Pub Date : 2020-05-01DOI: 10.5957/jspd.2020.36.2.152
Cüneyt Ezgi, Sinem Bayrak
Decreasing industrial energy sources and major environmental problems caused by uncontrolled energy consumption have led to studies on alternative energy sources. This study presents a design and experimental analysis of an exhaust gas-driven absorption refrigeration system for the purpose of air conditioning by using the exhaust heat of a diesel engine, which is installed in the Naval Academy Mechanics Laboratory. The diesel engine is loaded with a dynamometer, and water and ammonia are used as an absorbent and refrigerant, respectively. At various diesel engine loads, cooling capacity and coefficient of performance (COP) of the absorption refrigeration system are calculated. Experimental results have indicated the cooling capacity as 1.098 kW at a maximum engine power of 4.9 HP. The highest COP value in the designed system has been calculated to be .3022 for the generator temperature of 160 C. Although the COP of refrigeration is low, the absorption refrigeration system can be provided a great cooling load from the exhaust heat of diesel engines and can be used in naval surface ships. In addition to energy efficiency of naval surface ships, infrared and acoustic signature can be minimized and a ships susceptibility can be dramatically reduced.
{"title":"Experimental Analysis of a Laboratory-Scale Diesel Engine Exhaust Heat-Driven Absorption Refrigeration System as a Model for Naval Surface Ship Applications","authors":"Cüneyt Ezgi, Sinem Bayrak","doi":"10.5957/jspd.2020.36.2.152","DOIUrl":"https://doi.org/10.5957/jspd.2020.36.2.152","url":null,"abstract":"Decreasing industrial energy sources and major environmental problems caused by uncontrolled energy consumption have led to studies on alternative energy sources. This study presents a design and experimental analysis of an exhaust gas-driven absorption refrigeration system for the purpose of air conditioning by using the exhaust heat of a diesel engine, which is installed in the Naval Academy Mechanics Laboratory. The diesel engine is loaded with a dynamometer, and water and ammonia are used as an absorbent and refrigerant, respectively. At various diesel engine loads, cooling capacity and coefficient of performance (COP) of the absorption refrigeration system are calculated. Experimental results have indicated the cooling capacity as 1.098 kW at a maximum engine power of 4.9 HP. The highest COP value in the designed system has been calculated to be .3022 for the generator temperature of 160 C. Although the COP of refrigeration is low, the absorption refrigeration system can be provided a great cooling load from the exhaust heat of diesel engines and can be used in naval surface ships. In addition to energy efficiency of naval surface ships, infrared and acoustic signature can be minimized and a ships susceptibility can be dramatically reduced.","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46657949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A point set analysis method considering the practical engineering constraints has been proposed in this article. First, the coherent point drift method was used to obtain the initial values of data analysis. Second, the error distribution in different directions was expressed by weight vectors. Last, the multiobjective optimization model was built and the engineering constrains were introduced into the multioptimization objective function to achieve the optimal data analysis results. The experimental results proved that the method could obtain the reasonable data analysis results, which met the engineering constraints. It provides the important basis for the subsequent assembly.
{"title":"A Point Set Analysis Method for Hull Blocks Based on CPD and Engineering Constraints","authors":"Guan Guan, Hongling Liao","doi":"10.5957/JSPD.09170043","DOIUrl":"https://doi.org/10.5957/JSPD.09170043","url":null,"abstract":"A point set analysis method considering the practical engineering constraints has been proposed in this article. First, the coherent point drift method was used to obtain the initial values of data analysis. Second, the error distribution in different directions was expressed by weight vectors. Last, the multiobjective optimization model was built and the engineering constrains were introduced into the multioptimization objective function to achieve the optimal data analysis results. The experimental results proved that the method could obtain the reasonable data analysis results, which met the engineering constraints. It provides the important basis for the subsequent assembly.","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42912101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The recent increase in vessel shaftline bearing incidents indicates that a static shaft alignment design may not be suitable for all operational shaftline loading conditions. Hull deflections caused by vessel loading or propeller loads initiated by interaction with the wakefield have become important considerations in modern vessel design. Jack-up tests, typically used as a bearing load verification method, can only be accomplished under static shaft conditions and cannot verify the shaft dynamic behavior under running operational conditions. A newly developed sensor using strain gauge technology measures the bearing load and the shaft misalignment angle through the bearing housing's deformation-induced strain. It effectively converts the bearing housing into a weighing machine by mapping the bearing housing strain onto the bearing load. Unlike jack-up tests, this method allows for the continuous measurement of the bearing load and misalignment angle under all shaftline operational conditions. It is envisaged that this technologically simple system will allow for the earliest possible diagnosis of shaft alignment-related problems, such as bearing unloading, bearing overloading, or excessive shaft-bearing misalignment. This provides a much earlier warning indicator when compared with the bearing temperature alarm. The subject technology has been tested on intermediate bearings and is considered for future application into stern tube bearings. In post-IMO's (International Maritime Organization) Energy Efficiency Design Index vessel designs, the propulsion shafting arrangements become increasingly sensitive to shaft alignment with lower tolerances and margins, increasing the risk of stern tube bearing failures (Leontopoulos 2016a). This change is due to the wider use of more efficient, larger diameter propellers with increased cantilevered load on the shafting system and shorter shaftlines as a result of maximizing cargo space and minimizing engine room length. Widespread application of the single stern tube bearing design (an arrangement without a forward stern tube bearing) has also highlighted a decreased tolerance to eccentric propeller thrust and propeller forces in general. Reduced tolerance to shaft alignment sighting errors, bearing offset inaccuracies and other shaft installation errors, also affects the integrity of the shafting system and can result in complete bearing wiping with the consequence of vessel propulsion immobilization. This undesirable consequence has increased, particularly during the years 2013–2017.
{"title":"Smart Bearing Sensor","authors":"C. Leontopoulos, C. Mouzakis, Michail Petrolekas","doi":"10.5957/JSPD.11180046","DOIUrl":"https://doi.org/10.5957/JSPD.11180046","url":null,"abstract":"The recent increase in vessel shaftline bearing incidents indicates that a static shaft alignment design may not be suitable for all operational shaftline loading conditions. Hull deflections caused by vessel loading or propeller loads initiated by interaction with the wakefield have become important considerations in modern vessel design. Jack-up tests, typically used as a bearing load verification method, can only be accomplished under static shaft conditions and cannot verify the shaft dynamic behavior under running operational conditions. A newly developed sensor using strain gauge technology measures the bearing load and the shaft misalignment angle through the bearing housing's deformation-induced strain. It effectively converts the bearing housing into a weighing machine by mapping the bearing housing strain onto the bearing load. Unlike jack-up tests, this method allows for the continuous measurement of the bearing load and misalignment angle under all shaftline operational conditions. It is envisaged that this technologically simple system will allow for the earliest possible diagnosis of shaft alignment-related problems, such as bearing unloading, bearing overloading, or excessive shaft-bearing misalignment. This provides a much earlier warning indicator when compared with the bearing temperature alarm. The subject technology has been tested on intermediate bearings and is considered for future application into stern tube bearings.\u0000 \u0000 \u0000 In post-IMO's (International Maritime Organization) Energy Efficiency Design Index vessel designs, the propulsion shafting arrangements become increasingly sensitive to shaft alignment with lower tolerances and margins, increasing the risk of stern tube bearing failures (Leontopoulos 2016a). This change is due to the wider use of more efficient, larger diameter propellers with increased cantilevered load on the shafting system and shorter shaftlines as a result of maximizing cargo space and minimizing engine room length. Widespread application of the single stern tube bearing design (an arrangement without a forward stern tube bearing) has also highlighted a decreased tolerance to eccentric propeller thrust and propeller forces in general. Reduced tolerance to shaft alignment sighting errors, bearing offset inaccuracies and other shaft installation errors, also affects the integrity of the shafting system and can result in complete bearing wiping with the consequence of vessel propulsion immobilization. This undesirable consequence has increased, particularly during the years 2013–2017.\u0000","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45096238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shaji Krishna Prasad, A. Mathiazhagan, Pallichakkalayil Sasidharan Krishnadas
The study compared the effects of manual activated tungsten inert gas (A-TIG) welding and automated A-TIG welding on AISI (American Iron and Steel Institute)- 304 at three different values of current using commercially available powders of Al2O3, SiO2, Fe2O3, MgCl2, and TiO2 separately as activated flux and distilled water as carrier solvent. The effect of fluxes on the depth of penetration of the weldments, width of weldment, microstructure of the weldment, and microhardness of the weldment was investigated. Reverse Marangoni convection and arc constriction are found to be more effective in A-TIG manual welding, as aspect ratio obtained by A-TIG manual welding is greater as than that of automatic A-TIG welding. Microstructure of both the manual and automatic A-TIG-welded specimen is similar with no noticeable differences and almost same amount of intermetallic phases and carbon precipitates. Microhardness tests revealed that for Al2O3 and TiO2 fluxes, manual A-TIG-welded specimen have lower values of microhardness at weldment, heat-affected zone, and base metal than automated A-TIG-welded specimen. The aim of the study is to implement the manual A-TIG process in shipbuilding industry to improve the productivity of welding as automated A-TIG welding in the industry has limitations.
采用市售Al2O3、SiO2、Fe2O3、MgCl2和TiO2粉末分别作为活化助焊剂，蒸馏水作为载体溶剂，比较了在三种不同电流值下，手工活化钨惰性气体(A-TIG)焊接和自动A-TIG焊接对AISI (American Iron and Steel Institute)- 304的焊接效果。研究了焊剂对焊件渗深、焊件宽度、焊件显微组织和焊件显微硬度的影响。反向Marangoni对流和电弧收缩在A-TIG手工焊接中更为有效，因为A-TIG手工焊接获得的长径比大于A-TIG自动焊接。手工焊和自动焊试样的显微组织相似，无明显差异，金属间相和碳析出量几乎相同。显微硬度测试结果表明，对于Al2O3和TiO2助焊剂，手工a - tig焊接试样在焊件、热影响区和母材处的显微硬度值均低于自动a - tig焊接试样。研究的目的是在船舶工业中实施人工A-TIG工艺，以提高焊接的生产率，因为自动化A-TIG焊接在行业中存在局限性。
{"title":"Effect of Manual and Automatic Activated Tungsten Inert Gas Welding Using Single Component Fluxes on Stainless Steel AISI-304","authors":"Shaji Krishna Prasad, A. Mathiazhagan, Pallichakkalayil Sasidharan Krishnadas","doi":"10.5957/JSPD.11180041","DOIUrl":"https://doi.org/10.5957/JSPD.11180041","url":null,"abstract":"The study compared the effects of manual activated tungsten inert gas (A-TIG) welding and automated A-TIG welding on AISI (American Iron and Steel Institute)- 304 at three different values of current using commercially available powders of Al2O3, SiO2, Fe2O3, MgCl2, and TiO2 separately as activated flux and distilled water as carrier solvent. The effect of fluxes on the depth of penetration of the weldments, width of weldment, microstructure of the weldment, and microhardness of the weldment was investigated. Reverse Marangoni convection and arc constriction are found to be more effective in A-TIG manual welding, as aspect ratio obtained by A-TIG manual welding is greater as than that of automatic A-TIG welding. Microstructure of both the manual and automatic A-TIG-welded specimen is similar with no noticeable differences and almost same amount of intermetallic phases and carbon precipitates. Microhardness tests revealed that for Al2O3 and TiO2 fluxes, manual A-TIG-welded specimen have lower values of microhardness at weldment, heat-affected zone, and base metal than automated A-TIG-welded specimen. The aim of the study is to implement the manual A-TIG process in shipbuilding industry to improve the productivity of welding as automated A-TIG welding in the industry has limitations.","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43897790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Cheops Boat is the most complete, largest, and one of the oldest boats ever excavated, but it has received surprisingly little study by Naval Architects. The 43-m boat was constructed around 2500 BC and placed, disassembled, in a pit next to the Great Pyramid at Giza in Egypt. Since its discovery in 1954, there has been speculation about its original design, means of propulsion, and purpose. This article presents previously unpublished results of the first tank testing of a model of the Cheops Boat and some preliminary conclusions about the design, propulsion, and function of the original. It is shown that the stability characteristics of the boat make it suited for carrying lightweight cargo and people in the protected waters of the Nile. Towing tests have shown that the boat can be safely rowed in a variety of wind and current conditions. Windward sailing calculations have shown that, if fitted with sail, then boats such as the Cheops Boat perform well downwind, but sail no closer than a beam reach. During the 1954 clearing of debris from the Giza Plateau, it was noticed that the Great Pyramid's north and west enclosure walls were 23.6m from the base of pyramid, but the south wall was 5mcloser to the base. Careful inspection revealed that the south wall had been built in an asymmetrical location to conceal two boat pits beneath it. The two pits were end to end, one covered by 41 massive limestone blocks and the other by 40. When the eastern pit was opened, the remains of the disassembled boat were revealed. Figure 1 shows photographs of some of the pieces as they were removed from the pit. Remarkably, the 4500-year-old cedar had been so well preserved that it was possible to reassemble this boat like a kit. Even the rope was preserved, and looked like what could be bought today.
{"title":"Preliminary Stability and Resistance Analysis of the Cheops Boat","authors":"M. Morabito, B. Brier, S. Greene","doi":"10.5957/JSPD.02190006","DOIUrl":"https://doi.org/10.5957/JSPD.02190006","url":null,"abstract":"The Cheops Boat is the most complete, largest, and one of the oldest boats ever excavated, but it has received surprisingly little study by Naval Architects. The 43-m boat was constructed around 2500 BC and placed, disassembled, in a pit next to the Great Pyramid at Giza in Egypt. Since its discovery in 1954, there has been speculation about its original design, means of propulsion, and purpose. This article presents previously unpublished results of the first tank testing of a model of the Cheops Boat and some preliminary conclusions about the design, propulsion, and function of the original. It is shown that the stability characteristics of the boat make it suited for carrying lightweight cargo and people in the protected waters of the Nile. Towing tests have shown that the boat can be safely rowed in a variety of wind and current conditions. Windward sailing calculations have shown that, if fitted with sail, then boats such as the Cheops Boat perform well downwind, but sail no closer than a beam reach.\u0000 During the 1954 clearing of debris from the Giza Plateau, it was noticed that the Great Pyramid's north and west enclosure walls were 23.6m from the base of pyramid, but the south wall was 5mcloser to the base. Careful inspection revealed that the south wall had been built in an asymmetrical location to conceal two boat pits beneath it. The two pits were end to end, one covered by 41 massive limestone blocks and the other by 40. When the eastern pit was opened, the remains of the disassembled boat were revealed. Figure 1 shows photographs of some of the pieces as they were removed from the pit. Remarkably, the 4500-year-old cedar had been so well preserved that it was possible to reassemble this boat like a kit. Even the rope was preserved, and looked like what could be bought today.","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48915537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reducing vertical motions of high-speed planing hulls in rough water is one of the most important factors that help a boat to become more operable, and will benefit the structure of the boat and the crew on board. In the recent decade, stepped planing hulls have been investigated with emphasis on their better performance in calm water than that of nonstepped planing hulls. However, there are still doubts about their performance in rough water. In this study, we investigate this problem by providing numerical simulations for motions of a double-stepped and a non-stepped planing hull in a vertical plane when they encounter head waves. The problem will be solved using the finite volume method and volume of fluid method. To this end, a numerical computational fluid dynamics code (STARCCM1) has been used. Accuracy of the numerical simulations is evaluated by comparing their outcome with available experimental data. The dynamic response of the investigated hulls has been numerically modeled for two different wave lengths, one of which is smaller than the boat length and the other which is larger than the boat length. Using the numerical simulations, heave and pitch motions as well as vertical acceleration are found. It has been found that at wave lengths larger than the boat length, heave amplitude decreases by 10–40%when two steps are added to the bottom of a vessel. It has also been observed that pitch of a planing hull is reduced by 18–32% in the presence of the two steps on its bottom. Finally, it has been observed that for wave lengths larger than the boat length, the maximum vertical acceleration decreases by a gravitational acceleration of about .2–.7.
{"title":"Comparison between the Dynamic Behavior of the Non-stepped and Double-stepped Planing Hulls in Rough Water: A Numerical Study","authors":"Arman Esfandiari, S. Tavakoli, A. Dashtimanesh","doi":"10.5957/JSPD.11170053","DOIUrl":"https://doi.org/10.5957/JSPD.11170053","url":null,"abstract":"Reducing vertical motions of high-speed planing hulls in rough water is one of the most important factors that help a boat to become more operable, and will benefit the structure of the boat and the crew on board. In the recent decade, stepped planing hulls have been investigated with emphasis on their better performance in calm water than that of nonstepped planing hulls. However, there are still doubts about their performance in rough water. In this study, we investigate this problem by providing numerical simulations for motions of a double-stepped and a non-stepped planing hull in a vertical plane when they encounter head waves. The problem will be solved using the finite volume method and volume of fluid method. To this end, a numerical computational fluid dynamics code (STARCCM1) has been used. Accuracy of the numerical simulations is evaluated by comparing their outcome with available experimental data. The dynamic response of the investigated hulls has been numerically modeled for two different wave lengths, one of which is smaller than the boat length and the other which is larger than the boat length. Using the numerical simulations, heave and pitch motions as well as vertical acceleration are found. It has been found that at wave lengths larger than the boat length, heave amplitude decreases by 10–40%when two steps are added to the bottom of a vessel. It has also been observed that pitch of a planing hull is reduced by 18–32% in the presence of the two steps on its bottom. Finally, it has been observed that for wave lengths larger than the boat length, the maximum vertical acceleration decreases by a gravitational acceleration of about .2–.7.","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45177069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gerardo González-Cela, R. Bellas, Rafael Carreño, Javier Martínez, Ramón Touza, A. González-Gil, M. Gomez, Diego González
The new F-110 frigates project is currently in the conceptual design and definition phase. General arrangement has to be defined; there are many demands and proposals of changes. One of them is the design of the most crowded areas, the mess halls. The aim of this article is to provide the Spanish Navy Staff with a decision tool that helps in determining the optimal distribution of the future F-110 mess halls. For this purpose, a new "analytical decision maker" model was designed providing advanced statistical methods and computer pedestrian simulations within multicriteria decision-making framework that allows optimizing conceptual designs. To reduce subjectivity, crew movement simulations and statistical methods were added to the multicriteria decision model, thus creating a less-subjective decision tool. A sensitivity analysis was conducted to check the robustness of results. An integrative decision and design approach are necessary for broad acceptance of human factors adoption within naval architecture design. Ship design is a complex challenging process that requires the successful coordination of many different disciplines and that necessarily involves trade-offs between competing interests to achieve a balanced result. Hence, ship designers need to understand the complex interaction between different design drivers and their influence on the final solution, always being aware that the cost of rework may become drastically high if errors are found in the later stages of the design.
{"title":"A Framework for Integrating Human Factors in the Early Stages of Ship Design: Application to the Mess Halls of a Surface Combatant","authors":"Gerardo González-Cela, R. Bellas, Rafael Carreño, Javier Martínez, Ramón Touza, A. González-Gil, M. Gomez, Diego González","doi":"10.5957/JSPD.02190009","DOIUrl":"https://doi.org/10.5957/JSPD.02190009","url":null,"abstract":"The new F-110 frigates project is currently in the conceptual design and definition phase. General arrangement has to be defined; there are many demands and proposals of changes. One of them is the design of the most crowded areas, the mess halls. The aim of this article is to provide the Spanish Navy Staff with a decision tool that helps in determining the optimal distribution of the future F-110 mess halls. For this purpose, a new \"analytical decision maker\" model was designed providing advanced statistical methods and computer pedestrian simulations within multicriteria decision-making framework that allows optimizing conceptual designs. To reduce subjectivity, crew movement simulations and statistical methods were added to the multicriteria decision model, thus creating a less-subjective decision tool. A sensitivity analysis was conducted to check the robustness of results. An integrative decision and design approach are necessary for broad acceptance of human factors adoption within naval architecture design.\u0000 \u0000 \u0000 \u0000 \u0000 Ship design is a complex challenging process that requires the successful coordination of many different disciplines and that necessarily involves trade-offs between competing interests to achieve a balanced result. Hence, ship designers need to understand the complex interaction between different design drivers and their influence on the final solution, always being aware that the cost of rework may become drastically high if errors are found in the later stages of the design.\u0000 \u0000","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48781169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work deals with the design of the internal layout of a shuttle tanker formulated as a multi-objective optimization problem, balancing cargo capacity and minimizing still water bending moment with safety requirements, in particular survivability after damage. A parametric model is used to specify the internal layout of a tanker ship considering a fixed hull shape and regulatory framework. The design variables include positions of watertight members in the internal layout, such as watertight bulkhead position, double-bottom height, and wing tanks width. Merit functions are the minimization of oil outflow parameter, maximization of cargo capacity, and minimization of the longitudinal bending moment, which are, respectively, represented for reduction of environmental pollution due to damaged oil tankers, improvement of economic benefits, and safety during operation. The multi-objective genetic algorithm is used for approaching the Pareto frontiers, and the choices between the optimal designs are discussed while introducing a utility function. The internal layout of the ship's hull is established in the initial stage of ship design. The size and location of the internal spaces are defined taking into consideration the type of ship and the type of content and usage of the compartments. On the other hand, survivability regulations impose limitations in the subdivision arrangement of the ship. Also, the economic competitiveness has special importance in the design of a merchant ship. Cargo capacity and building cost are some of those economic objectives that are not necessarily in accordance with the improvement of safety objectives. Thus, the design of the internal layout of the vessels can be studied as a multi-objective optimization problem targeting safety improvement after damage besides decreasing the cost functions. A diversity of internal layout designs can be investigated within an optimization framework to choose the dominating design among the feasible solutions (Nowacki 2010). However, targeting a variety of objective functions complicates the process of internal compartment design, especially when the main hull dimensions have to be kept constant (Santos & Guedes Soares 2010).
{"title":"Multi-Objective Optimization of Internal Compartment Layout of Oil Tankers","authors":"H. Jafaryeganeh, M. Ventura, C. Soares","doi":"10.5957/JSPD.09180034","DOIUrl":"https://doi.org/10.5957/JSPD.09180034","url":null,"abstract":"This work deals with the design of the internal layout of a shuttle tanker formulated as a multi-objective optimization problem, balancing cargo capacity and minimizing still water bending moment with safety requirements, in particular survivability after damage. A parametric model is used to specify the internal layout of a tanker ship considering a fixed hull shape and regulatory framework. The design variables include positions of watertight members in the internal layout, such as watertight bulkhead position, double-bottom height, and wing tanks width. Merit functions are the minimization of oil outflow parameter, maximization of cargo capacity, and minimization of the longitudinal bending moment, which are, respectively, represented for reduction of environmental pollution due to damaged oil tankers, improvement of economic benefits, and safety during operation. The multi-objective genetic algorithm is used for approaching the Pareto frontiers, and the choices between the optimal designs are discussed while introducing a utility function.\u0000 \u0000 \u0000 The internal layout of the ship's hull is established in the initial stage of ship design. The size and location of the internal spaces are defined taking into consideration the type of ship and the type of content and usage of the compartments. On the other hand, survivability regulations impose limitations in the subdivision arrangement of the ship. Also, the economic competitiveness has special importance in the design of a merchant ship. Cargo capacity and building cost are some of those economic objectives that are not necessarily in accordance with the improvement of safety objectives. Thus, the design of the internal layout of the vessels can be studied as a multi-objective optimization problem targeting safety improvement after damage besides decreasing the cost functions. A diversity of internal layout designs can be investigated within an optimization framework to choose the dominating design among the feasible solutions (Nowacki 2010). However, targeting a variety of objective functions complicates the process of internal compartment design, especially when the main hull dimensions have to be kept constant (Santos & Guedes Soares 2010).\u0000","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49061468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dong-sheng Zhao, Zhen-yu Huang, Yujun Liu, T. Miao
Hot cracking is one of the major challenges in laser welding of Invar alloy. In this study, welding hot cracking susceptibility experiments are conducted with fish-bone-type Invar alloy sheets under pulsed laser welding condition. The pulse wave consists of two distinct power levels: welding pulse and post-heating pulse. The welding temperature field can be controlled by changing the duration of the post-heating pulse. The results of experimental measurements and finite element method calculation show that increasing of the post-heating pulse duration leads to a decline in the cooling rate of weld metal within the brittle temperature range, although the welding hot cracking susceptibility decreases at first and then increases. Neither the heat input nor the cooling rate is the only decisive factor for hot cracking during the welding process. Invar alloy is widely applied in precision measurement devices and low-temperature-resistant structures for its low linear expansion coefficient at ambient temperature, which is less than 1.6 × 10—6 k—1, about 1/10 of the low carbon steel, and it changes very little within a large temperature range (Corbacho et al. 1998; Park et al. 2011; Zhao et al. 2015; Qiu et al. 2016). With the increase in demand for natural gas, the liquefied natural gas (LNG) carrier has been developed rapidly as a means of long-distance transport. The material of primary and secondary barriers on the containment insulation system of membrane-type LNG carrier is welded Invar alloy with a thickness of .7 mm, which directly contacts the — 163°C LNG (American Bureau of Shipping 2006; Bureau Veritas 2011; Wang et al. 2006). The total weld length of Invar alloy on an LNG carrier over 13 million cubic meters can reach up to 100 km according to statistics. Hot cracking is the major problem in the welding of Invar alloy, and currently Tungsten inert gas (TIG) arc welding is commonly used. However, the problem of hot cracking cannot be solved completely, and requires that the operator have good technical knowledge. Invar alloy has high hot cracking susceptibility during the welding process because of its single-phase austenite structure and high content of Ni (Kou 2003). Studies show that the welding hot cracking susceptibility of Invar alloy can be reduced when elements such as Ti, Mn, and Mo are added (Hirata et al. 2001), but these alloying elements will increase the linear expansion coefficient of the weld, resulting in the deterioration of mechanical properties at low temperature. Thus, laser welding and friction stir welding are proposed by researchers to solve the welding hot cracking problem of Invar alloy from the aspect of reducing welding heat input.
热裂是英瓦尔合金激光焊接的主要难题之一。在脉冲激光焊接条件下，对鱼骨型Invar合金薄板进行了焊接热裂敏感性试验。脉冲波由两个不同的功率级组成:焊接脉冲和后加热脉冲。通过改变后加热脉冲的持续时间，可以控制焊接温度场。实验测量和有限元计算结果表明，随着后加热脉冲持续时间的增加，焊缝金属在脆性温度范围内的冷却速率有所下降，但焊接热裂敏感性先减小后增大。在焊接过程中，热输入和冷却速度都不是热裂的唯一决定性因素。因瓦尔合金因其在常温下的低线性膨胀系数，小于1.6 × 10-6 k-1，约为低碳钢的1/10，在较大的温度范围内变化很小，被广泛应用于精密测量装置和耐低温结构中(Corbacho et al. 1998;Park et al. 2011;Zhao et al. 2015;Qiu et al. 2016)。随着天然气需求的增加，液化天然气(LNG)运输船作为一种长途运输工具得到了迅速发展。膜式LNG运输船密封保温系统的主、次屏障材料采用厚度为0.7 mm的英瓦尔合金焊接，直接接触- 163℃LNG(美国船级社2006;Bureau Veritas 2011;Wang et al. 2006)。据统计，1300多万立方米LNG运输船的因瓦尔合金焊缝总长度可达100公里。热裂是英瓦尔合金焊接中的主要问题，目前常用的是钨惰性气体(TIG)电弧焊。但热裂问题并不能完全解决，需要操作人员具备良好的技术知识。因瓦尔合金由于其单相奥氏体组织和高镍含量，在焊接过程中具有较高的热裂易感性(Kou 2003)。研究表明，添加Ti、Mn、Mo等元素可降低Invar合金的焊接热裂敏感性(Hirata et al. 2001)，但这些合金元素会增加焊缝的线膨胀系数，导致低温下力学性能恶化。因此，研究人员提出了激光焊接和搅拌摩擦焊接，从减少焊接热输入的角度解决因瓦尔合金的焊接热裂问题。
{"title":"A Study of the Effect of Post-Heating Pulse on Hot Cracking Susceptibility in Pulsed Laser Welding of Invar Alloy","authors":"Dong-sheng Zhao, Zhen-yu Huang, Yujun Liu, T. Miao","doi":"10.5957/JSPD.07170037","DOIUrl":"https://doi.org/10.5957/JSPD.07170037","url":null,"abstract":"Hot cracking is one of the major challenges in laser welding of Invar alloy. In this study, welding hot cracking susceptibility experiments are conducted with fish-bone-type Invar alloy sheets under pulsed laser welding condition. The pulse wave consists of two distinct power levels: welding pulse and post-heating pulse. The welding temperature field can be controlled by changing the duration of the post-heating pulse. The results of experimental measurements and finite element method calculation show that increasing of the post-heating pulse duration leads to a decline in the cooling rate of weld metal within the brittle temperature range, although the welding hot cracking susceptibility decreases at first and then increases. Neither the heat input nor the cooling rate is the only decisive factor for hot cracking during the welding process.\u0000 \u0000 \u0000 Invar alloy is widely applied in precision measurement devices and low-temperature-resistant structures for its low linear expansion coefficient at ambient temperature, which is less than 1.6 × 10—6 k—1, about 1/10 of the low carbon steel, and it changes very little within a large temperature range (Corbacho et al. 1998; Park et al. 2011; Zhao et al. 2015; Qiu et al. 2016). With the increase in demand for natural gas, the liquefied natural gas (LNG) carrier has been developed rapidly as a means of long-distance transport. The material of primary and secondary barriers on the containment insulation system of membrane-type LNG carrier is welded Invar alloy with a thickness of .7 mm, which directly contacts the — 163°C LNG (American Bureau of Shipping 2006; Bureau Veritas 2011; Wang et al. 2006). The total weld length of Invar alloy on an LNG carrier over 13 million cubic meters can reach up to 100 km according to statistics.\u0000 Hot cracking is the major problem in the welding of Invar alloy, and currently Tungsten inert gas (TIG) arc welding is commonly used. However, the problem of hot cracking cannot be solved completely, and requires that the operator have good technical knowledge. Invar alloy has high hot cracking susceptibility during the welding process because of its single-phase austenite structure and high content of Ni (Kou 2003). Studies show that the welding hot cracking susceptibility of Invar alloy can be reduced when elements such as Ti, Mn, and Mo are added (Hirata et al. 2001), but these alloying elements will increase the linear expansion coefficient of the weld, resulting in the deterioration of mechanical properties at low temperature. Thus, laser welding and friction stir welding are proposed by researchers to solve the welding hot cracking problem of Invar alloy from the aspect of reducing welding heat input.\u0000","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43548180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Mascaraque‐Ramírez, L. Para‐González, P. Marco-Jornet
In an increasingly globalized sector such as the naval construction sector, the search for reduction in execution terms and production costs becomes essential. With this aim, the vessel project should be analyzed globally and in conjunction with the installations in which it will be built. The present research includes a series of improvement proposals for the construction of a 78-m-long ferry, designed for the transport of 700 passengers and 590 lineal meters of cargo space. These improvements are focused on the standardization of equipment and components in the accommodation area and engine room, as well as in the general arrangement of these spaces, by orienting their design toward manufacturing. All this will lead to a series of results, which demonstrate that the correct application of these changes considerably reduces production time and, consequently, the costs associated with it. In parallel, this study analyzes the facilities of the shipyard, proposing changes in its workshops and identifying new business lines to improve the strategic situation of the organization. Historically, European shipyards have manufactured in their installations a great variety of ships, each one with a high component of technological innovation. The high quality of their products and their adaptability to custom orders from the ship owners have led the naval construction sector to be currently identified at an international level as a sector with highly differentiated products. The impact that international competition has had in the last decades, and more recently the economic crisis and the file opening by the European Commission in relation to the old system of "tax lease" applied in Europe (Curtis 2014), reduced the level of new ships construction contracting in 2011. The published registers (LR-Lloyds-Fairplay 2015) about the new ship constructions places European manufacturers far from the construction volumes of Asian manufacturers in terms of compensated gross tonnage (CGT), which is a measure of the compensated gross arching related to the gross tonnage through a compensation coefficient for each ship type and size, which considers the construction complexity based on the manufacturing work hours needed.
{"title":"Management of a Ferry Construction Project Using a Production- Oriented Design Methodology","authors":"C. Mascaraque‐Ramírez, L. Para‐González, P. Marco-Jornet","doi":"10.5957/JSPD.07180023","DOIUrl":"https://doi.org/10.5957/JSPD.07180023","url":null,"abstract":"In an increasingly globalized sector such as the naval construction sector, the search for reduction in execution terms and production costs becomes essential. With this aim, the vessel project should be analyzed globally and in conjunction with the installations in which it will be built. The present research includes a series of improvement proposals for the construction of a 78-m-long ferry, designed for the transport of 700 passengers and 590 lineal meters of cargo space. These improvements are focused on the standardization of equipment and components in the accommodation area and engine room, as well as in the general arrangement of these spaces, by orienting their design toward manufacturing. All this will lead to a series of results, which demonstrate that the correct application of these changes considerably reduces production time and, consequently, the costs associated with it. In parallel, this study analyzes the facilities of the shipyard, proposing changes in its workshops and identifying new business lines to improve the strategic situation of the organization.\u0000 \u0000 \u0000 Historically, European shipyards have manufactured in their installations a great variety of ships, each one with a high component of technological innovation. The high quality of their products and their adaptability to custom orders from the ship owners have led the naval construction sector to be currently identified at an international level as a sector with highly differentiated products.\u0000 The impact that international competition has had in the last decades, and more recently the economic crisis and the file opening by the European Commission in relation to the old system of \"tax lease\" applied in Europe (Curtis 2014), reduced the level of new ships construction contracting in 2011. The published registers (LR-Lloyds-Fairplay 2015) about the new ship constructions places European manufacturers far from the construction volumes of Asian manufacturers in terms of compensated gross tonnage (CGT), which is a measure of the compensated gross arching related to the gross tonnage through a compensation coefficient for each ship type and size, which considers the construction complexity based on the manufacturing work hours needed.\u0000","PeriodicalId":48791,"journal":{"name":"Journal of Ship Production and Design","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46059219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：