• Title/Summary/Keyword: Intersection Design

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Generation of 5-axis NC Data for Machining Turbine Blades by Controlling the Heel Angle (Heel angle 조정에 의한 터빈 블레이드의 5축 NC가공 데이터 생성)

  • 이철수;박광렬
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.2
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    • pp.110-120
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    • 1999
  • In general, turbine blades are usually machined on 5-axis NC machine. The 5-axis machining of sculptured surface offers many advantages over 3-axis machining including the faster material-removal rates and an improved surface finish. But it is difficult and time-consuming to generated interference-free 5-axis tool path. This paper describes research on the algorithm for generation of an interference-free 5-axis NC data for machining turbine blades. The approach, using the section profile derived from the intersection of cutting planes with a triangulated-surface approximation, includes (1) CL-data generation by detecting an interference-free heel angle (2) the calculation method for finding a adaptive feed-rate value, and (3) the inverse kinematics depending on the structure of 5-axis machine.

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Extracting a Regular Triangular Net for Offsetting (옵셋팅을 위한 정규 삼각망 추출)

  • Jung W.H.;Jeong C.S.;Shin H.Y.;Choi B.K.
    • Korean Journal of Computational Design and Engineering
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    • v.9 no.3
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    • pp.203-211
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    • 2004
  • In this paper, we present a method of extracting a regular 2-manifold triangular net from a triangular net including degenerate and self-intersected triangles. This method can be applied to obtaining an offset model without degenerate and self-intersected triangles. Then this offset model can be used to generate CL curves and extract machining features for CAPP The robust and efficient algorithm to detect valid triangles by growing regions from an initial valid triangle is presented. The main advantage of the algorithm is that detection of valid triangles is performed only in valid regions and their adjacent selfintersections, and omitted in the rest regions (invalid regions). This advantage increases robustness of the algorithm. As well as a k-d tree bucketing method is used to detect self-intersections efficiently.

Optimization of Composite Laminated Plate Using Fuzzy Set Theory (퍼지 이론을 이용한 복합재 적층판의 최적설계)

  • 홍영기;이종호;구만회;우호길
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.11a
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    • pp.63-67
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    • 1999
  • This paper presents the optimization of CFRP laminated rectangular plates using fuzzy theory. In optimization, thickness of CFRP lamina and fiber angle are taken as design variables, and total thickness of the plates is minimized under Tsai-Hill failure criterion. The uncertainties are entered by introducing fuzzy material strengths and then the objective and constraints are represented by a membership function of their own according to the intersection method. Various design results are presented for the CFRP laminated composites plates.

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The study of bending and buckling behavior of sandwich structure according to design parameter variation (설계변수 변화에 따른 샌드위치 구조물의 굽힘 및 좌굴 거동에 관한 연구)

  • 한근조;안성찬;안성찬;김진영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.841-844
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    • 1997
  • Sandwich structure is widely used in various fields of industry due to its excellent strength and stiffness compared with weight. We studied the buckling and bending behavior with respect to the variation of design parameters such as length, height, and thickness of honeycomb sandwich core. We found that as the density and the thickness of core become higher, the value of critical bucking load increased significantly. We found that the effect of bending stress due to critical buckling load resulted in high bending stress and the value of bending stress decreased in half according to the increase of length of core. The effect by bending stress is dominant above the portion of the intersection line between bending stress and the effect of buckling is dominant below the potion of it. We could get proper thickness ratio and density of core according to applied load conditions.

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A Study on Design of a Damper for Reducing Torsional Vibrations of a Driveline with Universal Joints (Universal Joint를 갖는 구동축 시스템의 비틀림 진동 감소를 위한 Damper의 적정설계에 관한 연구)

  • Park, Bo-Yong;Song, Chang-Seop;Kang Hyo-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.4
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    • pp.137-145
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    • 1991
  • A universal joint is a connecting device of two hinges which can transmit torque from one shaft to another at fixed or at varying angles of intersection. It has been used properly not only as rotational but also as intermittent motion. For the particular kinematics condition of a universal joint, torsional and bending vibrations are produced excessively in an elastic driveline. In this paper only the torsional vibration behavior of a driveline with universal joints is analyzed numerically with the discrete model and a design method of the dynamic vibration damper is proposed, in order to reduce torsional vibrations especially in resonance region as a result of parametric variation.

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A Brief History of Study on the Bound for Derivative of Rational Curves in CAGD (CAGD에서 유리 곡선의 미분과 그 상한에 관한 연구의 흐름)

  • Park, Yunbeom
    • Journal for History of Mathematics
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    • v.27 no.5
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    • pp.329-345
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    • 2014
  • CAGD(Computer Aided Geometric Design) is a branch of applied mathematics concerned with algorithms for the design of smooth curves and surfaces and for their efficient mathematical representation. The representation is used for the computation of the curves and surfaces, as well as geometrical quantities of importance such as curvatures, intersection curves between two surfaces and offset surfaces. The $B\acute{e}zier$ curves, B-spline, rational $B\acute{e}zier$ curves and NURBS(Non-Uniform Rational B-Spline) are basically and widely used in CAGD. The definitions and properties of these curves are presented in this paper. And a brief history of study on the bound for derivative of rational curves in CAGD is also presented.

A Study on the Role of Free-standing Wall in the Architectural Composition (건축구성에 있어서 가벽의 역할에 관한 연구)

  • 곽기표
    • Korean Institute of Interior Design Journal
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    • no.41
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    • pp.80-87
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    • 2003
  • This paper attempts to examine the historical changes, the characteristics and the role of free-standing wall from the viewpoint of architectural composition. After modern times the wall gets free of structure and the view of formative art changes, which become a basis of the conscious use of free-standing wall. It plays a role of getting territoriality and placeness, by defining the space at the external territory and it is used as apparatus which controls circulation and orientation externally At the same time it is used as an instrument to blur the border to make mutual intersection and plays a role of introducing and controling the environment. The free-standing wall controls the architectural form to emphasize plasticity and is used to define a geometrical frame and maintain the urban context. In view of the results so far achieved, the free-standing wall is used as general vocabulary of modulating the border of space and the architectural form since modern architecture.

The Detection of Inflection Points on Planar Rational $B\'{e}zier$ Curves (평면 유리 $B\'{e}zier$곡선상의 변곡점 계산법)

  • 김덕수;이형주;장태범
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.4
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    • pp.312-317
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    • 1999
  • An inflection point on a curve is a point where the curvature vanishes. An inflection point is useful for various geometric operations such as the approximation of curves and intersection points between curves or curve approximations. An inflection point on planar Bezier curves can be easily detected using a hodograph and a derivative of hodograph, since the closed from of hodograph is known. In the case of rational Bezier curves, for the detection of inflection point, it is needed to use the first and the second derivatives have higher degree and are more complex than those of non-rational Bezier curvet. This paper presents three methods to detect inflection points of rational Bezier curves. Since the algorithms avoid explicit derivations of the first and the second derivatives of rational Bezier curve to generate polynomial of relatively lower degree, they turn out to be rather efficient. Presented also in this paper is the theoretical analysis of the performances of the algorithms as well as the experimental result.

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Cluster-Based Quantization and Estimation for Distributed Systems

  • Kim, Yoon Hak
    • Journal of information and communication convergence engineering
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    • v.14 no.4
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    • pp.215-221
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    • 2016
  • We consider a design of a combined quantizer and estimator for distributed systems wherein each node quantizes its measurement without any communication among the nodes and transmits it to a fusion node for estimation. Noting that the quantization partitions minimizing the estimation error are not independently encoded at nodes, we focus on the parameter regions created by the partitions and propose a cluster-based quantization algorithm that iteratively finds a given number of clusters of parameter regions with each region being closer to the corresponding codeword than to the other codewords. We introduce a new metric to determine the distance between codewords and parameter regions. We also discuss that the fusion node can perform an efficient estimation by finding the intersection of the clusters sent from the nodes. We demonstrate through experiments that the proposed design achieves a significant performance gain with a low complexity as compared to the previous designs.

Geometrical Analysis on the Formation Mechanism of Milling Burr on Arbitrary Feature (임의형상의 버 발생 메카니즘의 기하학적 해석)

  • 이제열;안용진;김영진
    • Korean Journal of Computational Design and Engineering
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    • v.6 no.4
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    • pp.222-228
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    • 2001
  • In the milling operation, the burr can be generated on the intersection of cutting tool and workpiece. Due to burr formation, we expect lower efficiency in the operation and the cost increase. In order to understand the burr formation mechanism in the milling operation on the arbitrary feature, we developed an algorithm to analyse and predict the exit burr formation mechanism. Firstly, the recognition of arbitrary shaped workpiece was done through the CAD data. This data includes point information on the vertices of the workpiece. Secondly, tile CAM data regarding tool geometry, tool path, cutting speed, and material data are retrieved to simulate the actual cutting process. Thirdly, we predict the exit burr formation on the edge of workpiece based on the geometric analysis. Lastly, an algorithm implemented in the Windows environment to visualize the burr formation simulation. With this information, we can predict which portion of workpiece would have the exit burr in advance so that we call manage to find a way to minimize the edit burr formation in the actual cutting.

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