• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.65-68
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• 2005

An analytical procedure to analyze reinforced concrete (RC) frame subject to cyclic as well as monotonic loadings is proposed on the basis of the layered section method. In contrast to the classical nonlinear approaches adopting the perfect bond assumption, the bond-slip effect along the reinforcing bar is quantified with the force equilibrium and compatibility condition at the post-cracking stage and its contribution is implemented into the reinforcing. The advantage of the proposed analytical procedure, therefore, will be on the consideration of the bond-slip effect while using the classical layered section method without additional consideration such as taking the double nodes. Through correlation studies between experimental data and analytical results, it is verified that the proposed analytical procedure can effectively simulate the cracking behavior of RC beams, columns and Frame accompanying the stiffness degradation caused by the bond-slip.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.4
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• pp.109-116
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• 2002

The solution of the aircraft wing spar cross-section area optimization problem is obtained by the response surface method. The object function of the problem is wing total weight, design variables are spar cross-section areas, constraints are the conditions that the stresses at the each spar is less than the allowable stress. D-Optimal condition is utilized to obtain the experimental points to construct the response surfaces. D-Optimal experimental points are obtained by the commercial software "Deign-Expert". Response values for the object function and constraints for each experimental point are calculated by the NASTRAN. Response surfaces for object function and constraints are approximated from the response values by the least square method. The optimization solution is obtained by the DOT for the response surfaces of object function and constraints. The optimization results obtained from the response surface are compared with the results obtained by the NASTRAN SOL200.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.11-14
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• 2002

Accurate sets of electron collision cross sections for atoms and molecules are necessary for quantitative understanding and modeling of plasma phenomena. So, in this study, we explains the concept of electron collision cross sections for gases, and the principle of determination of the electron collision cross sections for atoms and molecules by using the present electron swarm method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.130-135
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• 2011

A study of the bending-extension-transverse shear coupled random response of the composite beams with thin-walled open sections subjected to various types of concentrated and distributed random excitations is dealt with in this paper. First of all, equations of motion of thin-walled composite H-type cross-section beams incorporating a number of nonclassical effects of transverse shear and primary and secondary warping, and anisotropy of constituent materials are derived. On the basis of derived equations of motion, analytical expressions for the displacement response of the composite beams are derived by using normal mode method combined with frequency response function method.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.76-83
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• 2005

The marked increase in the number of environmental problems, combined with the increase in their intensity and spatial extent, has resulted in an ever-increasing need for constant monitoring. This is complicated by the occurrence of new and complicated environmental issues that often prevent a thorough understanding of the entire monitoring framework. In the present study, a diagrammatic method was developed to present the entire framework of a monitoring plan. The diagram was separated into three sections- "Problem Section", "Research Process and Data Section" and "Entities Section" - to clearly present the disparate relationships between monitoring objectives and the monitoring procedure. Notation of the diagrams was undertaken using Unified Modeling Language (UML). A hypothetical monitoring plan for an environmental problem was designed to assess usefulness of the diagrammatic method. The diagram was capable of reviewing and revising the monitoring plan and could be used to select a monitoring procedure according to the monitoring objectives of the plan. The results suggested that this diagrammatic method was effective for designing an appropriate monitoring plan for a given monitoring objective.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.119-124
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• 2004

In this study, a rotor blade of a Curtis turbine is investigated. Bezier curve is generally used to define the profile of turbine blades. However, this curve gives a feature of global control, which is not proper to a supersonic impulse turbine blade. Thus, a blade design method is developed by using B-spline curve so that local control is possible to obtain an optimized blade section. To design a Curtis turbine blade section systematically, the blade section has been changed by varying three design parameters using central composite design method. Flow analyses have been carried out for the blade sections, and the effects of design parameters are evaluated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.69-78
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• 1999

The stiffness of slab concrete section is not considered as effective in the existing method of construction for continued steel box girder bridge. Using lifting system and filled concrete, it is possible to make stiffness of slab concrete section effective and improve stiffness of negative moment section. It was proved that the stress of upper flange in positive moment is significantly lower than case of existing method through the stress comparison. This stress difference made possible to rearrange flange thickness and as the result of this rearrangement, the amount of steel and height of girder can be reduced up to 13.23% and 11.5%.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.583-588
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• 2007

For the purpose of optimum design of RC frame structures. pre-determined section database of column and beam are constructed and arranged in order of the resisting capacity. Then, regression equations representing the relation between section number and resisting capacity are derived. In advance. effective optimization algorithms which search optimized solution quickly using direct search method from these database are proposed. Moreover. the investigation for the applicability and effectiveness of the introduced design procedure is conducted through correlation study for example structures.

• Steel and Composite Structures
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• v.13 no.2
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• pp.171-185
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• 2012

The calculation of fire resistance for a composite structural element comprises the calculation of the temperature within its cross-section and of the load bearing capacity, considering the evolution of the steel and concrete mechanical properties, function of the temperature. The paper proposes a method to calculate the bending capacity under ISO fire, for Slim Floor systems using asymmetric steel beams, with a wider lower flange or a narrow upper flange welded onto a half hot-rolled profile. The temperatures in the cross-section are evaluated by means of empirical formulas determined through a parametrical analysis, performed with the special purpose non-linear finite element program SAFIR. Considering these formulas, the bending capacity may be calculated, using an analytical approach to determine the plastic bending moment, for different fire resistance demands. The results obtained with this simplified method are validated through numerical analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.155-163
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• 2001

Joint stiffnesses can affect the vibrational characteristics of car body structures and, therefore, should be included in vehicle system models. In this paper, a numerical approximation of joint stiffness is presented for considering joint flexibility of thin walled beam jointed structures. Using the proposed method, it is possible to optimize joint structures considering the change of section shapes in vehicle structures. The numerical approximation of joint stiffnesses is derived using the RSM(Response Surface Method) in terms of beam section properties. The study shows that joint stiffnesses can be effectively determined in designing vehicle structure.