• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.209-212
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• 2001

Aircraft industry is developed very fast so titanium scrap was generated to manufacture. Titanium scrap was wasted and used to deoxidize cast iron so we are study recycling of it. In this research were studied that metal hydride of reacted in hydrogen chamber of AMS4900, 4901, return scrap titanium alloy and sponge titanium granule. The temperature of hydrogenation was 40$0^{\circ}C$ in the case of pure sponge titanium but return scrap titanium alloy were step reaction temperature at 40$0^{\circ}C$ and 50$0^{\circ}C$, and after the hydride of titanium alloy were crushed by ball mill for 5h. Titanium hydride contains to 4wt.% of hydrogen theoretically as theory. It was determined by heating and cooling curve in reaction chamber. The result of XRD was titanium hydride peak only that it was similar to pure titanium. Titanium hydride Powder particle size was about 45${\mu}{\textrm}{m}$, and recovery ratio was 95w% compared with scrap weight for a aluminum foam agent.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.189-190
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• 2006

A patient table considering x-ray transparency, mechanical safety and compact multi-axis moving mechanism has been developed. The goal of medical imaging technology is to keep radiation exposure of patients during x-raying to a minimum. In order to obtain clear pictures at low dose, however, the x-ray table which supports the patient must be sufficiently permeable to radiation to allow good image resolution. The table top is made of low density foam for x-ray transparent effective area and structural aluminum plate to connect moving mechanism under the table, covered with thin carbon fiber. This sandwich construction is very rigid and lightweight, so the table top can handle relatively heavy load comparing to its cantilevered structure which is unavoidable as long as cooperate with C-arm radiography. To verify the design results finite element static analysis and experimental tests have been done. According to the verification the results well satisfy certification guide lines as a medical device.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.4
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• pp.493-500
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• 2013

In this study, it was evaluated the protective performance of the protection material for filed of the army by impact of fragment from the explosion of 155mm artillery shell to propose the improvement items. And it was evaluated the protection materials for structural boby such as corrugated steel plate, concrete block, prevention paint of explosion, aluminum foam and concrete T-wall by impact of fragment of 155mm artillery shells and explosion-induced pressure of C-4 explosive. As a result, protective performance of the existing protective material was superior but reinforcement is necessary for secondary damage because sand is leaking. The protective performance of new protective materials was greater than existing protective materials. And it can be used for protective materials.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.339-345
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• 2022

In this paper, the effect of porosity on the acoustic phase velocity of the 3D printed Kelvin closed-cell structure was investigated using the spectral phase analysis. Since Kelvin cells bring about the large amount of scattering, acoustic pulses in ultrasonic measurements undergoes a distortion of waveforms due to the dispersion effect. In order to take account on the dispersion, mathematical expressions for calculating the phase velocity of longitudinal waves propagating normal to the plane of the Kelvin structure are suggested by introducing a complex wave number based on Fourier transform. 3D Kelvin structure composed of identical unit-cells, a polyhedron of 14 faces with 6 quadrilateral and 8 hexagonal faces, was developed and fabricated by 3D CAD and 3D printer to represent the micro-structure of porous materials such as aluminum foam and cancellous bone. Total nine samples of 3D Kelvin structure with different porosity were made by changing the thickness of polyhedron. Ultrasonic pulse of 1MHz center frequency was applied to the Kelvin structures for the measurement of the phase velocity of ultrasound using the TOF(time-of-flight) and the phase spectral method. From the experimental results, it was found that the acoustic phase velocity decreased linearly with the porosity.

• Composites Research
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• v.30 no.6
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• pp.384-392
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• 2017

Sandwich panels with three different joint configurations were tested to design a novel sandwich joint structure that can effectively support both the tensile and compressive loads. The sandwich core was mainly aluminum flex honeycomb but the PMI foam core was limitedly applied to the ramp area which is transition part from sandwich to solid laminate. The face of sandwich panel was made of carbon fiber composite. For configuration 1, the composite flange and the sandwich panel were cocured. For configurations 2 and 3, an aluminum flange was fastened to the solid laminate by HI-LOK pins and adhesive. The average compressive failure loads of configurations 1, 2, and 3 were 295, 226, and 291 kN, respectively, and the average tensile failure loads were 47.3 (delamination), 83.7 (bolt failure), and 291 (fixture damage) kN, respectively. Considering the compressive failure loads only, both the configurations 1 and 3 showed good performance. However, the configuration 1 showed delamination in the corner of the composite flange under tension at early stage of loading. Therefore, it was confirmed that the structure that can effectively support tension and compressive loads at the same time is the configuration 3 which used a mechanically fastened aluminum flange so that there is no risk of delamination at the corner.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.63-73
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• 2009

Recently, the use of lightweight panels in building structures has been increasing. Of the various lightweight panel types, styrofoam sandwich panels are inexpensive and are excellent in terms of their insulation capacity and their constructability. However, sandwich panels that include organic material are quite vulnerable to fire, and thus can numerous casualties in the event of a fire due to the lack of time to vacate and their emission of poisonous gas. On the other hand, lightweight foamed concrete is excellent, both in terms of its insulation ability and its fire resistance, due to its Inner pores. The properties of lightweight concrete is influenced by foaming agent type. Accordingly, this study investigates the insulation properties by foaming agent type, to evaluate the possibility of using light-weight foamed concrete instead of styrene foam. Our research found thatnon-heating zone temperature of lightweight foamed concrete using AP (Aluminum Powder) and FP (animal protein foaming agent) are lower than that of light-weight foamed concrete using AES (alkyl ether lactic acid ester). Lightweight foamed concrete using AES and FP satisfied fire performance requirements of two hours at a foam ratio 50, 100. Lightweight foamed concrete using AP satisfied fire performance requirements of two hours at AP ratio 0.1, 0.15. The insulation properties were better in closed pore foamed concrete by made AP, FP than with open pore foamed concrete made using AES.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.89-95
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• 2007

This study was accomplished to compare energy saving effects of several heat insulation materials in greenhouse and to develop new automatic opening and closing equipment which is suitable to the most effective heat insulation material. To find out more effective heat insulation material, the magnitude of heat transfer occurred through aluminum screen (ALS), non-woven fabric (NWF), double-layer aluminum screen with chemical cotton sheet (DAL), and multi-layer fabric screen material quilted with non-woven fabric, chemical cotton, poly foam, and polypropylene (MLF) were compared relatively. The results showed that the relative magnitude of heat transfer occurred through MLF was lower than DAL and ALS by 23.3% and 43.0% respectively. MLF screen material was the most effective compared with other heat insulation materials. But because of thickness, there was a need of new mechanism for automatic operation in greenhouse. Accordingly, new screen system using MLF-thick but profitable for keeping warm in greenhouse-was developed. Opening & closing equipment was designed to roll MLF with pipe axis during opening process and pull MLF with string during closing process with electric motors, clutches, drums, and so on. In hot pepper cultivation and energy saving test during winter time, the early stage yield of pepper under MLF screen system was higher than NWF by 27%, and gasoline consumption of MLF screen system was lower than NWF by 46%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.2865-2871
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• 2012

In this study, the fracture behaviour of DCB(double cantilever beam) specimen with aluminum foam composite materials is analyzed by simulation. By comparing the analysis results with two models of 25 mm and 40 mm, the model with thickness of 25 mm is weaker than 40 mm at fatigue life and damage. Two models are unfavorable at 'SAE Transmission' in case of nonuniform fatigue load and rainflow matrices are weakest at 'SAE Bracket history'. In damage matrices, the model with 25 mm of thickness is weaker than the model with 40 mm of thickness but the model with 40 mm of thickness relative damage possibility is higher than in case of 25 mm. As two models are safest at 'SAE Transmission', the relative damage becomes the lowest value from 1.1 to 1.8 %. The mechanical property can be investigated by applying these analyses results with the real composite structure bonded with adhesive and analyzing fracture behaviour.

• Design & Manufacturing
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• v.13 no.4
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• pp.23-27
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• 2019

People's interest in the environmental problems of the Earth is growing as they come to the modern world, and research is being actively conducted on how to protect the environment. As a result, the automobile industry, one of the causes of environmental pollution, is also affected. Therefore, research is being conducted to improve the fuel economy and light weight of cars, development of pollution-free cars such as electric cars, and aluminium materials that are lighter than ordinary steel sheets and easier to recycle are gaining attention. In this experiment, the material was formed to form a form of aluminium and the material reduction rate of the side wall of the foam was tested according to the amount of side wall. The material used in the experiment was A3003-O, which is less plastic than normal steel plates, but has excellent corrosion resistance, plasticity and weldability compared to aluminium materials, but has poor tensile strength. For tensile testing, a certain array of Forming Shapes was molded and the height of the Forming was set to 5mm, and the height of the Forming was 4.7mm, indicating that the difference between the first 5mm Forming and the height was not large. In addition, the material reduction rate was tested by giving 15, 0, and -0.15 teas, respectively, and was found to be valuable as a product only for -0.15.

• Composites Research
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• v.22 no.3
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• pp.66-73
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• 2009

Total thickness, areal density and mass moment of inertia of materials are important material factors for structural characteristics. In this work, a material-structural optimization was performed up to the maximum ballistic limit of multi-layered composite structures under high impact velocity followed by the investigation of the influence of these factors on an impact absorption performance. A unified model combined with Florence's and Awerbuch-Bonder's models was used in optimizing the multi-layered composite structure consisting of CMC, rubber, aluminum and Al-foam. Total thickness, areal density and mass moment of inertia were used for the optimization constraint. As shown in the results, the ballistic limit determined from a newly developed unified model was closely similar to the finite clement analysis. Additionally, the ballistic limit and impact absorption energy obtained by the optimized structure were improved approximately 16.8% and 26.7%, respectively comparing with a not optimized multi-layered structure.