• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.241-249
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• 2004

There is an over head hoist transporter(OHT) by the system for delivering the wafer in semiconductor processing. The transfer system consist of carrier, vehicle, rail and support. The Tail supporting the wafer and the transfer system should maintain enough strength and stiffness. To achieve lightness and enough strength and stiffness, optimization algorithm should be introduced in design process. In this study, two kinds of section shapes as L-type, C-type is carried out the structure analysis and optimization. Total weight of rail is to be minimized while displacement should not exceed limit. To improve the initial model, topology optimization is done by the plain problem. Size optimization is done with 3D solid element and PLBA algorithm, the RQP algorithm. The weight of optimum model as L-type, C-type is decreased by 2.3%, 10% respectively. It is improved better than the initial model in the strength and stiffness of the structure.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.2
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• pp.95-103
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• 2007

An analytical closed-form solution for wave propagation velocity and damping in saturated porous media is presented in this paper The fully coupled field model with compressible solid Brains and pore water were used to derive this solution. An engineering approach for the analysis of fully saturated porous media was adopted and closed-form solutions for one dimensional wave propagation in a homogeneous domain were derived. The solution is highly versatile in that it considers compression of the solid grains, compression of the pore water, deformation of the porous skeleton, and spatial damping and can be used to compute wavespeeds of first and second kind and damping coefficients in various geologic materials. This solution provides a means of analyzing the influence of material property variations on wavespeed and attenuation. In Part 2 of this work the theoretical solution is incorporated into the numerical code and the code is used in a parametric study on wave propagation velocity and damping.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.46-52
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• 2015

Pump-turbine system is widely used by the hydropower industry for stabilizing the electrical grid in the vast growing economy of most developed countries. This study only investigates the Fluid-structure Interaction (FSI) analysis of the pump-turbine system at various operating conditions. The FSI analysis can show how reliable each component of the system is by providing the engineer with a better understanding of high stress and deformation points, which could reduce the lifespan of the pump-turbine. Pump-turbine components are categorized in two parts, pressurized static parts and movable stressed parts. The fixed parts include the spiral casing, top and bottom cover, stay vane and draft tube. The movable parts include guide vanes and impeller blades. Fine hexahedral numerical grids were used for CFD calculation and fine tetrahedral grids were used for structural analysis with imported load solution mapping greater than 90 %. The maximum equivalent stress are much smaller than the material yield stress, and the maximum equivalent stress showed an increasing tendency with the varying of operating conditions from partial to excessive at both modes. In addition, the total deformation of all the operating conditions showed a small magnitude, which have quite small influence on the structural stability. It can be conjectured that this system can be safely implemented.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.641-648
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• 2009

Concrete structures become more common in railway systems with an advancement of high speed train technologies. As the service life of concrete structures increases, structural strengthening for concrete structures may be necessary. There are several typical strengthening techniques using steel plate and fiber reinforced polymer (FRP) materials, which have their own inherent shortcomings. In order to enhance greater durability and resistance to fire and other environmental attacks, basalt fiber material attracts engineer's attention due to its characteristics. This study investigates bonding performance of basalt fiber sheet as a structural strengthening material. Experimental variables include bond width, length and number of layer. From the bonding tests, there were three different types of bonding failure modes: debonding, rupture and rip-off. Among the variables, bond width indicated more significant effect on bonding characteristics. In addition the bond length did not contribute to bond strength in proportion to the bond length. Hence this study evaluated effective bond length and effective bond strength. The effective bond strength was compared to those suggested by other researches which used different types of FRP strengthening materials such as carbon FRP.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.9-18
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• 2012

The BIM called information modeling is used by tool not only it will simply be appearing the image and can save the information. Recently, there is a lot of case that improves the construction productivity by using the BIM during the life cycle of bridge from order to management. Although we already recognize the advantage of BIM, it is a careful phase to use the BIM. Therefore, We made the BIM for bridge, evaluated the possibility that can build the object used in the civil engineer, studied about the utility, the improvement in order to use the BIM properly. As a result, the BIM can recycle the information by using parametric model and attribute the efficiency and accuracy on drawing and calculating the quantity. The BIM is able to help productivity increase by using the builded model after we spend the effort building a model in early stage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.91-100
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• 2018

The setting of values on door hinge mounting compensation for door assembly tolerance is a constant quality issue in vehicle production. Generally, heuristic methods are used in satisfying appropriate door gap and level difference, flushness to improve quality. However, these methods are influenced by the engineer's skills and working environment and result an increasement of development costs. In order to solve these problems, the system which suggests hinge mounting compensation value using CAE (Computer Aided Engineering) analysis is proposed in this study. A structural analysis model was constructed to predict the door gap and level difference, flushness through CAE based on CAD (Computer Aided Design) data. The deformations of 6-degrees of freedom which can occur in real vehicle doors was considered using a stiffness model which utilize an analysis model. The analysis model was verified using 3D scanning of real vehicle door hinge deformation. Then, system model which applying the structural analysis model suggested the final adjustment amount of the hinge mounting to obtain the target door gap and the level difference by inputting the measured value. The proposed system was validated using the simulation and showed a reliability in vehicle hinge mounting compensation process. This study suggests the possibility of using the CAE analysis for setting values of hinge mounting compensation in actual vehicle production.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.221-228
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• 2005

The economic growth brought the demand of bridge connected to island and land increasingly in Korea. Therefore, Civil engineer has faced a lot of problem to be considered such as structural stability, economic feasibility and constructional method. At the bridge site to be constructed, the depth of water is about 24m, the thickness of weathered rock overlaying bed rock is thicker than 36m. If open caisson foundation is supported in bed rock, the hight of foundation is about 60m. It is difficult to construct in these conditions. If open caisson foundation is supported in weathered rock, the size of the foundation should be increased. And If we apply the pile foundation, the higher construction cost will be needed. Under the circumstances, we need a new foundation type-composite foundation that is consisted of open caisson and cast-in-place piles. Because the design concept of composite foundation is not presented in Korea Bridge Design Standard, we are willing to clear the bearing behavior of composite foundation by numerical analysis in this paper.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.51-57
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• 2007

As a shot sleeve in die casting plays a critical role in delivering molten metal to a die cavity, any disruption to its function in the injection stage results in deterioration of the quality of final castings. To guarantee a smooth operation of a shot sleeve, its structural stability should be maintained. Despite the simple geometry, design of shot sleeve is based on individual engineer's experience and no agreement on the design is present. In this study, we newly propose a systematic methodology to determine a minimum wall thickness of a shot sleeve to prevent yielding or plastic deformation. Analytical calculations incorporating numerical analysis produce a rational design rule for minimum thickness of a shot sleeve subject to metal intensification pressure and geometric die constraint. To validate the proposed design guideline, authors present real data on a collection of actual shot sleeves. Upon checking their conformity to the new design rule, we discovered a strong correlation between the design of wall thickness and premature failures.

• Korean Institute of Interior Design Journal
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• no.19
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• pp.45-52
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• 1999

This study is on Buckminster Fuller, who is generally known as a structure engineering architect, and his influences. Fuller's radical and utopian ideas and designs were regarded as 'paper architecture'. But considering today's high cost of energy and the limited natural resources, Fuller's Dymaxion theory must be re-evaluated. Fuller's influences on the contemporary architecture are summarized as follows. 1) His idea of controlling the environment through the use of technology influenced today's 'High-Tech' architects. Architecture is no-longer designed purely by its formal character, but becomes a tool of investigating environmental significance of modern technology. 2) Through systemizing mechanical equipment, Dymaxion House prototype, and aggregation of high-tech mechanical equipments, influenced Archigram & Metabolist's capsule idea. It is expressed as a plug-in module equipment of 'High-Tech' architecture which has flexible interior with mechanical exterior image. 3) Megastructure. The Manhattan dome project gave an influence to many engineer/architects who tried to achieve an ideal artificial environment. This is in connection to 1960's utopian projects. Today's megastructures show new possibilities in urbanism and architecture. Fuller's comprehensive idea of humans living in harmony in the universe shows possibilities not only in structural engineering, but in solving various problems that confront today's architecture.

• Structural Engineering and Mechanics
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• v.19 no.1
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• pp.1-20
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• 2005

The expertise required in the judicious use of nonlinear finite element (FE) packages for design-assistance purposes is not widely available to the average engineer, whose sole aim may be to obtain an estimate for a single design parameter, such as the limit load capacity of a structure. Such a parameter may be required for the design of a proposed reinforced concrete (RC) floor slab or bridge deck with a given set of geometrical and material details. This paper outlines a procedure for developing design-assistance equations for carrying out such predictions for partially restrained RC slabs under uniformly distributed loading condition, based on a database of FE results previously generated from a large number of 'numerical model' slabs. The developed equations have been used for predicting the peak loads of a number of experimental RC slabs having varying degrees of edge restraints; with results showing a reasonable degree of accuracy and low level of scatter. The simplicity of the equations makes them attractive and their successful use in the field of application reported in this paper suggest that the outlined procedure may also be extended to other classes of concrete structures.