• CDE review
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• v.3 no.3
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• pp.57-60
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• 1997

기계 부품을 설계함에 있어 솔리드 모델링 시스템의 사용을 골격으로 하는 CAD 시스템의 사용은 삼차원 모델링된 단일 물체에 대한 물성치(mass property)의 계산, FEM 해석을 위한 유한요소의 자동생성, 곡면에 대한 NC 공구경로(NC tool path)의 자동계산, 부품의 생산을 위한 가공 정보의 도출 등의 분야에 많은 도움을 주어 설계와 생산, 관리의 전 분야에 혁신적 효율화를 도모해주었다. 한편 이렇게 설계된 단품들은 대개의 경우 조립되어 조립체를 이루게 되고, 그 상태로 혹은 부품간에 상대운동을 하면서 원하는 기능을 구현하게 된다. 단품에 대해서처럼 이 과정에서도 CAD 시스템은 조립체의 삼차원 형상을 인식하고 필요한 정보를 제공해줌으로써 설계자에게 유용한 도구로 사용될 수 있는데 이를 조립체 모델링 시스템(Assembly Modeling System)이라 부르며, 현재에는 대부분의 솔리드 모델링 시스템에 그 기능이 채택되어 있다. 조립체 모델링에 관한 연구동향을 비교적 잘 정리한 문헌으로는 Turner와 Libardi의 것을 들 수 있다. 여기서는 이러한 조립체 모델링 시스템의 연구분야와 동향에 대해 또 나름으로의 시각으로 정리하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.220-220
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• 2003

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.130-131
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• 2014

자동용접용 솔리드와이어를 위한 치환동도금층 밀착력 향상을 위해 착화제로 Alanine을 사용하였다. 테이프 시험결과 Alanine 첨가에 따라 밀착력이 현저히 증가하였다. 또한 도금층내에 혼입되는 H와 Fe 분석결과 Alanine을 첨가하지 않았을 때 도금층 전체 영역에서 H와 Fe의 검출강도가 높게 나타났으나, Alanine 10g/l추가시 도금층내에서 미량 검출되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.955-961
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• 2013

This study aimed for the scientific approach of Korean traditional house, so called Hanok, by analyses of structural elements and thermal environmental performance. Hanok is a very unique vernacular architectural style of the Middle East Asia that fits with climate conditions of the Korean Peninsular, designed to withstand high temperature and humidity in summer and cold and dry in winter seasons. In order to evaluate thermal environment of Hanok, its sectional structure such as floor, wall, roof structure and Ondol which is Korean traditional floor heating system, was built in 3D, as well as heat transfer mechanism of its composing elements was analyzed through 3 dimensional steady state analysis. The results of the thermal environmental performance of Hanok will be used as a basic datum of design guidelines for accomplishing ecologic housing fitted with local climate.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.277-280
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• 2008

In this paper behavior of U-Channel Bridge (UCB) was studied, and a new analysis model was proposed. Most of the time, permanent and traffic load actions are directly transmitted to main beams located under the carriageway, one of the most distinctive features of UCB is that the edge beams that support the bridge are above the deck, in contrast with a conventional overpass system. In This study models used with the frame elements, the frame and plate elements, and the solid elements were constructed. Assuming that the results of solid models were similar to the real behavior of UCB, results of another models was compared. The results of the models used with the frame and plate elements were similar to the results of solid models, the model used with the frame and plate elements was proposed as an analysis model.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.562-570
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• 2020

This study explores manufacturing technology and basic properties of high strength cement composites at 2,000kg/㎥ of specific weight. It is suggested that lightweight-high strength cement composites can be produced by substituting silica sand in ulta-high performance concrete mixture with lightweight materials such as solid bubbles and lightweight fine aggregates. The 28-day compressive strengths of cement composites with solid bubbles were from 116MPa to 141MPa at below 2.0g/㎤ of unit density while the cement composites with lightweight aggregates possessed lower compressive strength and higher unit density. The specific weight calculated from mixture proportions did not have significant difference with unit density of hardened cement composites, indicating that unit density of hardened cement composites can be estimated from the specific weight in mixture proportions.

• Korean Journal of Remote Sensing
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• v.36 no.6_1
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• pp.1349-1365
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• 2020

In recent years, in the fields of smart cities and digital twins, research on model generation is increasing due to the advantage of acquiring actual 3D coordinates by using point clouds. In addition, there is an increasing demand for a solid model that can easily modify the shape and texture of the building. In this paper, we propose a method to create a clustered solid building model based on point cloud data. The proposed method consists of five steps. Accordingly, in this paper, we propose a method to create a clustered solid building model based on point cloud data. The proposed method consists of five steps. In the first step, the ground points were removed through the planarity analysis of the point cloud. In the second step, building area was extracted from the ground removed point cloud. In the third step, detailed structural area of the buildings was extracted. In the fourth step, the shape of 3D building models with 3D coordinate information added to the extracted area was created. In the last step, a 3D building solid model was created by giving texture to the building model shape. In order to verify the proposed method, we experimented using point clouds extracted from unmanned aerial vehicle images using commercial software. As a result, 3D building shapes with a position error of about 1m compared to the point cloud was created for all buildings with a certain height or higher. In addition, it was confirmed that 3D models on which texturing was performed having a resolution of less than twice the resolution of the original image was generated.

• Polymer(Korea)
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• v.24 no.4
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• pp.520-528
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• 2000

New high solid acrylic resins (BMHA) containing 70% of solids content have been synthesized. The environmental friendly high solid coatings (BNHS) were prepared by using these acrylic resins and polyisocyanates. The BMHA was obtained by introducing a new functional group, acetoacetoxyethyl methacrylate (AAEM), in the copolymerization of n-butyl acrylate, methyl methacrylate, and 2-hydroxyethyl acrylate. Lowering T$_{g}$ and increasing the AAEM amount in the BMHA resulted in a high value of conversion. There was no difference in conversion with the variations of OH values. In the next step, high solid BNHS coatings were prepared by the curing reaction between BMHA and polyisocyanate at room temperature. The properties of these coatings were evaluated especially for the application of automotive top-coating materials. The introduction of AAEM in the BNHS enhanced the abrasion resistance and solvent resistance of the coatings, which indicated the possible use of BNHS coatings for top-coating materials of automobile..

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.689-694
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• 1994

In this paper, to develop a smart CAD/CAM system for systematically performing from the 3-D solid shape design of products to the CNC cutting operation of products by a machining center, a B-Rep solid modeler is realized based on the half edge data structure. Because the B-Rep solid modeler has the various capabilities related to the solid definition functions such as the creation operation of primitives and the translational and rotational sweep operation, the solid manipulation functions such as the split operation and the Boolean set operation, and the solid inversion function for effectively using the data structure, the 3-D solid shape of products can be easily designed and constructed. Also, besides the automatic generation of CNC code, the B-Rep solid modeler can be used as a powerful tool for realizing the automatic generation of finite elements, the interference check between solids, the structural design of machine tools and robots and so on.

• Composites Research
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• v.28 no.2
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• pp.58-64
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• 2015

The purpose of this paper is to suggest the effective equivalent finite element model for the impact limiter of a nuclear spent fuel shipping cask made of sandwich composite panels. The sandwich composite panels were composed of a metallic facesheet and a core material made of urethane foam, balsa wood and red wood, respectively. The effective equivalent finite element model for the impact limiter was proposed by comparing the results of low-velocity impact test of sandwich panels. An explicit finite element analysis based on LS-DYNA 3D was done in this study. The results showed that the solid elements were recommended to model the facesheet and core of sandwich panels for impact limiter compared to combination modeling method, in which the layered shell element for facesheet and solid element for core material are used. In particular, the solid element for balsa and red wood core materials should be modeled by the element elimination approach.