• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.647-654
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• 2006

In orthotropic steel decks, it is likely to have defects due to fatigue damages because most of structural joints(the connection of longitudinal rib and transverse rib, the connection of deck plate and longitudinal rib) are connected by welds. However. orthotropic steel decks have many advantages. such as light weight and reduction of construction time. in comparison with concrete decks. Therefore. they are mostly used in long-span bridges and urban highway bridges. This study consists of the cause identication of fatigue damage and the suggestion of rational thickness on deck plate about the connection of deck plate and longitudinal rib. The results are as follows: fatigue damage cause at the connection of deck plate and longitudinal rib is local deformation in deck plate. And, rational thickness of deck plate is 16mm thickness.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.719-724
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• 2006

Owing to its special features of light weight, high durability, corrosion-resistant, composite material used in civil infrastructure can not only solve fundamental problems of deterioration and corrosion, but also reduce both construction and maintenance cost significantly. Composite deck panels of 스냅핏 type connection previously designed and fabricated have been redesigned herein. The sensitivity of gaps between snap-fits and tip angles was investigated. Stacking sequence of plies was scrutinized in order to facilitate pultrusion process. Deck panels of redesigned configuration due to bending has been analyzed. A comparison between the preliminary and modified deck design has been made.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.05a
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• pp.126-131
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• 1993

Differential Scanning Calorimetry (DSC) and solvent swelling technique have been applied for identifying physical transition temperatures in the macromolecular structure of coals. The transition processes seem to be associated with physical relaxation of the coal structure and are irreversible processes. In Pittsburgh No. 8 high volatile bituminous (hvb) coat one physical transition was noted at 250-30$0^{\circ}C$ (at 8$^{\circ}C$/min) without any significant accompanying weight loss. Coals of higher rank than high volatile bituminous, i.e., Upper Freeport medium volatile bituminous (mvb) and Pocahontas No.3 low volatile bituminous (lvb) coals, exhibit structural relaxation just before the major thermal decomposition process and a sharp increase in solvent swellability accompanies this relaxation. In the case of both the Pittsburgh No.8 and the Upper Freeport coat structural relaxations at around 36$0^{\circ}C$ seem to coincide with release of "guest molecules".les".uot;.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.24-28
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• 2008

It expects demand of ships which equipped with JIB crane growth to continue. However, demand of JIB crane is increased, domestic shipment company imitated the design of Europe and Japan. And we need to develop the functional system of the JIB crane and modernize it. We need to find the optimum luffing angle for saving energy when JIB crane works. This study analyzed buckling load of JIB and reaction force of support point and stress of JIB according to the luffing angle through finite element analysis when JIB crane loads 40 ton weight. And this study considered the safety factor 1.8 of material. Every design condition was KS A1627 standard. This study used ANSYS 10.0.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.9
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• pp.593-598
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• 2015

In this paper, the silencer for large caliber gun to reduce the propagation of gun-generated noise was studied. The results of structural analysis and firing test were described. Structural analysis was conducted by using a commercial program, ANSYS, and showed that there was not any structural problem. The sound pressure level was diminished about 10 dB by the silencer adapted in front of the gun and the soundness of the material was verified from the internal pressure measurement. The reduction of weight, improvement of durability and speed-up of actuating device have to be studied later to improve the usability of silencer for large caliber gun.

• Steel and Composite Structures
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• v.22 no.5
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• pp.1141-1162
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• 2016

Concrete-filled double skin steel tube (CFDST) beam-columns are widely used in industrial plants, subways, high-rise buildings and arch bridges. The CFDST columns have the same advantages as traditional CFT members. Moreover, they have lighter weight, higher bending stiffness, better cyclic performance, and have higher fire resistance capacities than their CFT counterparts. The scope of this study is to develop finite element models that can predict accepted capacities of double skin concrete-filled tube columns under the combined effect of axial and bending actions. The analysis results were studied to determine the distribution of stresses among the different components and the effect of the concrete core on the outer and inner steel tube. The developed models are first verified against the available experimental data. Accordingly, an extensive parametric study was performed considering different key factors including load eccentricity, slenderness ratio, concrete compressive strength, and steel tube yield strength. The results of the performed parametric study are intended to supplement the experimental research and examine the accuracy of the available design formulas.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.786-792
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• 2009

Topology optimization is to find the optimal material distribution of the specified design domain minimizing the objective function while satisfying the design constraints. Since the genetic algorithm (GA) has its advantage of locating global optimum with high probability, it has been applied to the topology optimization. To guarantee the structural connectivity, the concept of compliance pattern is proposed and to improve the convergence rate, small number of population size and variable probability in genetic operators are incorporated into GA. The rank sum weight method is applied to formulate the fitness function consisting of compliance, volume, connectivity and checkerboard pattern. To substantiate the proposed method design examples in the previous works are compared with respect to the number of function evaluation and objective function value. The comparative study shows that the compliance pattern based GA results in the reduction of computational cost to obtain the reasonable structural topology.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.571-575
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• 2008

An engine cradle is a quite important structural assembly for supporting the engine, suspension and steering parts of vehicle and absorbing the vibrations during the drive and the shock in the car crash. Recently, the engine cradle having structural stiffness enough to support the surrounding parts and absorbing the shock of collision has been widely used. The hydroforming technology may cause many advantages to automotive applications in terms of better structural integrity of parts, reduction of production cost, weight reduction, material saving, reduction in the number of joining processes and improvement of reliability. We focus on increasing the durability and the dynamic performance of engine cradle. For realizing this objective, several optimization design techniques such as shape, size, and topology optimization are performed. This optimization scheme based on the sensitivity can provide distinguished performance improvement in using hydroforming.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.5
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• pp.562-571
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• 2006

Finite element analysis is performed to evaluate structural reliability of an automotive pedal arm under conditions of the stiffness, the load and the endurance test specifications. Results of the analysis shows that the pedal arm is safe enough under the tests. A topology optimization is numerically implemented, overall shape of the pedal arm being verified to be reasonable, A design concept to insert holes in the arm is established, which may be used to reduce its weight.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1572-1578
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• 2008

The effect of the organoclay_10A nanoparticles on the DSC and Structural and Dielectrics Properties(1Hz-1MHz) for epoxy/Organoclay_10A Nanocomposites has been studied. Dielectric properties of epoxy-Organoclay nanocomposites were investigated at 1, 3, 5, 7, 9 filler concentration by weight. Epoxy nanocomposites samples were prepared with good dispersion of layered silicate using power ultrasonic method in the particles. As structural analysis, the interlayer spacing have decreased with filled nanoparticles contents increase using power ultrasonic dispersion. The maximum increase interlayered spacing was observed to decease for above 5wt% clay loading. The other hand, as decrease with concentration filler of the layered silicate were increased dispersion degree of nanoparticles in the matrix. The interesting dielectric properties for epoxy based nanocomposites systems are attributed to the large volume fraction of interfacesin the bulk of the material and the ensuring interactions between the charged nanoparticle surface and the epoxy chains.