• 한국공작기계학회논문집
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• 제16권5호
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• pp.101-107
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• 2007

Assembly is mentioned as important process saving time and cost where we produce the machine with many parts relationships. In this study, parts assembly relationship is analysed for assembly information of micro milling machine which have been developing for research. Liaison diagram, datum flow chain and assembly tree are applied to discuss assembly characteristics of micro milling machine model. We can find out the characteristics of micro machine assembly and discuss about facility of assembly. Some analysis in this paper about micro milling machine will give a useful tools for assembly. We knew that the predicted results from analysis in this study are alignment and clearance among the parts. The 3D model of micro machine which is studied in this paper is not a complete model. Main parts of a micro milling machine are used and presented.

• 대한기계학회논문집
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• 제13권1호
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• pp.48-58
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• 1989

이 논문의 목적은 사용자가 부품간의 연결정보로는 단지 만남조건 (mating condition)만을 입력함으로써 조립체가 생성이 되고 또 그로부터 동역학 또는 기구학적 해석 프그램과의 연결을 위한 정보가 유도되는 조립체 모델링 시스템(assembly modeling system)을 개발하는 것이다. 만남조건을 통해 조립체를 생성하는 방법은 이미 Rocheleau와 Lee에 의해 개발되었으나 그들은 주로 각 부품의 위치를 찾아내는 데에만 관심을 두었고 본 논문에서는 그것의 확장으로 해석 프로그램과 연결시키는데 필요한 정보의 유도를 추가로 고려하였다.

• 한국CDE학회논문집
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• 제9권1호
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• pp.62-76
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• 2004

Many customers are no longer satisfied with mass-produced goods. They are demanding customization and rapid delivery of innovative products. Many companies are now realizing that the best way to reduce life cycle costs is to evolve a more effective product development paradigm using Internet and web based technologies. Yet there remains a gap between current market demands and product development paradigms. The existing CAD systems require that product developers possess all the design analysis tools in-house making it impractical to employ all the needed and newest tools. Hence, this paper addresses how assembly operation analysis can be embedded transparently and remotely into a service-oriented collaborative assembly design environment. A new assembly operation analysis framework is introduced and a relevant architecture and tools are developed to realize the framework. Instead of the current sequential process for verifying and validating an assembly design, a new Virtual Assembly Analysis (VAA) method is introduced in the paper to predict the various effects of joining during actual collaborative design. As a case study, arc welding and riveting processes are investigated. New service-oriented VAA architecture and its VAA components are proposed and implemented on prototype mechanical assemblies.

• Nuclear Engineering and Technology
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• 제30권3호
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• pp.212-221
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• 1998

In the present study, a method for the dynamic analysis of a reactor core is developed. Peak responses for the motions induced from earthquake are obtained for a core model. The dynamic responses such as fuel assembly shear force, bending moment, axial force and displacement, and spacer grid impact loads are investigated. Prediction of fuel assembly stress during an earthquake requires development of a fuel assembly stress analysis model capable of interfacing with the models and results discussed in the dynamic analysis of a reactor core. This analysis uses beam characteristics which describe the overall fuel assembly response. The stress analysis method and its application for the case of an increased seismic level are also presented.

• Nuclear Engineering and Technology
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• 제46권4호
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• pp.529-540
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• 2014

In this research, a drop impact analysis of a fuel assembly in a research reactor is carried out to determine whether the fuel plate integrity is maintained in a drop accident. A fuel assembly drop accident is classified based on where the accident occurs, i.e., inside or outside the reactor, since each occasion results in a different impact load on the fuel assembly. An analysis procedure suitable for each drop situation is systematically established. For an accident occurring outside the reactor, the direct impact of a fuel assembly on the pool bottom is analyzed using implicit and explicit approaches. The effects of the key parameters, such as the impact velocity and structural damping ratios, are also studied. For an accident occurring inside the reactor, the falling fuel assembly may first hit the fixing bar at the upper part of the standing fuel assembly. To confirm the fuel plate integrity, a fracture of the fixing bar should be investigated, since the fixing bar plays a role in protecting the fuel plate from the external impact force. Through such an analysis, the suitability of an impact analysis procedure associated with the drop situation in the research reactor is shown.

• 한국생산제조학회지
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• 제19권2호
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• pp.178-183
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• 2010

Base-mounted type(BMT) driving assembly in CNC machine tools is an indispensable part to improve productivity by reducing tool changeover time and to meet the ever-increasing demand of precision machine tools. This study aimed to perform finite element analysis and geometric parameter optimization to improve the efficiency of BMT driving assembly. First, simulations for three-dimensional structural and vibration analysis were performed using ANSYS/Workbench on the initial geometric models of BMT driving assembly. After analyzing stress and deformation concentration zones, several new geometrical models were designed and evaluated by design of experiments and ANSYS/DesignXplorer. Through a series of analysis-evaluation-modification cycles, it was seen that designed models were effective in determining optimal geometry of BMT driving assembly.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3353-3360
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• 2022

Using data from the design earthquake of the Korean standard nuclear power plant, seismic analyses of a fuel assembly are conducted in this study. The modal characteristics are used to develop an input deck for the seismic analysis. With a time history analysis, the responses of the fuel assembly in the event of an earthquake are obtained. In particular, the displacement, velocity, and acceleration responses at the center location of the fuel assembly are obtained in the time domain, with these outcomes then used for a detailed structural analysis of the fuel rods in the ensuing analyses. The response spectra are also generated to determine the response characteristics in the frequency domain. The structural integrity of the fuel assembly can be ensured through this type of time history analysis considering the input excitations of various earthquakes considered in the design.

• 한국콘텐츠학회논문지
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• 제16권12호
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• pp.143-150
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• 2016

다양한 접합부간의 조립으로 구조를 이루게 되는 모듈러공법에서 현장설치단계의 모듈조립은 구조물의 구조적인 안정성 및 품질에 직접적인 영향을 미칠 수 있는 매우 중요한 공정이다. 그러나 일반적으로 사용되는 수공구 또는 전동공구는 장시간 사용 시 생산성과 조립품질이 저하되는 문제점을 가지고 있다. 이에 에어공구의 장점을 활용한 모듈러주택 전용 조립공구가 개발되었으나, 공구별 성능을 비교하여 성능을 비교 및 평가하는 실험적인 분석은 미흡하였다. 이에 본 연구는 모듈러주택 조립에 사용되는 기존 조립용 공구와 모듈조립용 에어공구를 현장에 적용하여 구조물의 조립품질과 생산성을 공구별로 측정하여 비교 분석 하였다. 그 결과, 기존 조립용 공구와 비교하여 모듈조립용 에어공구가 생산성 및 품질 측면에서 더 우수한 것으로 분석되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.243-244
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• 2016

The assembly of the modular housing is an important phase in the construction of pre-fabricated houses. However, the assembly tools that are commonly used in a work site have a disadvantage of decreasing the productivity and the quality. We have developed a exclusive tool for assembling modular parts. The structural stability of the developed tool has been verified in the previous studies. However, the experimental analysis was not conducted. This study analyzed the effect of improving the productivity and quality of the developed assembly tool. The result of the experimental analysis shows improvements in productivity and quality compared to the conventional assembly tool.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1514-1524
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• 2006

This work presents the three-dimensional analysis of flow and heat transfer performed for a wire-wrapped fuel assembly of liquid metal reactor using Reynolds-averaged Wavier-Stokes analysis in conjunction with 557 model as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary conditions at inlet and outlet of the calculation domain. Three different assemblies, two 7-pin wire-spacer fuel assemblies and one bare rod bundle, apart from the pressure drop calculations for a 19-pin case, have been analyzed. Individual as well as a comparative analysis of the flow field and heat transfer have been discussed. Also, discussed is the position of hot spots observed in the wire-spacer fuel assembly. The flow field in the subchannels of a bare rod bundle and a wire-spacer fuel assembly is found to be different. A directional temperature gradient is found to exist in the subchannels of a wire-spacer fuel assembly Local Nusselt number in the subchannels of wire-spacer fuel assemblies is found to vary according to the wire-wrap position while in case of bare rod bundle, it's found to be constant.