• 한국정밀공학회지
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• 제13권6호
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• pp.78-89
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• 1996

Every mechanical component is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums. Since the range of shape variation can be represented by the variation of the coordinate system attached to the shape, the transformation matrix of the coordinate system would mathematically express the range of shape variation if the interval numbers are inserted for the elements of the transformation matrix. For the shape entity specified by the geometric tolerance with reference to datums, its range of variation can be also derived by propagating the transformation matrices composed of interval numbers. The propagation depends upon the order of precedence of datums.

• 대한기계학회논문집A
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• 제27권2호
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• pp.262-267
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• 2003

Error of the geometric series expansion method for the structural sensitivity analysis is estimated. Although the semi-analytic method has several advantages, accuracy of the method prevents it from practical application. One of the promising remedies is the use of geometric series formula for the matrix inversion. Its result of the sensitivity analysis converges that of the global difference method which is known as reliable one. To reduce computational efforts and to obtain reliable results, it is important to know how many terms need to expand. In this paper, the error formula is presented and Its usefulness is illustrated through numerical experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.660-662
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• 2000

It is demonstrated that the torque performance of the flux barrier type synchronous reluctance motor(SynRM) can be improved in terms of geometric parameters. Torque ana power factor are related to the difference of inductances and the saliency ratio. And these inductance characteristics are determined by the geometric parameters of rotor: the number of layers. the width of iron to the width of flux barrier($K_w$). slot number and shape, airgap, bridge, etc. The relationship between geometric parameters. especially, $K_w$ and motor performance will be studied. This paper shows that torque and power factor are improved through redesign with considering geometric parameters. Performance comparisons of proto type SynRM and improved SynRM are given by FEA(Finite Element Analysis).

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2004년도 추계 학술발표대회 논문집
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• pp.194-195
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• 2004

• 한국산학기술학회논문지
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• 제2권2호
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• pp.33-37
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• 2001

본 논문은 사출성형제품의 게이트 설계를 합리적으로 수행하기 위해 사출금형설계전문가의 축적된 지식과 경험을 발췌·정리하여 지식베이스를 작성하였으며, 설계에 필요한 제품의 형상정보를 제공하기 위해 총칭형상과 특징형상 개념을 이용하여 특징형상을 정의하였다. 또한 지식베이스를 통해 산출된 설계결과를 기하학적 모델러와의 인터페이스를 통해 3차원 형상으로 보여지도록 하였으며 최종 생성된 3차원 기하학적 형상정보는 CAE 모듈이나 CAPP 모듈에서의 후속작업을 위해 제공될 수 있도록 구축되었다.

• 대한기계학회논문집
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• 제19권1호
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• pp.301-309
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• 1995

Shape optimal design of an excavator boom to minimize weight can be formulated as a nonlinear programming problem with an automesh refinement carried out by using the finite element method. The design variables are the radii and the coordinates of the circle to describe the excavator boundary shape. In addition to the displacement and stress constraints, geometric constraints are imposed such that the nodes cannot cross the certain range. The optimum design is obtained by using the PLBA nonlinear programming code. The sensitivity derivatives are calculated using the semi-analytical scheme. Numerical results of an excavator boom show potential for weight reduction of 4.4%(65.6 kgf) when considering the displacement, stress and geometric constraints.

• 한국CDE학회논문집
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• 제3권2호
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• pp.113-120
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• 1998

Calculation of intersection points by two curves is fundamental to computer aided geometric design. Bezier clipping is one of the well-known curve intersection algorithms. However, this algorithm is only applicable to Bezier curve representation. Therefore, the NURBS curves that can represent free from curves and conics must be decomposed into constituent Bezier curves to find the intersections using Bezier clipping. And the respective pairs of decomposed Bezier curves are considered to find the intersection points so that the computational overhead increases very sharply. In this study, extended Bezier clipping which uses the linear precision of B-spline curve and Grevill's abscissa can find the intersection points of two NURBS curves without initial decomposition. Especially the extended algorithm is more efficient than Bezier clipping when the number of intersection points is small and the curves are composed of many Bezier curve segments.

• 산업경영시스템학회지
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• 제32권1호
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• pp.85-93
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• 2009

In this paper, the geometric design for the body of a 3"-PFA-lined plug valve is concerned, and body model which has less deformed PFA-resin after infection molding process is proposed. A CAE software is used to simulate the deformation due to heat in cooling. To reduce the deformation, some small shapes are added to PFA-resin surfaces related on wall of the valve housing. And thermal stress simulation with FEM methodology is followed after that. Also, the 3D-CAD package is used during the design processes. In this study, I tried to present the possibility to use the FEM analysis in the solid modeling process. So, the design engineer will be able to use analysis package effectively on his job within the limited range.

• 한국소음진동공학회논문집
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• 제26권1호
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• pp.63-68
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• 2016

This research investigates the deployment time of an active hood lift system(AHLS) activated a gunpowder actuator for the passenger vehicle. The deployment time of the system is investigated by changing the principal design parameters of the system. In order to achieve this goal, after introducing the geometric structure and operating principle of the AHLS, the dynamic equations of the system are formulated for deploying motion. Subsequently, using the dynamic equations, the deployment time of the system is determined by changing several geometric design parameters such as location of actuator. It is then identified which design parameters are main factors to affect the deployment time of AHLS.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권12호
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• pp.596-607
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• 2006

This paper presents Single Phase Switched Reluctance Motor (SPSRM) optimum design for vacuum cleaners using Response Surface Methodology (RSM) to determine geometric parameters, and the 2-D Finite Element Method (FEM) has been coupled with the circuit equations of the driving converter. Additionally, an optimum process for SPSRM has been proposed and peformed with geometric and electric parameters thereby influencing the inductance variation and effective torque generation as design variables. SPSRM performances have also been analyzed to determine an optimal design model for maximized efficiency at high power factor. In order to confirm the propriety of the Finite Element Method and motor performance calculation, simulation waveform and experiment waveform for motor voltage and current were compared.