• 제목/요약/키워드: Geometrical characteristic

검색결과 157건 처리시간 0.029초

볼엔드밀 가공면의 기하학적 특징선 해석 (Analysis of the Characteristic Lines on Geometrical Texture by Ball end Milling)

  • 정태성;최인휴;양민양
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1148-1153
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    • 2003
  • An adequate method for the prediction of machining errors is essential to improve productivity and product quality. But it is known that there is a remarkable difference between values calculated by conventional roughness model and measured values of actual machined surfaces under high efficient cutting condition. This paper introduces the theoretical analysis of characteristic lines of cut remainder to evaluate a geometrical surface roughness accurately. In this study, analytic equations of the characteristic lines are derived from the surface generation mechanism of ball end milling considering the actual trochoidal trajectories of cutting edges. The predicted results are compared with the results of conventional roughness model.

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Economic Design of the Specification for Geometrical Quality Characteristic

  • Ma, Yizhong;Zhao, Fengyu;Xu, Jichao
    • International Journal of Quality Innovation
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    • 제2권1호
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    • pp.50-57
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    • 2001
  • The economic design of specification limits must be determined on an economic basis where we minimize total loss to society, which consists of both the producer and the consumer. Economic specification limits have been developed based on the assumption that the quality characteristic is normally distributed. Unfortunately, the assumption is not to meet some practical cases. In this paper, some non-normal distributions are considered for quality characteristic with geometrical features. An economic model for selecting the optimum specification limits on the basis of minimizing total cost is introduced. A case study is presented to illustrate the application in practice.

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평면 작업용 병렬 메카니즘의 특성 해석을 위한 기하학적 접근 (A Geometrical Approach to the Characteristic Analysis of Parallel Mechanism for Planar Task)

  • 송낙윤;조황
    • 한국정밀공학회지
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    • 제15권9호
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    • pp.158-166
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    • 1998
  • This paper presents a geometrical approach to the characteristic analysis of parallel mechanism with free joints intended for use as a planar task robot. Solution of the forward and inverse kinematic problems are described. Because the mechanism has only three degree-of-freedom output, constraint equations must be generated to describe the inter-relationship between actuated joints and free joints so as to describe the position and orientation of the moving platform. Once these constraints are incorporated into the kinematics model, a constrained Jacobian matrix is obtained. and it is used for the solution of the forward kinematic equations by Newton-Raphson technique. Another Jacobian matrix was derived to describe the interrelationship between actuated joints and moving platform. The stiffness, velocity transmission ratio, force transmission ratio and dexterity of the mechanism are then determined based on this another Jacobian matrix. The geometrical construction of the mechanism for the best performance was investigated using the characteristic analysis.

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가스보일러 연소실 공기분배판의 기하학적 형상에 따른 유동특성 해석 (Flow Characteristic Analysis in Accordance with Geometrical Modification of Air Distribution Plate in Gasboiler Combustion Chamber)

  • 김재중;손영갑;장석원;유동수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.859-864
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    • 2000
  • This paper reports a numerical flow characteristic analysis in gas boiler combustion chamber. The numerical results with simplification and assumptions were found within 30% of the experiment. A lot of geometrical modification has been invested in attempt to obtain the uniform flow in the combustion chamber exit. As a result, the velocity magnitude of the combustion chamber is relate with the hole size in air distribution plate. The velocity uniformity of the combustion chamber is relate with the number of holes and location in air distribution plate.

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Cuban-8형 수평축 풍력터빈의 수학적 모델링에 관한 연구 (A Study on the Mathematical Modelling of Cuban-8 Type Horizontal Axis Wind Turbine)

  • 황창수;조환기;정형석
    • 신재생에너지
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    • 제4권3호
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    • pp.36-44
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    • 2008
  • This paper discusses about the mathematical modelling of a new conceptual shape of horizontal axis wind turbine. The geometrical characteristic of wind turbine is studied for the variation of azimuthal angles and elevation angles. The projecting trajectories of Cuban-8 blade due to rotation are analyzed on the each plane in the Cartesian coordinate system. Trajectories show several interesting graphical patterns since the geometrical shape is complicated with the rotational motion of two twisted circumferential blades with elevation angles.

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삼차원 단조공정의 지능적 시뮬레이션 (Intelligent Simulation of Three-Dimensional Forging Process)

  • 이민철;전만수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.155-159
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    • 2007
  • We conduct intelligent simulation of three-dimensional forging processes in this paper. A new remeshing technique is employed for this purpose. Not only the state variables including strain and strain-rate but also the geometrical features including die-material contact conditions and the characteristic lines or surfaces are taken into account during remeshing. The presented approach is applied to the Baden-Baden benchmark test example and its influence on the simulated results is discussed particularly in terms of the deformed shape with emphasis on the characteristic line.

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Snap-through buckling of single-layer squarely-reticulated shallow spherical shells continuously supported on springs

  • Nie, G.H.
    • Structural Engineering and Mechanics
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    • 제10권2호
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    • pp.111-123
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    • 2000
  • An asymptotic solution for snap-through buckling of single-layer squarely-reticulated shallow spherical shells continuously supported on springs is developed in this paper. Based on the fundamental governing equations and boundary conditions, a nondimensional analytical expression associated with the external load, stiffness of spring and central transverse displacement (deflection) is derived with the aid of asymptotic iteration method. The effects of stiffness of spring and characteristic geometrical parameter on buckling of the structures are given by the analyses of numerical examples. In a special case, for reticulated circular plates, the influence of stiffness of spring on the characteristic relation between load and deflection is also demonstrated.

광선 추적법을 이용한 우주 환경에서의 안테나 전파 특성 예측 (Prediction of Antenna Propagation Characteristic in Space Environment Using Ray Tracing Method)

  • 김창성;박용배
    • 한국전자파학회논문지
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    • 제27권11호
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    • pp.1023-1026
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    • 2016
  • 우주 환경에서의 굴절률 변화를 고려하여 안테나의 전파 특성을 계산한다. 대류권, 성층권, 전리권의 유효 굴절률을 계산하고, 대기권을 통과하면서 굴절되고 감쇠되는 전파 특성을 계산하기 위해 광선 추적법, 기하광학법, 호이겐스의 원리를 이용한다.

원통형 및 육면체 텅스텐 관통자의 기하형상비에 따른 관통 특성 (Penetration Characteristic of Cylindrical and Cubic Tungsten Penetrator due to Geometrical Shape Ratio)

  • 이상원;이영신;조종현;배용운
    • 한국CDE학회논문집
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    • 제18권5호
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    • pp.367-373
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    • 2013
  • In this study, the penetration characteristic from the cubic and cylindrical penetrator consisting of tungsten material with the velocity of 2,300 m/s is evaluated and the penetration possibility into the target is confirmed. The design of shape and size of penetrator is directly related to space and weight of the warhead. AUTODYN-3D simulation is used to study the penetration effect of penetrator. The purpose of numerical analysis is to verify the penetration characteristic with various L/D penetrator. The penetration performance of penetrator with identical weight due to the shape is also confirmed. The cylindrical and cubic penetrator has enough penetration energy on constant target body. Because the possibility of 2'nd penetration is important factor after 1'st penetration into target body, residual velocity of residual mass must be existed as much as possible. As geometrical shape ratio increases, penetration performance is confirmed to improve.

Aerodynamic stability analysis of geometrically nonlinear orthotropic membrane structure with hyperbolic paraboloid in sag direction

  • Xu, Yun-ping;Zheng, Zhou-lian;Liu, Chang-jiang;Wu, Kui;Song, Wei-ju
    • Wind and Structures
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    • 제26권6호
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    • pp.355-367
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    • 2018
  • This paper studies the aerodynamic stability of a tensioned, geometrically nonlinear orthotropic membrane structure with hyperbolic paraboloid in sag direction. Considering flow separation, the wind field around membrane structure is simulated as the superposition of a uniform flow and a continuous vortex layer. By the potential flow theory in fluid mechanics and the thin airfoil theory in aerodynamics, aerodynamic pressure acting on membrane surface can be determined. And based on the large amplitude theory of membrane and D'Alembert's principle, interaction governing equations of wind-structure are established. Then, under the circumstance of single-mode response, the Bubnov-Galerkin approximate method is applied to transform the complicated interaction governing equations into a system of second-order nonlinear differential equation with constant coefficients. Through judging the frequency characteristic of the system characteristic equation, the critical velocity of divergence instability is determined. Different parameter analysis shows that the orthotropy, geometrical nonlinearity and scantling of structure is significant for preventing destructive aerodynamic instability in membrane structures. Compared to the model without considering flow separation, it's basically consistent about the divergence instability regularities in the flow separation model.