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Optimisation Methodology Applied to Ship Design Amrane, Amirouche ; Bayatfar, Abbas ; Rigo, Philippe in Practical Design of Ships and Other Floating Structures, CECO 20-25 October 2013 (2013, October) 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 ... [more ▼] 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 and needs a big amount of manual work. This paper presents an innovative optimization workflow by which the following steps are automatically carried out, 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, loaded and solved. The obtained results (stress, 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 ▲] Detailed reference viewed: 61 (3 ULg)ASSESSMENT OF FATIGUE RELIABILITY FOR JACKET-TYPE OFFSHORE PLATFORMS CONSIDERING DYNAMIC BEHAVOIR ; Rigo, Philippe ; Amrane, Amirouche et al in Proceedings of the ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering OMAE 2013 (2013, June) In order to traditionally investigate the strength of marine structures, the structure is subjected to a maximum static load. However, the marine structures are usually suffering environmental forces ... [more ▼] In order to traditionally investigate the strength of marine structures, the structure is subjected to a maximum static load. However, the marine structures are usually suffering environmental forces varying with time. Wave forces are the most important time dependent loading that causes fatigue in structural elements and joints. In this paper different methods base on S-N curve and linear elastic failure mechanics are presented. The governing equations and theories that are used in each method are expressed and the application of each method will be discussed. The two main methods of deterministic analyses are: stressbased approach (S-N curve approach) and linear elastic fracture mechanics (LEFM) approaches. These approaches are applicable to different analyzing strategies, ie the first approach is used for cases in which general form of fatigue is dominant, but the latter involves the calculations of reliability as functions of crack geometry and its boundary conditions. The SPD12C jacket platform is also modeled as a case study and the results of fatigue reliability analysis are presented. In this paper a comprehensive method is presented to accurately predict the reliability of offshore platforms. This method is based on S-N curve and the results are compared with the fatigue life of joints. Due to nonlinear interaction of soil and piles and the other affecting parameters such as flexibility of joints, non Gaussian procedure of loading, and nonlinearity of reaction force, the precise analyzing of stress levels will be impossible and a complex numerical analysis could only give limited information about the statistical properties of stress. In order to perform the fatigue analysis and predicting the cycles of stress SACS was used which is known as a powerful software in designing and analyzing offshore structures. In this paper the whole structure was modeled subjected to different forces such as wave and sea currents. The effects of parameters such as marine growth and interaction of soil and piles are also included. The latter is shown to have a significant effect on determination of fatigue life of the platform. [less ▲] Detailed reference viewed: 109 (11 ULg)An Optimisation Methodology for Ship Structural Design using CAD/FEM Integration Amrane, Amirouche ; Bayatfar, Abbas ; Rigo, Philippe in 12th International Conference on Computer and IT Applications in the Maritime Industries, COMPIT’13, Cortona 15-17 April 2013 (2013, April) In ship structural design, scantling optimisation using mathematical algorithms is not yet largely implemented in industry. Optimisation with mathematical algorithms can be very helpful to find the best ... [more ▼] In ship structural design, scantling optimisation using mathematical algorithms is not yet largely implemented in industry. Optimisation with mathematical algorithms can be very helpful to find the best solution (minimum weight, minimum cost, maximum inertia,etc.). 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 optimisation 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 optimiser. The optimiser 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 ▲] Detailed reference viewed: 63 (4 ULg)Ship Structure Optimization Using CAD/FEM Integration Amrane, Amirouche ; Caprace, Jean-David ; Rigo, Philippe 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 ▲] Detailed reference viewed: 163 (21 ULg)Task 4.0 – Subsystem Optimization of the Structure Scantling Rigo, Philippe ; Yerna, Olivier ; Amrane, Amirouche 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 ▲] Detailed reference viewed: 57 (5 ULg)Projet HLC-AIMS- Rapport technique annuel n°1 Rigo, Philippe ; Amrane, Amirouche Report (2011) Le potentiel de l’éolien offshore est énorme en comparaison à l’éolien terrestre où le manque de place réduit fortement les potentialités. Ainsi, bon nombre d’éoliennes offshore fixes de type monopile ont ... [more ▼] Le potentiel de l’éolien offshore est énorme en comparaison à l’éolien terrestre où le manque de place réduit fortement les potentialités. Ainsi, bon nombre d’éoliennes offshore fixes de type monopile ont été installées au cours de ces dernières années et plusieurs projets d’éoliennes flottantes sont aujourd’hui à l’étude. En raison du coût de construction élevé des éoliennes offshore, le développement à grande échelle est nécessaire. Cependant, ces ouvrages étant difficiles d’accès, leur coût d’entretien est également conséquent. Un système de gestion en temps réel des parcs éoliens implantés en mer ainsi qu’une stratégie de maintenance adaptée et rapide deviendront donc rapidement indispensables. C’est dans ce cadre que s’inscrit le projet HLC-AIMS. Le présent document constitue le rapport technique annuel n°1 du projet HLC-AIMS pour la période s’étalant du 1ier mai 2010 au 30 avril 2011. [less ▲] Detailed reference viewed: 37 (4 ULg)Scantling Optimization of Ship Structures Considering Fatigue at the Early Design Stage Amrane, Amirouche ; Rigo, Philippe in Advances in Marine Structures - Proceedings of the 3rd International Conference on Marine Structures, MARSTRUCT 2011 (2011, March) ABSTRACT: Fatigue aspects are leading criterion for the scantling optimization of ships structures. LBR-5 software is an integrated package which performs, at the early design stage, cost and/or weight ... [more ▼] ABSTRACT: Fatigue aspects are leading criterion for the scantling optimization of ships structures. LBR-5 software is an integrated package which performs, at the early design stage, cost and/or weight optimization of ships structures (scantling). This software takes into account structural constraints (yielding, buckling, displacement, ultimate strength). Until now, the fatigue failure issue was not implicitly included in the optimization loop. At the early design stage, limited information and details are available. Therefore simplified methods have to be applied. LBR-5 software provides the nominal stress, so chosen procedure uses the nominal stress and the Miner’s rule. This approach requires a library of stress concentration factors for predefined typical structural details. The goal of the present work is to develop a tool for fatigue assessment that can be integrated on LBR5 optimization process, to realize global optimization taking into account the fatigue issues. Until now, the integration of the fatigue tool is not finished. Only fatigue verification on the optimized structure is possible. On the present paper, the procedure adopted is presented and a longitudinal scantling of the mid-ship section of a LNG is optimized with LBR-5. Production cost is considered as objective functions. The optimized scantling is checked by the fatigue tool. The fatigue criterion is not respected on some panels. Corrections are performed on these panels to have an optimized scantling without fatigue problems. [less ▲] Detailed reference viewed: 79 (2 ULg)Objective Function & Selection of Constraints (WP2 and WP3) Rigo, Philippe ; Amrane, Amirouche ; YERNA, Cindy Report (2011) The aim of this report is to present, define and explain the objective function used in the optimization process of the trimaran regarding some specific constraints. Therefore, Tasks 2.0(selection of ... [more ▼] The aim of this report is to present, define and explain the objective function used in the optimization process of the trimaran regarding some specific constraints. Therefore, Tasks 2.0(selection of constraints) and 3.0 (defining objective functions) are resumed herein. [less ▲] Detailed reference viewed: 17 (0 ULg)Rapport 2010- Windsteel : développement de solutions en acier pour la construction éolienne Rigo, Philippe ; Amrane, Amirouche ; Report (2010) Un logiciel appelé EOL-OS a été développé dans le cadre des WP4 et 5 du projet « Windsteel : développement de solutions en acier pour la construction éolienne ». Cet outil informatique est essentiellement ... [more ▼] Un logiciel appelé EOL-OS a été développé dans le cadre des WP4 et 5 du projet « Windsteel : développement de solutions en acier pour la construction éolienne ». Cet outil informatique est essentiellement destiné au dimensionnement et à l’optimisation structurelle des éoliennes offshores de type monopile en acier. Toutefois, lors des développements effectués dans le courant du second semestre de l’année 2010, son application aux éoliennes onshore en acier a été rendue également possible. Ce document s’inscrit dans la continuité du rapport technique semestriel S1 de 2010. Il est laissé au lecteur le soin de se référer à ce dernier pour ce qui concerne la nomenclature utilisée pour décrire les structures étudiées ainsi que le détail des modules implémentés au terme des 6 premiers mois de 2010. La première partie du présent rapport concerne les développements effectués sur le logiciel EOL-OS et se focalise en particulier sur les modules implémentés dans le courant du semestre S2 de 2010. La seconde partie traite des résultats d’optimisation obtenus au terme des différentes simulations et tirent des conclusions générales sur le dimensionnement des structures support des éoliennes. [less ▲] Detailed reference viewed: 36 (4 ULg)Advance Methods for Early Structural Assessment (WP7 - BESST Projet - FP7) Rigo, Philippe ; Amrane, Amirouche Report (2010) Optimisation software was chosen and the optimisation workflow was created. The capabilities of the CAD, FEM and optimisation software were investigated. The development of idealisation rules for the CAD ... [more ▼] Optimisation software was chosen and the optimisation workflow was created. The capabilities of the CAD, FEM and optimisation software were investigated. The development of idealisation rules for the CAD software was started [less ▲] Detailed reference viewed: 14 (0 ULg)Tools for early design stage: presentation of LBR-5 Software Rigo, Philippe ; Bair, Frédéric ; Caprace, Jean-David et al in Zanic, Vedran; Andric, Jerolim (Eds.) Proceedings of IMPROVE Final Workshop (2009, September) LBR-5 is a tool for early design stage. Taking into account numerous kinds of constraints – structural, geometrical, etc. – an optimum scantling can quickly been found. In the framework of IMPROVE ... [more ▼] LBR-5 is a tool for early design stage. Taking into account numerous kinds of constraints – structural, geometrical, etc. – an optimum scantling can quickly been found. In the framework of IMPROVE European project many new modules have been implemented to increase the quality of the optimised scantling. Mainly 6 major changes have been brought: implementation of a sloshing module, a fatigue module, a multi-structure module, a multi-materials module, a life cycle cost module and finally a vibration module. Tests to validate these modules have been carried out on the three ships studied in the IMPROVE project: a LNG, a Chemical Tanker and a ROPAX. [less ▲] Detailed reference viewed: 167 (16 ULg)LNG carrier- Structural design aspects Amrane, Amirouche ; ; Bair, Frédéric et al in IMPROVE Workshop (EU Project FP6 n°031382), DUBROVNIK 17-18 Sept. 2009, Croatia, Editor V. Zanic – Univ. of Zagreb, pp90-95 (Vol I) (2009, September) Detailed reference viewed: 75 (9 ULg)New and Updated Modules to Performed Stress and Strength Analysis ; ; et al in IMPROVE Workshop (EU Project FP6 n°031382), DUBROVNIK 17-18 Sept. 2009, Croatia (2009, September) Report about IMPROVE FP6 EU project Detailed reference viewed: 43 (2 ULg)Optimization or Rolling and Floating Lock Gates Rigo, Philippe ; Pircalabu, Eugen ; Amrane, Amirouche et al in PIANC'08 (2008, June) This paper presents a methodology to minimize the weight of the gate by optimizing simultaneously the height of the floating tanks, the number of their watertight partitions and the gate scantling while ... [more ▼] This paper presents a methodology to minimize the weight of the gate by optimizing simultaneously the height of the floating tanks, the number of their watertight partitions and the gate scantling while considering the floating stability (Richir et al. 2006) The rolling gate, considered for this lock, has to float to be led into the port for maintenance or repairing operations. Two partitioned floating tanks are used inside the gate. Water ballast can be pumped from the floating tanks to float the structure or to restore the mass equilibrium in case of damage due to boat impact. [less ▲] Detailed reference viewed: 120 (14 ULg)Structural Optimization of a 220 000 m³ LNG Carrier ; ; et al in Conference on Computer Applications and Information Technology in the Maritime Industries (COMPIT) (2008, April) 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 ... [more ▼] 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. [less ▲] Detailed reference viewed: 240 (34 ULg)Estimation of Welding Distortions and Straightening Workload Through a Data Mining Analysis Losseau, Nicolas ; Caprace, Jean-David ; et al in Design, Fabrication and Economy of Welded Structures (DFE) (2008, April) This paper will present a way to minimize cost in shipbuilding industry by using the results of a data mining analysis aiming to improve the cost knowledge of the straightening process. This statistical ... [more ▼] This paper will present a way to minimize cost in shipbuilding industry by using the results of a data mining analysis aiming to improve the cost knowledge of the straightening process. This statistical analysis was based on production data from a shipyard and has the scope to establish an assessment formula of the straightening workload. An intermediate step of the analysis was to estimate the welding distortions appearing in stiffened panels. Those generated formulae are useful to improve the research in the following domains: production simulation, cost assessment of ship hull, structure optimization, design for production, etc. [less ▲] Detailed reference viewed: 132 (9 ULg)IMPROVE - Design of Improved and Competitive Products using an Integrated Decision Support System for Ship Production and Operation Rigo, Philippe ; ; et al in COMPIT’2008, Edit. Rigo-Bertram, Univ. of Liege, Belgium, ISBN-10 2-9600785-0-0 (2008) Detailed reference viewed: 33 (1 ULg) |
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