• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.4
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• pp.68-80
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• 2005

This study intends to analysis problems and propose of EIA(Environmental Impact Assessment) and PER(Pre-Environmental Review) especially on division of landscape impacts. The problems of EIA and PER are first, on analysis of existing conditions side, insufficiency of the list of landscape elements and their descriptions and presentations, and the number of viewpoints and each validity second, on estimation of landscape impacts, the methods and techniques of estimation and simulation, and the process of impact estimation, third, on suggestion of reduction plans, reduction devices covering impacts, the lack of influence reduction forecasting devices, the deficiency of execution power of reduction plans, finally, the systematic connection of impact estimation with existing conditions analysis and reduction plans. Therefore, on each step from existing condition analysis to reduction plan suggestion, the solutions to each problem are proposed.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.8-15
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• 2013

Wide range frequency pulses occur in a car crash test. Until now, low frequency under 400Hz has been used to determine an airbag deployment criteria. Also, FIS (Front Impact Sensor) has been used to detect the crash pulse in early stage. Nowadays, technology to determine an airbag delpoyment criteria by using a high frequency crash pulse without FIS is being focused on. In this paper, the signal transmissibility of high frequency pulse for two different cars was studied. Also, signal transfer test of high frequency pulse was done by using a high speed ball impact. Signal runtime of the frontal impact is compared with that of the side impact. The signal transmissibility difference due to the car structure difference was discussed and structure change for improving the signal transmissibility was proposed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1036-1043
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• 2006

Damping materials for reducing heavy-weight floor impact noise in reinforced concrete structures were tested in apartment buildings. The effect of damping materials and an impact isolator were compared with an on-site experiment conducted in a high-rise apartment building. The loss factor of damping material analyzed more than 2 times than rubber to $1.5{\sim}2.3$, could know that Damping layer has excellent attenuation performance in side of vibration reduction. The results showed that the resonance frequency increased but vibration acceleration level decreased when the damping materials were used. The heavy-weight impact sound levels of the structure decreased substantially at 63 Hz, whereas the sound levels of the structure with the impact isolator increased.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.295-300
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• 2002

To establish an optimum condition in the surface treatment and curing process will be an important parameters for the fabrication of multilayered hybrid composite materials, A17075/CFRP (CARALL : carbon fiber reinforce aluminum laminates). Effects of carbon fiber direction and thickness variation in tensile strength were investigated. And impact damage behavior of carbon fiber reinforce plastic (CFRP) and CARALL were investigated also, it was found that a partial stress increase in order of epoxy adhesive, A17075, CFRP. And the partial stress of CFRP carried out a great portion of applied stress. The impact damage resistance of CARALL was higher than that of CFRP. This is because both side Al sheet of CARALL absorb a great of impact damage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.254-255
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• 2017

The aim of this study is to investigate the impact resistant performance of steel short fiber-reinforced cement based composites (SFRCCs) containing 1.0, 1.5, 2.0 and 3.0% volume fraction of steel short fibers subjected to high velocity impact of steel projectile (the diameter of 19.05mm and the mass of 28.13g). The gunpowder impact facility was used for impact tests, and the impact velocity was from about 350 to 700m/s. The specimens were damaged in various failure modes, which are penetration, scabbing, and perforation. Comparing with Plain specimen, SFRCCs have superior capacity on the scabbing limit, and slightly bulged in the back side under the impact velocity of 700m/s. In addition, the impact resistant performance of SFRCCs improved with increase of steel short fiber volume ratio. The fibers play an important role in controlling the local damage of SFRCCs.

• Steel and Composite Structures
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• v.44 no.1
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• pp.105-117
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• 2022

Impact resistance efficiency of the newly designed sandwich beam with a laterally arched core as bio-inspired by the woodpecker is numerically investigated. The principal components of the beam comprise a dual-core system sandwiched by the top and bottom laminated CFRP skins. Different materials, including hot melt adhesive, high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), epoxy resin (EPON862), aluminum (Al6061), and mild carbon steel (AISI1018), are considered for the side-arched core layer of the beam for impact efficiency assessment. The aluminum honeycomb takes the role of the second core. Contact force, stress, damage formation, and impact energy for beams equipped with different materials are examined. A diversity in performance superiority is noticed in each of these indicators for different core materials. Therefore, for overall performance appraisal, the impact resistance efficiency index, which covers several chief impact performance parameters, of each sandwich beam is computed and compared. The impact resistance efficiency index of the structure equipped with the AISI1018 core is found to be the highest, about 3-10 times greater than other specimens, thus demonstrating its efficacy as the optimal material for the bio-inspired dual-core sandwich beam system.

• Journal of the Korean Society of Safety
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• v.25 no.2
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• pp.89-94
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• 2010

This study deals with the traffic accident according to the improvement projects of frequent accident locations. The objective is to analyze the impact of improvements on the accident reduction. In pursuing the above, the study gives the particular attentions to developing the models based on the data of 70 intersections improved. The main results analyzed are as follows. First, 4 multiple linear regression accident models(total, side right-angle, rear end and side stripe accident) which were statistically significant were developed. Second, total accidents reduction by sight-distance and turning traffic flow improvements, side right-angle by sight-distance, over-speed and lane operation, rear end by turning traffic flow, signal and lane operation, and side stripe by traffic impedance improvements were analyzed. Finally, the above 4 models were evaluated to be statically significant through the correlation analysis and pair-sample t-test.

• Transactions of Materials Processing
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• v.30 no.5
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• pp.236-241
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• 2021

This study describes the cold stamping process design procedure to secure the formability and dimensional accuracy of the automotive structural component fabricated by 1.5GPa grade ultra-high strength steel sheet. The target product is selected as the front side rear lower member which is the most important energy absorption part in the frontal impact condition. To secure the product quality, an intermediate product shape is added while considering the low elongation and high strength characteristics of 1470Mart. The sequential optimization procedure of the intermediate product shape, the fine dimensional quality is then achieved without any crack or wrinkling. The cold stamping method with ultra-high strength steel sheets is validated by conducting the die tryout of the front side rear lower member.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.19-28
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• 2007

In this study, a nonlinear 2 degree of freedom mathematical model has been developed for impact analysis of the nose landing gear of a light aircraft which is composed of an wheel & tire, an Oleo-pneumatic shock strut and the castering wheel fork for the differential braking steering, and then the response of impact is computed using a numerical method. The mathematical model of a nose landing gear contains nonlinear characteristics which are an impact load - deflection property of a tire and internally frictional forces between an inner surface of an upper cylinder and a bearing of a lower rod due to side forces like the declined angle of strut, the moment due to an wheel fork, the side drag due to a steering and it is computed using the 4th-order Runge-Kutta method. The comparison process between analytical results and experimental results of the other proven nose landing gear is carried out to verify the mathematical model.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.143-148
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• 2013

The aim of this study is to investigate the characteristics on the profile of local ice load acting on side shell of port side in bow part due to broken ice during icebreaking of ships in ice covered waters. The first Korean icebreaking research vessel 'ARAON' had a sea ice field trial in the Arctic Sea during early August, 2010, and the signals due to local ice impact measured from several strain gauges installed at bow part were gathered. It is known that these data with structural response characteristics due to local ice impact have some different characteristics with a typical hydraulic impact pressure - time history. In this study, the time history on the measured signals was analyzed and the characteristic values were presented using non-dimensional parameters.