• 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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.866-875
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• 1994

The problem of a rigid rod sliding on a rough horizontal surface in the plane is analyzed, which is commonly cited as an example of the inconsistency of rigid body frictional mechanics. The inconsistency is demonstrated by analyzing the normal reaction force at the contact point with the surface, and the concept of tangential collision is derived to resolve the inconsistency. Using the Poisson's hypothesis for the coefficient of restitution and Coulomb's law for the friction, the general methodology for solving the tangential collision is presented. The problem of the inconsistency generated in the sliding rod is completely resolved, building the concept of the tangential collision and adopting the theory of frictional impact. The result presented in this paper will obviate a generic obstacle to the development of simulation packages for planar rigid body mechanical systems with temporary contacts, and planning efficient motion strategies for robot manipulators.

• Journal of ILASS-Korea
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• v.22 no.3
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• pp.129-136
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• 2017

Effects of collision angle on heat transfer characteristics of a liquid droplet impinging on a heated wall above the Leidenfrost point temperature were experimentally investigated. The heated wall and droplet temperatures were $506^{\circ}C$ and $100^{\circ}C$, respectively, and the impact angle varied from $20^{\circ}$ to $90^{\circ}$ while the normal collision velocity was constant at 0.27 m/s. The droplet collision behaviors and the surface temperature distribution were measured using synchronized high-speed video and infrared cameras. The major physical parameters influencing upon droplet-wall collision heat transfer, such as residence time, wall heat flux, effective heat transfer area, heat transfer amount, were analyzed. It was found at the constant normal collision velocity that the residence time, wall heat flux and effective heat transfer area were hardly not changed, resulting in the almost constant heat transfer amount.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.320-323
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• 2008

In this study the effect of collision model was evaluated in spray field by CFD. A collision is basically the interaction between droplets and criteria of collision is determined by drop Weber number, impact parameter, and drop-size ratio. Early developed collision model considered coalescence and grazing collision with the exchange of momentum. However in experimental research there were bouncing, coalescence, reflexive separating and stretching separating in interaction between droplets. In this study the collision considering such complex phenomena is modeled and was compared with the basic collision model.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.23-29
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• 2003

The spot welded sections of automobiles (hat and double hat shaped sections) absorb most of the energy in a front-end collision. The target of this paper is to analyze the energy absorbing capacity of the structure against the front-end collision, and to obtain useful information for designing stage. Changed the spot welded pitches on the flanges, the hat and double hat shaped section members were tested on the axial collapse loads at various impact velocities. It was expected that para-closed sections would show collapse characteristics which be quite different from those of perfectly closed sections. Hat shaped section members were tested at the impact collapse velocities of 4.72m/sec, 6.54m/sec and 7.1m/sec and double hat shaped section members were tested at the impact collapse velocities of 6.54m/sec, 7.1 m/sec and 7.27m/sec.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.507-513
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• 2021

This study examined the final stop position and posture of both vehicles, the damaged part of the vehicle, the road surface, the specifications of the vehicle, and the angle of impact, centering on the case of a collision in which no surface trace was found. As a result of the simulation, the impact velocity of an SM5 and Lexus was 131 km/h and 74 km/h, respectively, and the impact angle of the SM5 and Lexus was 0.91° and -161.07°, respectively. The cause of the accident was that the SM5 passed through the intersection exceeding the maximum speed limit of 61 km/h and entered the Lexus' left turn lane. Lexus collided during the evacuation to avoid the collision. The collision trajectory error rate of the simulation was approximately 1.4%. Of the subjective experience of accident investigators, the collision dynamics and vehicle engineering aspects and simulations were actively utilized to provide close-to-fact cause identification.

• Journal of the Korean Society of Safety
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• v.31 no.1
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• pp.33-40
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• 2016

Coupling systems under train's collision should take the impact by absorbing the impact energy caused from the collision, so the systems are very important parts for the safety of the trains. However, it is not easy to evaluate the performance of the system because it requires a huge testing facility, which is able to control the impact and to handle many safety issues. In this paper, test results are provided, which are obtained from collision tests of a single train having a coupling system in the front, and the results are analyzed in order to understand the characteristics and the dynamic behaviors of energy absorbing materials in the coupling system, such as a hydraulic buffer, and two rubber buffers. The results show that the force of each component could be empirically described by the compression displacement and velocity. The analyzed results will be applied to simulation models, and advanced studies wouuld be available if the simulation models are well validated with the test results.

• Journal of Ocean Engineering and Technology
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• v.38 no.3
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• pp.124-136
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• 2024

As the number of offshore wind-power installations increases, collision accidents with vessels occur more frequently. This study investigates the risk of collision damage with operating vessels that may occur during the operation of an offshore wind turbine. The floater used in the collision study is a 15 MW UMaine VolturnUS-S (semi-submersible type), and the colliding ships are selected as multi-purpose vessels, service operation vessels, or anchor-handling tug ships based on their operational purpose. Collision analysis is performed using ABAQUS and substantiation is performed via a drop impact test. The collision analyses are conducted by varying the ship velocity, displacement, collision angle, and ship shape. By applying this numerical model, the extent of damage and deformation of the collision area is confirmed. The analysis results show that a vessel with a bulbous bow can cause flooding, depending on the collision conditions. For damage caused by collision, various collision angles must be considered based on the internal stiffener arrangement. Additionally, the floater can be flooded with relatively small collision energy when the colliding vessel has a bulbous bow.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.463-473
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• 2008

In this study, we measure damage depth and calculate effective impact speed in case of rear-end collision using real car insurance data. We study the relationship between demage depth and effective impact speed, and present statistical model for these two variables. In our real data study, 3-degree polynomial equation model is better fit to effective impact speed and demage depth than the simple linear model that are estimated in previous other studies. Damage depth is a major factor to see the extent of impact in a car collision, and by using this equation, it is possible to evaluate the severity of driver's injury.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.195-204
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• 2000

In this paper a complicated structural behavior in collision and its effect of energy translation to the collision bulkhead was examined through a methodology of the numerical simulation to obtain a ideal bow construction and a location of collision bulkhead against head on collision. In the present the bow structure is normally designed in consideration of its specific structural arrangements and internal and external loads in these area such as hydrostatic and dynamic pressure, wave impact and bottom slamming in accordance with the Classification rules, and the specific location of collision bulkhead by SOLAS requirement. By these studies the behavior of the bow collapse due to collision was synthetically evaluated for the different size of tankers and its operational speed limits, and by the result of these simulation it provides the optimal design concept for the low construction to prevent the subsequent plastic deformation onto or near to the collision bulkhead boundary and to determine the rational location of collision bulkhead.