• 시스템엔지니어링학술지
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• 제9권2호
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• pp.83-90
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• 2013

Integrated aircraft synthesis process for rapid analysis and design is described in this paper. Data flow between different analysis fields is described in details. All the data are divided into several groups according to importance and source of the data. Analysis of design requirements and certification regulations is carried out to determine baseline configuration of an aircraft. Overall design process can be divided into initial sizing, conceptual and preliminary design phases. Basic data for conceptual design are obtained from initial sizing, CAD and geometry analysis. Basic data are required input for weight, aerodynamics and propulsion analyses. Results of this analysis are used for stability and control, performance, mission, and load analysis. Feasibility of design is verified based on analysis results of each discipline. Design optimization that involves integrated process for aircraft analysis is performed to determine optimum configuration of an aircraft on a conceptual design stage. The process presented in this paper was verified to be used for light aircraft design.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.127-132
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• 2005

Despite all efforts, many product development projects fail and lead to an introduction of products that do not meet customers' expectations. In general, designers usually relies upon their past experiences of similar products as a source of design knowledge when they work on a new design project. Designers need a set of practical step-by-step tools and methods which ensure a understanding of customers' needs and requirements, as well as a past design experience knowledge. In this paper we propose a design initial value module for an excavator that proposes a key initial design parameter value in an early design stage to improve a design process on Customer Requirements. It makes possible to support designers more effectively, objectively, and easily. Also it can propose better products in terms of a customer satisfaction.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.358-361
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• 2004

This paper describes the development process of high stiffness body for ride and handling performance. High stiffness and light weight vehicle is a major target in the refinement of passenger cars to meet customers' contradictable requirements between ride and handling performance and fuel economy. This paper describes the analysis approach process for high stiffness body through the data level of body stiffness. According to the frequency band, we can suggest the design guideline about Is cornering static stiffness, torsional and lateral stiffness, body attachment stiffness. The ride and handling characteristic of a vehicle is significantly affected by vibration transferred to the body through the chassis mounting points from front and rear suspension. It is known that body attachment stiffness is an important factor of ride and handling performance improvement. And high stiffness helps to improve the flexibility of bushing rate tuning between Handling and road noise. It makes it possible to design the good handling performance vehicle at initial design stage and save vehicles to be used in tests by using mother car at initial design stage. These improvements can lead to shortening the time needed to develop better vehicles.

• 한국산학기술학회논문지
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• 제17권10호
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• pp.696-701
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• 2016

다단계 딥 드로잉(multi-stage deep drawing)은 산업현장에서 대형의 금속 제품 뿐만 아니라 소형의 제품에 까지 많은 제품으로 확대되고 있는 제조 공정 중 하나이다. 예를 들어, 스마트 폰에 사용되는 USB-C형 소켓은 매우 작고, 정밀하며 세장비가 큰 부품이며, 이 제품은 타원형 다단계 딥드로잉 방법으로 제조된다. 다단계 딥 드로잉에 최종 제품의 두께 분포를 보장하기 위해서 다단계 딥드로잉 전체 공정에서 제품의 두께 분포가 균일하게 유지되어야 한다. 따라서 첫 번째 드로잉 작업 후에 타원형 제품의 장변과 단변쪽 측벽의 높이 차를 최소화하는 것은 최종 제품의 균일한 두께를 보장하는 가장 중요한 공정 설계 인자이다. 본 연구에서는 첫 번째 드로잉 공정 후 소재가 균일한 높이를 지속적으로 유지될 수 있도록 하기 위해서 유한요소해석을 기반으로 초기의 타원형 소재 형상 결정에 대한 최적 설계를 수행하였다. 최적 설계된 초기 블랭크 형상으로 성형된 제품의 경우 전체 균일한 두께 분포를 가질 뿐만 아니라 드로잉 후 제품의 장변과 단변의 높이 단차가 최소화 되었다. 최종적으로 최적 설계로 예측된 초기 소재 형상은 실제 실험 결과와 비교하여 검증되었고, 매우 양호한 결과의 일치를 보여주었다.

• 소성∙가공
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• 제27권5호
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• pp.276-280
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• 2018

This paper has developed a forging process for conical shells for making aluminum cylindrical large shells. An incremental forging process was applied to reduce forging loads and die cost. The preform is designed based on the crosssectional area of the final forged shape. Inner diameter of the preform for mandrel forging is constant, and outer diameter is conical so that it matches the cross-sectional area of the product. However, simulation confirmed that the larger diameter is smaller than predicted and the length is larger than predicted because in the initial stage of forging, the large diameter portion first comes into contact with the anvil at the initial stage of forging and stretches in longitudinal direction. So, it has developed a rule to design the preform considering 3-D deformation instead of plane strain deformation at the beginning stage of mandrel forging. The developed mandrel forging process can be applied to more similar products and economic benefits may be obtained.

• 소성∙가공
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• 제7권6호
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• pp.594-602
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• 1998

The design analysis of axisymmetric, multi-stage deep drawing dies was performed using the rigid-viscoplastic finite element formulation. In the formulation the axisymmetric CFS algorithm was employed. Hill's non-quadratic normal anisotropic yield criterion and isotropic hardening rule were considered. For trial initial displacements and tool contact points. the geometric force equilibrium method was adopted. In order to see the validity of the formulation, the multi-stage deep drawing processes of shell-cylinder front part of hydraulic booster were simulated. The simulation showed good agreements with measurments and PAM-STAMP results.

• 대한조선학회논문집
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• 제57권4호
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• pp.191-197
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• 2020

Pipe routing is a important part of the whole design process in the shipbuilding industry. It has a lot of constraints and many tasks that should be considered together. Also, the result of this stage affects follow-up works in a wide scope. Therefore, this part requires skilled designers and a lot of time. This study aims to reduce the workload and time during the design process by automating the pipe route design on initial stage. In this study, the reinforcement learning was used for pipe auto-routing. Reinforcement learning has the advantage of dynamically selecting routes, unlike existing algorithms. Therefore, it is suitable for the pipe routing design in ship design process which is frequently modified. At last, the effectiveness of this study was verified by comparing pipelines which were designed by piping designer and reinforcement learning results.

• 한국구조물진단유지관리공학회 논문집
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• 제7권4호
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• pp.149-158
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• 2003

기존의 프리스트레스 콘크리트 거더의 설계개념은 초기에 긴장된 강선의 긴장력으로 초기상태에서의 응력과 사용상태에서의 응력이 허용한계내에 들도록 설계하여 왔다. 이러한 설계방법은 거더의 단면이 커지는 단점이 있다. 본 연구에서는 철도하중을 받는 교량에 대하여 강선의 긴장력을 단계적으로 증가시키는 프리스트레스 콘크리트 설계이론을 제안하여 거더의 단면을 감소시켜 설계의 간편성과 시공성 및 경제성을 확보하고자 하였다. 그리고 제안된 설계방법을 적용하여 기존의 철도교보다 거더의 단면을 감소시켜 장지간의 교량을 설계하였으며 긴장재를 연속적으로 배치하여 IPC교량의 연속화를 제안하였다.

• 품질경영학회지
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• 제42권3호
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• pp.279-290
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• 2014

Purpose: The purpose of this study is to propose adoption of QFD and Stage-gate in order to analyze the quality of korea defense system. Methods: Drawing change data of initial production phase in korea defense system were anlayzed and a practical method was proposed. Results: The results of this study are as follows; Off line Quality Control should be introduced in development phase. Specially, in case of defense system, the best method is QFD(Quality Function Deployment) and Stage-gate process. At first, QFD 1 step defines product planning from VOC(Voice Of Customer), QFD 2 step specifies part planning from product planning, QFD 3 step defines process planning from part planning, QFD 4 step defines production planning from previous process planning. Secondly, Stage-gate process is adopted. This study is proposed 5 stage-gate in case of korea defense development. Gate 1 is located after SFR(System Function Review), Gate 2 is located after PDR(Preliminary Design Review), Gate 3 is located after CDR(Critical Design Review), Gate 4 is located after TRR(Test Readiness Review) and Gate 5 is located before specification documentation submission. Conclusion: Off line QC(Quality Control) in development phase is necessary prior to on line QC(Quality Control) in p roduction phase. For the purpose of off line quality control, QFD(Quality Function Deployment) and Stage-gate process can be adopted.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.63-68
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• 2005

Optimum design of the big brackets is performed through iterated 3-D FE analyses to meet the permissible limits of stress, which consumes an excessive amount of calculation time. Therefore, this study has been prepared to determine rapidly and accurately an optimum size and scantling of the big brackets at the initial design stage. The generalized slope deflection method (GSDM) based on the span point concept is applied to enhance the efficiency of iterated structural analyses. The accuracy and applicability of the present method is verified by comparing with a detail 3-D FE analysis of web frame structures. As an optimization technique, evolution strategies (ES) are applied using discrete design variables for practical design.