• 소성∙가공
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• 제9권3호
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• pp.284-292
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• 2000

Optimization of the process parameters is carried out for process design in sheet metal forming processes. The scheme incorporates with a rigid-plastic finite element method for the deformation analysis and response surface methodology for the optimum searching of process parameters. The algorithm developed is applied to design of the draw bead force and the die radius in deep drawing processes of rectangular cups. The present algorithm shows the capability of designing process parameters which enable the prevention of the weak part of fracture during processes.

• 소성∙가공
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• 제9권2호
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• pp.165-170
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• 2000

In this paper, a general approach to structural analysis of forging die sets is presented and the related design system, AFDEX/DIE, is introduced. Structural analysis of die sets is conducted by the finite element method considering both contact problem and shrink fit. In the approach, amount of shrink fit is controlled by thermal load, i.e., temperature difference between die insert and shrink rings. The loading conditions are extracted automatically from the simulation results obtained by a rigie-thermoviscoplatic finite element method. Typical application examples are given, which show the applicability of the approach and the related program.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1260-1265
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• 2001

It is important to model the mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structural dynamics. In the finite element modeling, the errors can be contained from the physical parameters, the approximation of the boundary conditions, and the element modeling, From the dynamic test. more precise dynamic characteristics can be obtained. Model updating using parameter modification is appropriate when the design parameter is used to analyze the input parameter like finite element method. Finite element analysis for free-free-free-free(FFFF) and clamped-free-free-free(CFFF) plate with uniform area and shape change are carried out as model updating examples, Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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• pp.233-240
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• 1998

In the design of the high-speed railway vehicles of low noise and vibration characteristics, it is desirable to develop efficient and systematic procedures for analyzing large structures. In this paper, some finite-element modelling techniques and an efficient analytical method are proposed for this purpose. The analytical method is based on substructuring approach such as a free-interface method and a generalized synthesis algorithm. In final, the proposed approaches are applied to the finite-element modelling, modal analysis and subsequent model updating procedures of the high-speed railway intermediate trailers.

• Steel and Composite Structures
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• 제29권5호
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• pp.623-633
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• 2018

A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is explicitly integrated into the element formulation, and, therefore, the P-${\delta}$ effect can be directly captured in the analysis. The series of zero-length springs are placed at the element ends to model the effects of semi-rigid joints and material yielding. One-element-per-member model is adopted for design bringing considerable savings in computer expense. The incremental secant stiffness method allowing for large deflections is used to describe the kinematic motion. Finally, several problems are studied in this paper for examining and validating the accuracy of the present formulations. The proposed element is believed to make DA simpler to use than existing elements, which is essential for its successful and widespread adoption by engineers.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.335-340
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• 2001

It is important to model the mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structure dynamics. In the finite element modeling, the errors can be contained from the physical parameters, the approximation of the boundary conditions, and the element modeling. From the dynamic test, more precise dynamic characteristics can be obtained. Model updating using parameter modification is appropriate when the design parameter is used to analyze the input parameter like finite element method. Finite element analysis for cantilever and simply supported beams with uniform area and shape change are carried out as model updating examples. Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권11호
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• pp.546-555
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• 2001

ln this paper, the optimum design of electrical apparatus using design variable parametrization is presented. For analysis and design, the finite element method and the design sensitivity method is used, respectively. By applying the parametrization of the design variables, the obtained designed shape is continuous and smooth. For the parametrization the Bezier spline is used. The designed shape with parametrization is characterized by the control points. By delivering control points to the commercial CAD packages or NC machines, the exact designed shape can be realized in the manufacturing the electrical apparatus. The designed results with and without parametrization are compared and the validity of the parametrization is verified.

• Journal of Magnetics
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• 제18권3호
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• pp.283-288
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• 2013

This paper presents structural topology optimization that is being applied for the design of electromagnetic vibration energy harvester. The design goal is to maximize the root-mean-square value of output voltage generated by external vibration leading structures. To calculate the output voltage, the magnetic field analysis is performed by using the finite element method, and the obtained magnetic flux linkage is interpolated by using Lagrange polynomials. To achieve the design goal, permanent magnet is designed by using topology optimization. The analytical design sensitivity is derived from the adjoint variable method, and the formulated optimization problem is solved through the method of moving asymptotes (MMA). As optimization results, the optimal location and shape of the permanent magnet are provided when the magnetization direction is fixed. In addition, the optimization results including the design of magnetization direction are provided.

• 대한전기학회논문지
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• 제35권12호
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• pp.567-572
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• 1986

In this paper, a new type of step motor with two degree of mechanical freedom, which is named rotary-Linear Step Motor(RLSM), is presented. Its rotor axis can perform linear and rotary motions either separately or simultaneously. This paper discribes the design of RLSM using finite element method in which the magnetic saturation effect of the iron core is taken into account. The design parameters such as torques, forces and inductances are obtained from the computed magnetic vector potentials. A new type of Rotary-Linear Step Motor was constructed. The calculated parameters agree well with measurements.

• 연구논문집
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• 통권32호
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• pp.111-120
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• 2002

In this paper, the design of a decatizing cylinder with uniformly distributed pressure in a decatizing system is investigated by using the Finite Element Method. Particularly, since deflection of a cylinder will not perform to iron the fabrics, the cylinder design insuring uniform pressure is very important. In this paper proposed two improved cylinder model obtained by changing the support type of the bean and the support location. And perform optimization with two improved cylinder model.