• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.212-215
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• 2004

The hybrid composite carbody structures were considered as the carbody system of Korean Tilting Train eXpress(TTX) to achieve the lightweight design. The TTX carbodies are composed of the carbody shell made of the sandwich composite structure and the undeframe made of the metal structure. The sandwich structures were used to minimize the weight of carbody, and the metal underframe was used to modify the design easily and to keep the strength of underframe by the installation of the electrical equipments. The sandwich carbody structures will be cured in an autoclave. In this paper, the manufacturing processes of the TTX carbody structures were introduced briefly.

• Journal of KSNVE
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• v.6 no.6
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• pp.781-790
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• 1996

The goal of current research is to suppress the acoustic noise radiated from vibration of composite plate structure. The induced noise can be reduced through the control of the corresponding structural vibration modes by using the piezoelectric materials as actuator. The acoustic fields are to be analyzed through the boundary element method (BEM) based on the Rayleigh intergral equation and structural system through the finite element method (FEM). The suppression of rediated sound is studied by adaping the piezoelectric material as the distributed actuator. Numerical results are presented on the sound radiation from composite plate of arbitrary boundary conditions, the noise reduction adapting the piezoelectric materials as distributed actuator. The results show the effectiveness and possibility of piezoelectric actuator in the control of sound radiation from composite structure.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.71-74
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• 2004

A composite-aluminum hybrid joint of composite external fuel tank of an aircraft has been analyzed by a 3-dimensional finite element method. Curvature and contact of the joint structure were considered in the analysis. Yamada-Sun failure criteria was utilized for the failure evaluation. A finite element program ABAQUS was used for the nonlinear contact analysis. The joint structure was predicted to be safe in both the test and analysis.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.199-202
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• 2000

Compared with existing construction materials, ACM(Advanced Composites Material) possesses many advantage such as light-weight, high-strength, corrosion resistant properties, etc. In this study, utilizing those advantages of ACM, composite skin and comer plate for protection of concrete port structure are developed. Detailed procedure fur analysis, design and fabrication along with site installation for demonstration project are described. It is also demonstrated that pultrusion process for comer plate and VARTM process for composite skin are promising fabrication methods fer future civil infrastructure application.

• Structural Engineering and Mechanics
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• v.24 no.3
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• pp.291-306
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• 2006

In order to improve the constructability and meanwhile ensure excellent seismic behavior, several innovative composite connection details were conceived and studied by the authors. This paper reports experimental results and observations on seismic behavior of steel beam bolted to reinforced concrete column connections (bolted RCS or BRCS). The proposed composite connection details involve post tensioning the end plates of the steel beams to the reinforced concrete or precast concrete columns using high-strength steel rods. A rational design procedure was proposed to assure a ductile behavior of the composite structure. Strut-and-tie model analysis indicates that a bolted composite connection has a favorable stress transfer mechanism. The excellent capacity and behavior were then validated through five full-scale beam to column connection model tests.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.338-343
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• 2005

We have evaluated the structural integrity of a sandwich composite train roof which can find a lightweight, cost saving solution to large structural components for rail vehicles in design stages. The sandwich composite train roof was 11.45 meter long and 1.76 meter wide. The reinforced frame was inserted in sandwich panels to improve the structural performance of train roof structure and had the shape of hollow rectangular box. The finite-element analysis was used to calculate the stresses, deflections and natural frequencies of the sandwich composite train roof against the weight of air-condition system. The 3D sandwich FE model was introduced to simulate the hollow aluminum frames which jointed to both sides of the sandwich train roof. The results shown that the structural performance of a sandwich composite train roof under load conditions specified was proven and the use of aluminum reinforced frame was beneficial with regard to weight savings in comparison to steel reinforced frame.

• Journal of the Korean Society of Safety
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• v.34 no.2
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• pp.7-14
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• 2019

A palladium can adsorb hydrogen and detect leaking hydrogen through changes in color and electrical resistance. This study is to evaluate the structural behavior of carbon fiber adding palladium composite materials used in the hydrogen storage vessel. A multi-scale analysis technique was used to analyze accurately the behavior of each material in relation to the microscopic composition. The multi-scale analysis is more proper and precise for composite materials because of considering the individual microscopic structure and properties of each material for composite materials. Also the crack evaluation was performed by XFEM analysis to confirm the reinforcement performance of aluminum as a liner of the hydrogen vessel. The results show that the addition of the palladium material increased the macroscopic stress, but microscopically the carbon fiber stress was reduced. It means the performance improvement of the palladium added carbon fiber/Al composite.

• Structural Engineering and Mechanics
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• v.89 no.6
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• pp.571-578
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• 2024

The bistable thin cylindrical shell is developable structure with the ability to transition between its two stable configurations. This structure offers significant potential applications due to its excellent deformability. In this paper, the composite thin cylindrical shell consisting of the composite layer and the piezoelectric layer was investigated. The material and geometric parameters of the shell were found to influence its stable characteristics. The analysis model of the composite thin cylindrical shell incorporating the piezoelectric layer was developed, and the expressions for its strain energy were derived. By applying the minimum energy principle, the impact of the electric field intensity on the bi-stable behaviors of the cylindrical shell was analyzed. The results showed that the shell exhibited the bistability only under the appropriate electric field strength. And the accuracy of the theoretical prediction was verified by simulation experiments. This study provides an important reference for the application of deployable structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.185-191
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• 2003

This paper presents the thermal problems of steel-concrete composite structure and the basic references in placing concrete into the structure. Based on the analytical investigation, application of the composite structure has the effect of highly decreasing the temperature difference between the center section and the surface section of the structure, though its application has little influence on the decrement of the maximum temperature under the same using material and placing temperature. Meanwhile, its application causes the section decrement of a concrete structure, and in the section which the decrement ratio is relatively large, the restraint action by a old concrete structure takes place highly tensile stresses over a tensile strength. And, the stress is concentrated on sharp edges of the steel-concrete boundary. Both restraint action and stress concentration considerably decrease the reduction effect of the temperature difference. Therefore, the prediction of thermal response and the reasonable steps are required through the simulation considering the factors and the sections related to those problems.

• Steel and Composite Structures
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• v.28 no.2
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• pp.223-231
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• 2018

Nowadays, there are a great number of various structures that have been retrofitted by using different FRP Composites. Due to this, more researches need to be conducted to know more the characteristics of these structures, not only that but also a comparison among them before and after the retrofitting is needed. In this research, a model steel structure is tested using a bench-scale earthquake simulator on the shake table, using recorded micro tremor data, in order to get the dynamic behaviors. Columns of the model steel structure are then retrofitted by using GFRP composite, and then tested on the Quanser shake table by using the recorded micro tremor data. At this stage, it is needed to evaluate the dynamic behaviors of the retrofitted model steel structure. Various types of methods of OMA, such as EFDD, SSI, etc. are used to take action in the ambient responses. Having a purpose to learn more about the effects of GFRP composite, experimental model analysis of both types (retrofitted and no-retrofitted models) is conducted to evaluate their dynamic behaviors. There is a provision of ambient excitation to the shake table by using recorded micro tremor ambient vibration data on ground level. Furthermore, the Enhanced Frequency Domain Decomposition is used through output-only modal identification. At the end of this study, moderate correlation is obtained between mode shapes, periods and damping ratios. The aim of this research is to show and determine the effects of GFRP Composite implementation on structural responses of the model steel structure, in terms of changing its dynamical behaviors. The frequencies for model steel structure and the retrofitted model steel structure are shown to be 33.916% in average difference. Finally, it is shown that, in order to evaluate the period and rigidity of retrofitted structures, OMA might be used.