Processing math: 100%
  • Title/Summary/Keyword: Three-dimensional Model

Search Result 4,703, Processing Time 0.029 seconds

A Study on Three-dimensional Coordinates Analysis Using Mirror Images (거울영상을 이용한 3차원 좌표해석에 관한 연구)

  • 유복모;이현직;정영동;오창수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.4 no.1
    • /
    • pp.25-36
    • /
    • 1986
  • Minimum three pairs of model are necessary to determine absolute coordinates of three-dimensional objects. This paper researches the method of analyzing three-dimensional coordinates of all sides of objects by photographing a pair of stereo model through the medium of mirror. An objective lies in improving the accuracy and the efficiency of mirror images method by introducing an error correction function for distortion of the mirror. Projected-onto-mirror points are transformed on the object plane through mirror plane equation. As the result, X-coordinates error is the largest and Y, Z-coordinates error represents about 1mm. Also, accuracy can be improved by introducing correction function for left and right mirror and correcting the distortion of mirror.

  • PDF

Assessment of Numerical Optimization Algorithms in Design of Low-Noise Axial-Flow Fan (축류송풍기의 저소음 설계에서 수치최적화기법들의 평가)

  • Choi, Jae-Ho;Kim, Kwang-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.10
    • /
    • pp.1335-1342
    • /
    • 2000
  • Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, incompressible, three-dimensional Reynolds-averaged Navier-Stokes equations are used as governing equations, and standard k- ε turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the searching directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of generation rate of the turbulent kinetic energy to pressure head. Two variables concerning sweep angle distribution are selected as the design variables. Performance of the final fan designed by the optimization was tested experimentally.

Finite Element Method Analysis of Film Bulk Acoustic Resonator (유한 요소법(FEM)을 이용한 압전 박막 공진기(FBAR)의 공진 모드 해석)

  • 송영민;정재호;이용현;이정희;최현철
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
    • /
    • 2000.11a
    • /
    • pp.95-98
    • /
    • 2000
  • Film bulk acoustic resonator used in microwave region can be analyzed by one-dimension Mason's model and one-dimensional numerical method, but it had several constraints to analyze effects of area variation, electrode-area variation, electrode-shape variation and spurious characteristics. To overcome these constraints film bulk acoustic resonator must be analysed by three dimensional numerical method. So, in this paper three dimensional finite element method was used to analyze several moles of resonance and was compared with the one dimension Mason's model analysis and analytic solution.

  • PDF

NUMERICAL STUDY ON WIND TUNNEL GROUND PLATE WITH A PRESSURE CONTROL DEVICE (압력 조절 장치를 갖는 풍동 지면판에 관한 수치해석적 연구)

  • Lee, M.J.;Kim, C.W.
    • Journal of computational fluids engineering
    • /
    • v.15 no.4
    • /
    • pp.53-59
    • /
    • 2010
  • Preliminary design of a ground plate, a device installed close to the aircraft model for wind tunnel test to simulate the ground effect, was performed by a numerical simulation. A two-dimensional numerical study was performed initially to decide the optimal leading edge and flap configurations. Then, three-dimensional studies were conducted to decide the optimal flap deflection angle for pressure distribution reduction since the plate and the plate supporting system generate static pressure difference between the upper and lower flow regions. Three-dimensional simulation additionally studied the effect of the clearance between the plate and the wind tunnel side wall. For the efficiency of computation, half model was simulated and a symmetric boundary condition was applied on the center plane. Based on the preliminary design, a ground plate was designed, manufactured and tested at the Korea Aerospace Research Institute(KARI) wind tunnel. The measured pressure differences versus flap deflection angle agreed well with the predicted results.

A Study on Automatic Generation for 3-Dimensional Geometry of Gerotor and Hob (제로터와 호브의 3차원 형상 자동 생성에 관한 연구)

  • 정태형
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 1999.10a
    • /
    • pp.458-463
    • /
    • 1999
  • When designing a gerotor, designers determine basic dimensions of a gerotor with transmitted power considering strength, interference and so on. But, designers can not easily obtain the tooth profile generated by dimensions as well as the geometry of generating hob for cutting the tooth profile. In order to resolve these problems, an automatic design system creating not only the solid model of a gerotor but also that of the generating hob using the design parameters of dimensions is developed. Through the developed system, designers can improve the efficiency of design and satisfy the variable requirements of design as well. In this research, the three-dimensional solid model of gerotor is generated considering the design parameters. Besides, that of generating hob with respect to the design parameters of hob is created automatically. The system is developed using Visual Basic and its three-dimensional geometric modeling module is constructed using SolidWorks.

  • PDF

Analysis of the Effect of Met Tower Shadow using Computational Fluid Dynamics (전산유체역학을 이용한 풍황탑 차폐효과 해석)

  • Kim, Taesung;Rhee, Huinam;Kim, Hyun-Goo
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2011.11a
    • /
    • pp.35.1-35.1
    • /
    • 2011
  • When the wind speed is measured by the met-mast sensor it is distorted due to the shadow effect of tower. In this paper the tower shadow effect is analyzed by a computational fluid dynamics code. First three dimensional modeling and flow analysis of the met-mast system were performed. The results were compared with the available experimental wind-tunnel test data to confirm the validity of the meshes and turbulence model. Two-dimensional model was then developed based on the three-dimensional works and experimental data. 2D analysis for various Reynolds numbers and turbulence strengths were then performed to establish the tower shadow effect database, which can be utilized as correction factors for the measured wind energy.

  • PDF

3-D Behavior and Strut-and-Tie Model Analysis of Diaphragm in PSC Train Bridge (PSC철도교량 격벽부의 3차원 거동 및 스트럿-타이 모델 해석)

  • 송하원;변근주;김형운;김영훈
    • Proceedings of the KSR Conference
    • /
    • 1998.05a
    • /
    • pp.564-571
    • /
    • 1998
  • The function of diaphragms at abutments and piers of prestressed concrete (PSC) box girder train bridge is to transfer forces from the superstructure onto bearings or column and to stiffen the superstructure cross-section against in-plane deformation. Due to large stress disturbance at diaphragm, the design for the diaphragm using conventional design method is relatively irrational than designs for other structual members. And, due to contribution to boundary condition of deck slab by the diaphragm, the behavior of deck slab near the diaphragm is different from behavior of the deck slab obtained from two dimensional analysis of the bridge, which is basis far the design of deck slab. In this paper, three dimensional behavior of deck slab near diaphragm of PSC box girder train bridge constructed by the precast span method are analyzed by using three dimensional finite element modeling. Then, strut-and-tie model is applied to design the diaphragm of PSC box girder train bridge. The modeling techniques in this paper can be applied effectively to examine the causes of cracks at deck slab near diaphragm and to design diaphragm rationally.

  • PDF

Assessment of Optimization Methods for Design of Axial-Flow Fan (축류송풍기 설계를 위한 최적설계기법의 평가)

  • Choi, Jae-Ho;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
    • /
    • 1999.12a
    • /
    • pp.221-226
    • /
    • 1999
  • Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, Incompressible, three-dimensional Reynolds-averaged Wavier-Stokes equations are used as governing equations, and standard k-ϵ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the searching directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of generation rate of the turbulent kinetic energy to pressure head. Sweep angle distributions are used as design variables.

  • PDF

A Study on Algorithm Development of Offset Data Generation in Stereolithography (광조형법에 있어서 OFFSET정보생성 알고리즘 개발에 관한 연구)

  • Kim, Jun-An;Hong, Sam-Nyol;Paik, In-Hwan
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.13 no.9
    • /
    • pp.70-76
    • /
    • 1996
  • In the Stereolithography process, three-dimensional objects are built by sequentially curing, generated by horizontal slicing of a three-dimensional CAD model. The dimensional accuracy of a menufactured part depends on the accuracy of curing performed by laser beam radius and the half of curing width. When offsetting, some slices have collinear segments, coincident vertices, line jerks and open loops. After remove above issues we have correct offsets data. And in last step, these data are used to scan paths.

  • PDF

A THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS ON STRESS AND DISPLACEMENT RELATED TO ISTHMUS WIDTH OF GOLD INLAY CAVITY (금인레이 와동의 폭경이 응력분포와 변위에 미치는 영향에 관한 3차원 유한요소법적 연구)

  • Hwang, Ho-Keel;Im, Mi-Kyung
    • Restorative Dentistry and Endodontics
    • /
    • v.19 no.2
    • /
    • pp.384-408
    • /
    • 1994
  • The purpose of this study was to evaluate the fracture resistance of tooth restored with gold inlay. A profound understanding of the isthmus width factor, which is one of the several parameters of cavity designs, would facilitate the appropriate cavity preparation in a specific clinical situation. In this study, the cavities for gold inlay were prepared in maxillary left first premolar. A three-dimensional model was designed using I-DEAS program. The model was composed of 2515- nodes and 2172 isoparametric brick elements. In the model isthmus width was varied into 1/4, 1/3 and 1/2 of intercuspal width respectively, and numeric values of the material properties of enamel, dentin and gold was set. Three types of load : concentrated load, divided load and distributed load was 500N. The empty cavities in the model were also examined using divided load and distributed load. The three - dimensional Finite Element Method was used to analysis the displacement and stress distribution. The results were as follows : 1. All of the experimental models which were filled with gold inlay revealed similar direction of displacement to that of the natural tooth model under the same load type. But in the models with empty cavities, as the isthmus width increased, the degree of displacement increased in the case of divided load type. 2. All experimental models which were filled with gold inlay showed stress concentration at load points, but in the models with empty cavities at divided load type, as isthmus width increased, stress was concentrated at the comer of the pulpal floor. 3. In the models with empty cavities at divided load type, tooth fracture was expected regardless of isthmus width, but all experimental models which were filled with gold inlay after cavity preparation were not susceptible to fracture. 4. In all experimental models which were filled with gold inlay after cavity preparation, displacement patterns were similar under both concentrated and divided load types. In the models with empty cavities, a divided load resulted in a bucco-lingual cuspal displacemenat in both sides, but a distributed load resulted in a lingual displacement of the tooth.

  • PDF