• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.11a
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• pp.85-90
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• 2001

The microstructure and mechanical property of 0.19C-1.17Cr steel were investigated with cold drawing. This commercial steel has the microstructure that is consist of ferrite and pearlite. The tensile and yield strength are increased as the reduction ratio of cold drawing is increased. It was clear that mechanical properties could be improved by combination of the heat treatments and reduction ratio. Yield strength. tensile strength, and impact value were formulated as a constitutive function of cold drawing ratio, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.458-458
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• 2012

Fuel Cell is used stacking metal or polymer substrate. This hydro property of substrate surface is very important. Usually, surface property is hydrophilic. The surface oxidation of SUS is investigated through plasma treatments with an atmospheric-pressure dielectric barrier discharge (DBD) for increasing hydrophilic property. The plasma process makes an experiment under various operating conditions of the DBD, which operating conditions are treatment time, plasma gas mixture ratio, the plasma source supply frequency. Two kinds of SUS substrate, SUS-304 and SUS 316L, were used. Discharge frequency has a crucial impact on equipment performance and gas treatment. After the plasma treatment of a SUS plate, highly improved wettability was noted. But, when high oxygen supply, the substrate damaged seriously.

• Journal of the Korean institute of surface engineering
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• v.35 no.4
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• pp.206-210
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• 2002

The use of Spectra fibers as fiber cloth is increasing because of their excellent impact resistance. However, a major limitation on the use of Spectra fibers is a chemical inertness. In this Study, Spectra fibers were surface-treated using Ar$^{+}$ ion beam under oxygen environment to improve the tensile property of Spectra/vinylester composites. The effect of surface treatment of Spectra fibers on the tensile property of Spectra/vinylester composites was determined from tensile tests using Spectra/vinylester composite specimens with and without a hole. It was found that the tensile stiffness and strength of surface-treated case were 22% and 17% higher than those of untreated case for specimens with no hole. The maximum load of surface-treated case was about 15% higher than that of untreated case for specimens with a hole.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.374-379
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• 2017

In vehicle to pedestrian accidents, cracks occur in the vehicle laminated glass due to impact of a pedestrian's head. In this study, FMH(Free Motion Headform) was used to experiment on and analyze the crack patterns on a vehicle laminated glass that collides with an adult headform at speeds of 20 km/h, 30 km/h, and 40 km/h, respectively. Applying the acquired experimental data and material property of the vehicle laminated glass to the structural analysis program LS-Dyna, we could develop the FE model of vehicle laminated glass similar to real vehicle laminated glass. We could estimate the head impact velocity and pedestrian's vehicle impact velocity using the Madymo program.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.390-398
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• 2014

Heavy-weight floor impact noise is directly related to the impact source and floor vibration property. Dynamic properties of the standard floating floor that is used in Korea was investigated using accelerance, acceleration energy spectral density(ESD), and structural modal test. In the standard floating floor, natural frequency was decreased by the finishing mortar mass and the damping ratio was increased. Bang-machine force spectrum acting on the concrete slab can be calculated using inverse system analysis. Impact force acting on concrete slab is changed by interaction of finishing mortar and resilient material. The amplitude of the bang-machine force spectrum was amplified in low frequency range(below 100 Hz), and over 100 Hz was decreased. Changed force spectrum influence to the response of structure vibration, so the heavy-weight floor impact noise level was changed.

• Journal of the Korea Safety Management & Science
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• v.26 no.3
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• pp.93-100
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• 2024

Outdoor storage fires have a significant impact on the surrounding environment, including adjacent storage facilities and buildings. Therefore, it is essential to review and manage the fire impact to minimize damage to human life and property on the outdoor storage fires. In this study, the heat release rate and radiant heat flux were simulated according to the fire time, wind veolcity, and presence or absence of water spray equipment in an outdoor storage facility fire, and the fire impact was analyzed. The outdoor storage was designed to simulate two scenarios on the outdoor storage fires containing gasoline, and FDS was used for fire simulation. As a results, when the water spray facility was not operating and the wind velocity was 5 m/s, the maximum radiant heat flux was 24.80 kW/m2, which exceeded the limit radiant heat flux of 20 kW/m2. When the water spray facility was operating and the wind veolcity was 10 m/s, the maximum radiant heat flux was 18.77 kW/m2, which did not exceed the limit radiant heat flux, indicating that the fire impact on adjacent storage facilities was relatively small.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.89-90
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• 2010

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.26-27
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• 2001

• 한국기계연구소 소보
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• s.11
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• pp.39-46
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• 1984

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.787-793
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• 2002

In this study, a bar impact test of low velocity was carried out to gain an insight into the damage mechanism and sequence induced in alumina plates(AD 85 and AD 90) under impact conditions. An experimental setup utilizing an instrumented long bar impact was devised, that can measure directly the impact force applied to the specimen and supply a compressive contact pressure to the specimen. During the bar impact testing, the influences of the contact pressure applied along the impact direction to the specimen on the fracture behavior were investigated. The measured impact force profiles explained well the damage behavior induced in alumina plates. The higher contact pressure to the specimen led to the less damage due to the suppression of radial cracks due to the increase in the apparent flexural stiffness of plate. It had produced the change of damage pattern developed in the specimen; from the radial cracks to the local contact stress dominant damage. It would contribute to the improvement of the ballistic property in ceramic plates. The observed results showed the following sequence in damage developed: The development of cone crack at impact region, the formation of radial cracks from the rear surface of plate depending on the plate thickness, the occurrence of crushing within the cone envelope and the fragmentation.