• Journal of Advanced Marine Engineering and Technology
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• v.35 no.7
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• pp.891-898
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• 2011

The present work was conducted to get the best geometric information for the optimum design of the complex heat exchanger. The objective function for optimal design was expressed as a combination of pressure drop and heat transfer rate. The geometric parameters for the variables of louver pitch and height, tube width, etc., were limited to ranges set by manufacturing conditions. The optimum geometric parameters were calculated by using empirical correlations and theory. The sensitivity of the parameters and optimum values are shown and discussed. The weighting factor in the objective function is important in the selection of the louver fin-tube heat exchanger.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.1-11
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• 1999

surface texture denotes set of tiny repetitive geometric features on an object surface. 3D Printing can readily create a surface of controlled macro-textures of high geometric complexity. Designing surface textures for 3D Printing, however, is difficult due to complex macro-structure of the tiny texture geometry since it needs to be compatible with the non-traditioal manufacturing method. In this paper we propose a visual simulation technique involving development of a virtual model-an intermediate geometric model-of the surface texture design prior to fabricating the physical model. Careful examination of the virtual model before the actual fabrication can help minimize unwanted design iterations. The proposed technique demonstrated visualization capability by comparing the virtual model with the physical model for several test cases.

• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.293-300
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• 2000

The non-manifold geometric modeling technique is to improve design process and to Integrate design, analysis, and manufacturing by handling mixture of wireframe model, surface model, and solid model in a single data structure. For the non-manifold geometric modeling, Euler operators and other high level modeling methods are necessary. Boolean operation is one of the representative modeling method for the non-manifold geometric modeling. This thesis studies Boolean operations of non-manifold model with the data structure of selective storage. The data structure of selective storage is improved non-manifold data structure in that existing non-manifold data structures using ordered topological representation method always store non-manifold information even if edges and vortices are in the manifold situation. To implement Boolean operations for non-manifold model, intersection algorithm for topological cells of three different dimensions, merging and selection algorithm for three dimensional model, and Open Inventor(tm), a 3D toolkit from SGI, are used.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.698-704
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• 2007

Articulated vehicles which have a pivoting joint allowing the vehicle to rotate more easily are difficult to turn the curves because of their long length. In order to review operational safety, turning characteristics related to geometric design should be investigated when articulated vehicles run on the road which can be interfered with other vehicles. The vehicles to review the turning characteristics are the normal articulated bus in Seoul with FWS(front wheel steering) and new bimodal tram with AWS(all wheel steering). Steering characteristics and geometric design were investigated such as turning radius, offtracking, swept path width and swingout. The results were reviewed with respect to the standards of vehicle safety and road design.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.369-378
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• 2016

The design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. The horizontal spectrum is defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.65-71
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• 2006

Based on the smoothness criterion of minimum curvature variation of the curve, tangent angle constraints guaranteeing an optimized geometric Hermite (OGH) curve both mathematically and geometrically smooth is given, and new methods for constructing composite optimized geometric Hermite (COH) curves are presented in this paper. The comparison of the new methods with Yong and Cheng's methods based on strain energy minimization is included.

• The KSFM Journal of Fluid Machinery
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• v.15 no.6
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• pp.58-63
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• 2012

This paper presents a numerical study on the performance improvement of axial-flow pump with guide vanes. Design optimization for guide vanes in an axial-flow pump has been studied through the implementation of a commercial CFD code and DOE (design of experiments). We also discussed how to improve the performance of the axial-flow pump by designing the guide vanes. Geometric design variables were defined by the meridional plane and vane plane development of guide vanes. The effect of hub tip ratio analyzed the meridional plane of guide vanes. The importance of the geometric design variables was analyzed using $2^k$ factorial designs. The objective functions for guide vane geometric variables were defined as the total efficiency and the total head at the design flow rate. From the $2^k$ factorial design results, the important design variables were found and the performance was increased in comparison with the base design model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.105-117
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• 2004

In each industry field, many engineers have tried to develop integrated environments using information technology. The core technology in building integrated environments is the database based on standardized information. To meet the requirements, this study builds a database with detailed design information as a part of integrating digital information generated from every work of steel bridges. The data model used to build the database was developed based on the international standard, namely ISO/STEP. The data model is classified into geometric and non-geometric parts to represent the design information of steel bridges. The geometric parts are represented by a three dimensional solid model so that they may be able to reuse existing information. Also, the non-geometric parts represent information requirements that are analyzed by the development method of standard data model. To verify the data model, this study validates the syntax of the model on EXPRESS Engine and verifies the validation of the model by applying the design data of Hannam bridge to the database.

• Korean Journal of Computational Design and Engineering
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• v.20 no.2
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• pp.104-113
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• 2015

In developing a tire, many CAE analyses are performed to make a better tire. But its meshing work is not easy, and it takes much time. One of the reasons of taking much time is that there are many overlapped geometric entities in CAD data that are modeled in CAD system by CAD engineers. In this study, we studied about the features of the overlapped geometric entities, and the method to find out and delete them. I developed a program using the proposed algorithm, and applied it in meshing tire pattern and tire case. I proved that the time in meshing a tire reduced dramatically by removing overlapped geometric entities by using the developed program.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.298-303
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• 2004

parameters in surface grinding. Taguchi method which is one of the design of experiments has been introduced in achieving the aims. The process parameters were the grain size, the wheel speed, the depth of cut and the table speed. The effect of the process parameters on the geometric error was examined and an optimal set of the parameters was selected to minimize the geometric error within the controllable range of the used grinding machine. The reliability of the results was evaluated by the ANOVA.