• Title, Summary, Keyword: 비선형 동적 충돌해석

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A Protection Capacity Evaluation of Vessel Protective Structures by Quasi-Static Collision Analysis (준정적 충돌해석을 통한 선박충돌방공호의 방호능력평가)

  • Lee, Gye-Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.6
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    • pp.691-697
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    • 2011
  • In this study, the vessel collision protective structure and the vessel were modeled numerically and the quasi-static collision analysis was performed to evaluate the maximum protection capacity. In the modeling process of protective structure, the nonlinear behaviors of structure and the supporting conditions of ground including pull-out action were considered. In that of collision vessel, the bow of vessel was modeled precisely, because of the nonlinear behaviors were concentrated on it. For the efficient analysis, the mass scaling scheme was applied, also. To evaluate the differences and efficiency, the dynamic analyses were performed for the same model, additionally. Based on the obtained energy dissipation curves of the structure and the vessel, the moment that the collision force affected to the bridge substructures was determined and the maximum allowable collision velocity was evaluated. Because of the energy dissipation bound can be recognized clearly, this scheme can be used efficient in engineering work.

Dynamic Interaction Modelling between Arctic Offshore Structures and Ice Floe (극지 해양 구조물과 얼음의 동적 모델화)

  • 황철성;김상준
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.1 no.1
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    • pp.87-92
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    • 1989
  • In this study, the nonlinear dynamic model of the systems which include the offshore structure, the surrounding sea water in terms of the added mass, the foundation in terms of frequency independent springs, dashpots, and the floating ice feature with its hydrodynamic added mass, are proposed for the problem of the large ice floes impact. Dynamic Analysis is performed on two site conditions, sand site and silt site, and on two seasons, winter and summer, for various ice floe velocities. As a result of study, Ice floes from energy balenced method is lower than that from dynamic modeling on sand site, and higher than the on silt site.

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자동차의 Crashworthiness 해석을 위한 Pinball Contact-Impact

  • 이상호
    • Computational Structural Engineering
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    • v.8 no.3
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    • pp.5-10
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    • 1995
  • 공학분야에서 흔히 접하게 되는 접촉충격 문제들의 해석을 위해 접촉충격의 지배방정식과 효율적인 해석방법인 pinball contact-impact 알고리즘에 대해 기술하였다. 예제로 보여준 충돌하는 두 구조계의 접촉충격 해석과 자동차의 crashworthiness 해석결과들은 전술한 알고리즘이 매우 효율적임을 입증하고 있다. 자동차의 crashworthiness 해석과 같이 해석대상 모델이 크고 복잡한 경우에는 짧은 경과시간 동안의 거동변화를 파악하고자 하더라도 엄청난 계산시간이 소요된다. 따라서 효율적인 crashworthiness 해석을 위해서는 전술한 접촉충격 알고리즘 외에도, 논외의 대상이라 본문에서 소개하지는 않았으나, 강력한 요소(one-point integration element), 효과적인 비선형 동적해석 알고리즘, 해의 정확도를 높일 수 있는 adaptive method, 효율적인 시간적분을 위한 mixed time integration method(subcycling)와 explicit method 등을 복합적으로 혼합하여 사용하여야 한다.

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Collision Behaviors Analysis of Sandwich Concrete Panel for Outer Shell of LNG Tank (LNG외조를 구성하는 샌드위치 콘크리트 패널의 충돌거동해석)

  • Lee, Gye Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.6
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    • pp.485-493
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    • 2017
  • In this study, the collision analysis of SCP(Sandwich Concrete Panel) composing the outer tank of LNG storage was performed and its collision behavior was analyzed. For the same collision energy value proposed in BS7777 code, the collision conditions are composed by using two types of missiles and various collision speeds. Nonlinear dynamic analysis models were constructed to perform numerical analysis on the various collision conditions. Also, the collision behavior was analyzed assuming that the second collision with the same collision energy occurs at the same point after the first collision. As a result of the analysis, it was found that with smaller missile and low collision speed had caused larger deformation. The collision energy dissipated in ratio of about 6: 4 in the outer steel plate and the inner filling concrete. In the results of double collision analysis, the final collisional deformation was dominated by the size of the second missile, and the amount of deformation due to the second collision was smaller than that of the first collision because of the membrane behavior of the steel plates. In the offset double collision cases, the largest deformation occurs at the secondary collision point regardless of the offset distance.

Analysis of impact damage behavior of GFRP-strengthened RC wall structures subjected to multiple explosive loadings (복합 폭발하중을 받는 GFRP 보강 RC 벽체 구조물의 비선형 충격 손상거동 해석)

  • Noh, Myung-Hyun;Lee, Sang-Youl;Park, Tae-Hyo
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.1033-1036
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    • 2008
  • In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with glass fiber reinforced polymer (GFRP) composites are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a GFRP-strengthened RC wall structure.

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Analysis of Ship Collision Behavior of Pile Supported Structure (파일지지 구조물의 선박 충돌거동에 대한 해석)

  • Bae, Yong Gwi;Lee, Seong Lo
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.3A
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    • pp.323-330
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    • 2008
  • The ship collision analysis of steel pile group as protection system of bridge in navigable waterways was performed to analyze the structural characteristics of protective structure during ship collision. The analysis encompassed finite element modeling of ship and pile, modeling of material non-linearity, hard impact analysis, displacement-based analysis and soft impact analysis for collision scenarios. Through the analysis of hard impact with a rigid wall, impact load for each collision type of ship bow was estimated. In the displacement-based analysis the estimate of energy which protection system can absorb within its maximum horizontal clearance so as to secure bridge pier from vessel contact during collision was performed. Soft impact analysis for various collision scenarios was conducted and the collision behaviors of vessel and pile-supported protection system were reviewed for the design of protection system. The understanding of the energy dissipation mechanism of pile supported structure and colliding vessel would give us the optimized design of protective structure.

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Finite element analysis on supercomputers (슈퍼컴퓨터를 이용한 유한요소해석)

  • 이재석
    • Computational Structural Engineering
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    • v.1 no.2
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    • pp.26-33
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    • 1988
  • 유한요소해석프로그램들의 적용대상이 최근들어 다(多) 자유도의 비선형문제로 확대됨에 따라 컴퓨터의 계산속도가 특히 중요한 제한조건으로 대두되기 시작하였으며 금속성형해석, 자동차 등의 충돌해석(자유도가 2만-6만), 토질 및 콘크리트 등의 점소성해석과 더불어 항공기, 터빈 등의 열응력해석 및 동적해석 등에 있어서는 막대한 계산시간으로 인하여 해석의 효율성에 대한 문제가 제기되고 있다. 따라서 슈퍼컴퓨터를 포함하여 고속연산기능을 가진 병렬처리컴퓨터를 이용하여 유한요소해석을 수행하여야 할 필요성이 증가하고 있다. 88년 9월중에 한국과학기술원 시스템공학센터에 현존하는 슈퍼컴퓨터중 최상위 성능을 가진 CRAY2S가 설치됨에 따라 국내에도 슈퍼컴퓨터시대가 열리게 되었으며 따라서 본 고에서는 CRAY2S의 시스템개요 및 응용소프트웨어에 대하여 소개하고 슈퍼컴퓨터를 이용한 유한요소해석에 관하여 간략히 기술하고저 한다.

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High Velocity Impact Analysis of Kevlar29/Phenolic Composite Plate (케블라 복합재 평판의 고속충돌 특성 수치해석)

  • Ahn, Jeoung-Hee;Kweon, Jin-Hwe;Choi, Jin-Ho
    • Composites Research
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    • v.22 no.2
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    • pp.18-23
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    • 2009
  • Failure of Kevlar29/Phenolic composite plate under high velocity impact of FSP(Fragment Simulation Projectile) is investigated using a non-linear explicit finite element code, LS-DYNA. Composite laminate and impactor are idealized by solid element and interface between laminas are modeled by tied-break element in LS-DYNA. Interaction between impactor and laminate is simulated face-to-face eroding contact algorithm. When the stress level meets a failure criteria, the layer in the element is eroded. Numerical results are verified by existing test results.

Investigation of Ice Impacts on Aluminum Skin Structure (알루미늄 표피 구조의 Ice 충돌 특성에 관한 연구)

  • Park, Gyu Cheol;Myeong, No Sin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.5
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    • pp.110-116
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    • 2003
  • With the growth of aircraft performance and needs for light aircraft, the problems associated with hail impacts on aircraft during flights and grounding become and important issue. These hail encounters can cause severe damages to aircraft and result in major concerns in safety and cost. Since nearly all external components of the commercial and military aircraft-in particular, the nose section and the leading edge of the wing and tail-are subject to damages, much effort has been put into understanding of this problem. However, most of the previous studies have focused on the composite components and few results have been reported for the metallic components. In this paper, we study the ice impacts on the aluminum component with the finite element analysis method utilizing commercial non-linear dynamics solver LS-DYNA. The results are compared with the experimental data and a simple measure of the ice impact effects is proposed.

Evaluation of Impact Damage Behavior of a Reinforced Concrete Wall Strengthened with Advanced Composite Materials (복합신소재로 보강된 철근 콘크리트 구조물의 충돌손상거동 평가)

  • Noh, Myung-Hyun;Lee, Sang-Youl
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.3
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    • pp.41-48
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    • 2010
  • In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with advanced composite materials (ACM) are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a ACM-strengthened RC wall structure.

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