Y. Mulyadi, E. Kobayashi, N. Wakabayashi, T. Pitana, Wahyudi, E. Prasetyo
Recently, many subsea pipelines have been developed in busy port areas, including industrial ports, recreational areas, fishing areas, and other port facilities. Under busy ship traffic conditions, these subsea pipelines are likely to be exposed to the risk of damage by a dragged anchor or other dropped objects. In this paper, a model is proposed to estimate the dragged anchor accident frequency on subsea pipelines based on the concept introduced by Fujii. The proposed model is approached by estimating the number of dragged anchor candidates on subsea pipelines, Na, based on an analysis of the anchor stopping distance in a critical subsea pipeline area. The causation probability Pc is estimated using a Bayesian network method that is modified from the model of Det Norske Veritas (DNV) and Hanninen. Various factors are considered to estimate Pc, including the human factor, weather factor, technical factor, and support factor. Automatic Identification System (AIS) and Geographic Information System (GIS) data are combined to estimate the lateral probability distribution of the ship traffic around a subsea pipeline area. A case study of anchors dragging on the subsea pipeline in the Madura Strait of Indonesia is performed to demonstrate the implementation of the proposed model. The proposed model is validated by comparing the results for the estimated dragged anchor accident frequency on the subsea pipeline using the proposed model with the actual accidents recorded in the Madura Strait. The results of this validation analysis show that there is reasonable agreement.
{"title":"Estimation Method for Dragged Anchor Accident Frequency on Subsea Pipelines in Busy Port Areas","authors":"Y. Mulyadi, E. Kobayashi, N. Wakabayashi, T. Pitana, Wahyudi, E. Prasetyo","doi":"10.2534/JJASNAOE.20.173","DOIUrl":"https://doi.org/10.2534/JJASNAOE.20.173","url":null,"abstract":"Recently, many subsea pipelines have been developed in busy port areas, including industrial ports, recreational areas, fishing areas, and other port facilities. Under busy ship traffic conditions, these subsea pipelines are likely to be exposed to the risk of damage by a dragged anchor or other dropped objects. In this paper, a model is proposed to estimate the dragged anchor accident frequency on subsea pipelines based on the concept introduced by Fujii. The proposed model is approached by estimating the number of dragged anchor candidates on subsea pipelines, Na, based on an analysis of the anchor stopping distance in a critical subsea pipeline area. The causation probability Pc is estimated using a Bayesian network method that is modified from the model of Det Norske Veritas (DNV) and Hanninen. Various factors are considered to estimate Pc, including the human factor, weather factor, technical factor, and support factor. Automatic Identification System (AIS) and Geographic Information System (GIS) data are combined to estimate the lateral probability distribution of the ship traffic around a subsea pipeline area. A case study of anchors dragging on the subsea pipeline in the Madura Strait of Indonesia is performed to demonstrate the implementation of the proposed model. The proposed model is validated by comparing the results for the estimated dragged anchor accident frequency on the subsea pipeline using the proposed model with the actual accidents recorded in the Madura Strait. The results of this validation analysis show that there is reasonable agreement.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129443244","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}
In this paper, variational principles related to motions of an elastic plate in waves considering wave radiation condition at infinity, which are very important in calculations of the elastic response of the pontoon- type floating structure, are discussed. First, Sommerfeld radiation condition at infinity is extended to treat a case with an incident wave. Second, four kinds of variational principles related to motions of the elastic floating plate considering the incident and radiated waves are proposed and clarified the mutual relationship of these variational principles. Third, numerical results for elastic response of a floating plate of rectangular plan geometry in waves, which are obtained by using proposed variational principles, are shown.
{"title":"Variational Principles Related to Motions of a Floating Elastic Plate in Waves","authors":"S. Nagata, H. Isshiki, Y. Imai, K. Toyota","doi":"10.2534/JJASNAOE.17.31","DOIUrl":"https://doi.org/10.2534/JJASNAOE.17.31","url":null,"abstract":"In this paper, variational principles related to motions of an elastic plate in waves considering wave radiation condition at infinity, which are very important in calculations of the elastic response of the pontoon- type floating structure, are discussed. First, Sommerfeld radiation condition at infinity is extended to treat a case with an incident wave. Second, four kinds of variational principles related to motions of the elastic floating plate considering the incident and radiated waves are proposed and clarified the mutual relationship of these variational principles. Third, numerical results for elastic response of a floating plate of rectangular plan geometry in waves, which are obtained by using proposed variational principles, are shown.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130159885","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}
To cope with the problems in the marine ecosystem caused by the ballast water from ships, the International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004. In response to this legislation, ballast water treatment systems are being developed worldwide. The ballast-free ship concept proposed by Yokohama National University is aimed at solving this ballast water problem from a completely different standpoint. In the proposed system, seawater continuously passes through the buoyancy control tank to keep the contents of the water inside the tank the same as that outside the ship. A series of studies on this new concept has been carried out by the authors, including the analysis of seawater circulating performance inside the buoyancy control tanks, an examination of the increase in resistance caused by adding small appendages such as intake and exit gates on the ship bottom, a study of structural integrity of the system, and related work. In the present study, the authors used a scale model of an actual double bottom tank and carried out an experiment to examine the water exchange performance of the proposed system on the open sea. In the model experiment, the water inside the tank was set as fresh water initially, and as time passed, the water inside the tank changed to the seawater outside the tank. The water locality ratio inside the tank was evaluated based on the salinity change of the water inside the tank and the change of the numbers of phytoplankton cells inside the tank. Numerical results and experimental results were compared to examine the performance of the proposed ballast-free system.
{"title":"Study on the Water-exchange Performance of Buoyancy-control Type Ballast-free Ship by Model Tests at Sea","authors":"M. Arai, K. Wakabayashi, T. Kikuchi, S. Shimode","doi":"10.2534/JJASNAOE.17.177","DOIUrl":"https://doi.org/10.2534/JJASNAOE.17.177","url":null,"abstract":"To cope with the problems in the marine ecosystem caused by the ballast water from ships, the International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004. In response to this legislation, ballast water treatment systems are being developed worldwide. The ballast-free ship concept proposed by Yokohama National University is aimed at solving this ballast water problem from a completely different standpoint. In the proposed system, seawater continuously passes through the buoyancy control tank to keep the contents of the water inside the tank the same as that outside the ship. A series of studies on this new concept has been carried out by the authors, including the analysis of seawater circulating performance inside the buoyancy control tanks, an examination of the increase in resistance caused by adding small appendages such as intake and exit gates on the ship bottom, a study of structural integrity of the system, and related work. In the present study, the authors used a scale model of an actual double bottom tank and carried out an experiment to examine the water exchange performance of the proposed system on the open sea. In the model experiment, the water inside the tank was set as fresh water initially, and as time passed, the water inside the tank changed to the seawater outside the tank. The water locality ratio inside the tank was evaluated based on the salinity change of the water inside the tank and the change of the numbers of phytoplankton cells inside the tank. Numerical results and experimental results were compared to examine the performance of the proposed ballast-free system.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115581424","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}
Recent developments with offshore terminals and floating liquefied natural gas (FLNG) production, storage and offloading applications have included the new requirement that the storage tanks be able to handle unrestricted filling with LNG. If membrane-type tanks are used in such new systems, the occurrence of sloshing in the half-load condition becomes one of the most important design issues. In this paper, the authors propose a simple anti-sloshing floating device to be installed inside a liquid cargo tank. By setting the device on the free surface of the liquid cargo, the original free surface is divided into two or more sub-surfaces, and resonant sloshing of the liquid can be avoided by changing the natural frequency of its motion. This floating device can follow the liquid height change in the tank during loading and unloading operations of the liquid cargo, a feature that is especially preferable in FLNG applications. The authors examine the performance of the proposed anti-sloshing device by a series of model experiments and numerical simulations, which indicate that the device's performance is very promising.
{"title":"Experimental and Numerical Study of an Anti-Sloshing Floating Device for Membrane-Type LNG Tanks","authors":"M. Arai, R. Suzuki, N. Kishimoto, T. Ando","doi":"10.2534/JJASNAOE.17.185","DOIUrl":"https://doi.org/10.2534/JJASNAOE.17.185","url":null,"abstract":"Recent developments with offshore terminals and floating liquefied natural gas (FLNG) production, storage and offloading applications have included the new requirement that the storage tanks be able to handle unrestricted filling with LNG. If membrane-type tanks are used in such new systems, the occurrence of sloshing in the half-load condition becomes one of the most important design issues. In this paper, the authors propose a simple anti-sloshing floating device to be installed inside a liquid cargo tank. By setting the device on the free surface of the liquid cargo, the original free surface is divided into two or more sub-surfaces, and resonant sloshing of the liquid can be avoided by changing the natural frequency of its motion. This floating device can follow the liquid height change in the tank during loading and unloading operations of the liquid cargo, a feature that is especially preferable in FLNG applications. The authors examine the performance of the proposed anti-sloshing device by a series of model experiments and numerical simulations, which indicate that the device's performance is very promising.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124784048","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}
Hideyuki Uchimura, Masao Takuno, K. Murakami, K. Gotoh
The authors investigated the fatigue crack propagation behavior of solid austenitic stainless steels SUS304L, SUS316L and SUS316LN in order to conduct the characteristics of fatigue behavior of each stainless steel. Not only the constant stress amplitude tests, but also the load decreasing tests called by ΔKth test regulated by ASTM E647 were performed to identify the material constants of fatigue crack propagation. Comparison of the fatigue crack growth behavior of SUS304L, SUS316L and SUS316LN with mild steels was also performed. The authors also investigated the fatigue life of load-carrying type cruciform joints of austenitic stainless steels,which were modeled upon the lower end of vertically corrugated bulkhead of chemical tankers. Besides, the possibility of quantitative numerical simulation of the fatigue crack propagation for the stainless steels was also investigated. This simulation procedure was applied for the advanced effective stress intensity factor range based on a Re-tensile Plastic zone Generation (RPG) load and the fatigue crack closure phenomenon was quantitatively considered. The experimental results are compared with the numerical simulation results in this study and the validity of fatigue crack growth simulation procedure applied in this study is confirmed.
{"title":"Fatigue strength of austenitic stainless steels applied to chemical tankers","authors":"Hideyuki Uchimura, Masao Takuno, K. Murakami, K. Gotoh","doi":"10.2534/JJASNAOE.16.89","DOIUrl":"https://doi.org/10.2534/JJASNAOE.16.89","url":null,"abstract":"The authors investigated the fatigue crack propagation behavior of solid austenitic stainless steels SUS304L, SUS316L and SUS316LN in order to conduct the characteristics of fatigue behavior of each stainless steel. Not only the constant stress amplitude tests, but also the load decreasing tests called by ΔKth test regulated by ASTM E647 were performed to identify the material constants of fatigue crack propagation. Comparison of the fatigue crack growth behavior of SUS304L, SUS316L and SUS316LN with mild steels was also performed. The authors also investigated the fatigue life of load-carrying type cruciform joints of austenitic stainless steels,which were modeled upon the lower end of vertically corrugated bulkhead of chemical tankers. Besides, the possibility of quantitative numerical simulation of the fatigue crack propagation for the stainless steels was also investigated. This simulation procedure was applied for the advanced effective stress intensity factor range based on a Re-tensile Plastic zone Generation (RPG) load and the fatigue crack closure phenomenon was quantitatively considered. The experimental results are compared with the numerical simulation results in this study and the validity of fatigue crack growth simulation procedure applied in this study is confirmed.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116711053","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}
A new model for dynamic crack propagation and arrest in steel plates is proposed. The model is based on the local fracture stress criterion and incorporates the influence of plastic deformation on the tip of a dynamically propagating crack. Under extremely high applied stress intensity factor, the crack-tip plastic zone develops so as to decrease plane strain condition region along the crack front. This leads to the relaxation of plastic constraint and the lowering tensile stress at the crack tip. It is thereby difficult for the crack to keep propagating. The proposed model is applied to the past published ultra-wide crack arrest tests, where a crack was arrested even if stress intensity factor K was higher than arrest toughness Kca obtained by the standard crack arrest test. Although the results have been unexplained for many years, the numerical results of the proposed model show good agreement with the past test results. It is found out that the primary reason of the crack arrest of ultra-wide plate tests can be explained by the loss of plane strain condition at the crack front.
{"title":"Development of Numerical Model for Brittle Crack Propagation/Arrest Behaviors","authors":"S. Aihara, Kazuki Shibanuma, Y. Watabe","doi":"10.2534/JJASNAOE.16.109","DOIUrl":"https://doi.org/10.2534/JJASNAOE.16.109","url":null,"abstract":"A new model for dynamic crack propagation and arrest in steel plates is proposed. The model is based on the local fracture stress criterion and incorporates the influence of plastic deformation on the tip of a dynamically propagating crack. Under extremely high applied stress intensity factor, the crack-tip plastic zone develops so as to decrease plane strain condition region along the crack front. This leads to the relaxation of plastic constraint and the lowering tensile stress at the crack tip. It is thereby difficult for the crack to keep propagating. The proposed model is applied to the past published ultra-wide crack arrest tests, where a crack was arrested even if stress intensity factor K was higher than arrest toughness Kca obtained by the standard crack arrest test. Although the results have been unexplained for many years, the numerical results of the proposed model show good agreement with the past test results. It is found out that the primary reason of the crack arrest of ultra-wide plate tests can be explained by the loss of plane strain condition at the crack front.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131276206","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}
M. Tsujimoto, M. Kuroda, Koichiro Shiraishi, Yasuo Ichinose, N. Sogihara
The Actual Sea Model Basin was completed at August, 2010 at National Maritime Research Institute, Japan. The basin is equipped with wave generators surrounding the basin, towing carriage and wind blowers in which actual sea conditions are realized. Using the basin verification on the resistance test in waves was carried out. Comparison with the added resistance in waves is carried out between the other tanks in our institute using models of a container carrier and a bulk carrier. Through the evaluation of the decrease of ship speed, it is confirmed the deviation is smaller than that carried out the cooperative tank tests previously using the same ship form among the other tank institutes in Japan. Here the result of the verification is reported.
{"title":"Verification on the Resistance Test in Waves Using the Actual Sea Model Basin","authors":"M. Tsujimoto, M. Kuroda, Koichiro Shiraishi, Yasuo Ichinose, N. Sogihara","doi":"10.2534/JJASNAOE.16.33","DOIUrl":"https://doi.org/10.2534/JJASNAOE.16.33","url":null,"abstract":"The Actual Sea Model Basin was completed at August, 2010 at National Maritime Research Institute, Japan. The basin is equipped with wave generators surrounding the basin, towing carriage and wind blowers in which actual sea conditions are realized. Using the basin verification on the resistance test in waves was carried out. Comparison with the added resistance in waves is carried out between the other tanks in our institute using models of a container carrier and a bulk carrier. Through the evaluation of the decrease of ship speed, it is confirmed the deviation is smaller than that carried out the cooperative tank tests previously using the same ship form among the other tank institutes in Japan. Here the result of the verification is reported.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123427731","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}
The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) on board of the Advanced Land Observing Satellite (ALOS) was launched for earth observation and there are more than 12 million scenes of archives including coastal areas during period of five years. Nowadays, the number of AIS (Automatic Identification System)-equipped ships is increasing for maritime safety and monitoring vessel traffic. The purpose of this paper is to acquire the knowledge about kinetic analysis of vessel traffic by satellite images with simultaneous acquisition of AIS data. The authors extracted vessel information from ALOS images with AIS data by using Geographic Information System (GIS) in the Straits of Malacca on 4th May 2010. It should be noted that this process would enable to classify various length vessels with AIS-equipped or AIS-unequipped. Then, Speed and Course of each vessel was obtained from observation time differences between two satellite images. The comparison between the information of each vessel from satellite images and AIS data (SOG:Speed over ground and COG:Course over ground) as actual measurement value show a quite good agreement.
{"title":"Kinetic Analysis of Ships using Satellite Image","authors":"M. Watagawa, E. Kobayashi, N. Wakabayashi","doi":"10.2534/JJASNAOE.16.165","DOIUrl":"https://doi.org/10.2534/JJASNAOE.16.165","url":null,"abstract":"The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) on board of the Advanced Land Observing Satellite (ALOS) was launched for earth observation and there are more than 12 million scenes of archives including coastal areas during period of five years. Nowadays, the number of AIS (Automatic Identification System)-equipped ships is increasing for maritime safety and monitoring vessel traffic. The purpose of this paper is to acquire the knowledge about kinetic analysis of vessel traffic by satellite images with simultaneous acquisition of AIS data. The authors extracted vessel information from ALOS images with AIS data by using Geographic Information System (GIS) in the Straits of Malacca on 4th May 2010. It should be noted that this process would enable to classify various length vessels with AIS-equipped or AIS-unequipped. Then, Speed and Course of each vessel was obtained from observation time differences between two satellite images. The comparison between the information of each vessel from satellite images and AIS data (SOG:Speed over ground and COG:Course over ground) as actual measurement value show a quite good agreement.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114901564","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}
Kazuhisa Otsubo, Sotaro Masanobu, Y. Yaguchi, Takayuki Asanuma, K. Maeda
Recently, the natural gas is expected to be an environmentally friendlier energy and alternative to the nuclear energy. In the social situation, many oil and gas and engineering companies had studied FEEDs of the FLNG expected to be a new production system for offshore natural gas development in the near future. The FLNG system is no proven technology and there is no operation, which can make it difficult to design the FLNG. Furthermore, it is noted that the FLNG designers can't get enough information for the design and need the design standard. Gas explosion is the technical problems for the topside facilities of FLNG. Though it is so difficult to understand the gas explosion phenomenon, the FLNG designers have to evaluate the peak over pressure of gas explosion for the design of topside layout to prevent gas explosion from damaging the facilities. The objective of this paper is to study the gas explosion by the numerical simulation. The authors have conducted the gas explosion analysis for FLNG model by the numerical simulation program AutoReaGas which was developed by TNO and the Century Dynamics. The results show that the physical factors such as ignition location can make significant effects on the peak over pressure of gas explosion.
{"title":"Gas Explosion Analysis for FLNG Plant Layout Design","authors":"Kazuhisa Otsubo, Sotaro Masanobu, Y. Yaguchi, Takayuki Asanuma, K. Maeda","doi":"10.2534/JJASNAOE.19.255","DOIUrl":"https://doi.org/10.2534/JJASNAOE.19.255","url":null,"abstract":"Recently, the natural gas is expected to be an environmentally friendlier energy and alternative to the nuclear energy. In the social situation, many oil and gas and engineering companies had studied FEEDs of the FLNG expected to be a new production system for offshore natural gas development in the near future. The FLNG system is no proven technology and there is no operation, which can make it difficult to design the FLNG. Furthermore, it is noted that the FLNG designers can't get enough information for the design and need the design standard. Gas explosion is the technical problems for the topside facilities of FLNG. Though it is so difficult to understand the gas explosion phenomenon, the FLNG designers have to evaluate the peak over pressure of gas explosion for the design of topside layout to prevent gas explosion from damaging the facilities. The objective of this paper is to study the gas explosion by the numerical simulation. The authors have conducted the gas explosion analysis for FLNG model by the numerical simulation program AutoReaGas which was developed by TNO and the Century Dynamics. The results show that the physical factors such as ignition location can make significant effects on the peak over pressure of gas explosion.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115802269","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}
Automatic designing of piping layout is challenging since it is composed of several numerical and/or combinational optimization problems, e.g., routing problems of pipes including branches, and arrangement problems of equipments. This paper presents a new approach based on a simple idea that the branches of pipes are considered to be a variety of equipment. Accordingly, the pipe routing problems are fairly simplified by removing the branches, and it derives a lot of efficient algorithms to solve the pipe arrangement problems. One is a multi-objective genetic algorithm (MOGA) in which the gene represents both the locations of the equipments and the arrangement of the pipes. And a new simple and efficient crossover operation which appropriately merges two different piping layouts (but of course the PID is the same) is proposed. In order to provide a fairly good initial population for the MOGA, a new heuristics making use of self-organization techniques to arrange equipments is proposed. The efficiency of the proposed approach is demonstrated through two experiments, one is a designing problem including five valves, one pump, and five branches, and the other includes seven valves, one pump, and six branches. The objective of the optimization in the experiments is to minimize the length of the pipes, the number of elbows, and the valve operability cost. The algorithms are programmed using Java language. Although the automatic arrangement system used in the experiments is academic, the concept of the proposed approach will be accepted in practical systems.
{"title":"Automatic Designing System for Piping and Instruments Arrangement including Branches of Pipes : Multi-objective Optimization of Piping Material Costs and Valve Operability","authors":"H. Kimura","doi":"10.2534/JJASNAOE.14.165","DOIUrl":"https://doi.org/10.2534/JJASNAOE.14.165","url":null,"abstract":"Automatic designing of piping layout is challenging since it is composed of several numerical and/or combinational optimization problems, e.g., routing problems of pipes including branches, and arrangement problems of equipments. This paper presents a new approach based on a simple idea that the branches of pipes are considered to be a variety of equipment. Accordingly, the pipe routing problems are fairly simplified by removing the branches, and it derives a lot of efficient algorithms to solve the pipe arrangement problems. One is a multi-objective genetic algorithm (MOGA) in which the gene represents both the locations of the equipments and the arrangement of the pipes. And a new simple and efficient crossover operation which appropriately merges two different piping layouts (but of course the PID is the same) is proposed. In order to provide a fairly good initial population for the MOGA, a new heuristics making use of self-organization techniques to arrange equipments is proposed. The efficiency of the proposed approach is demonstrated through two experiments, one is a designing problem including five valves, one pump, and five branches, and the other includes seven valves, one pump, and six branches. The objective of the optimization in the experiments is to minimize the length of the pipes, the number of elbows, and the valve operability cost. The algorithms are programmed using Java language. Although the automatic arrangement system used in the experiments is academic, the concept of the proposed approach will be accepted in practical systems.","PeriodicalId":321056,"journal":{"name":"Journal of the Society of Naval Architects of Japan","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129240322","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}
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：