• Journal of the Korean Society for Precision Engineering
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• 제13권6호
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• pp.90-101
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• 1996

Determination of assembly sequence of components is a key issue in assembly operation. Although a number of articles dealing with assembly sequence determination have appeared, an efficient and general methodology for complex products has yet to appear. The objective of this paper is to present the problems and models used to generate assembly sequence from design data. An essential idea of this research is to acquire a finite number of voxels from any complex geometric entity, such as 3D planar polygons, hollow spheres, cylinders. cones, tori, etc. In order to find a feasible assembly sequence, the following four steps are needed: (1) The components composing of an assembly product are identified and then the geometric entities of each component are extracted. (2) The geometric entities extracted in the first step are translated into a number of voxels. (3) All the mating or coupling relations between components are found by considering relations between voxels. (4) The components to be disassembled are determined using CCGs (Component Coupling Graph).

• Journal of Korean Institute of Industrial Engineers
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• 제20권4호
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• pp.153-180
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• 1994

The assemblability is determined by the structure of product and the relationship between composing parts and machining parts. In this paper, the bolt was divided into bolt-head, -shaft, -thread and -end. For higher assemblability in bolting process, it was analyzed the geometric and technological characteristics of bolts were analysed regarding pre- and in-assembly process. And this paper presents the knowledge-based expert system to assist for designer in the processor of designing bolt for easier assembly. The developed expert system for supporting bolt design assemblability which is named as BDFA SYSTEM consists of two system such as "BOLT DESIGN SYSTEM" which provide feasible assembly bolt design to designer and "EVALUATION SYSTEM" which provide assembly evaluation to alternative of bolt design.

• Proceedings of the KSME Conference
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.300-304
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• 2007

The reactor head structure assembly(RHSA) is the structure located on the reactor assembly. The purpose of the assembly is providing interface location for cables, preventing pipe whips, prohibiting instruments from becoming missiles, and restraining CEDMs' horizontal motion. On the RHSA, reactor disconnect panels(RDP) are installed. The installation location of RDP is to be decided to minimize the geometric interface with other components. Since the neighborhood of RHSA is crowded due to many connectors and cables, it is necessary to find the good design of RHSA to make an intricate situation attenuated and the required function maintained. The geometric shape and overall configuration of RHSA are determined by axiomatic design approach. The FRs of RHSA are specified and the corresponding DPs are found to satisfy FRs in sequence. The finite element analysis is carried out based on the result of the axiomatic design to evaluate the structural integrity.

• Journal of the Korean Society for Precision Engineering
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• 제20권9호
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• pp.180-187
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• 2003

In engineering design environment it is hard to link design data and systems because the types of them are disparate. Therefore, the importance of metadata has increased. Some researches have been executed to develop metadata. But they cannot interact with other metadata and are difficult to extend. The purpose of this paper is to develop a common document structure which represents the general information of mechanical part assembly using XML, and to use it as base documents in order to integrate design data and systems. It is composed of part, assembly and user documents. Part document represents the information of a part independently to part type. Assembly document represents the location of constituent part documents. User document represents user's information. Common documents can be used as a broker between design data and systems, and it can improve the interpretability and reusability of document. We applied the developed common document structure to 2-stage spur gear drive.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제33권1호
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• pp.35-46
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• 2013

A parametric modeling method, one of the core technology of BIM (Building Information Modeling), is proposed for efficient 3D assembly design among components of a superstructure module of modular steel bridge. Assembly system is classified into 3 levels as LoD (Level of Details) for 3D assembly design of the parts. Components forming 3D shape of the parts are identified and defined as parameters, variables depending on parameters, or constants independent of the parameters. Then, spatial assembly rules among the parts are defined according to the assembly system. Positional relations among the identified shape components are defined for mating spatial position and geometrical relations are defined for constraining degree of freedom on X, Y, and Z axis. Finally, a standardized template is designed by applying the rules to 3D based assembly design for the parts of the superstructure module. In addition, applicability of the parametric modeling method is demonstrated by testing the shape variation of the superstructure module according to changing the defined parameters.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.855-864
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• 2017

The control rod assembly controls reactor power by adjusting its position during normal operation and shuts down chain reactions by its free drop under scram conditions. Therefore, the drop performance of the control rod assembly is important for the safety of a nuclear reactor. In this study, the drop performance of the conceptually designed control rod assembly for the prototype generation IV sodium-cooled fast reactor that is being developed at the Korea Atomic Energy Research Institute as a next-generation nuclear reactor was experimentally investigated. For the performance test, the test facility and test procedure were established first, and several free drop performance tests of the control rod assembly under different flow rate conditions were then carried out. Moreover, performance tests under several types and magnitudes of seismic loading conditions were also conducted to investigate the effects of seismic loading on the drop performance of the control rod assembly. The drop time of the conceptually designed control rod assembly for 0% of the tentatively designed flow rate was measured to be 1.527 seconds, and this agrees well with the analytically calculated drop time. It was also observed that the effect of seismic loading on the drop time was not significant.

• Journal of the Korea Society for Simulation
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• 제12권2호
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• pp.45-53
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• 2003

This paper presents a retargetable compiled assembly simulation technique for fast ASIP(application specific instruction processor) simulation. Development of ASIP which satisfies design requirements in various fields of applications such as telecommunication, wireless network, etc. needs formal design methodology and high-performance relevant software environments such as compiler and simulator In this paper, we employ the architecture description language(ADL) named ${HiXR}^2$ to automatically synthesize an instruction-level compiled assembly simulator. A compiled simulation has benefit of time efficiency to interpretive one because it performs instruction fetching and decoding at compile time. Especially, in case of assembly simulation, instruction decoding is usually a time-consuming job(string operation), so the compiled simulation of assembly simulation is more efficient than that of binary simulation. Performance improvement of the compiled assembly simulation based on ${HiXR}^2$ is exemplified with an ARM9 architecture and a CalmRISC32 architecture. As a result, the compiled simulation is about 150 times faster than interpretive one.

• Journal of the Korean Society for Precision Engineering
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• 제20권6호
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• pp.151-159
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• 2003

This paper presents a new DFA methodology to estimate the standard assembly time and evaluate the assemblablity of a product. The assembly time is estimated with some decision and influencing factors of assembly using motion analysis. The assemblability is evaluated using weights of the decision and influencing factors and assembly difficulty scores, and the tables that include the time and score of assembly are suggested. Finally, a new DFA system supporting the DFA is implemented to help designers to analyze the product during the design process in concurrent engineering.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제24권4호
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• pp.811-823
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• 2000

In design and manufacturing airframe structures which are composed of a lot of sub-assemblies and large complex profile shapes it is difficult to reduce so called hardware variations. Accordingly cost increasing factors for manufacturing airframe parts are much more than other machine parts because of the variability of fabricated details and assemlies. To improve cost and quality, accurate assembly methods and DPD techniques are proposed in this paper which are based upon using CAD/CAM techniques, the concept of KC's and the coordinated datum and index throughout the design, tooling, manufacturing and inspection. The proposed methods are applied to produce fuselage frame assemblies and related engineering aspects are described regarding the design of parts and tools in the context of concurrent digital definition. First articles and consequent mass production of frame assemblies shows a great improvement of the process capability ratio from 0.7 by the past processes to 1.0 by the proposed methods in addition to the cost reduction due to the less number of tools, reduced total assembly times and the space compaction needed by massive inventory. The need to achieve better Cpk, however, and future studies to be investigated will be addressed briefly.

• Journal of Aerospace System Engineering
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• 제6권4호
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• pp.18-23
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• 2012

The fuel boost pump for the aircraft was first indigenously developed in Korea. It is one of the core component for fuel subsystem and composed of motor assembly, impeller assembly, and body assembly with BLDC motor. It shall provide some amount of fuel to engine system continuously for any flight condition considering sudden altitude change and any attitude. This paper describes the procedures and the results for the design, the integration, and the performance analysis of the fuel boost pump.