• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.271-275
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• 2010

Forming tool design is carried out for a manufacturing a outer shell structure of the nozzle extension of regenerative cooling thrust chamber. The method which manufactures outer shell structure of nozzle extension is a metal forming process using thin plate. Because the configuration of outer shell structure is changed after forming process by springback effect, the outer shell structure can't be exactly formed with the same forming tool as configuration of the nozzle extension. Therefore forming tool design considering springback effect is necessary for manufacturing the outer shell structure of the nozzle extension. In this study, new designed forming tool configuration was generated to decrease the errors between nozzle contour and formed structure. The analysis results show that the errors between nozzle contour and formed structure is significantly decreased using the new designed forming tool.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.357-366
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• 2012

To schedule a Reconfigurable Manufacturing Cell (RMC), reconfiguration and setting decisions should be made first. Those decisions, together with characteristics of production orders, affect attainable performance of a system. So an integrative approach is required considering all decisions and characteristics rather than dealing with each of them separately. Pallet-fixture allocation, as a decision problem in setting, which determines the number of pallets to be equipped with each fixture type to produce different types of products, has rarely been investigated. In this study, several pallet-fixture allocation rules are proposed including both simple and novel ones. Then system performance is investigated through various combinations of setting and scheduling decisions (rules) for given system configurations and production orders, via simulation. The result shows that one of proposed pallet-fixture allocation rules which considers both configuration and order characteristic outperforms the others, justifying the necessity of an integrative approach in the RMC operation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.428-432
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• 2010

A study on the forming characteristics of outer shell structure for thrust chamber nozzle extension has been performed. In order to identify anisotropy of cold rolled sheet metal, three types of tensile specimens according to the direction to the sheet rolling axis were prepared and tested, and Landford's values were obtained using the results and applied to structural analysis. Forming characteristics of the outer shell structure of the nozzle extension are investigated through manufacturing and forming of the full scale outer shell structures, and strain values obtained by the forming processes are compared to the numerical analysis results. The results obtained by this study will be utilized to design forming tools and processes for manufacturing other outer shell structures which have a bigger expansion area ratio.

• Composites Research
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• v.15 no.6
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• pp.24-29
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• 2002

For the development of all composite unmanned aerial vehicle(UAV), the consideration for manufacturing in design phase and events in composite parts fabrication, subassembly and final assembly are summarized. In design phase, to maximize the advantages of composite material such as cocuring, cobonding and secondary bonding for manufacturing, the advanced structural concept is introduced. For the curing of designed parts, the manufacturing tools for composite parts are designed and manufactured. The assembly jigs are designed to meet dimensional tolerance requirements of the vehicle structure. And the inspection criteria are established and applied for the manufacturing. Technical data for inspection items and methodologies are summarized to utilize for the exclusive specifications of the manufacturing sequence.