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Ship-to-ship collision simulations
using a state-of-the-art non-linear CAE Technology

 


●Our institute could provide following simulation technology using state of the art non-linear CAE technology.
These simulation technologies are utilized in various projects to provide solution.
(1) ship-to-ship collision simulation
(2) Hull girder ultimate strengthanalysis
(3) Fluid-structure interaction (FSI) analysis

●Nonlinear FEM
In our institute, general purpose non-linear structural analysis software “LS-DYNA (LSTC, USA)” is usually utilized to carry out ship-to-ship collision simulations. This software is widely used in various industries including car and airplane industries. Especially this software is a de facto standard software in collision and grounding analysis of ships. In collision simulation time-domain analysis is carried out and by using time domain analysis, after the contact of two-ships, phenomena of buckling, collapse and failure are well simulated. This software also provides, multi-physics analysis including fluid-structure coupling, heat-structure coupling .

What is non-linear ?
・Material Non-linearity(Material constitutive model, nonlinear relation between stress and strain)
・Geometric Non-linearity(Large deformation, infinite deformation)
・Boundary Non-linearity(Contact, static or dynamic friction)



【ship-to-ship collision simulation】
●Collision and grounding is main causes of maritime accidents. Therefore, from the view point of safety of life and maritime environment it is important to keep enough structural strength so as not to make disastrous consequences including sinking of ships.

●It is difficult and not practical to evaluate crashworthiness of ships using real ships due to its large structures. Instead, the crashworthiness of ships is usually evaluated by advanced large-scale numerical simulations.

●Our institute provides ship-to-ship numerical simulations considering ship motions, added mass effects, restoring force (Roll, Pitch), failure of material, strain-rate dependency, contact between structural members, friction (static/dynamic) where 6 degree of freedom is set on the center of gravity of the ship. As a material constitutive model, relation between effective-plastic strain and effective stress needs to be defined. Failure strain is used as one of failure criteria, and which is dependent on the element sizes and effect of stress-axiality, and various know-how is needed.

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     Example of ship-to-ship collision simulation


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     Example of ship-to-ship collision simulation
         and failure of side shell.



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     Example of ship-to-ship collision simulation.
         Penetration of side shell.



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       Damage hole of side structure of bulk carrier
             due to ship collision



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       Example of ship-to-ship collision simulation


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       Example of ship-to-ship collision simulation


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       Penetration of side shell due to bulbous bow of striking ship


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       Rupture of side shell due to ship collision


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       Rupture of side shell due to ship collision


【References】
(1) Yamada, Y., Endo, H., Pedersen, P.T., "Collapse Strength of the Bulbous Bow Structure in Oblique Collision"", Proceedings of International Conference of Collision and Groundings of Ships (ICCGS-2004),pp.160-171, (2004)"

(2) Yamada, Y., Endo, H., Kawano, H, ""Collapse Mechanism of the Buffer Bow Structure on Axial Crushing"",International Journal of Offshore and Polar Engineering (IJOPE),Vol. 15, No. 2, pp. 147-154, (2005)"

(3) Yamada, Y., Endo, H., Pedersen, P.T., ""Numerical Study on the Effect of Buffer Bow Structure in Ship-Ship Collision"", Proceedings of The Fifteenth International Offshore and Polar Engineering Conference(ISOPE-2005),pp.604-611, (2005)"

(4) Yamada, Y., Pedersen, P.T., , ""Simplified Analysis Tool for Ship-Ship Collision"", Proceedings of The Seventeenth International Socciety of Offshore and Polar Engineering Conference (ISOPE-2007),pp.3760-3767, (2007)"

(5) Yamada, Y., Pedersen, P.T., Friis-Hansen, P., ""The Effect of Buffer Bow Structures on Probabilistic Collision Damages of Oil Tankers"", Proceedings of International Conference of Collision and Groundings of Ships (ICCGS-2007),pp.235-242, (2007)"

(6) Yamada, Y., Pedersen, P.T., Friis-Hansen, P., "Risk Reducing Effect of Buffer Bow Structures on the Collision Damage of Oil Tankers, Risk Workshop at Technical University of Denmark,, (2007)

(7) Yamada, Y., Endo, H., , "Experimental and Numerical Study on the Collapse Strength of the Bulbous Bow Structure in Oblique Collision", Marine Technology,Vol.45, No.1, pp.42-53, (2008)

(8) "Yamada, Y., Endo, H., Pedersen, P.T., ""Effect of Buffer Bow Structure in Ship-Ship Collision"", International Journal of Offshore and Polar Engineering (IJOPE),Vol.18, No.2, pp.133-141, (2008)"

(9) Yamada, Y., Pedersen, P.T., , "A Benchmark Study of Procedures for Analysis of Axial Crushing of Bulbous Bows", Marine Structure,Vo.21, pp.257-293, (2008)

(10) Yamada, Y., Ogawa, Y., , "Study on the residual ultimate longitudinal strength of hull girder of a bulk carrier against a sagging moment after ship collision", Advances in Marine Structures - Guedes Soares & Fricke(eds),pp.429-436, (2011)