Pub Date : 2018-12-31DOI: 10.35219/ANNUGALSHIPBUILDING.2018.41.10
Ş. Florescu, Geoecology, D. Bîrsan, D. Mihailescu, C. Mocanu
The thermal field has a major influence during the welding process. The heat transfer resulting from welding has an influence on the metallurgical and mechanical properties of steels and welded joints. The most affected regions are: fusion zone (FZ) and heat affected zone (HAZ) due to high temperatures to structural transformations of welded joints. The research is based on the theoretical investigations on high-temperature welding areas through MAG-M mechanized butt welding with solid wire of the naval high strength steel, EH 36. For theoretical research, a model with 3D finite elements was used. For the welded joint, the filler technique was used, which means the filler material is modelled with finite elements. The finite elements are activated when the heat flow passes through
{"title":"Researches on the thermal fields analysis at MAG-M mechanized butt welding with solid wire","authors":"Ş. Florescu, Geoecology, D. Bîrsan, D. Mihailescu, C. Mocanu","doi":"10.35219/ANNUGALSHIPBUILDING.2018.41.10","DOIUrl":"https://doi.org/10.35219/ANNUGALSHIPBUILDING.2018.41.10","url":null,"abstract":"The thermal field has a major influence during the welding process. The heat transfer resulting from welding has an influence on the metallurgical and mechanical properties of steels and welded joints. The most affected regions are: fusion zone (FZ) and heat affected zone (HAZ) due to high temperatures to structural transformations of welded joints. The research is based on the theoretical investigations on high-temperature welding areas through MAG-M mechanized butt welding with solid wire of the naval high strength steel, EH 36. For theoretical research, a model with 3D finite elements was used. For the welded joint, the filler technique was used, which means the filler material is modelled with finite elements. The finite elements are activated when the heat flow passes through","PeriodicalId":33188,"journal":{"name":"Annals of Dunarea de Jos University of Galati Fascicle XI Shipbuilding","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69959420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-31DOI: 10.35219/ANNUGALSHIPBUILDING.2018.41.19
Gabriel Constantin, M. Amorăriței, Dunărea de Jos
As a technical measure to control CO2 emissions from ships, the International Maritime Organization (IMO) has developed the Energy Efficiency Design Index (EEDI). IMO takes into consideration the technical development of all the components that influence CO2 emissions, to achieve a minimum level of energy efficiency per capacity mile for new ships. The paper is focused on Energy Efficiency Design Index calculation for two container ships: 800 TEU and 1805 TEU and analysis of EEDI requirements influence on propulsion performances. Ships propulsion systems have been designed: three main engines have been selected for each ship and the propellers have been redesigned to consume delivered power. To achieve an EEDI within standards, a balance of performances is needed between: ship capacity, power, speed, minimum fuel consumption and the smallest amount of gas emitted into the atmosphere.
{"title":"Analysis of the energy efficiency design index for two container ships and EEDI influence on propulsion performances","authors":"Gabriel Constantin, M. Amorăriței, Dunărea de Jos","doi":"10.35219/ANNUGALSHIPBUILDING.2018.41.19","DOIUrl":"https://doi.org/10.35219/ANNUGALSHIPBUILDING.2018.41.19","url":null,"abstract":"As a technical measure to control CO2 emissions from ships, the International Maritime Organization (IMO) has developed the Energy Efficiency Design Index (EEDI). IMO takes into consideration the technical development of all the components that influence CO2 emissions, to achieve a minimum level of energy efficiency per capacity mile for new ships. The paper is focused on Energy Efficiency Design Index calculation for two container ships: 800 TEU and 1805 TEU and analysis of EEDI requirements influence on propulsion performances. Ships propulsion systems have been designed: three main engines have been selected for each ship and the propellers have been redesigned to consume delivered power. To achieve an EEDI within standards, a balance of performances is needed between: ship capacity, power, speed, minimum fuel consumption and the smallest amount of gas emitted into the atmosphere.","PeriodicalId":33188,"journal":{"name":"Annals of Dunarea de Jos University of Galati Fascicle XI Shipbuilding","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69959522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-31DOI: 10.35219/ANNUGALSHIPBUILDING.2018.41.12
Anişoara-Gabriela Cristea, Dunărea de Jos
This paper presents the determination of deformations and of indirect stress in the double hull panel by FEM in a container ship of 3451 TEU. The idea of FEM consists in modeling the field studied through a set of finite-size elements, connected to each other in a number of nodal points in which solution is searched. The relationship between generalized displacements and generalized forces of an element is made through the stiffness ma-trix, usually obtained on the Ritz or Galerkin methods. To be more certain about the results obtained from the analysis, a more complex structure has been built that gives a more accurate construction of the ship.Following the comparisons made between the analyzes of the two structures, the results are recorded in a chart where one can easily see the differences and similarities between the two results.
{"title":"Determination of deformations and of indirect stress in the double hull panel by FEM in a container ship of 3451 TEU","authors":"Anişoara-Gabriela Cristea, Dunărea de Jos","doi":"10.35219/ANNUGALSHIPBUILDING.2018.41.12","DOIUrl":"https://doi.org/10.35219/ANNUGALSHIPBUILDING.2018.41.12","url":null,"abstract":"This paper presents the determination of deformations and of indirect stress in the double hull panel by FEM in a container ship of 3451 TEU. The idea of FEM consists in modeling the field studied through a set of finite-size elements, connected to each other in a number of nodal points in which solution is searched. The relationship between generalized displacements and generalized forces of an element is made through the stiffness ma-trix, usually obtained on the Ritz or Galerkin methods. To be more certain about the results obtained from the analysis, a more complex structure has been built that gives a more accurate construction of the ship.Following the comparisons made between the analyzes of the two structures, the results are recorded in a chart where one can easily see the differences and similarities between the two results.","PeriodicalId":33188,"journal":{"name":"Annals of Dunarea de Jos University of Galati Fascicle XI Shipbuilding","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69959549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-31DOI: 10.35219/ANNUGALSHIPBUILDING.2018.41.13
Anişoara-Gabriela Cristea, Dunărea de Jos
This paper shows the effects of variable stresses acting on structures, the positioning modes of stress raisers, as well as the determination of stress concentration factor and the establishment of some cracking scenarios in order to determine the main characteristics of the crack. The problem of numerical analysis of various engineering problems is not new; it has been used over the centuries. A classification of numerical modeling methods can be done mathematically in 3 main directions: finite difference method, finite element method and method of border elements. The structural analysis has the following stages: determining the type of analysis, modeling the structure and of the boundary conditions, the actual analysis. The area taken into consideration was the structure of the double bottom, which is composed of the following elements, namely: the floor to the bottom floor of the double bottom, lateral support, and bottom longitudinal to double bottom longitudinal. The numerical analyses were performed using the program SolidWorks Cosmos/M of the cumulative damage factor. In most cases the structures made of composite materials are complex structures due to the material and in most cases they must be verified in terms of the endurance strength.
{"title":"Stress concentrators positioning modes and determination of the stress concentration factor using FEM. Establishing cracking scenarios to determine the characteristics of the crack","authors":"Anişoara-Gabriela Cristea, Dunărea de Jos","doi":"10.35219/ANNUGALSHIPBUILDING.2018.41.13","DOIUrl":"https://doi.org/10.35219/ANNUGALSHIPBUILDING.2018.41.13","url":null,"abstract":"This paper shows the effects of variable stresses acting on structures, the positioning modes of stress raisers, as well as the determination of stress concentration factor and the establishment of some cracking scenarios in order to determine the main characteristics of the crack. The problem of numerical analysis of various engineering problems is not new; it has been used over the centuries. A classification of numerical modeling methods can be done mathematically in 3 main directions: finite difference method, finite element method and method of border elements. The structural analysis has the following stages: determining the type of analysis, modeling the structure and of the boundary conditions, the actual analysis. The area taken into consideration was the structure of the double bottom, which is composed of the following elements, namely: the floor to the bottom floor of the double bottom, lateral support, and bottom longitudinal to double bottom longitudinal. The numerical analyses were performed using the program SolidWorks Cosmos/M of the cumulative damage factor. In most cases the structures made of composite materials are complex structures due to the material and in most cases they must be verified in terms of the endurance strength.","PeriodicalId":33188,"journal":{"name":"Annals of Dunarea de Jos University of Galati Fascicle XI Shipbuilding","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69959620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-28DOI: 10.35219/ANNUGALSHIPBUILDING.2018.41.08
A. Maimon
The main purpose of this article is to point out the actual progress on offshore wind turbine projects by stressing their differences of construction in all their main parts: turbines, floats, mooring and foundations systems and the installation characteristics. Floating offshore wind turbines offer great savings in terms of installation: the float-turbine assembly can be done in basin or dock, regardless of weather conditions, the towing to the site is done by simple offshore tugs, the anchorage of the wind turbine requires the help of anchor hoisting vessels, very common in the offshore oil and the anchorage is done quickly by comparison to the installation of a conventional offshore wind turbine that requires many specialized vessels, type heavy haulage carrier for foundations and jack-up vessels for the installation of the turbine.
{"title":"Brief review about floating offshore wind turbines projects","authors":"A. Maimon","doi":"10.35219/ANNUGALSHIPBUILDING.2018.41.08","DOIUrl":"https://doi.org/10.35219/ANNUGALSHIPBUILDING.2018.41.08","url":null,"abstract":"The main purpose of this article is to point out the actual progress on offshore wind turbine projects by stressing their differences of construction in all their main parts: turbines, floats, mooring and foundations systems and the installation characteristics. Floating offshore wind turbines offer great savings in terms of installation: the float-turbine assembly can be done in basin or dock, regardless of weather conditions, the towing to the site is done by simple offshore tugs, the anchorage of the wind turbine requires the help of anchor hoisting vessels, very common in the offshore oil and the anchorage is done quickly by comparison to the installation of a conventional offshore wind turbine that requires many specialized vessels, type heavy haulage carrier for foundations and jack-up vessels for the installation of the turbine.","PeriodicalId":33188,"journal":{"name":"Annals of Dunarea de Jos University of Galati Fascicle XI Shipbuilding","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69959027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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