and impedance, are calculated at the resonance frequency. Besides, to design the piezoelectric bimorph cantilever shape that maximizes displacement at the tip, the ES (Evolution Strategy) algorithm is applied. Finally, optimal design for the fan of the piezoelectric cantilever is fulfilled to obtain maximum displacement at the tip. From these results, the application potentiality of the piezoelectric bimorph cantilever fan is identified.

The Numerical Study on the Supersonic Flow field with a Bump (Bump가 있는 초음속 유동장의 수치적 연구)

  • Kim S. D.;Song D. J.
    • 한국전산유체공학회:학술대회논문집
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    • 2005.04a
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    • pp.213-218
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    • 2005
  • The purpose of this study is the characteristics of an innovative inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. This study performs a comprehensive numerical effort that be directed at better understanding the three-dimensional flowfield includes shock/boundary layer interaction and growth of turbulent boundary layer that occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicates the potential capability of the three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

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The natural convection in a three dimensional enclosure using color capturing technique and computation (색상 포착 기법과 수치계산을 이용한 3차원 밀폐 공간내의 자연대류 연구)

  • Lee, Gi-Baek;Kim, Tae-Yeong;Yang, Jang-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.12
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    • pp.1595-1607
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    • 1997
  • The natural convection of a horizontal layer heated from below in a three-dimensional rectangular enclosure was dealt with both numerically and experimentally. The aspect ratios are 1:2:3.5 and Boussinesq fluid is water with the Prandtl number of 5.0. This experimental study showed how to measure the variation of temperature field in a 3-D rectangular enclosure with small aspect ratios by using TLC(Thermochromic Liquid Crystal) and color capturing technique. The experimental temperature field had periodic characteristics of 75 sec at Ra=2.37*10$^{5}$ . But the numerical convection flow had periodic characteristics of 79 sec at the same Rayleigh number. In three dimensional computation it was found that the convection roll structure bifurcated from four rolls to two rolls as the Rayleigh number is increased.

Computational Analysis of the Three-Dimensional Flow Fields of Sirocco Fan

  • Hah, Jae-Hong;Moon, Young-J.;Park, Jin-Moo
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.2
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    • pp.44-50
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    • 2001
  • The Sirocco fan performance and its three-dimensional flow characteristics are numerically prediction by STAR-CD. Turbulent flow computations are performed using approximately 500,000 mesh points, and the performance results of tow computational methods, transient and quasi-static flow analyses are compared with experimental data. In the present study, our attention is focused on the three-dimensional flow characteristics of the Sirocco fan blades and the secondary flow structure in the scroll. For a design optimization study, the scroll shape is titled by $10^\circ$ to modify the secondary flow structure, which yields some improvement of the fan performance.

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On exact wave propagation analysis of triclinic material using three-dimensional bi-Helmholtz gradient plate model

  • Karami, Behrouz;Janghorban, Maziar;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • v.69 no.5
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    • pp.487-497
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    • 2019
  • Rapid advances in the engineering applications can bring further areas to provide the opportunity to manipulate anisotropic structures for direct productivity in design of micro/nano-structures. For the first time, magnetic affected wave characteristics of nanosize plates made of anisotropic material is investigated via the three-dimensional bi-Helmholtz nonlocal strain gradient theory. Three small scale parameters are used to predict the size-dependent behavior of the nanoplates more accurately. After owing governing equations of wave motion, an analytical approach based harmonic series is utilized to fine the wave frequency as well as phase velocity. It is observed that the small scale parameters, magnetic field and wave number have considerable influence on the wave characteristics of anisotropic nanoplates. Due to the lack of any study on the mechanics of three-dimensional bi-Helmholtz gradient plates made of anisotropic materials, it is hoped that the present exact model may be used as a benchmark for future works of such nanostructures.