• 제목/요약/키워드: dynamic collision properties

검색결과 26건 처리시간 0.023초

Dynamic analysis of high-speed railway train-bridge system after barge collision

  • Xia, Chaoyi;Ma, Qin;Song, Fudong;Wu, Xuan;Xia, He
    • Structural Engineering and Mechanics
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    • 제67권1호
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    • pp.9-20
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    • 2018
  • In this paper, a framework is proposed for dynamic analysis of train-bridge systems with a damaged pier after barge collision. In simulating the barge-pier collision, the concrete pier is considered to be nonlinear-inelastic, and the barge-bow is modeled as elastic-plastic. The changes of dynamic properties and deformation of the damaged pier, and the additional unevenness of the track induced by the change of deck profile, are analyzed. The dynamic analysis model for train-bridge coupling system with a damaged pier is established. Based on the framework, an illustrative case study is carried out with a $5{\times}32m$ simply-supported PC box-girder bridge and the ICE3 high-speed train, to investigate the dynamic response of the bridge with a damaged pier after barge collision and its influence on the running safety of high-speed train. The results show that after collision by the barge, the vibration properties of the pier and the deck profile of bridge are changed, forming an additional unevenness of the track, by which the dynamic responses of the bridge and the car-body accelerations of the train are increased, and the running safety of high-speed train is affected.

침투성 구형 모델에 관한 분자 전산 연구: II. 충돌 특성 (Molecular Simulation Studies for Penetrable-Sphere Model: II. Collision Properties)

  • 김춘호;서숭혁
    • 폴리머
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    • 제35권6호
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    • pp.513-519
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    • 2011
  • 침투 가능한 구형 모델 유체의 충돌 특성을 고찰하고자 분자 동력학 방법을 이용한 전산 모사를 수행하였다. 이로부터 다양한 범위의 입자 충전 분율 ${\phi}$ 및 척력적 에너지 ${\varepsilon}^*$ 조건에 대한 충돌 빈도수, 평균 자유 행로, 강체형 반사 충돌각 및 연체형 침투 충돌각의 분포도, 유효 충전 분율 등을 계산하였다. 낮은 척력적 에너지 조건에서는 연체형 충돌이 주된 특성이나, 반면 높은 척력적 에너지 조건에서는 강체형 충돌이 주된 요인이었다. 매우 흥미롭게도, 전체 충돌 빈도수에 대한 연체형 충돌비(또는, 강체형 충돌비)는 정준 앙상블의 몬테카를로 전산 모사에서 받아들임 확률(또는, 되돌림 확률)로 표시되는 볼쯔만 인자와 직접적으로 관계되었다. 이와 같은 거동 입자들의 동적 충돌 특성들은 ${\varepsilon}^*{\geqq}3.0$${\phi}{\geqq}0.7$ 범위의 높은 척력적 에너지 및 높은 충전 분율 조건에서 제한적이었으며, 이는 침투성 구형 모델에서 나타나는 클러스터 형성 구조를 함축하고 있다.

차량용 MR충격댐퍼의 동특성 해석 (Dynamic Characteristic Analysis of MR Impact Damper for Vehicle System)

  • 송현정;우다윗;최승복
    • 한국소음진동공학회논문집
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    • 제16권7호
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    • pp.754-761
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    • 2006
  • This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed to reduce force transmitted to the vehicle chassis and finally to protect occupants from injury. In the case of head-on collision, the bumper makes main role of isolation material for collision attenuation. In this study, the proposed bumper system consists of MR impact damper and structures. The MR impact damper utilizes MR fluid which has reversible properties with applied magnetic field. The MR fluid operates under flow mode. The bellows is used for generation of fluid flow. A mathematical model of the MR impact damper is derived incorporating with Bingham model of the MR fluid. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.

차량용 MR 충격댐퍼의 동특성 해석 (Dynamic Characteristic Analysis of MR Impact Damper for Vehicle System)

  • 송현정;우다윗;최승복
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.147-152
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    • 2006
  • This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed for reduce transmitted force to vehicle chassis and finally protect occupants from injury. In the case of frontal collision, the bumper make main role of isolation material for collision attenuation. In this study, proposed bumper system composed of MR impact damper and structures. The MR impact damper is to adopted MR fluid which has reversible properties with applied magnetic field. MR fluid operates under flow mode with Bingham flow and bellows is used for generation of fluid flow. Mathematical model of MR impact damper incorporated with MR fluid is established. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.

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철도차량 충돌 시뮬레이션 (Crash Simulation of Rolling Stock)

  • 김필환;이장욱;김진태;김창수
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 1998년도 창립기념 춘계학술대회 논문집
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    • pp.401-407
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    • 1998
  • Recently, as the railway vehicles become speedy and massive, the collision is being regarded as an important factor for the assessment of safety for passenger. And the study of collision is being in progress more actively in advanced nations. In this study, the collision analysis is performed by using non-linear dynamic finite element program PAM-CRASH. The carbody used in analysis is made of Aluminum AL6005A to realize lightweight, and designed and manufactured by DHI (Daewoo Heavy Industry) lately. For the accuracy of the result in the practical collision, the experiment of material properties has been performed. The result of the analysis shows the underframe of rolling stock is the most important part as a collision energy absorbing structure. Further study is needed for optimal design which enables the carbody shell structure to disperse absorbing energy adequately.

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DAF 공정에서 무기 고형입자의 유체역학적 충돌효율과 부상특성 (Hydrodynamic Collision Efficiency and Flotation Characteristics of Inorganic Particles in DAF Process)

  • 곽동희;김성진;이화경;정흥조;이재욱;정팔진
    • 상하수도학회지
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    • 제16권6호
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    • pp.655-662
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    • 2002
  • Separation characteristics of inorganic particles occurred during heavy rainwater were investigated in DAF (dissolved air flotation) process. In order to remove the inorganic particles effectively, the collision and flotation efficiencies were examined from a hydrodynamic point of view. Generally, the collision efficiency increased with floc size under the variation of fluid dynamic conditions including inertial force. However, more precise model should be required to analysis the collision efficiency expressed both the physical properties for inorganic particles and hydrodynamic conditions for a reactor.

A Track Scoring Function Development for Airborne Target Detection Using Dynamic Programming

  • Won, Dae-Yeon;Shim, Sang-Wook;Kim, Keum-Seong;Tahk, Min-Jea;Kim, Eung-Tai
    • International Journal of Aeronautical and Space Sciences
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    • 제13권1호
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    • pp.99-105
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    • 2012
  • Track-before-detect techniques based on dynamic programming have provided solutions for detecting targets from a sequence of images. In its application to airborne threat detection, dynamic programming solutions should take into account the distinguishable properties of objects in a collision course. This paper describes the development of a new track scoring function that accumulates scores for airborne targets in Bayesian framework. Numerical results show that the proposed scoring function has slightly better detection capabilities.

유빙 및 평탄빙의 충돌에 의한 빙하중과 선체구조응답 해석기법 (Analysis Method of Ice Load and Ship Structural Response due to Collision of Ice Bergy Bit and Level Ice)

  • 노인식;이재만;오영택;김성찬
    • 대한조선학회논문집
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    • 제53권2호
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    • pp.85-91
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    • 2016
  • The most important factor in the structural design of ships and offshore structures operating in arctic region is ice load, which results from ice-structure interaction during the ice collision process. The mechanical properties of ice related to strength and failure, however, show very complicated aspect varying with temperature, volume fraction of brine, grain size, strain rate and etc. So it is nearly impossible to establish a perfect material model of ice satisfying all the mechanical characteristics completely. Therefore, in general, ice collision analysis was carried out by relatively simple material models considering only specific aspects of mechanical characteristics of ice and it would be the most significant cause of inevitable errors in the analysis. Especially, it is well-known that the most distinctive mechanical property of ice is high dependency on strain rate. Ice shows brittle attribute in higher strain rate while it becomes ductile in lower strain rate range. In this study, the simulation method of ice collision to ship hull using the nonlinear dynamic FE analysis was dealt with. To consider the strain rate effects of ice during ice-structural interaction, strain rate dependent constitutive model in which yield stress and hardening behaviors vary with strain rate was adopted. To reduce the huge amount of computing time, the modeling range of ice and ship structure were restricted to the confined region of interest. Under the various scenario of ice-ship hull collision, the structural behavior of hull panels and failure modes of ice were examined by nonlinear FE analysis technique.

A finite element-experimental study of the impact of spheres on aluminium thin plates

  • Micheli, Giancarlo B.;Driemeier, Larissa;Alves, Marcilio
    • Structural Engineering and Mechanics
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    • 제55권2호
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    • pp.263-280
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    • 2015
  • This paper describes a study of the collision of hard steel spheres against aluminium thin circular plates at speeds up to 140 m/s. The tests were monitored by a high speed camera and a chronoscope, which allowed the determination of the ballistic limit and the plate deformation pattern. Quasi-static material parameters were obtained from tests on a universal testing machine and dynamic mechanical characterization of two aluminium alloys were conducted in a split Hopkinson pressure bar. Using a damage model, the perforation of the plates was simulated by finite element analysis. Axisymmetric, shell and solid elements were employed with various parameters of the numerical analysis being thoroughly discussed, in special, the dynamic model parameters. A good agreement between experiments and the numerical analysis was obtained.

Investigation of Stereo-dynamic Properties for the Reaction H+HLi by Quasi-classical Trajectory Approach

  • Wang, Yuliang;Zhang, Jinchun;Jiang, Yanlan;Wang, Kun;Zhou, Mingyu;Liang, Xiaorui
    • Bulletin of the Korean Chemical Society
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    • 제33권9호
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    • pp.2873-2877
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    • 2012
  • Quasi-classical trajectory (QCT) calculations of H+HLi reaction have been carried out on a new potential energy surface of the ground state reported by Prudente et al. [Chem. Phys. Lett. 2009, 474, 18]. The four polarization-dependent differential cross sections have been carried out in the center of mass (CM) frame at various collision energies. The reaction probability for the depletion channel has been studied over a wide collision energy range. It has been found that the collision energy decreases remarkably reaction probability, which shows the expected behavior of the title reaction belonging to an exothermic barrierless reaction. The results are in good agreement with previous RMP results. The P(${\theta}_r$), P(${\phi}_r$) and P(${\theta}_r,\;{\phi}_r$) distributions, the k-k'-j' correlation and the angular distribution of product rotational vectors are presented in the form of polar plots. The average rotational alignment factor <$P_2(j{\prime}{\cdot}k)$> as a function of collision energy is also calculated. The results indicate that the collision energy has a great influence on the polarization of the product rotational angular momentum vector j'.