Ship collisions are marine accidents that may have catastrophic outcome. Commonly, an orthogonal collision with a fully laden oil tanker at its amidships area is considered. Much less attention is given to collisions affecting struck ship fore and aft part, the effect of struck ship speed, collisions with other floating objects etc. In most of these cases the effect of surrounded water becomes pronounced. Present work aims to investigate the consequences of applying two different realistic ship collision modelling techniques involving fluid-structure interaction (FSI) analysis in LS-Dyna: arbitrary Lagrangian–Eulerian (ALE) technique and rigid body MCOL coupling, using LPG ship and a ferry collision scenario as a study case. First, calibration of ALE parameters was made and then ship collision simulation is performed by ALE technique. In parallel, struck ship hydrodynamic parameters were calculated and collision simulation is performed again using MCOL/LS-Dyna coupling. Then, results are compared and discussed.

The paper presents the principal steps in the definition of a practical design model for multi-criteria synthesis of complex thin-walled ship structures in concept and preliminary design. It elaborates the general requirements on the design procedure, balanced and applicable combinations of design models and a practical example of the basic analysis models/IT modules within the MAESTRO/OCTOPUS design support system. System identification from the multi-stakeholder perspectives of owner and society, and the formulation and solution to the dimensionally large-scale structural designs are presented as a step towards the practical implementation of multi-criteria decision-making in ship design practice since only a joint effort could lead to the satisfaction of all stakeholders in today's challenging ship-building industry. The practical structural design procedure/methodology, capable of embedding multiple design quality criteria, is demonstrated using a benchmark case study on the innovative RoPax ship.

The paper presents the main structural aspects of the innovative car carrier being designed and built by the Uljanik Shipyard as a Newbuilding 513-514. To increase deadweight and reduce structural mass, vertical centre of gravity and fuel consumptions, three upper fixed vehicles decks have been designed as a hybrid concept, i.e. a combination of steel deck grillage and composite sandwich panels. Various relevant aspects and results of the case study are undertaken with the aim to determine a feasible structural design of the lightweight, cost-effective and easily installable composite sandwich panels intended to carry vehicles loaded on fixed decks. For a predefined sandwich panel geometry and interaction with the supporting deck steel grillage, structural capability and compliance with the relevant Bureau Veritas (BV) rules of various feasible configurations were evaluated, whereby structural response was determined using the finite element method (FEM) on the local (panel) level. On the global level, composite sandwich panels do not contribute to the hull girder bending, so longitudinal and racking strengths of the new structural concept have been evaluated using the complete full ship FEM model. Finally, benefits of the suggested concept have been summarised and compared to the conventional car carrier design.