Pub Date : 2015-12-25DOI: 10.12989/OSE.2015.5.4.261
N. Kurup, S. Shi, Leiyong Jiang, Moo-Hyun Kim
Internal solitary waves occur due to density stratification and are nonlinear in nature. These waves have been observed in many parts of the world including the South China Sea, Andaman Sea and Sulu Sea. Their effect on floating systems has been an emerging field of interest and recent offshore developments in the South China Sea where several offshore oil and gas discoveries are located have confirmed adverse effects including large platform motions and riser system damage. A valid numerical model conforming to the physics of internal waves is implemented in this paper and the effect on a spar platform is studied. The physics of internal waves is modeled by the Korteweg-de Vries (KdV) equation, which has a general solution involving Jacobian elliptical functions. The effects of vertical density stratification are captured by solving the Taylor Goldstein equation. Fully coupled time domain analyses are conducted to estimate the effect of internal waves on a typical truss spar, which is configured to South China Sea development requirements and environmental conditions. The hull, moorings and risers are considered as an integrated system and the platform global motions are analyzed. The study could be useful for future guidance and development of offshore systems in the South China Sea and other areas where the internal wave phenomenon is prominent.
{"title":"Numerical modeling of internal waves within a coupled analysis framework and their influence on spar platforms","authors":"N. Kurup, S. Shi, Leiyong Jiang, Moo-Hyun Kim","doi":"10.12989/OSE.2015.5.4.261","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.4.261","url":null,"abstract":"Internal solitary waves occur due to density stratification and are nonlinear in nature. These waves have been observed in many parts of the world including the South China Sea, Andaman Sea and Sulu Sea. Their effect on floating systems has been an emerging field of interest and recent offshore developments in the South China Sea where several offshore oil and gas discoveries are located have confirmed adverse effects including large platform motions and riser system damage. A valid numerical model conforming to the physics of internal waves is implemented in this paper and the effect on a spar platform is studied. The physics of internal waves is modeled by the Korteweg-de Vries (KdV) equation, which has a general solution involving Jacobian elliptical functions. The effects of vertical density stratification are captured by solving the Taylor Goldstein equation. Fully coupled time domain analyses are conducted to estimate the effect of internal waves on a typical truss spar, which is configured to South China Sea development requirements and environmental conditions. The hull, moorings and risers are considered as an integrated system and the platform global motions are analyzed. The study could be useful for future guidance and development of offshore systems in the South China Sea and other areas where the internal wave phenomenon is prominent.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"261-277"},"PeriodicalIF":0.9,"publicationDate":"2015-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501772","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 : 2015-12-25DOI: 10.12989/OSE.2015.5.4.319
M. Ketabdari, Mohammad Barzegar Paiin Lamouki, Ali Moghaddasi
Submerged breakwaters are used to prevent shore line erosion and sediment transportation. One of their advantages is low visual impact. In this paper, the effects of discontinuous submerged breakwaters over water surface elevation was numerically studied considering the extended Boussinesq equations as governing equations using MIKE21 software. The result of discontinuous breakwater was compared with a beach without breakwater. The results showed that the gap dramatically effects on surface elevation from shore line to offshore. It is also evident from results that with approaching the center of the gap, fluctuation of surface elevation is generated. It is because of passing longshore currents towards offshore through the gap which leads to an increase in sediment transportation rate. Nevertheless, transferring water mass from breakwater gap results in powerful rip currents leading to high changes on longshore wave profile. As waves propagate towards shore line the transformation phenomena occurs related to sea bottom bathymetry changes. The length and the height of waves moving from deep water to shallow water change and as the wave slope goes over the critical limit and waves reach the breaking line they break and most of the wave energy releases. When high waves approaching the shoreline, water fluctuations occurs leading to beach erosion and sediment transportation. Therefore, preventing land erosion by wave attacks and decreasing the impact of inducing waves on shore structures are important subjects in coastal engineering. Breakwater is a structure which is mainly used to protect the area in its lee from wave attack. In reality, the purpose of building breakwaters is providing a sheltered area for loading and offloading of the ships; as well as to manipulate the littoral transport conditions by trapping the moving sand particles. There are different types of breakwaters like detached breakwater that is completely isolated from shore and attached breakwater that is connected to the shoreline. Both of these types of breakwaters can be floating, emerged and submerged structures. Today the use of detached low-crested or submerged breakwaters in conjunction with beach nourishment is advised for stabilization of beaches. This is mainly related to their small
{"title":"Effects of discontinuous submerged breakwater on water surface elevation","authors":"M. Ketabdari, Mohammad Barzegar Paiin Lamouki, Ali Moghaddasi","doi":"10.12989/OSE.2015.5.4.319","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.4.319","url":null,"abstract":"Submerged breakwaters are used to prevent shore line erosion and sediment transportation. One of their advantages is low visual impact. In this paper, the effects of discontinuous submerged breakwaters over water surface elevation was numerically studied considering the extended Boussinesq equations as governing equations using MIKE21 software. The result of discontinuous breakwater was compared with a beach without breakwater. The results showed that the gap dramatically effects on surface elevation from shore line to offshore. It is also evident from results that with approaching the center of the gap, fluctuation of surface elevation is generated. It is because of passing longshore currents towards offshore through the gap which leads to an increase in sediment transportation rate. Nevertheless, transferring water mass from breakwater gap results in powerful rip currents leading to high changes on longshore wave profile. As waves propagate towards shore line the transformation phenomena occurs related to sea bottom bathymetry changes. The length and the height of waves moving from deep water to shallow water change and as the wave slope goes over the critical limit and waves reach the breaking line they break and most of the wave energy releases. When high waves approaching the shoreline, water fluctuations occurs leading to beach erosion and sediment transportation. Therefore, preventing land erosion by wave attacks and decreasing the impact of inducing waves on shore structures are important subjects in coastal engineering. Breakwater is a structure which is mainly used to protect the area in its lee from wave attack. In reality, the purpose of building breakwaters is providing a sheltered area for loading and offloading of the ships; as well as to manipulate the littoral transport conditions by trapping the moving sand particles. There are different types of breakwaters like detached breakwater that is completely isolated from shore and attached breakwater that is connected to the shoreline. Both of these types of breakwaters can be floating, emerged and submerged structures. Today the use of detached low-crested or submerged breakwaters in conjunction with beach nourishment is advised for stabilization of beaches. This is mainly related to their small","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"319-329"},"PeriodicalIF":0.9,"publicationDate":"2015-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501932","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 : 2015-12-25DOI: 10.12989/OSE.2015.5.4.301
Stefanos A. Katifeoglou, I. Chatjigeorgiou
The present investigations introduce the shell-finite element discretization for the dynamics of slender marine pipelines. A long catenary pipeline, corresponding to a particular Steel Catenary Riser (SCR), is investigated under long-standing cyclic loading. The long structure is divided into smaller tubular parts which are discretized with 8-node planar shell elements. The transient analysis of each part is carried out by the implicit time integration scheme, within a Finite Elements (FE) solver. The time varying external loads and boundary conditions on each part are the results of a prior solution of an integrated line-dynamics model. The celebrated FE approximation can produce a more detailed stress distribution along the structural surface than the simplistic “line-dynamics” approach.
{"title":"A shell-dynamics model for marine pipelines of large suspended length","authors":"Stefanos A. Katifeoglou, I. Chatjigeorgiou","doi":"10.12989/OSE.2015.5.4.301","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.4.301","url":null,"abstract":"The present investigations introduce the shell-finite element discretization for the dynamics of slender marine pipelines. A long catenary pipeline, corresponding to a particular Steel Catenary Riser (SCR), is investigated under long-standing cyclic loading. The long structure is divided into smaller tubular parts which are discretized with 8-node planar shell elements. The transient analysis of each part is carried out by the implicit time integration scheme, within a Finite Elements (FE) solver. The time varying external loads and boundary conditions on each part are the results of a prior solution of an integrated line-dynamics model. The celebrated FE approximation can produce a more detailed stress distribution along the structural surface than the simplistic “line-dynamics” approach.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"301-318"},"PeriodicalIF":0.9,"publicationDate":"2015-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501859","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 : 2015-12-25DOI: 10.12989/OSE.2015.5.4.245
Yucheng Zhao, Hamn-Ching Chen, Xiaochuan Yu
The numerical simulation of wave slamming on a 3D platform deck was investigated using a coupled Level-Set and Volume-of-Fluid (CLSVOF) method for overset grid system incorporated into the Finite-Analytic Navier-Stokes (FANS) method. The predicted slamming impact forces were compared with the corresponding experimental data. The comparisons showed that the CLSVOF method is capable of accurately predicting the slamming impact and capturing the violent free surface flow including wave slamming, wave inundation and wave recession. Moreover, the capability of the present CLSVOF method for overset grid system is a prominent feature to handle the prediction of wave slamming on offshore structure.
{"title":"Numerical simulation of wave slamming on 3D offshore platform deck using a coupled Level-Set and Volume-of-Fluid method for overset grid system","authors":"Yucheng Zhao, Hamn-Ching Chen, Xiaochuan Yu","doi":"10.12989/OSE.2015.5.4.245","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.4.245","url":null,"abstract":"The numerical simulation of wave slamming on a 3D platform deck was investigated using a coupled Level-Set and Volume-of-Fluid (CLSVOF) method for overset grid system incorporated into the Finite-Analytic Navier-Stokes (FANS) method. The predicted slamming impact forces were compared with the corresponding experimental data. The comparisons showed that the CLSVOF method is capable of accurately predicting the slamming impact and capturing the violent free surface flow including wave slamming, wave inundation and wave recession. Moreover, the capability of the present CLSVOF method for overset grid system is a prominent feature to handle the prediction of wave slamming on offshore structure.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"245-259"},"PeriodicalIF":0.9,"publicationDate":"2015-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66502185","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 : 2015-09-25DOI: 10.12989/OSE.2015.5.3.161
H. Y. Wang, J. Ren, J. Yang, J. Wang
. An emergency response system (ERS) for vessel oil spills is a complex and dynamic system comprising a number of subsystems and activities. Failures may occur during the emergency response operations, this has negative impacts on the effectiveness of the ERS. Of the classes of problems in analyzing failures, the lack of quantitative data is fundamental. In fact, most of the empirical data collected via questionnaire survey is subjective in nature and is inevitably associated with uncertainties caused by the human being‟s inability to provide complete judgement. In addition, incomplete information and/or vagueness of the meaning about the failures add difficulties in evaluating the effectiveness of the system. Therefore this paper proposes a framework to evaluate the ERS effectiveness by using the combination of fuzzy reasoning and evidential synthesis approaches. Based on analyzing the procedure of ERS for oil spills, the failures in the system could be identified, using Analytic Hierarchy Process (AHP) to determine the relative weight of identified failures. Fuzzy reasoning combined with evidential synthesis is applied to evaluate the effectiveness of ERS for oil spills under uncertainties last. The proposed method is capable of dealing with uncertainties in data including ignorance and vagueness which traditional methods cannot effectively handle. A case study is used to illustrate the application of the proposed method. spills using
{"title":"Evaluating the effectiveness of ERS for vessel oil spills using fuzzy evidential reasoning","authors":"H. Y. Wang, J. Ren, J. Yang, J. Wang","doi":"10.12989/OSE.2015.5.3.161","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.3.161","url":null,"abstract":". An emergency response system (ERS) for vessel oil spills is a complex and dynamic system comprising a number of subsystems and activities. Failures may occur during the emergency response operations, this has negative impacts on the effectiveness of the ERS. Of the classes of problems in analyzing failures, the lack of quantitative data is fundamental. In fact, most of the empirical data collected via questionnaire survey is subjective in nature and is inevitably associated with uncertainties caused by the human being‟s inability to provide complete judgement. In addition, incomplete information and/or vagueness of the meaning about the failures add difficulties in evaluating the effectiveness of the system. Therefore this paper proposes a framework to evaluate the ERS effectiveness by using the combination of fuzzy reasoning and evidential synthesis approaches. Based on analyzing the procedure of ERS for oil spills, the failures in the system could be identified, using Analytic Hierarchy Process (AHP) to determine the relative weight of identified failures. Fuzzy reasoning combined with evidential synthesis is applied to evaluate the effectiveness of ERS for oil spills under uncertainties last. The proposed method is capable of dealing with uncertainties in data including ignorance and vagueness which traditional methods cannot effectively handle. A case study is used to illustrate the application of the proposed method. spills using","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"161-179"},"PeriodicalIF":0.9,"publicationDate":"2015-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501558","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 : 2015-09-25DOI: 10.12989/OSE.2015.5.3.199
M. Fang, Z. Lee
The paper described the nonlinear dynamic motion behavior of a barge equipped with the portable outboard Dynamic Positioning (DP) control system in short-crested waves. The DP system based on the fuzzy theory is applied to control the thrusters to optimally adjust the ship position and heading in waves. In addition to the short-crested waves, the current, wind and nonlinear drifting force are also included in the calculations. The time domain simulations for the six degrees of freedom motions of the barge with the DP system are solved by the 4 th order Runge-Kutta method. The results show that the position and heading deviations are limited within acceptable ranges based on the present control method. When the dynamic positioning missions are needed, the technique of the alternative portable DP system developed here can serve as a practical tool to assist those ships without equipping with the DP facility.
{"title":"An alternative portable dynamic positioning system on a barge in short-crested waves using the fuzzy control","authors":"M. Fang, Z. Lee","doi":"10.12989/OSE.2015.5.3.199","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.3.199","url":null,"abstract":"The paper described the nonlinear dynamic motion behavior of a barge equipped with the portable outboard Dynamic Positioning (DP) control system in short-crested waves. The DP system based on the fuzzy theory is applied to control the thrusters to optimally adjust the ship position and heading in waves. In addition to the short-crested waves, the current, wind and nonlinear drifting force are also included in the calculations. The time domain simulations for the six degrees of freedom motions of the barge with the DP system are solved by the 4 th order Runge-Kutta method. The results show that the position and heading deviations are limited within acceptable ranges based on the present control method. When the dynamic positioning missions are needed, the technique of the alternative portable DP system developed here can serve as a practical tool to assist those ships without equipping with the DP facility.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"199-220"},"PeriodicalIF":0.9,"publicationDate":"2015-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501654","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 : 2015-09-25DOI: 10.12989/OSE.2015.5.3.181
Dong-Hoon Jeong, M. Roh, S. Ham
An OSV (Offshore Support Vessel) is being used to install a structure which is laid on its deck or an adjacent transport barge by lifting off the structure with its own crane, lifting in the air, crossing splash zone, deeply submerging, and lastly landing it. There are some major considerations during these operations. Especially, when lifting off the structure, if operating conditions such as ocean environmental loads and lifting off velocity are not suitable, the collision can be occurred due to the relative motion between the structure and the OSV or the transport barge. To solve this problem, this study performs the physics-based simulation of the lifting off step while the OSV installs the structure. The simulation includes the calculation of dynamic responses of the OSV and the structure, including the collision detection between the transport barge and the structure. To check the applicability of the physics-based simulation, it is applied to a problem of the lifting off step by varying the ocean environmental loads and the lifting off velocity. As a result, it is confirmed that the operability of the lifting off step are affected by the conditions.
{"title":"Lifting off simulation of an offshore supply vessel considering ocean environmental loads and lifting off velocity","authors":"Dong-Hoon Jeong, M. Roh, S. Ham","doi":"10.12989/OSE.2015.5.3.181","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.3.181","url":null,"abstract":"An OSV (Offshore Support Vessel) is being used to install a structure which is laid on its deck or an adjacent transport barge by lifting off the structure with its own crane, lifting in the air, crossing splash zone, deeply submerging, and lastly landing it. There are some major considerations during these operations. Especially, when lifting off the structure, if operating conditions such as ocean environmental loads and lifting off velocity are not suitable, the collision can be occurred due to the relative motion between the structure and the OSV or the transport barge. To solve this problem, this study performs the physics-based simulation of the lifting off step while the OSV installs the structure. The simulation includes the calculation of dynamic responses of the OSV and the structure, including the collision detection between the transport barge and the structure. To check the applicability of the physics-based simulation, it is applied to a problem of the lifting off step by varying the ocean environmental loads and the lifting off velocity. As a result, it is confirmed that the operability of the lifting off step are affected by the conditions.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"181-198"},"PeriodicalIF":0.9,"publicationDate":"2015-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501614","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 : 2015-09-25DOI: 10.12989/OSE.2015.5.3.221
B. Kim, S. Hong, H. Sung, Seok-Won Hong
Abstract. This paper compares simplified and finite element method (FEM) models for tower and blade in dynamic coupled analysis of floating wind turbine. A SPAR type wind turbine with catenary mooring lines is considered in numerical analysis. Floating body equation is derived using boundary element method (BEM) and convolution. Equations for mooring line, tower and blade are formulated with theories of catenary, elastic beam and aerodynamic rotating beam, respectively and FEM is applied in the formulation. By combining the equations, coupled solutions are calculated. Tower or blade may be assumed rigid or lumped body for simplicity in modeling. By comparing floating body motions, mooring line tensions and tower stresses with the simple model and original FEM model, the effect of including or neglecting elastic, rotating and aerodynamic behavior of tower and blade is discussed.
{"title":"Comparison of simplified model and FEM model in coupled analysis of floating wind turbine","authors":"B. Kim, S. Hong, H. Sung, Seok-Won Hong","doi":"10.12989/OSE.2015.5.3.221","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.3.221","url":null,"abstract":"Abstract. This paper compares simplified and finite element method (FEM) models for tower and blade in dynamic coupled analysis of floating wind turbine. A SPAR type wind turbine with catenary mooring lines is considered in numerical analysis. Floating body equation is derived using boundary element method (BEM) and convolution. Equations for mooring line, tower and blade are formulated with theories of catenary, elastic beam and aerodynamic rotating beam, respectively and FEM is applied in the formulation. By combining the equations, coupled solutions are calculated. Tower or blade may be assumed rigid or lumped body for simplicity in modeling. By comparing floating body motions, mooring line tensions and tower stresses with the simple model and original FEM model, the effect of including or neglecting elastic, rotating and aerodynamic behavior of tower and blade is discussed.","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"221-243"},"PeriodicalIF":0.9,"publicationDate":"2015-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501288","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 : 2015-09-25DOI: 10.12989/OSE.2015.5.3.139
H. C. Kim, M. H. Kim
{"title":"Global performances of a semi-submersible 5 MW wind-turbine including second-order wave-diffraction effects","authors":"H. C. Kim, M. H. Kim","doi":"10.12989/OSE.2015.5.3.139","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.3.139","url":null,"abstract":"","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"139-160"},"PeriodicalIF":0.9,"publicationDate":"2015-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501534","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 : 2015-06-25DOI: 10.12989/OSE.2015.5.2.077
Chen Xiqia, Fu Shixiao, Gaojie Yun, Du Xiaying
【As the exploitation of oil and gas resources advances into deeper waters and harsher environments, the design and analysis of the flexible risers has become the research focus in the offshore engineering filed. Due to the complexity of the components and the sliding between the adjacent layers, the bending response of the flexible risers is highly non-linear. This paper presents the finite element analysis of the flexible risers under bending loads. The detailed finite element model of the flexible riser is established in ABAQUS software. This finite element model incorporates all the fine details of the riser to accurately predict its nonlinear structural behavior. Based on the finite element model, the bending moment-curvature relationships of a flexible riser under various axisymmetric loads have been investigated. The results have been compared with the analytical ones obtained from the literature and good agreements have been found. Moreover, the stress of the tendon armors has been studied. The non-linear relationship between the armor tendons' stress and the bending loads has been obtained.】
{"title":"A finite element analysis for unbonded flexible risers under bending loads","authors":"Chen Xiqia, Fu Shixiao, Gaojie Yun, Du Xiaying","doi":"10.12989/OSE.2015.5.2.077","DOIUrl":"https://doi.org/10.12989/OSE.2015.5.2.077","url":null,"abstract":"【As the exploitation of oil and gas resources advances into deeper waters and harsher environments, the design and analysis of the flexible risers has become the research focus in the offshore engineering filed. Due to the complexity of the components and the sliding between the adjacent layers, the bending response of the flexible risers is highly non-linear. This paper presents the finite element analysis of the flexible risers under bending loads. The detailed finite element model of the flexible riser is established in ABAQUS software. This finite element model incorporates all the fine details of the riser to accurately predict its nonlinear structural behavior. Based on the finite element model, the bending moment-curvature relationships of a flexible riser under various axisymmetric loads have been investigated. The results have been compared with the analytical ones obtained from the literature and good agreements have been found. Moreover, the stress of the tendon armors has been studied. The non-linear relationship between the armor tendons' stress and the bending loads has been obtained.】","PeriodicalId":44219,"journal":{"name":"Ocean Systems Engineering-An International Journal","volume":"5 1","pages":"77-89"},"PeriodicalIF":0.9,"publicationDate":"2015-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66501351","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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