• Steel and Composite Structures
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• v.28 no.4
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• pp.403-414
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• 2018

In this paper, the lateral-torsional buckling of axially-transversally functionally graded tapered beam is investigated. The structure cross-section is assumed to be symmetric I-section, and it is continuously laterally supported by torsional springs through the length. In addition, the height of cross-section varies linearly throughout the length of structure. The proposed formulation is obtained for the case that the elastic and shear modulus change as a power function along the beam length and section height. This structure carries two concentrated moments at the ends. In this study, the lateral displacement and twisting angle relation of the beam are defined by sinusoidal series. After establishing the eigenvalue equation of unknown constants, the beam critical bending moment is found. To validate the accuracy and correctness of results, several numerical examples are solved.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.954-957
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• 1987

This paper proposes a kind of function-concentrated signaling service equipment structure, in which various kind of signaling service are efficiently made for call processing control. Based upon the typical switching system models, a philosophical study on the capacity, features of structure in world systems, and interfaces with peripheral equipments has been performed in order to provide the rationale on the merits or efficiency of the proposed digital signaling service equipment.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.131-134
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• 2011

In this study, we propose an optimal design and new fabrication method for a slim tactile sensor. Slim tactile sensor can detect 3-axial forces and has suitable flexibility for intelligent robot fingers. To amplify the contact signal, a unique table-shaped structure was attempted. A new layer-by-layer fabrication process for polymer micromachining that can make a 3D structure by using a sacrificial layer was proposed. A table-shaped epoxy sensing plate with four legs was built on top of a flexible polymer substrate. The plate can convert an applied force to a concentrated stress. Normal and shear forces can be detected by combining responses from metal strain gauges embedded in the polymer substrate. The optimal positions of the strain gauges are determined using the strain distribution obtained from finite element analysis.

• Korean Journal of Computational Design and Engineering
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• v.2 no.3
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• pp.142-149
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• 1997

This study is intended to develop a Feature based modeler. It is difficult to integrate CAD and CAM/CAPP with information that is given only by a conventional CAD system. Therefore a lot of studies have concentrated on a Feature based CAD system. But conventional Feature based modelers have had limitation on providing sufficient information related to Feature interaction. If a Feature based modeler is to be used in assembly simulation, a new Feature-based modeling method needs to be developed. Also to support collision detection between parts, we have to handle Feature interaction systematically. Therefore we suggest Cell data structure which handles interaction of Features by volume. The volume created by Feature interaction is saved as a Cell. With the Cell structure we solve problems involved with Feature interaction. This study shows how the Cell data structure can manage Feature interaction and give enough information in assembly simulation.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.137-145
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• 2012

In the previous study, the construction guide line of IT infra-structure for a u-City was introduced. However, it is only concentrated on the components and construction procedure for provider-oriented and technology-oriented sensor networks. In this paper the architecture and building process of demander-oriented sensor networks for sustainable u-City service are proposed. In the paper it is described (1) the enhancement methods of the procedure that can be flexibly constructed according to the scale of the project, (2) the methods that can improve the structure from the wireless sensor network such as RFID/USN to the hybrid sensor network, and (3) the consideration factors for providing the sustainable u-City service.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.131-138
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• 1997

The equivalent vehicle load factors which can consider the concentrated wheel load effect in slab design of parking garage structure are proposed. Based on the standard vehicle with total weight of 2.4 ton which is designed through the investigation of small to medium vehicle produced in Korea and the review of numerous foreign design codes for parking garage structure, the effects of moving vehicle loads on slab are analyzed using the finite element method. Besides. the relationships between the equivalent load factors and the sectional dimensions are established by regression analysis. The calculation of design forces can be easily accomplished without taking sophisticated numerical analysis for the moving vehicle load as the results obtained to the distributed load are multiplied by the proposed load factors in practice.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.155-162
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• 2016

This study attempts to reveal structures of two-dimensional ring polymer solutions in various polymer concentrations ranging from dilute to concentrated regime. Polymer sizes, single molecule structure factors, bond correlation functions and monomer density distribution functions from center of mass are given in order to clarify the polymer structures. Our study shows that a ring in dilute solution maintain pseudo-circular structure with self-avoiding walk (SAW) statistics, and it seems to be composed of two connecting SAW linear chains. In semidilute solutions, ring polymers are not entangled with each other and adopt collapsed configurations. Such assumption of collapsed structures in the semidilute regime gives an overlap concentration of ${\varphi}^*{\sim}N^{-1/2}$ where N is degree of polymerization. By normalizing the polymer concentration by these overlap concentration, we find universal behaviors of polymer sizes and structure factors regardless of N.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.149-158
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• 2008

This article provides strength estimation of T-joint area which made of composite material. Inner and outer structures of medium range surveillance radar are all made of sandwich structure which is made with composite material(CFRP) and aluminum honeycomb core. Since the radar is voluminous and has very complex inner structure, the whole structure cannot be made as one piece. Therefore, usage of T-joints is inevitable. Since some of stress concentration areas were located around T-joint area, series of strength estimations were conducted. Three different configurations were tested to improve mechanical properties(primarily on strength). The results show an improvement on strength to meet calculated strength on stress concentrated T-joint area.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.281-288
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• 1999

This paper studied the efficiency of retrofitting of reinforced concrete structure which was not designed to endure an earthquake. The earthquake in Kobe Japan showed that there was a great possibility of having an earthquake even in big city and the damages were concentrated on mid or low story buildings which were not considered to be protected from an earthquake, . This experiment used reinforced concrete structure which restrained side-by-side displacement to test durability against an earthquake. This study deals with the structural performance of reinforced concrete frame structures strengthened with steel materials.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.28-36
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• 1998

This investigation is the result of a structural analysis by the finite element method and static loading test for the optimal structural design of an electric railway vehicle made of stainless 301L materials. We analyzed the stress and displacement of the existing electric car-body structure for predicting the position of concentrated stress, the flow of stress, rigidity to be occurred in the car-body structure when it is subjected to the vertical load. It was exposed that the side sills and window corners around the bolsters are the weak parts of the electric car-body structure because the bolsters of the electric car-body structure were subjected to the vertical load and dynamic load to be occurred during running. The flow of stress and the cause of stress concentration in the weak zone were studied in order to prevent the concentration of stress and buckling. The rearrangement of the structure and the selection of the beam elements were also carried out for optimum design of the structure.