• Korean Journal of Computational Design and Engineering
• /
• v.10 no.3
• /
• pp.217-223
• /
• 2005

Tight integration between design and analysis processes and the data representation in the ship design application domain have been studied in this paper. Multi-Representation Architecture for design and analysis integration, proposed at Georgia Institute of Technology, has been carefully investigated for the application in the initial ship design stage. The MRA approach facilitates efficient generation of analysis models from the initial ship design data, thus reducing design lead time. Easy generation of analysis model is important because it allows quick analysis iteration under frequent design changes. The SMM, ABB and PBAM are defined for the analysis model of the typical ship structure. Only a part of the typical initial ship design data has been considered in the experimental implementation of the proposed approach. However, the prototype implementation shows that the application of MRA approach in the structural ship design domain is quite feasible. It is also contemplated that the same approach can be extended for other design and analysis views in the ship design domain.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.1
• /
• pp.61-69
• /
• 2005

In the global ship structure and vibration analysis, the FE(finite element) analysis model is required in the early design stage before the 3D CAD model is defined. And the analysis model generation process is a time-consuming job and takes much more time than the engineering work itself. In particular, ship structure has too many associated structural members such as stringers, stiffness and girders etc. These structural members should be satisfied as the constraints in analysis modeling. Therefore it is necessary to support generation of analysis model with satisfying these constraints as an automatic manner. For the effective support of the global ship analysis modeling, a method to generate analysis model using initial design information within ship design process, that hull form offset data and compartment data, is developed. In order to easily handle initial design information and FE model information, flexible data structure is proposed. An automatic quadrilateral mesh generation algorithm using initial design information to satisfy the constraints imposed on the ship structure is also proposed. The proposed data structure and mesh generation algorithm are applied for the various type of vessels for the usability test. Through this test, we have verified the stability and usefulness of this system including mesh generation algorithm.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.4
• /
• pp.244-253
• /
• 2005

In the initial ship design stage of shipyards, the hull form design, the basic design (compartment modeling and ship calculation), and the hull structural design are being performed by different systems. Thus, the problem on interfaces between these systems occurs. To solve this, we developed the hull form design system 'EzHULL' and the compartment modeling and ship calculation system 'EzCOM-PART' for developing finally an integrated ship design system. And, in this study, we present an object-oriented hull structural design .system 'EzSTRUCT', which is developed recently. A structural design in an initial design stage can be frequently changed, because the design is not firmly determined yet. Therefore, designers perform the simplified structural modeling with bigger structural parts (or objects) such as deck, longitudinal bulkhead, etc. in the initial design stage, and the detailed structural modeling with smaller structural parts such as plate, seam, slot, etc. in the detailed design stage. However, the existing hull structural CAD system used in a shipyard is not efficient in generating a 3D CAD model in the initial design stage, because it has difficulty in handling frequent changes in design. Therefore, designers initially draw 2D drawings in the initial design stage, and generate the 3D CAD model from these 2D drawings in the detailed design and production design stages. In this study, the hull structural design system, which can efficiently generate a 3D CAD model through rapid modeling at an initial design stage, was developed in this study To evaluate the applicability of the developed system, we applied it to hull structural modeling of various ships such as a VLCC, a bulk carrier, etc. As a result, it could efficiently generate a 3D CAD model of a hull structure.

• Journal of Mechanical Science and Technology
• /
• v.18 no.11
• /
• pp.1923-1931
• /
• 2004

Manufacturing of complex surface plates in stern and stem is a major factor in cost of a preliminary ship design by computing process. If these hull plate parts are effectively classified, it helps to compute the processing cost and find the way to cut-down the processing cost. This paper presents a new method to classify surface plates effectively in the preliminary ship design using neural network. A neural-network-based ship hull plate classification program was developed and tested for the automatic classification of ship design. The input variables are regarded as Gaussian curvature distributions on the plate. Various applicable rules of network topology are applied in the ship design. In automation of hull plate classification, two different numbers of input variables are used. By observing the results of the proposed method, the effectiveness of the proposed method is discussed. As a result, high prediction rate was achieved in the ship design. Accordingly, to the initial design stage, the ship hull plate classification program can be used to predict the ship production cost. And the proposed method will contribute to reduce the production cost of ship.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.3
• /
• pp.268-275
• /
• 2005

Tight integration between design and analysis process and data representation in the ship design application domain has been studied in this paper. Multi-Representation Architecture proposed at Georgia Institute of Technology has been carefully investigated for the application in the initial ship design stage. The prototype implementation shows that the application of MRA in the structural ship design domain is quite possible and can be extended for other design and analysis views in ship design.

• Korean Journal of Computational Design and Engineering
• /
• v.21 no.2
• /
• pp.186-195
• /
• 2016

The finite element modeling of a ship for hull structural analysis on the basis of new harmonized common structural rules (CSR-H) is to be extended to the cargo holds in fore and after body of a ship. Unlike the parallel middle-body where the external and internal features of hull are equal along to the longitudinal direction of a ship, in fore and after body, the external and internal features of hull vary linearly or even irregularly in forms of a surface or a curve along to the longitudinal direction of a ship. Thus, it needs lots of design man-hours for the modeling for structural analysis. In order to save man-hours in initial structural design phase of a ship, the specified 3D CAD system has been adopted in shipbuilding industry. Through the interface between CAD and CAE (rule scantling and direct strength assessment), design man-hour in initial design phase can be saved even under the environment of CSR-H.

• Korean Journal of Computational Design and Engineering
• /
• v.4 no.4
• /
• pp.360-370
• /
• 1999

The paper proposed a basic architecture of an agent system to support exchange and sharing of design informations by means of ACL(Agent Communication Language) which can represent design informations and knowledges. Based on the architecture of the agent system a ship initial design agent system was implemented in order to show the effectiveness of the agent-based system. The basic architecture of the agent consists of an ACL handlerand CORBA(Common Object Request Broker Architecture) objects for the exchange of ACL messages in the heterogeneous and distributed environment. The ACL handler can process expressions of knowledge and manage communication messages among the agents. The paper mainly focuses on the implementation of the ACL handler. The ACL handler consist of a KQML(Knowledge Query and Manipulation Language) handler that manages KQML messages, a conversation module, and a content handler that handles message contents. The conversation modulo implements conversation policies and checks all messages if they are allowable and meaningful messages based on the conversation policies. The implemented agent-based system was applied to the ship initial design to show the handling procedure of the agent system.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.5 no.3
• /
• pp.414-430
• /
• 2013

This paper shows the study of preswirl duct as an effective energy saving devices that have been devised and reviewed to support the propeller performance, especially for the ship of VLCC with large block coefficients. From the bare hull wake measurements, typical upper/lower asymmetry of hull wake at the propeller disk was found. The 2 kinds of pre-swirl duct, Unconventional half circular duct and Conventional circular pre-swirl duct have been designed and reviewed to recover the loss of propeller running in that condition. The general function of the pre-swirl duct was set to work against this asymmetry of wake and generate pre-swirled flow into the propeller against the propeller rotating direction. The optimum self propulsion tests with various angle configurations were carried out and the best configuration was decided. Accordingly, cavitation test was carried out with best configuration of unconventional half circular duct. The blade surface and tip vortex cavitation behaved smoother when the duct was mounted. The hull pressure amplitudes reflected this difference, so the hull pressure amplitude with duct was smaller than that of without duct.

• Journal of Ocean Engineering and Technology
• /
• v.29 no.2
• /
• pp.111-119
• /
• 2015

In the initial ship design stage, performance predictions are generally carried out before and after the hull form design. The former is based on the main dimensions and power information, and the latter is based on the geometry of the hull form and propeller. This paper deals with the practical application of neural networks for the prediction of a ship's performance factors before and after the hull form design. For this, the hull form parameters that affect the performance are studied, and an optimal neural network structure based on the SSMB database is constructed. By comparing the results predicted by neural networks and the model test results, we confirmed that neural networks can be applied to practically evaluate the performance in the initial ship design stage.

• Computational Structural Engineering
• /
• v.23 no.2
• /
• pp.72-79
• /
• 2010