• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.264-265
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• 2014

This Paper reports the photocatalytic activity of $g-C_3N_4/NaTaO_3$ hybrid composite photocatalysts synthesized by ball-mill method. The $g-C_3N_4$ and $NaTaO_3$ were individually prepared by Solid state reaction and microwave hydrothermal process, respectively. The $g-C_3N_4/NaTaO_3$ composite showed the enhanced photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light irradiation. The results revealed that the band-gap energy absorption edge of hybrid composite samples was shifted to a longer wavelength as compared to $NaTaO_3$ and the 50 wt% $g-C_3N_4/NaTaO_3$ hybrid composite exhibited the highest percentage (99.6 %) of degradation of Rh. B and the highest reaction rate constant ($0.013min^{-1}$) in 4 h which could be attributed to the enhanced absorption of the hybrid composite photocatalyst in the UV-Vis region. Hence, these results suggest that the $g-C_3N_4/NaTaO_3$ hybrid composite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial $NaTaO_3$.

• Steel and Composite Structures
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• v.43 no.1
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• pp.19-30
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• 2022

The static strength and fatigue crack resistance of the aircraft skin structures depend on the materials used and joint type. Most of the commercial aircraft's skin panel structures are made from aluminium alloy and carbon fibre reinforced epoxy. In this study, the fatigue resistance of four joint configurations (metal/metal, metal/composite, composite/composite and composite/metal) with riveted, adhesive bonded, and hybrid joining techniques are investigated with experiments and finite element analysis. The fatigue tests were tension-tension because of the typical nature of the loads on aircraft skin panels susceptible of experimenting fatigue. Experiment results suggest that the fatigue life of hybrid joints is superior to adhesive bonded joints, and these in turn much better than conventional riveted joints. Thanks to the fact that, for hybrid joints, the adhesive bond provides better load distribution and ensures load-carrying capacity in the event of premature adhesive failure while rivets induce compressive residual stresses in the joint. Results from FE tool ABAQUS analysis for adhesive bonded and hybrid joints agrees with the experiments. From the analysis, the energy release rate for adhesive bonded joints is higher than that of hybrid joints in both opening (mode I) and shear direction (mode II). Most joints show higher energy release rate in mode II. This indicates that the joints experience fatigue crack in the shear direction, which is responsible for crack opening.

• Journal of Electrochemical Science and Technology
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• v.6 no.2
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• pp.59-64
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• 2015

Spherical Li₄Ti₅O₁₂ and Li₄Ti₅O₁₂ carbon nanotube (CNT) composites were synthesized using a colloid system. The electrochemical properties of the composites were thoroughly examined to determine their applicability as hybrid capacitor anodes. The electrical conductivity of the spherical Li₄Ti₅O₁₂-CNT composite was improved over that of the spherical Li₄Ti₅O₁₂ composite. The synthesized composites were utilized as the anode of a hybrid capacitor, which was assembled with an activated carbon (AC) positive electrode. The CNTs attached on the spherical Li₄Ti₅O₁₂ particles contributed to a 51% reduction of the equivalent series of resistance of the Li₄Ti₅O₁₂-CNTs/AC hybrid capacitor compared to the Li₄Ti₅O₁₂/AC hybrid capacitor. Moreover, the Li₄Ti₅O₁₂-CNTs/AC hybrid capacitor showed a larger capacitance than the Li₄Ti₅O₁₂/AC hybrid capacitor; specifically, the Li₄Ti₅O₁₂-CNT/AC hybrid capacitor showed 1.6 times greater capacitance at 40 cycles with a 10 mA cm⁻² loading current density.

• Composites Research
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• v.17 no.1
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• pp.18-28
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• 2004

In order to evaluate the strength of carbody structures of railway rolling stock made of laminated fiber-reinforced composite materials, total laminate approach was introduced. Structural analyses were conducted to check the basic design of hybrid composite carbody structures of the Korean Tilting Train eXpress(TTX) with the service speed of 180km/h. The mechanical tests were also conducted to obtain strengths of composite laminates. The results show that all stress components of composite carbody structures are inside of failure envelopes and total laminate approach is recommended to predict the failure of hybrid composite carbody structures at the stage of the basic design.

• Composites Research
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• v.17 no.4
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• pp.18-24
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• 2004

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

• Composites Research
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• v.12 no.1
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• pp.47-58
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• 1999

This paper describes the results of experiments to analyze the free vibration of the laminated composite and hybrid composite plates with various shapes and boundary conditions. The materials of specimens were the carbon fiber reinforced plastic (CFRP), the glass fiber reinforced plastic (GFRP), the GFRP-Aluminum hybrid composite and the CFRP-CFRP hybrid composite. The natural frequencies and nodal patterns of plates with various shapes were experimentally obtained by impact exciting test using an impact hammer and an accelerometer. The experimental results were presented with normalized frequency parameters. The effects of composite material properties, fiber orientation angles, various geometrical shapes and boundary conditions on the vibration characteristics of composite plates were evaluated. To compare and verify these experimental results, the finite element analysis was carried out, and was well agreed with experimental results.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.1
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• pp.37-42
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• 2003

Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping have been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2256-2261
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• 2017

Carbon nanotube (CNT) and alumina ($Al_2O_3$) are synthesized into hybrid composites, and an advanced electrical discharge machining (EDM) system is developed for the machining of hard and conductive materials. CNT nanoparticles are mixed with $Al_2O_3$ powder and the $Al_2O_3$/CNT slurry is sintered by spark plasma. The hardness and the electrical conductivity of the $Al_2O_3$/CNT hybrid composite were investigated. The electrical discharge is controlled by a capacitive ballast circuit. The capacitive ballast circuit is applied to the tungsten carbide and the $Al_2O_3$/CNT hybrid composite. The voltage-current waveforms and scanning electron microscope (SEM) images were measured to analyze the characteristics of the boring process. The developed EDM process can manufacture the ceramic based hybrid composites, thereby expecting the variety of applications.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.1
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• pp.28-42
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• 2017

Moisture transfer characteristics of high emotional garments are important to evaluate wear comfort. Wicking and drying measurement methods are also critical for perspiration absorption and quick dry fabric made of high functional fibers. In this study, the wicking and drying properties of high emotional fabrics made from hybrid composite yarns using CoolMax, Tencel, Bamboo staple fibers and PP. PET CoolMax filaments were also measured and analyzed according to various measuring methods. The wicking property of hybrid composite yarn fabrics by Bireck method was mostly influenced by the structure of hybrid yarns than the absorption rate of constituent fibers; however, both the hygroscopicity of fibers and the composite yarn structure affected the wicking property of the fabrics in the drop method. Concerning drying properties, the KSK 0815B method measuring distilled moisture weight was more relevant to explain the drying characteristics of hybrid yarn fabrics than the KSK 0815A method measuring the time to drying. This study revealed that the drying properties of hybrid yarn fabrics were influenced by the hygroscopicity of constituent fibers, wicking properties of constituent yarns and structure of composite yarns.

• Advances in materials Research
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• v.7 no.2
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• pp.119-136
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• 2018

In this paper, static and vibration analysis for anti-symmetric cross-ply and angle- ply carbon/glass hybrid laminates rectangular composite plate are presented. In this analysis, the equations of motion for simply supported thick laminated hybrid rectangular plates are derived and obtained through the use of Hamilton's principle. The closed-form solutions of anti-symmetric cross-ply and angle- ply laminates are obtained using Navier solution. The effects of side-to-thickness ratio, aspect ratio, and lamination schemes on the fundamental frequencies loads are investigated. The study concludes that shear deformation laminate theories accurately predict the behavior of composite laminates, whereas the classical laminate theory over predicts natural frequencies. The excellent accuracy of the present analytical solution is confirmed by making some comparisons of the present results with those available in the literature. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behaviors of anti-symmetric cross-ply and angle- ply hybrid laminated composite plates.