• 동력기계공학회지
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• 제14권5호
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• pp.24-29
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• 2010

TFT-LCD module with thin, small and layered structure makes its shock analysis very difficult and complicated. As TFT-LCD becomes more thinner, it is more difficult to assure its required shock resistance. Recently, the drop/impact simulation using the commercial explicit dynamic analysis software such as LS-DYNA3D is actively applied to assess the shock characteristics of TFT-LCD. In this study, the effects of analysis parameters and design modifications in the drop/impact simulation are carefully studied. the reliability of the present analysis results can be assured through the experimental verification.

• 한국CDE학회논문집
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• 제13권2호
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• pp.109-120
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• 2008

ISO 10303-112 is an integrated application resource of ISO 10303, commonly known as STEP, and specifies the procedural_sketch schema. The ISO 10303-112 provides general resources for the representation of modeling commands for the exchange of procedurally represented 2D CAD models. Procedural models have the advantage of being easy to edit, simply by changing values of parameters of their constructional operations. Such models are said to embody design intent, in the sense that modifications to them conform to the method of creation used by their original creator, and they also comply with any constraints implied by the particular constructional operations used. This paper introduces the development and standardization process of the ISO 10303-112, and describes the concept of procedural 2D CAD modeling, the way to represent the procedural 2D CAD models in STEP and the harmonization with other STEP resources.

• 한국군사과학기술학회지
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• 제13권1호
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• pp.22-29
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• 2010

In this study, computational multi-body dynamics and structural vibration analyses including some impact condition have been conducted for the ground flight test system of the developed smart UAV model. Designed ground test system has four degree-of-freedom motions with limited motion control mechanism. Design safety margin designs for several structural components are tested and verified considering expected critical motions (pitching and rolling) of the test smart UAV model. Computational results for various analysis conditions are practically presented in detail. Futhermore, proper design modifications of the initially designed test equipment in order to guarantee or increase structural safety have been successfully conducted in the design stage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1291-1293
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• 2005

Switched reluctance motors have the advantage a high torque/weight ratio, as the large reluctance torque is made by salient poles of both stator and rotor, and a high reliability. On the other hand, the switched reluctance motors have the disadvantage of a large ripple torque which is made by salient poles. So the application for the industrial fields have been limited to special cases. This paper describes the design of a 12/8 switched reluctance motor using a enemy layer method of the asymmetry rotor. The design is focussed to reduce the torque ripple and radial force in the demanded value. The three dimension finite element analysis method(3D-FEM) was used for decides a enemy layer angle of the asymmetry rotor. This paper presents modifications of the rotor pole shape which reduces the torque ripple.

• Nuclear Engineering and Technology
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• 제29권1호
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• pp.85-91
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• 1997

Cross-flow existing in a shell-and-tube steam generator can cause a tube to vibrate. There are four regions subjected to cross-flow in Yonggwang units 3 and 4 (YGN 3 and 4) steam generators, which are of the same design as the steam generators for Palo Verde nuclear power plant Palo Verde units 1 and 2 steam generators have experienced localized oar at the comers of the cold side recirculating fluid inlet regions. A number of design modifications were made to preclude tube failure in specific regions of YGN 3 and 4 steam generators. Therefore, flow induced vibration experiments were done to determine the vibration magnitude of tubes in the economizer tube free lane region. The objective of this experiment is to demonstrate that the tube displacement is less than 0.01 inch rms at 100% of full power flow and to quantify the remaining design margin at 120ft and 140% of full power flow.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.60-70
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• 2020

The outfitting design of ships and offshore structures is mainly undertaken in a restricted space. Pipes occupying a large portion of outfitting design are normally manufactured outside the shipyard. This complicated manufacturing process results in frequent delivery delays. Inevitable design modifications and material changes have also resulted in inefficient pipe installation works. In this study, an algorithm is proposed to systematically determine the pipe installation sequence. An accurate and fast algorithm to identify the geometric relationship of piping materials is presented. To improve the calculation efficiency, the interference is gradually examined from simplified to complicated shapes. It is demonstrated that the calculation efficiency is significantly improved with successive geometric operations such as back-face culling and use of bounding boxes. After the final installation sequence is determined, the entire installation process is visualized in a virtual reality environment so that the process can be rendered and understood for a full-scale model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.130-136
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• 2009

The goal of this paper is to develop a standard side mirror geometry that will perform well across multiple vehicles. One of the important performance attributes of a side mirror is the amount of wind noise generated under the flow conditions on a car. PowerFLOW can be used for Computer Aided Testing of the aeroacoustics performance of a design in addition to directing design modifications based on a detailed analysis of the flow structures responsible for the noise generation. Alternatively, a Design of Experiment (DOE) approach is useful to explore the design space without any a-priori assumptions of the effects of design parameter changes. Some general design guidelines regarding the significant mirror geometry factors will be determined which may help to reduce vehicle development time and cost in the future. The results of this research will also allow us to estimate the trade-off between cost saving and performance optimum related to using a standard mirror shape for different vehicles.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.55-62
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• 2011

Although the performance of the commercial vessel has been dramatically improved through innovations, there has been no big changes on the traditional anchoring method of commercial vessels, both on design and operation until now. In this paper, two cases of design modifications were introduced for optimized design of pocket type anchor handling, which resulted in improved performance of the vessel's anchoring. From the first time fully balanced type anchors were applied on vessels in Korean shipyard, main design problem on this application was that the anchor doesn't normally slide into the pocket when the anchor fluke is not in line with pocket, as the anchor freely rotates by the swivel on forerunner. In order to prevent the problem, swivel has been deleted on the forerunner to prevent anchor rotation until now, but this solution caused problems such as twist lock of anchor chain, restriction of windlass direction, etc. On this paper, one of the solution is introduced to overcome the design problem by tilting the hawse pipe to some extent, which makes anchor turned at the time anchor ring touches the pocket skirt and that it properly slides into the pocket. Secondly, one of the solution is introduced to overcome misalignment problem between anchor chain cable and roller of chain compressor, which has been frequently occurred, by modification of roller design.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.672-680
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• 2018

본 연구에서는 유한요소해석을 이용하여 냉장고 얼음 디스펜서 작동 시에 덕트 캡 조립체가 열리는 과정을 해석하고 캡의 개방각도를 평가하였으며, 얼음 배출을 원활하게 하기 위하여 캡의 개방각도를 최대화할 수 있는 설계개선안을 도출하였다. 덕트 캡 조립체의 기존설계안에 대하여 모터 작동 시의 입력회전각에 대한 과도구조해석을 수행하였으며 해석결과, 캡의 개방각도는 레버가 강체일 경우에만 가능한 개방각도 상한값의 78%로 나타났다. 캡 개방각도에 미치는 주요 설계인자의 영향을 검토하기 위한 여러 가지의 설계수정안을 도출하고 해석을 수행하였다. 설계수정안의 해석결과, 레버 재질을 탄성계수가 큰 재질로 변경하거나, 지지부의 위치를 모터 측으로 이동하거나, 레버의 축 직경을 증가시키면 개선효과가 높아지는 것으로 나타났다. 구조설계의 변경에 따라 수반되는 제작비용 측면도 고려하면, 얼음 디스펜서 케이스의 기존 구조를 변경하지 않고 레버 재질만 기존의 합성수지에서 알루미늄합금으로 변경하는 설계수정안이 가장 우수한 것으로 나타났다. 결론적으로, 레버 재질을 알루미늄합금으로 변경하면 캡의 개방각도를 상한값의 95%까지 개선할 수 있을 것으로 판단된다. 본 연구에서 제시한 해석 방법 및 결과는 얼음 배출이 원활하도록 덕트 캡 조립체의 구조를 설계하는데 큰 도움이 될 것으로 기대된다.

• Steel and Composite Structures
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• 제1권1호
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• pp.97-110
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• 2001

Architectural steel structures with visible tension and compression members are becoming more prevalent as a popular form of construction that reflects the nature of the resistance to the applied loads. These members require the use of structural steel pins at their ends to ensure either axial tension or axial compression in the members. Structural pins have been used as a means of connection for centuries and it would appear that their behaviour is relatively well understood. However, the rules for the design of pins vary quite considerably from code to code and this has caused some confusion amongst consulting structural engineers operating internationally. To provide some insight into this problem, a comprehensive testing program has been carried to examine the influence of parameters such as pin diameter, material properties of the pin, thickness of the loading plates, material properties of the loading plates and the distance of the pin to the edge of the loading plates. The modes of failure have been carefully examined. Based on this study, modifications to current design procedures are proposed that properly take into account the different possible modes of failure.