• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.447-450
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• 2005

A prefabricated composite hollow slab with perforated I-beams was suggested for the replacement of deteriorated concrete decks or the construction of new composite bridges with long-span slabs. Composite slabs with embedded I-beams have considerably higher stiffness and strength. For the application of prefabricated composite slabs to bridges, joints between slabs should satisfy the requirements of the ultimate limit state and the serviceability limit state. In this paper, three types of the detail for loop joints were selected and their structural performance in terms of strength and crack control was investigated through static tests on continuous composite slabs. A main parameter was the detail of the joint, such as an ordinary loop joint and loop joint with additional reinforcements. Even though there was no connection of the steel beams at the joints, the loop joints showed good performance in terms of strength. In terms of crack control, the loop joint with additional reinforcements showed better performance. In ultimate limit state, the continuous composite slabs showed good moment redistribution and ductility.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.127-130
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• 2004

In this paper, active shape control of composite structure actuated by shape memory alloy (SMA) wires is presented. Hybrid composite structure was established by attaching SMA actuators on the surfaces of graphite/epoxy composite beam using bolt-joint connectors. SMA actuators were activated by phase transformation, which induced by temperature rising over austenite finish temperatures. In this paper, electrical resistive heating was applied to the hybrid composite structures to activate the SMA actuators. For faster and more accurate shape or deflection control of the hybrid composite structure, PID feedback controller was designed from numerical simulations and experimentally applied to the SMA actuators.

• Advanced Composite Materials
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• 제17권2호
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• pp.177-190
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• 2008

As the first step in discussing the reliability of composite structures, a fundamental study was performed to obtain the scattering characteristics of glass-fiber reinforced plastics (GFRP) and woven carbon fiber reinforced plastics (WCFRP) as well as a reference metal. The Euler buckling load was obtained experimentally for each material. The experiments were conducted for specified rectangular specimens with simply supported edges. A new attachment to realize the simply support boundary conditions for composite materials have been prepared before these experiments. The scattering data in the results for GFRP and WCFRP composites were compared with those of a typical metal of aluminum alloy. The experimental data were also compared with numerical simulations including the uncertainties.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.361-365
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• 2001

Laboratory tests are conducted to validate the mechanical model of a filament-wound composite shaft. Also, design charts are produced by validated analytical calculations based on the Timoshenko beam model of a layered steel/composite structure. The major results found are that steel/composite hybrid shafts can lead to better dynamic and static performances over steel or pure composite shafts of the same volume, and the most effective composite structures contain some steel in the form of a tubular core. These results can be used in the design process of composite boring bars and automotive drive shafts.

• Steel and Composite Structures
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• 제6권5호
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• pp.435-457
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• 2006

The paper presents the cost optimization of composite floor trusses composed from a reinforced concrete slab of constant depth and steel trusses consisting of hot rolled channel sections. The optimization was performed by the nonlinear programming approach, NLP. Accordingly, a NLP optimization model for composite floor trusses was developed. An accurate objective function of the manufacturing material, power and labour costs was proposed to be defined for the optimization. Alongside the costs, the objective function also considers the fabrication times, and the electrical power and material consumption. Composite trusses were optimized according to Eurocode 4 for the conditions of both the ultimate and the serviceability limit states. A numerical example of the optimization of the composite truss system presented at the end of the paper demonstrates the applicability of the proposed approach.

• Structural Engineering and Mechanics
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• 제55권5호
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• pp.931-951
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• 2015

To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.45-49
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• 2002

In this paper, we have studied about electromagnetic wave absorbing properties of ferrite-rubber composite with a variation of ferrite. Amounts of ferrite in a composite absorber were changed from 52 wt.% to 62 wt.%. As a result, it has been shown that the electromagnetic wave absorbing properties of ferrite-rubber composite are related to the amount of ferrite in composite absorber. As a summary, it could be controled the electromagnetic wave absorbing property of ferrite-rubber composite by changing some kinds of annex A and amount of ferrite.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.370-373
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• 1999

The purpose of this study is to research and develop PAn composite electrode for EDLC. EDLC cell of PAn composite electrode with 1M LiClO$_4$/PC brings out good capacitor performance below 4.0V. The radius of semicircle of PAn composite electrode adding 15wt% SP270 was absolutely small. The total resistance of EDLC cell mainly depended on internal resistance of the electrode. The discharge capacitance of PAn composite with 15wt% SP270 in 1st and 200th cycles was 42 and 42 F/g at current density of 1mA/cm$^2$. The capacitance of PAn composite with 15wt%. SP270 capacitor was larger than that of PAn capacitor without SP270. The coulombic efficiency of EDLC at discharge process of 1 and 200 cycles were 94 and 100% respectively. PAn composite EDLC with 15wt% SP270 content showed good capacitance and stability with cycling.

• Journal of Welding and Joining
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• 제26권5호
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• pp.36-42
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• 2008

Carbon nanotube (CNT) aluminum composite coatings were built up through kinetic spraying process. Deposition behavior of CNT aluminum composite on an aluminum 1050 alloy substrate was analyzed based on deposition mechanism of kinetic spraying. The microstructure of CNT aluminum composite coating were observed and analyzed. Also, the electrical resistivity, bond strength and micro-hardness of the CNT aluminum composite coatings were measured and compared to kinetic sprayed aluminum coatings. The CNT aluminum composite coatings have a dense structure with low porosity. Compared to kinetic sprayed aluminum coating, the CNT aluminum composite coatings present lower electrical resistivity and higher micro-hardness due to high electrical conductivity and dispersion hardening effects of CNTs.

• Advances in aircraft and spacecraft science
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• 제7권2호
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• pp.151-168
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• 2020

The present study deals with the repair of composite structures by bonding composite patches. The composite structure is a carbon/epoxy laminate with stacking sequence [45/-45/0/90]S. The damaged zone is simulated by a central crack and repaired by bonding symmetrical composite patches. The repair is carried out using composite patches laminated from the same elemental folds as those of the cracked specimen. Three-dimensional finite element method is used to determine the energy release rate along the front of repaired crack. The effects of the repair technique used single or double patch, the stacking sequence of the cracked composite patch and the adhesive properties were highlighted on the variations of the fracture energy in mode I and mixed mode I + II loading.