Improve Papers Released to the public
Maintenance/repair and production oriented life-cycle cost/earning model for
ship structural optimisation during conceptual design stage
Abstract: The aim of this paper is to investigate the effect of the change in structural weight
due to optimisation experiments on life-cycle cost and earning elements using the life-cycle cost/earning model, which was developed for structure optimisation. The relation between structural variables and relevant cost/earning elements are explored and discussed in detail. The developed model is restricted to the relevant life-cycle cost and earning elements, namely production cost, periodic maintenance cost, fuel oil cost, operational earning and dismantling earning. Therefore it is important to emphasize here that the cost/earning figure calculated through the developed methodology will not be a full life-cycle cost/earning value for a subject vessel, but will be the relevant life-cycle cost/earning value though. The maintenance/repair data was collected from three ship operators and was solely used for the purpose of regression analysis. An illustrative example for a Chemical Tanker is provided to show the applicability of the proposed approach.
Download Paper
Multi-objective optimization of ship structures: using guided search vs. conventional concurrent optimization
Abstract: ?ABSTRACT: Structural optimization regularly involves conflicting objectives, where beside the eligible
weight reduction, increase in e.g. safety or reliability is imperative. For large structures, such as ships, to obtain a well-developed Pareto frontier can be difficult and time-demanding. Non-linear constraints, involving typical failure criteria, result in complex design space that is difficult to investigate. Evolutionary algorithms can cope with such problems. However they are not a fast optimization method. Here we aim to improve their performance by guiding the search to a particular part of Pareto frontier. For this purpose we use a genetic algorithm called VOP, and use it for optimization of the 40 000 DWT chemical tanker midship section. Beside weight minimization, increase in safety is investigated through stress reduction in deck structure. Proposed approach suggests that in the first stage one of the objectives is optimized alone, preferably more complicated
one. After obtaining satisfactory results the other objective is added to optimization in the second stage. The results of the introduced approach are compared with the conventional concurrent optimization of all objectives utilizing widespread genetic algorithm NSGA-II. Results show that the guided search brings benefits particularly with respect to structural weight, which was a more demanding objective to optimize. Salient optimized alternatives are presented and discussed.
Download Paper
17th International Ship and Offshore Structures Congress - Committee IV.1 Design Methods
Committee Mandate: Concern for the synthesis of the overall design process for marine structures, and its integration with
production, maintenance and repair. Particular attention shall be given to the roles and requirements of
computer-based design and production, and to the utilization of information technology.
Download Paper
IMPROVE - Design of Improved and Competitive Products
Abstract: The paper is treating the subject of the EC Project FP6-IMPROVE, in which SDG is involved. The Project proposes to deliver an integrated decision support system for a methodological as-sessment of ship designs to provide a rational basis for making decisions pertaining to the de-sign, production and operation of three new ship generations. The product types focused on this project are three next-generation ship types (LNG, RoPax, chemical tanker). Such support can be used to make more informed decisions, which in turn will contribute to reducing the life-cycle costs and improving the performance of those ship generations.
This paper was presented at the InfoDBlaS’08
I&CT International Conference
organised on the 16th-18th June 2008
in Istanbul, Turkey (for more information on the conference click here)
Download Paper
IMPROVE - Design of Improved and Competitive Products using an Inte-grated Decision Support System for Ship Production and Operation
Abstract: The paper gives an overview over the EC project IMPROVE. The project develops a decision support system for a methodological assessment of ship designs to provide a rational basis for making decisions pertaining to the design, production and operation of three next-generation ship types (LNG, RoPax, chemical tanker).The system is expected to reduce life-cycle costs and improve ship performance.
Download Paper
Structural Optimization of a 220 000 m³ LNG Carrier
Abstract: This paper relates to the development of a new concept of 220.000 m³ LNG designed by AKERYARDS France. This work is performed in the framework of FP6 IMPROVE project. The first phase of the activity related to the identification of stakeholder’s requirements and the definition of key performance indicators. In parallel, several calculations have been performed to test the existing tools and to evaluate the potential gain at the concept design. These activities, associated with the definition of a 220000 m³ QuatarFlex prototype, including the aspects related to the naval architecture and general arrangement, have been re-grouped in the so-called “first design loop”. The second phase concerns the development of new modules to be integrated in the optimization tools in order to satisfy the requirements defined in the first phase. The final phase will be the application of the new (improved) optimization tools for the final LNG product. We highlight that the main target will be the multi-objective structural optimization of the prototype defined by “the first design loop”. However, some feed-back concerning the naval architecture point of view could be expected in this phase. The aim of the paper is to present the results of the first phase, as well as an overview of the analyses carried out during the “first design loop”. Details about the different methodologies proposed for the second phase of the development are given.
Download Paper
Development of a New Innovative Concept of Ropax Ship
Abstract: This paper relates to the development of a new innovative concept of RoPax ship at the IT environment of ULJANIK Shipyard, Pula, CROATIA. This work is performed within the framework of the EU FP6 IMPROVE project and includes two levels of concept design: general and structural. The primary design focus is the general ship design preformed by ULJANIK cascade of various design oriented analyses tools for the first design loop (resistance/stability/operability). Comparisons of selected design variants are given, including large savings due to novel propulsion concept. Second part of the paper briefly presents the design methodology necessary to perform extensive multi-objective structural optimization of RoPax structure using the extended OCTOPUS-MAESTRO software. It performs multi-objective optimization, (minimum cost/minimum weight/maximum safety measures/etc.) while satisfying structural constraints: yielding, buckling, displacements and ultimate strength of hull girder and ship panels.
Download Paper
Structural Omni-Optimization of a Tanker
Abstract: Omni-optimization assumes a capability to perform several types of optimization, e.g. single- and multi-objective, using the same optimization algorithm, or the omni-optimizer. Here we consider omni-optimization to investigate the capabilities of a proposed structural arrangement of a 40 000 DWT chemical tanker. The interest is to gain more knowledge about the capabilities of this arrangement and optimize it for reduction in weight and increase in safety. Omni-optimization is performed with a simple genetic algorithm though the re-formulated ‘vectorized’ structural optimization problem. The overall process is managed through Matlab where also the structural response and strength calculations are performed.
Download Paper
