• Journal of the Korean Society for Precision Engineering
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• v.33 no.12
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• pp.1039-1045
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• 2016

We investigated the protection capability of a plate against high speed projectiles demonstrating collision and penetration behaviors by finite element analysis. The element erosion method was used for penetration analysis, which showed that the speed of the projectile was slightly reduced by the collision with the protection plate. Protection capability was measured by the projectile's attitude angle change because the damage of our tanks by projectiles was also dependent on the projectile-tank collision angle. When the length of the protection plate was sufficiently long, the projectile was severely deformed and incapacitated. In the case of a small plate, the projectile was deformed only in the collision region. Thus, projection capability was investigated by the change of attitude angle. The effect of collision angle, velocity, and length of the plate on the rotational and vertical velocities of the projectile was investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.165-166
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• 2010

Collision scenario was 12 cases considering gate location, water level and lateral location of collision etc. And then, analysis result of trunnion by collision loads (reservoir side gate). Compressive fracture may not occur because the maximum compressive stress of concrete is below the allowable compressive strength. but, it is possible to appear some local crack because the maximum tensile stress exceed the tensile strength.

• 연구논문집
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• s.32
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• pp.103-111
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• 2002

In this study, the crashworthiness of KHST has been evaluated by analysing a nonlinear spring/bar-damper-mass model of 1-dimensional collision dynamics. The numerical results show that KHST can easily absorb kinetic energy at lower impact force and acceleration in heavy collisions, when compared with KTX. Also, in a Light collision like a traint-to-train accident at lower speed under 8 kph, the carbody and components of KHST can be protected without any damage except the energy absorbing tube to be replaced easily. However, KTX may be much damaged in the light collision because there is no energy absorbing tube. In conclusion, the crashworthy performance of KHST has been much improved than that of KTX, although there are something to be improved for a better crashworthy performance

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.530-537
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• 2016

This study investigates frontal crashes, analyzes the driver's action related to the change of the collision direction and determines the severity of (bodily injury). This study was conducted from August, 2013, to January, 2014, and the data for the car damage and human body damage were collected by emergency medical teams. In terms of data collection, we collected the accident vehicle, crash direction, body damage, etc., based on the Korea In-depth Accident Study (KIDAS) and Injury Severity Score (ISS). We used Minitab 17 and SPSS 22.0 to do the frequency analysis and ANOVA. In the analysis results, the prevalence of frontal collisions was 55.8% and mostly occurred in the 12 o'clock direction. In the analysis of the frontal crash direction according to age, the average ages for the 11, 12 and 1 o'clock directions were $46.46{\pm}13.47$, $44.43{\pm}13.40$ and $52.46{\pm}12.04$, respectively, so the older age drivers had a high probability of the accident occurring in the 1 o'clock direction. In the analysis of men's frontal collision direction according to age, the average ages in the 11, 12 and 1 o'clock directions were $47.10{\pm}13.88$, $45.24{\pm}13.78$ and $55.73{\pm}13.38$, respectively, so older aged men had a high probability of having collisions in the 1 o'clock direction. However, the statistical analysis of the frontal crash direction according to age in women didn't show any meaningful trend. When comparing the ISS according to age of the men and women in the collision direction, the men were less likely to have a 12 o'clock collision when $ISS{\geq}9$ and more likely to have a 1 o'clock collision when ISS<9. As a result, frontal crashes are more likely to occur in the 12 o'clock direction and the ISS decreases because the likelihood of frontal crashes in the 1 o'clock direction increases with increasing age. Therefore, when men recognize that they are heading for a 12 o'clock direction collision, they try to steer to the left to reduce the body damage.

• Journal of Astronomy and Space Sciences
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• v.24 no.2
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• pp.135-144
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• 2007

Space environment becomes more hazardous for satellite because of increasing number of space debris. This research is to analyze collision hazards between KOMPSAT 3 in low-earth orbit and space debris generated by the explosion of FengYun satellite on the January 11, 2007. Based on the observed data of the space debris from FengYun satellite, the mass and number distribution of the debris are estimated including undetectable debris from the explosion of FengYun satellite. The spatial density and flux for the space debris can be calculated according to size. This study also brings out the analysis for the assessment of collision probability and damage probability. The algorithm developed in the current paper can be used to estimate the level of risk due to space debris for the satellites that will be launched in the future.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.65-71
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• 2008

In many cases, open-type plate breakwaters use plates with multiple holes; the holes serve as energy dissipaters and weight reducers. Because of the multi-holes configuration, stress concentration should be considered during the design process. Among several design loading conditions, the loads from a possible collision with a man-made vessel or other unexpected events many damage a multi-perforated steel plate. In that case, the structural behavior of a multi-perforated steel plate is quite significant, and is not well understood. This study presents a collision analysis for a multi-perforated steel plate. First, four different perforation topologies (three with circles and one with squares) were selected to investigate the effect of different hole shapes on the structural response. Second, the wave force at a specific site was calculated and loaded onto a steel plate as a static load. The static stresses were used for reference values. Third, two rigid body impacters (cubical & cylindrical) were applied to the steel plates to investigate the transient stress responses. In addition, two different impacting angles ($45^{\circ}\;&\;90^{\circ}$) were selected to investigate the angle effect. From the collision analysis, the significance of the transient stresses was emphasized.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.3
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• pp.236-242
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• 2018

Damage due to ice collision is the most serious threat for the structural safety of ships operating in arctic region. Since such hull damages are usually caused by the collision of floating ice at excessive voyage speed of ships, the authorities responsible for the shipping at arctic sea are required to provide the speed limit for safe voyage, so-called safe speed. In countries near arctic ocean, such as Canada and Russia, empirical methods to determine the safe speed of ships based on their long experience of arctic voyage have been established and applied them in the real arctic navigation. However, in Korea, it is not easy to accumulate the arctic voyage experience and related technical database, so it seems to be a realistic approach to adopt a safe voyage speed estimating method in arctic sea based on the ice collision simulation technology using the nonlinear finite element analysis. The aim of this study is to develop a technique for estimating the safe voyage speed of vessels operating at arctic sea through the ice collision analysis, In order to achieve this goal, the standard procedure of the ice collision analysis is dealt with and example analysis was carried out and the results were considered. To investigate the validity of developed method, POLARIS system proposed by IMO was studied for comparison.

• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.205-211
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• 2011

As the increase in maritime traffic and leisure, the marine accident risk has increased in the domestic coast. In this study, the cause and the environment of domestic marine accidents from 1990 to 2009 have been investigated and analyzed by using the statistics issues of Korean Maritime Safety Tribunal. Based on the analysis of most domestic marine accidents such as engine damage, collision, capsizing of small vessels, we propose how to use mobile telecommunication terminals for preventing marine accidents and the best countermeasures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.265-274
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• 2015

The structural safety of nuclear power plant against impact from aircraft crash has been performed so far in two viewpoints such as local behavior and global behavior, and the local behavior has been evaluated using local damage evaluation formulas suggested based on the results of experimental data of RC (Reinforcement Concrete) wall. However, few data have been collected from recent research to evaluate the local behavior and damage of SC (Steel plate reinforced Concrete) wall, which is recently applied to the newly designed nuclear power plant. In this study, local damages of SC wall and RC wall against an idealized aircraft engine projectile impact are evaluated through FE simulation analyses with various wall thicknesses and steel ratio. Through analysis of local collision simulation results of SC and RC wall, the penetration depth of SC wall and RC wall are compared.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.87-96
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• 2006

A ship collision analysis by finite element method is performed considering the effects of mass and speed of ship and material and shape of structures to analyze the dynamic characteristics by ship collision. From this analysis, collision load-time history and damage of ship and structures are obtained. In this study, results of finite element analysis are compared with previous studies in USA, Japan and some countries of Europe. Dynamic characteristics are different from each other according to interaction between ship and structures. It seems that there are lots of factor to have effects on the ship-structures interaction. Because little information is available on the behavior of the inelastic deformation of materials and structures during the type of dynamic impacts associated with vessel impact, assumptions based on experience and sound engineering practice should be substituted. Therefore more researches on the interaction between ship and structures are required.