• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.593-599
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• 2016

Incheon Bridge is 13.38 km long with an 800 m span, connecting Incheon International Airport and Songdo International City, Per hour 73.8 vessels navigate this space. The purpose of this study was to suggest a safe passing speed based on the displacement of a vessel based on the safety criteria of Incheon Bridge's anti-collision fence, which was designed during its initial construction. As AASHTO LRFD suggested, vessel collision energy, vessel collision velocity, and the hydrodynamic mass coefficient were considered to derive a safe vessel traffic speed. Incheon Bridge's anti-collision fence was designed so that 100,000 DWT vessels can navigate at a speed of 10 knot. This research suggests a safe speed for vessel traffic through a comparative analysis of an experimental ship's (300,000 DWT) speed and cargo conditions, regulation speed has been calculated according to the collision energy under each set of conditions. Additionally, safe traffic vessel's safe speed was analyzed with reference to tidal levels. Results from the experimental ship showed that a vessel of maximum 150,000 DWT is able to pass Incheon Bridge at a maximum of 7 knots with an above average water level, and is able to pass the bridge with a maximum of 8 knots under ballast conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.177-185
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• 2000

The deformation characteristics is one of the major factors to resume the crash configuration in collision accident reconstruction. Crash analysis are carried out using finite element method and body stiffness equations representing force-deformation relationship are derived, Two different crash conditions : 1) frontal barrier impact 2) frontal impact between cars are given for the derivation of the equations. The stiffness coefficient of equation by method 2) is larger than that by method. 1). Crash analysis between two vehicles is accomplished with three crash angles and three velocities for each angle condition. The deformations are measured for six selected points and deformation energies are calculated using the derived equations. Equation by method 2) results in better estimation of deformation energy than that by method 1) for all crush configurations. The estimated energies can be utilized as one of indices to identify the type of the collision accident result.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.604-608
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• 2010

This paper proposed a new 2D multibody dynamic modeling technique to analyze overriding behavior taking place during train collision. This dynamic model is composed of nonlinear spring, damper and mass by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model of rollingstock, collision energy absorption capacity, acceleration of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we choose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3D finite element analysis, and established a 2D multibody dynamic model. This 2D dynamic model was suggested to describe the collision behavior of 3D Virtual Testing Model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.93-100
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• 2022

The collision behaviors of the tripod and jacket structures, which are considered as support structures for offshore wind towers at the Southwest sea of Korea, were compared by nonlinear dynamic analysis. These structures, designed for the 3 MW capacity of the wind towers, were modeled using shell elements with nonlinear behaviors, and the tower structure including the nacelle, was modeled by beam and mass elements with elastic materials. The mass of the tripod structure was approximately 1.66 times that of the jacket structure. A barge and commercial ship were modeled as the collision vessel. To consider the tidal conditions in the region, the collision levels were varied from -3.5 m to 3.5 m of the mean sea level. In addition, the collision behaviors were evaluated as increasing the minimum collision energy at the collision speed (=2.6 m/s) of each vessel by four times, respectively. Accordingly, the plastic energy dissipation ratios of the vessel were increased as the stiffness of collision region. The deformations in the wind tower occurred from vibration to collapse of conditions. The tripod structure demonstrated more collision resistance than the jacket structure. This is considered to be due to the concentrated centralized rigidity and amount of steel utilized.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1891-1896
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• 2004

The present article proposes a new droplet collision model including the stretching separation regime and the formation of satellite droplets. The new model consists of a several equations to calculate the post-collision characteristics of colliding droplets and satellite droplets. These equations are derived from the energy balance of droplets between before and after collision. For binary collision of water droplets, the new model shows good agreement with experimental data for the number of satellite droplets. Nevertheless, it is thought that, in order to guarantee the generality of the new model, the improvements should be performed to consider the effects of the bouncing and the reflexive separation, which is essential process in the collision of hydrocarbon droplets.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.1063-1066
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• 2012

• Structural Engineering and Mechanics
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• v.12 no.5
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• pp.541-558
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• 2001

The design specifications of guard fences in Japan were reexamined and the revised specifications were implemented from April 1999. Because of the huge consumption in time and cost to test the performances of full-scale guard fences in the field, some assumptions are adopted while modifying the design specifications, and numerical analyses are necessary to confirm the impact performance and safety level of new types of steel highway guard fences. In this study, the finite element models are developed for the heavy trucks and steel highway guard fences to reenact their behaviors, and the solution approach is carried out using nonlinear dynamic analysis software of structures in three dimensions (LS-DYNA). The numerical simulation results are compared with the full-scale on-site testing results to verify the proposed analysis procedure. The collision process is simulated and it is also made possible to visualize the movement of the truck and the performances of guard fences. In addition, the energy shift of the truck kinetic energy to the truck and guard fence Internal energy, and the energy absorption of each guard fence component are studied for the development of a new design methodology of steel highway guard fences based on the energy absorption capacity.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.289-294
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• 2011

The purpose of this paper is to validate energy absorbing capacity that satisfies APTA SS-C&S-034-99, REV.2 with North America type Electric Multiple Units. The FE models for collision and corner post simulation were developed. Two type of simulation were conducted. One is quasi-static analysis for collision post and the other is quasi-static analysis for corner post. And the energy absorption capacity of the analytical model was verified.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.217-222
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• 2001

The best method to evaluate crashworthiness of a trainset as a whole is to analyse one dimensional dynamic model composed of nonlinear dampers, springs and bars, and masses. In this study, crashworthiness of KHST was evaluated by analysing a nonlinear spring/bar-damper-mass model. The numerical results show that the KHST can easily absorb kinetic energy at lower impact force and acceleration in a heavy collision, when compared with KTX. Also, the KHST can be protected from any damage in its carbody and components except the prepared energy absorbing tube in a light collision, like a traint-to-train accident at speed under 8 kph. However, the KTX can be much damaged in the a light collision because there is no energy absorbing tube.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.161-167
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• 1996

In five-axis milling, optimal CL-data (cutter location data) should be generated to have advantages over three-axis milling in terms of accuracy and efficiency. This paper presents an algorithm for generating collision-free CL-data for five-axis milling using potential energy method. By virtually charging the cutter and part surfaces with static electricity, global collision as wells as local interference is eliminated. Additionally, machining efficiency is improved by minimizing the curvature difference between the part surface and tool swept surface at a CC-point (cutter contact point) simultaneously.