• Title/Summary/Keyword: Heavy Collision

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An Evaluation of Crashworthiness for the Full Rake KHST Using 1-D Dynamic Model (1차원 동역학 모델을 이용한 한국형 고속전철의 충돌 안전도 평가)

  • 구정서;조현직;김동성;윤영한
    • Journal of the Korean Society for Railway
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    • v.4 no.3
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    • pp.94-101
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    • 2001
  • One of the best methods to evaluate crashworthiness of a full rake trainset is to analyse 1-dimensional dynamic model using dampers, nonlinear springs and bars, and masses. In this study, the crashworthiness of KHST has been evaluated by analysing a nonlinear dynamic model made up of springs/bars-dampers-masses. The numerical results show that the KHST can absorb more kinetic energy at lower impact forces and lower accelerations in case of heavy collisions, if compared with KTX. Also, the KHST can be protected from any damage in its car-body and electric components except the energy absorbing tube in case of light collisions, like train-to-train accidents at speed under 8 kph. On the other hand, the KTX may be more damaged in the light collisions because there is no energy absorbing tube.

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A study on passive safety regulations of Korean standard urban train (도시철도 차량의 충돌안전 기준에 관한 연구)

  • 구정서;노규석;조현직;권태수;최성규
    • Proceedings of the KSR Conference
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    • 2000.05a
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    • pp.645-651
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    • 2000
  • In this paper, numerically evaluated is the regulations for crashworthy design of the Korean standard urban train suggested by KRRI. The 4-car consist of K-EMU(Korean Electric Multiple Unit) train developed in recent is analyzed under various collision conditions such as normal coupling, heavy shunt, light and heavy collisions. The collision conditions are assumed as K-EMU collides against another stationary one at 5 kph, 10 kph, 25 kph and 32 kph. According to the numerical results and bibliographical study, it is necessary that the regulations by KRRI be complemented from crashworthy point of view. Furthermore, the K-EMU train is recommended to adopt a new coupler with an additional energy absorber or a mechanical fuse.

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An Experimental Study on the Oil Spillage of Damaged Oil Tanker (유조선의 선체손상 시 기름의 해상유출에 대한 실험적 연구)

  • Kim, Ul-Nyeon;Ha, Woo-Il;Choe, Ick-Heung
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.4
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    • pp.398-408
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    • 2009
  • Crude oil carriers or product oil carriers are confronted with sea pollution due to hull damage from various accidents. To reduce the oil spillage of tankers, IMO(International Maritime Organization) and OPA 90(Oil Pollution Act 1990) adopted the hull structures of double skin type. In this study, oil spillage test of the double skin tanker with 1/100 scaled model was carried out under damaged condition due to collision and grounding accidents. A new structural type of oil tanker was also tested with pipe and valve system arranged in double side and single bottom hulls. Their results were compared with that of conventional type double hull on the view point of ship safety and oil spillage.

A study on collision strength assessment of a jack-up rig with attendant vessel

  • Ma, Kuk Yeol;Kim, Jeong Hwan;Park, Joo Shin;Lee, Jae Myung;Seo, Jung Kwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.241-257
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    • 2020
  • The rapid proliferation of oil/gas drilling and wind turbine installations with jack-up rig-formed structures increases structural safety requirements, due to the greater risks of operational collisions during use of these structures. Therefore, current industrial practices and regulations have tended to increase the required accidental collision design loads (impact energies) for jack-up rigs. However, the existing simplified design approach tends to be limited to the design and prediction of local members due to the difficulty in applying the increased uniform impact energy to a brace member without regard for the member's position. It is therefore necessary to define accidental load estimation in terms of a reasonable collision scenario and its application to the structural response analysis. We found by a collision probabilistic approach that the kinetic energy ranged from a minimum of 9 MJ to a maximum 1049 MJ. Only 6% of these values are less than the 35 MJ recommendation of DNV-GL (2013). This study assumed and applied a representative design load of 196.2 MN for an impact load of 20,000 tons. Based on this design load, the detailed design of a leg structure was numerically verified via an FE analysis comprising three categories: linear analysis, buckling analysis and progressive collapse analysis. Based on the numerical results from this analysis, it was possible to predict the collapse mode and position of each member in relation to the collision load. This study provided a collision strength assessment between attendant vessels and a jack-up rig based on probabilistic collision scenarios and nonlinear structural analysis. The numerical results of this study also afforded reasonable evaluation criteria and specific evaluation procedures.

A Study on the Tree based Memoryless Anti-Collision Algorithm for RFID Systems (RFID 시스템에서의 트리 기반 메모리래스 충돌방지 알고리즘에 관한 연구)

  • Quan Chenghao;Hong Wonkee;Lee Yongdoo;Kim Hiecheol
    • The KIPS Transactions:PartC
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    • v.11C no.6 s.95
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    • pp.851-862
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    • 2004
  • RFID(Radio frequency IDentification) is a technology that automatically identifies objects containing the electronic tags by using radio wave. The multi-tag identification problem is the core issue in the RFID and could be resolved by the anti-collision algorithm. However, most of the existing anti-collision algorithms have a problem of heavy implementation cost and low performance. In this paper. we propose a new tree based memoryless anti-collision algorithm called a collision tracking tree algorithm and presents its performance evaluation results obtained by simulation. The Collision Tracking Tree algorithm proves itself the capability of an identification rate of 749 tags per second and the performance evaluation results also show that the proposed algorithm outperforms the other two existing tree-based memoryless algorithms, i.e., the tree-walking algorithm and the query tree algorithm about 49 and 2.4 times respectively.

An Evaluation of Crashworthiness for the Full Rake KHST Using ID Model (1차원 모델을 이용한 한국형 고속전철의 충돌 안전도 평가)

  • 구정서;조현직;김동성;윤영한
    • 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.

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A Theoretical Study on Wet Scavenging of Atmospheric Aerosols by Rain Drops (대기에어로졸 입자의 이론적 강수세정에 관한 연구)

  • 박정호;최금찬
    • Journal of Korean Society for Atmospheric Environment
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    • v.15 no.1
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    • pp.1-11
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    • 1999
  • In this work, a theoretical model has been formulated which allows the study of the scavenging efficiencies of aerosol particles by the rain drops. Aerosol particles are scavenged by the simultaneous brownian diffusion, interception and inertial impaction force. In addition the calculations based on the collision efficiency model are carried out for the collision of aerosol particles with diameter range 0.01~30 $mu extrm{m}$ and rain drops with diameter 0.02$\times$$2^{n/3}$(n=1, 2, …, 17)cm. The results indicate that: (1) the below-cloud scavenging affects mainly the coarse particles (>3 ${\mu}{\textrm}{m}$), the fine particles remaining almost unchanged; (2) the scavenging efficiencies by below-cloud in the heavy rain (rain intensity, 10 mm/hr) surpass the efficiency found in the drizzle rain (rain intensity, 1 mm/hr).

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Derivation of the Standard Design Guidelines for Crashworthiness of the High-Speed EMU (동력분산형 고속전철의 충돌안전도 설계 가이드라인 도출)

  • Kim, Geo-Young;Cho, Hyun-Jik;Koo, Jeong-Seo
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.772-779
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    • 2008
  • Through this study, standard design guidelines for the high speed EMU have been derived to meet the crashworthiness requirements of the Korean rollingstock safety regulation. The crashworthiness regulation requires some performance requirements for two heavy collision accident scenarios; a train-to-train collision at the relative speed of 36 kph, and a collision against a standard deformable obstacle of 15 ton at 110 kph. The complete train set will be composed of 2TC-6M with 13 ton axle load, different from KTX with the power car of 17 ton axle load. Using theoretical and numerical analyses, some crashworthy design guidelines were derived in terms of mean crush forces and energy absorptions for main crushable structures and devices. The derived design guidelines were evaluated and improved using one dimensional spring-mass dynamic simulations. It is shown from the simulation results that the suggested design guidelines can easily satisfy the domestic crashworthiness requirements.

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A Priority-based Interactive Approach to Multi-agent Motion Planning (우선 순위 기반 쌍방향 다개체 동작 계획 방법)

  • Ji, Sang-Hoon;Jung, Youn-Soo;Lee, Beom-Hee
    • The Journal of Korea Robotics Society
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    • v.1 no.1
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    • pp.46-57
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    • 2006
  • It is well known that mathematical solutions for multi-agent planning problems are very difficult to obtain due to the complexity of mutual interactions among multi-agent. Most of the past research results thus are based on the probabilistic completeness. However, the practicality and effectiveness of the solution from the probabilistic completeness is significantly reduced by heavy computational burden. In this paper, we propose a practically applicable solution technique for multi-agent planning problems, which assures a reasonable computation time and a real world application for more than 3 multi-agents for the case of general shaped paths in agent movement. First, to reduce the computation time, a collision map is utilized for detecting potential collisions and obtaining collision-free solutions for multi-agents. Second, to minimize the maximum of multi-agent task execution time, a method is developed for selecting an optimal priority order. Simulations are finally provided for more than 20 agents to emphasize the effectiveness of the proposed interactive approach to multi-agent planning problems.

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Scattering of Noble Gas Ions from a Si(100) Surface at Hyperthermal Energies (20-300 eV)

  • 이현우;Kang, H.
    • Bulletin of the Korean Chemical Society
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    • v.16 no.2
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    • pp.101-104
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    • 1995
  • In an attempt to understand the nature of hyperthermal ion-surface collisions, noble gas ion beams (He+, Ne+, Ar+, and Xe+) are scattered from a Si(100) surface for collision energies of 20-300 eV and for 45°incidence angle. The scattered ions are mass-analyzed using a quadrupole mass spectrometer and their kinetic energy is measured in a time-of-flight mode. The scattering event for He+ and Ne+ can be approximated as a sequence of quasi-binary collisions with individual Si atoms for high collision energies (Ei > 100 eV), but it becomes of a many-body nature for lower energies, Ar+ and Xe+ ions undergo mutliple large impact parameter collisions with the surface atoms. The effective mass of a surface that these heavy ions experience during the collision increases drastically for low beam energies.