• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.491-498
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• 2000

This study was carried out about the design and FEM analysis of articulated Trailer car with aluminum bodyshell for Korean High Speed Train of maximum operating speed of 350㎞/h. The integral design by extra-long extruded sections made possible through the use of aluminium alloys and continuous window shape with skin were adopted in the design of aluminium bodyshell. Articulated structures in each trailer's end were bolted laterally on end structure. FEM analysis showed that the design satisfied the specified load criteria. This study describes process and result of development of aluminum trailer bodyshell for KHST.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.592-597
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• 2001

An automobile lower arm has been fabricated in a prototype form by hydroforming with the aids of numerical analysis and experiments. For the numerical process design, a program called HydroFORM-3D developed here on the basis of a rigid-plastic model, has been applied to the lower arm hydroforming. The friction calculation between die and workpiece has been dealt carefully by introducing a new scheme in three-dimensional surface integration. To accomplish successful hydroforming process design, thorough investigation on proper combination of process parameters such as internal hydraulic pressure, axial feeding, and tool geometry has been performed. Results obtained from numerical simulation for a lower arm in hydroforming process are compared with a series of experiments. The comparison shows that the numerical analysis successfully provides the manufacturing information on the lower arm hydroforming, and it predicts the geometrical deformation and the thinning.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 추계학술대회 논문집
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• pp.97-100
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• 2000

Today deep drawing and ironing are the major process in manufacturing of battery case used in cellular phone from aluminum. The same technology is utilized in manufacturing of steel or aluminum cans for components of medical instrument, portable PC, walkman and so on. Most of these processes require multi-stage ironing following the deep drawing and redrawing processes. The practical aspects of this technology are well known and gained through extensive experiment and production know-how. However, the fundamental aspects of theses processes are relatively less known. Thus, it is expected that process simulations using FEM techniques would provide additional detailed information that could be utilized to improve the process condition. This paper illustrates the application of process modeling to deep drawing and redrawing operations for High Precision Rectangular Battery Case. A commercially avaliable finite element code LS-DYNA3D was used to simulate deep drawing and redrawing operations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.125-127
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• 2001

Switched reluctance motor (SRM) has some advantages such as low cost, high torque density etc. However SRM has inevitably high torque ripple due to the double salient structure. To apply SRM to industrial field, we have to minimize torque ripple, which is the weak-Point of SRM. This paper presents optimal design process of SRM using numerical method such as 2D finite element method (FEM) and 3D equivalent magnetic circuit network method (EMCNM). The electrical and geometrical design parameters have been adopted as 2D design variables. The overhang structure of rotor has been also adopted as 3D design variable. From this work, we can obtain the optimal design, which minimize the torque ripple and maximize energy conversion loop.

• 소성∙가공
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• 제19권6호
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• pp.329-336
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• 2010

Ring forging process is more appropriate for high-length and thin walled ring, because it utilizes the forging press and hence does not require heavy-duty ring rolling mill. Although ring forging process is very simple and economic for facilities, the process is not efficient because of multi-forging-step and low material utilization. An effective ring forging process is developed using a hollow ingot. When a hollow ingot is used with a workpiece, the ingot can be forged into a final ring without multi-stage pre-forging process, such as, cogging, upsetting, and piercing, etc.. Finally it has advantages of the material utilization and process improvement because a few reheating and forging process are not necessary to make workpiece for ring forging. The important design variables are the applied plastic deformation energy to eliminate cast structure and make uniform properties. In this study, the mechanical properties after forging of hollow cast ingot were investigated from the experiment using circumferential sectional model. Also, the effects of process variables were studied by FEM simulation on the basis of thermo-visco-plastic constitutive equation. Applied strain is different at each position in length direction because diameter of hollow ingot is different in length direction. The different strain distribution become into a narrow gap by additional plastic deformation during diameter extension process.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1395-1401
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• 2010

A paradigm shift in driving system of transportation vehicle from engine to electric motor is required as the problems on air pollution and drain of petroleum resource are on the rize. Moreover while it is possible to control the motor with variable frequency driver, the application of motor in various kinds of vehicles is spread rapidly. In the paper, the effective design method of IPMSM for EV and HEV by using equivalent magnetic circuit and finite element method (FEM) is suggested. First of all, load conditions of the application are calculated. And basic design process of IPMSM is proposed with two design point. Finally, in order to verify the proposed design process, it was compared with the basic design parameter and the FEM analysis results.

• 한국기계가공학회지
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• 제2권2호
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• pp.75-83
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• 2003

Recently, the machine tools have been needed for high speed and accuracy to increase productivity. The most Important thing to get a more stabilized machine is to know the frequency response which has an effect on manufacture a lot. This problem should be considered seriously by many researchers. There are many application programs about FEM but Just using FEM program to get information of the object is not enough to put our confidence in the stability of the machine tool design. Therefore, the purpose of this research is to make a study for proving one of the ways to design to produce stabilized a machine more efficiently by comparing FRT method and FEM. At these two tests, we can learn about the frequency response area causing resonance and we can reconfirm the result to trust.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.291-295
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• 2003

The occurrence of ductile fracture is the working limit of many metal forming processes. It is necessary to predict the criteria and to apply the condition in a process design. Over the years. the way for clarifying conditions have been studied and presented. However such a way needs lots of experiments and analysis. In this study, in order to determine the critical damage value of a used material Cu 4N, it was performed a tensile test and FEM analysis by using DEFORM 2D. For applying the obtained critical damage value it was also performed a upsetting test by using DEFORM 2D. The way of determining a critical damage value which is presented in this study will make possible to find easily it which is one of the working limit factor. And the way of determining a critical damage value will make possible to find in multi-pass drawing process.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.143-147
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• 2003

Despite of outstanding optical performance of glass lens, glass lens have not been widely used because of poor productivity and high cost due to manufacturing process i.e. grinding, polishing. However, press-forming method of glass lens overcomes this disadvantage because of mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform precisely measured in order to prevent incomplete products and to increase in life of die. The present paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameter of open die is selected in standard of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.

• 소성∙가공
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• 제12권4호
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• pp.296-301
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• 2003

Though a glass tens has outstanding optical performance, it has not been widely used because manufacturing process shows poor productivity and high cost. However, press-forming method of glass lens overcomes these disadvantages with mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform is precisely measured in order to prevent incomplete products and to increase in life of die. The present. paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameters of open die are selected on the basis of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.