• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.237-243
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• 2002

Recently, in computer-aided geometric modeling(CAGD), subdivision surfaces are frequently employed to construct free-form surface. Subdivision schemes have been very popular in computer graphics and animation community, but the community of CAGD adopts this tool only recently to handle surface geometry. In the present study, Loop scheme and Catmull-Clark scheme are applied to generate smooth surfaces. To be consistent with the limit points of target surface, the initial sampling points are properly rearranged. The pointwise curvature errors and coordinate value errors between the points in the sequence of subdivision process and the points on the target surface are evaluated In the numerical examples in both Loop scheme ＆ Catmull-Clark subdivision scheme.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.1
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• pp.13-25
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• 1997

전 세계의 대형 저속 디젤 엔진을 설계.제작하는 회사는 1980년대에 들어오면서 MAN - B&W, SULZER, MITSUBISHI의 3파전 양상을 띠고 있으며, 세계 시장점유율에서는 MAN - B&W가 50%이상을 차지하고 있다. 한국은 현재 한국중공업, 현대중공업, 쌍용중공업 및 삼성중공업에서 대형 저속 디젤 엔진을 생산하고 있다. 국내에서 생산되고 있는 대형 저속 디젤 엔진은 대부분이 MAN - B&W형이고 SULZER형이 약 20%를 차지하고 있다. 기술력은 위의 3사에 거의 의존하고 있으며, 설계보다는 생산에 치중하고 있는 실정이다. 선박용 엔진 구조물은 베드 플레이드(bed plate), 실린더 프레임(cylinder frame), 프레임 박스(frame box)등이 주 스테이 볼트(long stay bolt)에 의하여 체결되어 한 개의 대형 수직 구조물을 이루고 있으며, 프레임 박스의 안내면(guide plate)과 베드 플레이트의 베어링 지지부(bearing support)등은 엔진의 폭발력과 선박의 추진력을 직접적으로 받으므로 구조적 결함과 하자 보수의 문제들이 발생하고 있다. 이와 같은 사용상 및 제작상의 제문제를 해결하기 위해서는 유한요소 구조 해석 능력을 자체 보유하여 구조 설계상의 문제점을 분석하고 엔진 구조물의 취약 부위를 집중 검토하여야하며, 이를 통해 선박의 운항 중에 일어날 수 있는 사고를 미연에 방지할 수 있다. 그러나 국내에서는 이러한 대형 엔진 구조물의 설계/해석 기술이 거의 없고 구조적 문제점이 발생할 경우에는 모든 사항을 설계사(licensor)에 전적으로 의존하고 있는 실정이다. 한편, 설계 기술을 보유하고 있는 MAN - B&W, NEW SULZER DIESEL사 등은 정밀 구조 해석을 통하여 기존 엔진 구조물에 대한 안전성 및 신뢰성을 높임과 동시에 신 모델 개발에 박차를 가하고 있으나, 기술 이전은 회피하고 있어 대형 엔진 구조물에 대한 구조 해석 기술의 개발이 시급하다고 할 수 있다. 본 해설에서는 CAD/CAE(Computer Aided Design/Computer Aided Engineering)를 이용하여 위에서 제시된 대형 엔진 구조물의 구조해석 절차와 방법에 대해 간략히 설명하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.38-44
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• 1996

The CAD system for design and drawing of limit gauges was constructed and developed. This system was made by Visual Basic program. Using this system, drawings together with concerned data for the manufacturing of limit gauges are generated on the screen, file and printer. The data base was constructed by referring handbooks, textbooks, relevant standards and regulations. This system was proved a powerful tool for design and drawing of limit gauges by actual applications. The output drawings from this system are in good agreement with the drawings and data of the concerned standards and regulations.

• Journal of the Korea Society for Simulation
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• v.10 no.2
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• pp.33-46
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• 2001

Recently, the usage of containers in marine transportation is rapidly increasing. The problem of ship stability is important because of its direct influence to the loss of the human-life, ship, and merchandise. However, the assessment for ship stability during container loading/unloading in port is dependent on human experience only. On the other hand, the emerging information and communication technologies of shipbuilding industrial environments are rapidly changing. To respond to the situation, a new paradigm has been matured with new concepts such as the concrete method. Especially, all the efforts are shown to be concentrated to realize the concept of Simulation Based Design(SBD) based on three dimensional Computer Aided Design(CAD) model. In this paper, ship model-based simulation methodology for design and operation of ship is suggested, and for the verification of suggested methodology, the system for stability assessment of ship during container loading/unloading was developed using ENVISION, a general-purpose simulation system. The developed system consists of geometric modeling subsystem, basic calculation subsystem, and Computer Aided Engineering(CAE) subsystem. In addition, interface to CAE/CAD /simulation system such as SIKOB and ENVISION is provided.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.17-23
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• 2006

Rubber materials have the nonlinear, large deformation and viscoelastic behavior. W.D. Kim et al. studied these characteristics through the static, fatigue, dynamic, aging and viscoelastic test. This paper discussed that the properties of engine mounting rubber, such as static stiffness, fatigue life and damping factor, are predicted based on CAE by using material properties acquired by the report of Kim et al. In result, the static stiffness of engine mounting rubber is predicted approximately in comparison with test value. Also, it was confirmed that the relationship of fatigue life and Green-Lagrange strain in specimen was the valid tool to predict the fatigue life of engine mounting rubber. From the results of transient viscoelastic analysis the damping factor changed rapidly at the range less than 8hz.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.50-55
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• 2010

In recent years, the development of fuel cell vehicles has further accelerated because of environmental problem and petroleum resources shortage. The fuel cell vehicles have the stack which converts fuel to electricity. The stack is usually mounted by bush to isolate the vibration of chassis and body. This paper analyzed the vibratory characteristics of stack and chassis, body system. The wheel forces of fuel cell vehicle are measured to estimate the road load data. And the paths of vibration from wheel to stack are analyzed by CAE. According to the test and CAE results, the improvement of stack vibration are evaluated.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.22-29
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• 1998

The natural convection cooling of simulated electronic chips located on a printed circuit board(PCB) has been studied by Computer Aided Engineering(CAE). In CAE, 3-dimensional finite element model of simulated electronic chip was made to accomplish heat transfer analysis at each design stage of a printed circuit boards for thermal optimization. The simulated electronic chips are installed protrudent from the plate about 3mm. The materials the plates are epoxy and aluminum. The results show that the chip with relatively high heat generation rates should not be close to each other. It is found, as well that cooling effect for the aluminum plate is superior to the epoxy plate and location of maximum temperature is significantly influenced by the structure variation of PCB. In developing PCB and electronic chips, it's recommended that CAE is very useful to estimate to the distribution of temperature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.423-426
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• 2005

The injection molding process has applied to a variety of fields by a development of various plastic resins. Recently, this process has been extending to a field of parts of shoes. In this study, the injection mold of shank which is a one of the parts of shoes has been designed. The position of gate and the injection procedure have been optimized by a simulation using the CAE software and an analysis using the DOE. As a result, the improved injection mold of shank has been manufactured in a short time. Appling the CAE and the DOE at the process of the injection mold design eventually lead an increase in the productivity and the quality of parts.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.327-336
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• 2016

Manufacturers of aircraft engines have introduced computer-aided manufacturing (CAM) software to operate and control computerized numerical control (CNC) machine tools. However, the generation of a CAM model is a time consuming and error-prone task since machining procedure and operational details are manually defined. For the automatic generation of a CAM model, feature recognition techniques have been widely studied. However, their recognition coverage is limited so that complex shapes such as a jet engine cannot be fully developed. This study presents a novel approach to quickly generate a CAM model from a CAD model using shape search techniques. Once an operator sets a machining operation as a reference operation, the same shapes as the shapes referenced by the operation are searched. The reference operation is copied to the positions of the searched shapes. The proposed method was verified through experiments with a jet engine compressor case.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.717-718
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• 2008