• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.96-96
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• 2009

The purpose of this study is to clarify the transitional behavior and main factor of excessive welding distortion caused by fabrication process of STS 304 vacuum vessel having double curvature for the efficient quality control of vacuum vessel. In order to do it, the predictive equations of the welding distortion in simple weldment of vacuum vessel were established by conventional finite element analysis. And the principal factor controlling the welding distortion was identified by evaluating the welding distortion of vacuum vessel in each fabrication process with FEA and simplified thermo elastic method. Based on the results, the principal factors of distortion of vacuum vessel were clarified as angular distortion and transverse shrinkage which are a source of excessive out-of plane distortion in the double curved vacuum vessel. It was expected that the FE analysis results of this study could contribute to establish the proper control method of welding distortion for double curved vacuum vessel.

• 한국산학기술학회논문지
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• 제18권1호
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• pp.1-7
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• 2017

RAR(Reinforced Abutment for Railways)은 뒤채움을 선 시공하고, 교대를 후 시공하여 접속부의 침하와 교대 수평토압 및 변위를 저감할 수 있는 교대 구조로 교대 구체 및 저판의 사이즈와 말뚝의 설치 수를 줄인 경제적인 교대 구조이다. 본 논문에서는 말뚝 설치 수에 따른 RAR의 성능을 수치 해석을 이용하여 평가하였다. 말뚝의 설치 수를 1~4열을 적용한 RAR을 지반 변형계수를 달리한 조건에 대하여 수치 해석을 수행하고, 그 결과를 동일한 지반 조건에서 기존 교대의 수치해석결과와 비교, 분석하였다. 해석결과 말뚝 설치 수를 증가시키는 경우 접속부 침하저감 효과는 비교적 크지 않았고, 교대수평변위 및 토압 저감에 더 효과적인 것으로 나타났다. 말뚝 설치 열 수가 1~4열로 변할 때 RAR의 수평변위는 기존교대의 26~37%, 수평토압은 59~83%수준으로 말뚝 설치수가 증가할수록 기존교대(말뚝5열)에 비해 수평변위와 토압을 크게 저감할 수 있는 것으로 나타났다. 또한 RAR의 수평 토압은 보강재, 말뚝, 기초저판, 원지반 강성 등의 영향을 복합적으로 받는 것으로 평가되었다.

• Journal of Mechanical Science and Technology
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• 제17권6호
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• pp.896-905
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• 2003

A linear motor has many advantages next to conventional feed mechanisms: high transitional speed and acceleration, high control performance, and good positioning accuracy at high speed. Through the omission of a power transfer element, the linear motor shows no wear and no backlash, has a long lifetime, and is easy to assemble. A disadvantage of the linear motor is low efficiency and resultant high-temperature rise in itself and neighboring structures during operation. This paper presents the thermal behavior of the linear motor as a feed mechanism in machine tools. To improve the thermal behavior, an insulation layer is used. By placing the insulation layer between the primary part and the machine table, both the temperature difference and the temperature fluctuation in the machine table due to a varying motor load are reduced.

• International Journal of Precision Engineering and Manufacturing
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• 제2권3호
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• pp.61-68
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• 2001

A linear motor has a lot of advantages in comparison with conventional feed mechanisms: high transitional speed, acceleration, high control performance and good positioning at high speed. Through the omission of a power transfer element, the linear motor shows no wear and no backlash, has along lifetime and is easy to assemble. Recently, the two types of linear motors, asynchronous and synchronous linear motors, are often applied to machine tools as a fast feed mechanism. In this paper, a comparison between the two types of linear motors as to power loss and thermal behavior is made. The heat sources of the linear motor-the electrical power loss in the motor and the frictional heat on the linear guidance-are measured and compared. Also, the temperature on the linear motor and machine structure is measured and presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.528-532
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• 1997

The structure of satellite was of six parts of control system, power system, thermal control system, remote measurement command system, propellant system and thrust system. In these parts, propellant system consists of propellant tank and thrust device. What we want to perform is optimum design to minimaize the weight of propellant tank. In order to design optimal propellant tank, several parameters should be adopted form the tank geometry like the relative location of the lug and variation of the wall thickness. So the analysis was executed by finite element analysis for finding optimal design parameters. The structure was devided into 3 parts, the initial thickness zone, the transitional zone, and the weak zone,whose effects on the pressure vessel strength was investigated. Finally the optimal lug location and the three zone thickness were obtained and the weight was compared with the uniform thickness vessel.

• 디자인학연구
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• 제3권1호
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• pp.71-81
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• 1990

Style have been changing by the situations and the background of contemporary politics, society and economics, and which influence significantly to create new forms. Since the style of ART DECOC 1929s -1930s) has been studied with main reference to its cause and motivation, it is known that the style of ART DECO is one that has given $$\mu$h potential and chance to the development of interior design.In the study, it was focussed on to study on interior design, architecture, funiture, etc. in America where ART DECO had been once successful in his career. The following are the contents of the study implying the establishment of directions concerning styles in accordance with the transitional process of the era, etc.; i.e., the purpose of the study, the range + period of the study, contemporary backgrounds, elements of ART DECO' style, ART DECO in AmericaCthe background of ART DECO s subject, etc.).The writer of this study, while referring to the study and groping for any help to finding a brilliant concept of design and the merit of the trend of a contemporary era, hope to contribute more my own interior design.

• 한국조경학회지
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• 제20권2호
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• pp.43-61
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• 1992

Recently, people in urban areas ask for the creation of space for amenity and improvement of environmental problems, in such a condition the activation and reformation of city have become an important subject. The basic element of a city structure is the street. Therefore in this study, a transition of street spaces of a city was investigated. This study will be a basis for the planning of urban space in order to realize a comfortable and fascination urban life. In this paper, the study areas chosen were "Ginza", "Kyobashicho", "Nihonbashicho", "Honcho", "Tsukizi", "Hatchoboricho", "Ningyocho", "Ningyocho" which are the central places and business areas of capital Tokyo of Japan. The main streets were chosen for investigative subjects because they were planned as making a division of block in a city planning. Using maps and references the data was illustrated and the investigation was focused on the period from the Edo era to present time. (1) A periodical division for the basis of a street transition. (2) Consideration of methods in a plan and design for street spaces in each period. (3) A special feature and process of a street transition in each period. (4) A structure of a street and a construction form. (5) A classified structure of streets. (6) A process of a transition for each street.

• 한국실내디자인학회논문집
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• 제14권5호
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• pp.44-51
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• 2005

This study focuses 'Korean characteristics' in architectural interior design. In this study, some Korean characteristics was extracted by analysing traditional Korean spaces and as well as by considering the architectural interior spaces which are designed with Korean character since 1970. This paper started with differenciating the elements and principles that consist of space, and then classified the elements into 8 categories such as Spatial system, Enclosure system, Circulation system, Material system, Furnishing system, Light, Color, Context which are analysing frames. As a conclusion, the concepts of Korean characteristics are extracted and suggested as design concept with Korean characteristics by analysing the contents of each category. These concepts were presented with simple diagrams and supporting cases were also presented in this paper. The design concepts of 'Korean characteristics' are classified in the 25 concepts: Holonic composition, Transitional space, Hierarchy by floor level, Gradation of privacy, Changeability, Various central yards, Space with opened edges, Gray space, Continuity of space, Translucent wall, Folding-lifting wall, Skeleton, Abstract facet, Path as a message, Mild light, Multii-layered vista, Fluidity, framed scenery, Serial view, Interpenetrating Space, Harmony with nature, Organic interrelationship, Complementary Dual Structure, Temporal change of space, Hierarchical order.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.606-611
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• 2000

It has been noted that the low frequency absorption coefficient of a porous sample placed in a standing wave tube is affected by the nature of the sample's edge constraint. The edge constraint has the effect of stiffening the solid phase of the sample, which itself can be strongly coupled to the material's fluid phase, and hence the incident sound field, by viscous means at low frequencies. In recent work it has also been shown that such a circumferential constraint causes the low frequency transmission loss of a layer of fibrous material to approach a finite low frequency limit that is proportional to the flow resistance of the layer and which is substantially higher than that of an unconstrained sample of the same material. However, it was also found that the benefit of the circumferential edge constraint was reduced in a transitional frequency range by a shearing resonance of the sample. Here it will be shown that the effect of that resonance can be mitigated or eliminated by adding additional axial and radial constraints running through the sample. It will also be shown that the constraint effect can be modeled closely by using a finite element procedure based on the Biot poroelastic theory. Implications for low frequency barrier design are also discussed.

• 한국주조공학회지
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• 제30권4호
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• pp.130-136
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• 2010

Sulfide segregation behavior, characteristics of solidification microstructure and compositional distribution in the riser/castings junction of heavy-section main bearing support (MBS) steel castings were investigated; Sulfide streaks of A segregation were formed in the transitional region from columnar grain to coarse equiaxed grain and floated with aggregation of the dendritic free crystal. Solute segregation behaviors of elements Si, P and S were V shape negative segregation from the bottom of the castings to upper part of the riser with the reference of vertical center-line of the specimen block. Those of elements C and Mn were V shape negative segregation in the main body and A shape positive segregation in the riser of the casting. Just beneath the pipe shrinkage in the riser segregation ratio of each element was the highest, and that of S was 3.6 times higher, C 3.3 times, P 2.1 times, Si 1.6 times and Mn 1.0 times respectively. [Mn/S] ratio of the specimen block was distributed in the wide range of 20~275.