Ship Manoeuvring Behaviour in Crossing Current Near-by a Lock

in VanTorre, Marc (Ed.) Third International Conference on Ship Manoeuvring in Shallow and Confined Water (2013, June 03)

Ship behaviour in current is one of the classical problems in ship manoeuvrability. However, it is not yet fully investigated. The study is motivated by an assessment study on the ship navigation near by ... [more ▼]

Ship behaviour in current is one of the classical problems in ship manoeuvrability. However, it is not yet fully investigated. The study is motivated by an assessment study on the ship navigation near by a river lock where relatively strong current exists. It is demonstrated how a ship behaves in the current and relatively large drift angle may happen, if the current is comparative to ship speed. In this situation, the hydrodynamic forces and moment acting on a ship is not any more at the range of lift force/moment, and therefore normal mathematical model cannot be applied. Similar situation may occur in case of rapid river stream condition, when a ship losts its power in current. At East Japan Great Earthquake happened in 2011, many ships without their power were drifting in tsunami. It is urgent matter to investigate on the ship behaviour in such situation. [less ▲]

A new super-element for estimating the collision resistance of an inclined ship side

in Advancements in Marine Structures : Proceedings of MARSTRUCT 2013, the 4th International Conference on Marine Structures, Espoo, Finland, 25th – 27th March 2013 (2013)

The effects of hull modification on design parameters of medium speed monohuhll passenger ferries

in ICSOT : Developments in ship design & construction (2012, November 01)

Developments in ship design & construction

The effects of geometrical imperfections on the ultimate strength of aluminium stiffened plates subject to combined uniaxial compression and lateral pressure

in Ships and Offshore Structures (2012)

The present study aims at determining the effects of the geometrical imperfections on the ultimate strength and load-carrying capacity of aluminium stiffened plates under combined axial compression and ... [more ▼]

The present study aims at determining the effects of the geometrical imperfections on the ultimate strength and load-carrying capacity of aluminium stiffened plates under combined axial compression and lateral pressure. The finite element models proposed by the Committee III.1 ‘Ultimate Strength’ of ISSC’2003 are used in the present investigation. Initial imperfections as proposed by ISSC committee as well as those recommended by Ship Structure Committee are considered in the analyses. Models are tested using non-linear finite element elastic–plastic analyses. Aluminium alloy AA6082-T6 is selected as the material for the models. The studied models are triple-span panels stiffened by either extruded or non-extruded angle-bar profiles. Different arrangements of heat-affected zone (HAZ) are considered. The main outcomes of this study show the need for a subtle assessment of the real shapes of the initial deformations. The way they affect the ultimate strength of models is clarified through finite element analyses. [less ▲]

ULTIMATE STRENGTH ANALYSIS OF STEEL PLATES USING ISO/DIS 1872-2 AND ULSAP

in Nguyen Thien Tong (Ed.) International Conference on Advances in Computational Mechanics (2012, August)

Ultimate limit states (or ultimate strength) have been assessed that is the much better basis than the allowable working stresses. Today, we design and strength assessment the structural types such as ... [more ▼]

Ultimate limit states (or ultimate strength) have been assessed that is the much better basis than the allowable working stresses. Today, we design and strength assessment the structural types such as aerospace structures, offshore platforms, ships and land-based structures following the ISO STANDARD. Aim of this paper is to perform benchmark calculation in order to validating formulas of ISO Standard [1]. An effective approach for plate, using the ISO/DIS 1872-2 standard [1] and ULSAP (Mestro software) [2], are calculated in the current research for studying the ultimate strength problems of plates with six load cases: longitudinal compression, transverse compression, biaxial compression with/without lateral pressure. The trends of ISO Standard results in some cases agree well to the Maestro results. Other cases are not similar. The values of ISO results were found smaller than Maestro results. For this reason, the ISO results are not more conservative than ULSAP results. [less ▲]

Ship Structure Optimization Using CAD/FEM Integration

in 11th INTERNATIONAL MARINE DESIGN CONFERENCE (2012, June 11)

In ship structural design, scantling optimization using mathematical algorithms is not yet largely implemented in industry. Optimization with mathematical algorithms can be very helpful to find the best ... [more ▼]

In ship structural design, scantling optimization using mathematical algorithms is not yet largely implemented in industry. Optimization with mathematical algorithms can be very helpful to find the best solution (minimum weight, minimum cost, maximum inertia,…). Typically, finite element analysis (FEA) tools are used in ship structural assessment. But, to build a FEM model from a CAD one is not easy. It needs a big amount of manual work. In the present work, an innovative optimization workflow was developed. The following steps are carried automatically without any manual intervention. First, from the 3D CAD model, an idealized CAD model is created by the idealization module to take into account the FEM needs. Then, the idealized CAD model is transferred to the FEM tool. After that, the FEM model is meshed and loaded. After FEM solving, the results (stress, displacement, volume etc.) are transferred to the optimizer. The optimizer evaluates the values of the objective function and the constraints previously defined and modify the design variables (plate thickness and the stiffener scantling) to create a new structural model. After several iterations, the optimum solution is evaluated. [less ▲]

Towards a Short Time "Feature-Based Costing" for Ship Design

in Journal of Marine Science & Technology (2012), 17(2), 216-230

Cost is perhaps the most influential factor in the outcome of a product or service within many of todays industries. Cost assessment during the early stage of ship design is crucial. It influences the go ... [more ▼]

Cost is perhaps the most influential factor in the outcome of a product or service within many of todays industries. Cost assessment during the early stage of ship design is crucial. It influences the go, no-go decision concerning a new development. Cost assessment occurs at various stages of ship design development. Economic evaluation as early as possible, in the design phase, is therefore vital to find the best pricefunction compromise for the ship projects. The authors have developed a Feature-Based Costing (FBC) model for cost effectiveness measurements intended to be used by ship designers for the real time control of cost process. The outcome is that corrective actions can be taken by management in a rather short time to actually improve or overcome predicted unfavourable performance. [less ▲]

Task 4.0 – Subsystem Optimization of the Structure Scantling

Report (2012)

In the present report concerning Task 4.0 – Subsystem Optimization of the Structure Scantling, the structural optimization of the ship is carried out. This optimization is performed with regard to the ... [more ▼]

In the present report concerning Task 4.0 – Subsystem Optimization of the Structure Scantling, the structural optimization of the ship is carried out. This optimization is performed with regard to the objective functions and the constraints defined in Deliverables 2.0 & 3.0 [1]. Task 4.0 is divided into three parts: - The initial scantling - The load cases and loadings - The optimized scantling This report presents the results and benefits of optimization. Comments and analysis are provided throughout the report. [less ▲]

A real-time assessment of the ship design complexity

in Computer-Aided Design (2012), 44

The paper introduces an innovative complexity metric for passenger ships taking into account the shape complexity of steel parts, the assembly complexity and the material complexity. The goal is to ... [more ▼]

The paper introduces an innovative complexity metric for passenger ships taking into account the shape complexity of steel parts, the assembly complexity and the material complexity. The goal is to provide the designer with such information throughout the design process so that an efficient design is obtained at the first design run. Real-time assessment of complexity and quality measurements is rather imperative to ensure efficient and effective optimality search, and to allow real-time adjustment of requirements during the design. Application and validation on a real passenger ship show that the new method is effective in giving a complementary aid to decision process for ship designers. [less ▲]

Simplified analytical method for estimating the resistance of lock gates to ship impacts

in Journal of Applied Mathematics (2012)