• Title, Summary, Keyword: Collision Post

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Energy Absorption of Collision Post Based on North American CFR Regulations for Railway Vehicles (철도차량의 북미 CFR 법규에 대한 충돌 기둥에너지 흡수에 관한 연구)

  • Kim, Seung-Tech;Jeong, Ji-Ho;Choi, Jeong-Yong;Woo, Kwan-Je
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.935-943
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    • 2012
  • In accidents involving the collision of railway vehicles, there is a risk that structural members might penetrate the cab frame of the railway vehicle in the space in which the driver or passengers are seated. To reduce this risk, worldwide, studies on the collision of railway vehicles are underway. In North America, the Code of Federal Regulations (CFR) was revised in 2010 to include crush criteria for a collision and the corner post in an end frame. In this study, a crush analysis and crush test for a collision post and a crash analysis for a rigid cylinder were performed according to the CFR. The analysis and test results were compared and reviewed. This study aims to determine the usefulness of crush analysis for developing various end frames, and to understand the crush and crash characteristics and review the accuracy of the analysis.

Review on the Triassic Post-collisional Magmatism in the Qinling Collision Belt (친링 충돌대의 트라이아스기 충돌 후 화성작용에 대한 리뷰)

  • Oh, Chang Whan;Lee, Byung Choon;Yi, Sang-Bong;Zhang, Cheng Li
    • The Journal of the Petrological Society of Korea
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    • v.23 no.4
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    • pp.293-309
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    • 2014
  • The Qinling-Dabie-Sulu-Hongseong-Odesan collision belt was formed by the collision between the North China and South China Cratons during late Permian to Triassic. During the collision, Triassic post-collision igneous rocks regionally intruded in the Qinling and the Hongseong-Odesan collision belts which represent the western and eastern ends of the collision belt, respectively. However, no and minor Triassic post-collision igneous activities occur in the Dabie and Sulu belts respectively. The peak metamorphic pressure conditions along the Qinling-Dabie-Sulu-Hongseong-Odesan belt indicate that the slab break-off occurred at the depth of ultra-high pressure (UHP) metamorphic condition in the Dabie and Sulu belts and at the depths of high pressure (HP) or high pressure granulite (HPG) metamorphic condition in the Qinling and Hongseong-Odesan belts. In the Dabie and Sulu belts the heat supply from the asthenospheric mantle through the gab formed by slab break-off could not cause an extensive melting in the lower continental crust and lithospheric mantle directly below it due to the very deep depth of slab break-off. On the other hand, in the Qinling and Hongseong-Odesan belts, shallower slab break-off caused the emplacement of regional post collision igneous rocks. The post-collision igneous rocks occur in the area to the north of the Mianlu Suture zone in the western Qinling belt and crop out continuously eastwards into the areas to the north of the Shangdan Suture zone in the eastern Qinling belt through the areas within the South Qinling block. This distribution pattern of post collision igneous rocks suggests that the Triassic collision belt in the Mianleu Suture zone may be extended into the Shangdan Suture zone after passing through the South Qinling block instead into the boundary between the South Qinling block and the South China Craton.

Automobile Collision Reconstruction Using Post-Impact Velocities and Crush Profile (충돌 후 속도와 충돌 변형으로부터 자동차 충돌 재구성)

  • 한인환
    • Journal of Korean Society of Transportation
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    • v.18 no.4
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    • pp.107-115
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    • 2000
  • We suggest a method which solves the planar, two vehicle collision reconstruction problem. The method based on the Principle of impulse and momentum determines the pre-impact velocity components from Post-impact velocity components, vehicle Physical data and collision geometry. A novel feature is that although the impact coefficients such as the restitution coefficient and the impulse ratio are unknown, the method can estimate automatically the coefficients and calculate the pre-impact velocity components. This reverse calculation is important for vehicle accident reconstruction, since the pre-impact velocities are unknown and Post-impact Phase is the starting Point in a usual collision analysis. However. an inverse solution is not always Possible with the analytical rigid-body impact model. Mathematically, one does not exist under the common velocity condition. On the other hand, our method has a capability of reverse calculation under the condition if the absorbed energy during the collision process can be estimated using the crush profile. To validate the developed collision reconstruction a1gorithm, we use car-to-car collision test results. The analysis and experimental results agree well in the impact coefficients and the Pre-impact velocity components.

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A Study on the Energy Absorption Capacity of Collision and Corner Posts of EMU according to APTA SS-C&S-034-99 Standard (미국 규격에 따른 전두부 충돌에너지 흡수 요구조건의 해석적 평가)

  • Jeong, Ji-Ho;Lee, Jan-Wook;Park, Gun-Soo;Woo, Kwan-Je
    • Proceedings of the KSR Conference
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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.

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A Study on Avoiding Collision between a Ship and Bridge and Minimizing Damages if Unavoidable (선박과 교량의 충돌예방과 충돌시 손상의 감소방법에 관한 연구)

  • Yoon, Byoung-Won;Yun, Jeom-Dong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.376-382
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    • 2007
  • A Collapse of bridge by ship's collision to the bridge post may lead a great calamity. This paper investigates on avoiding collision between a ship and bridge by improvement of environmental factors, submitting a counter plan of reducing collision effect by triangular type of collision protecting bar and ship maneuvering skills. Putting up collision protecting bar fences of triangular type around the bridge posts would decrease the collision impact force by 75 percent.

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Development of a New Droplet Collision Model Including the Stretching Separation Regime (스트레칭 분리 영역을 포함한 새로운 액적 충돌 모델의 개발)

  • Ko, Gwon-Hyun;Ryou, Hong-Sun
    • Proceedings of the KSME Conference
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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.

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The Vehicle Accident Reconstruction using Skid and Yaw Marks (스키드마크 및 요마크를 이용한 차량사고재구성)

  • 이승종;하정섭
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.12
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    • pp.55-63
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    • 2003
  • The traffic accident is the prerequisite of the traffic accident reconstruction. In this study, the traffic accident (forward collision) and traffic accident reconstruction (inverse collision) simulations are conducted to improve the quality and accuracy of the traffic accident reconstruction. The vehicle and tire models are used to simulate the trajectories for the post-impact motion of the vehicles after collision. The impact dynamic model applicable to the forward and inverse collision simulations is also provided. The accuracy of impact analysis for the vehicular collision depends on the accuracy of the coefficients of restitution and friction. The neural network is used to estimate these coefficients. The forward and inverse collision simulations for the multi-collisions are conducted. The new method fur the accident reconstruction is proposed to calculate the pre-impact velocities of the vehicles without using the trial and error process which requires the repeated calculations of the initial velocities until the forward collision simulation satisfies with the accident evidences. This method estimates the pre-impact velocities of the vehicles by analyzing the trajectories of the vehicles. The vehicle slides on a road surface not only under the skidding during an emergency braking but also under the steering. A vehicle over steering or cornering with excessive speed loses the traction and leaves tile yaw marks on the road surface. The new critical speed formula based on the vehicle dynamics is proposed to analyze the yaw marks and shows smaller errors than ones of the existing critical speed formula.

Development of a New Droplet Binary Collision Model Including the Stretching Separation Regime (스트레칭 분리 영역을 포함한 새로운 액적간 충돌 모델의 개발)

  • Ko, G.H.;Lee, S.H.;Roh, J.S.;Ryou, H.S.
    • Journal of ILASS-Korea
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    • v.11 no.2
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    • pp.75-80
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    • 2006
  • 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 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 far the number of satellite droplets.

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Influence of end fixity on post-yield behaviors of a tubular member

  • Cho, Kyu Nam
    • Structural Engineering and Mechanics
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    • v.13 no.5
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    • pp.557-568
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    • 2002
  • For the evaluation of the capability of a tubular member of an offshore structure to absorb the collision energy, a simple method can be employed for the collision analysis without performing the detailed analysis. The most common simple method is the rigid-plastic method. However, in this method any characteristics for horizontal movement and rotation at the ends of the corresponding tubular member are not included. In a real structural system of an offshore structure, tubular members sustain a certain degree of elastic support from the adjacent structure. End fixity has influences in the behaviors of a tubular member. Three-dimensional FEM analysis can include the effect of end fixity fully, however in viewpoints of the inherent computational complexities of the 3-D approach, this is not the recommendable analysis at the initial design stage. In this paper, influence of end fixity on the behaviors of a tubular member is investigated, through a new approach and other approaches. A new analysis approach that includes the flexibility of the boundary points of the member is developed here. The flexibility at the ends of a tubular element is extracted using the rational reduction of the modeling characteristics. The property reduction is based on the static condensation of the related global stiffness matrix of a model to end nodal points of the tubular element. The load-displacement relation at the collision point of the tubular member with and without the end flexibility is obtained and compared. The new method lies between the rigid-plastic method and the 3-demensional analysis. It is self-evident that the rigid-plastic method gives high strengthening membrane effect of the member during global deformation, resulting in a steeper slope than the present method. On the while, full 3-D analysis gives less strengthening membrane effect on the member, resulting in a slow going load-displacement curve. Comparison of the load-displacement curves by the new approach with those by conventional methods gives the figures of the influence of end fixity on post-yielding behaviors of the relevant tubular member. One of the main contributions of this investigation is the development of an analytical rational procedure to figure out the post-yielding behaviors of a tubular member in offshore structures.

A Numerical Study on the Spray-to-Spray Impingement System

  • Lee, Seong-Hyuk;Ko, Gwon-Hyun;Ryou, Hong-Sun
    • Journal of Mechanical Science and Technology
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    • v.16 no.2
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    • pp.235-245
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    • 2002
  • The present article aims to perform numerical calculations for inter-spray impingement of two diesel sprays under a high injection pressure and to propose a new hybrid model for droplet collision on the basis of literature findings. The hybrid model is compared with the original O'Rourke's model, which has been widely used for spray calculations. The main difference between the hybrid model and the O'Rourke's model is mainly in determination of the collision threshold condition, in which the preferred directional effect of droplets and a critical collision radius are included. The Wave model involving the cavitation effect inside a nozzle is used for predictions of atomization processes. Numerical results are reported for different impingement angles of 60°and 90°in order to show the influence of the impinging angle on spray characteristics and also compared with experimental data. It is found that the hybrid model shows slightly better agreement with experimental data than the O'Rourke's model.