Pub Date : 2025-10-23DOI: 10.1016/j.marstruc.2025.103956
Youhai Guan , Kaixin Liang , Jincheng Hu , Huanyu Lv , Zhaohui Yang , Bo Wang , Meng Zhao , Shaojian Liu , Zhe Wang
Local scour constitutes a critical threat to structural safety of offshore suction bucket foundations, while conventional countermeasures demonstrate constrained efficacy. To mitigate scour depths around suction bucket foundations, flowable stabilized soil (FSS) was applied to the upper seabed layer adjacent to structures. Flume experiments under steady current conditions were conducted to evaluate scour characteristics of tripod suction bucket foundations with versus without FSS protection. Results indicate that FSS exhibits significantly higher compressive and shear strength than natural seabed, characterized by densely compacted microstructure. Scour patterns for FSS under varied protection radii were categorized as "joint erosion" and "surface erosion". A correction coefficient for horseshoe vortex intensity was incorporated based on energy conservation theory, while the equilibrium scour depth formula was refined to account for FSS influences. Under identical conditions, FSS protection demonstrates superior efficiency relative to riprap and collar devices, with lower costs and simpler construction than grouting methods, empirically validating its enhanced scour mitigation capabilities.
{"title":"Experimental study on flowable solidified soil for scour protection of tripod suction bucket foundations in offshore wind farms","authors":"Youhai Guan , Kaixin Liang , Jincheng Hu , Huanyu Lv , Zhaohui Yang , Bo Wang , Meng Zhao , Shaojian Liu , Zhe Wang","doi":"10.1016/j.marstruc.2025.103956","DOIUrl":"10.1016/j.marstruc.2025.103956","url":null,"abstract":"<div><div>Local scour constitutes a critical threat to structural safety of offshore suction bucket foundations, while conventional countermeasures demonstrate constrained efficacy. To mitigate scour depths around suction bucket foundations, flowable stabilized soil (FSS) was applied to the upper seabed layer adjacent to structures. Flume experiments under steady current conditions were conducted to evaluate scour characteristics of tripod suction bucket foundations with versus without FSS protection. Results indicate that FSS exhibits significantly higher compressive and shear strength than natural seabed, characterized by densely compacted microstructure. Scour patterns for FSS under varied protection radii were categorized as \"joint erosion\" and \"surface erosion\". A correction coefficient for horseshoe vortex intensity was incorporated based on energy conservation theory, while the equilibrium scour depth formula was refined to account for FSS influences. Under identical conditions, FSS protection demonstrates superior efficiency relative to riprap and collar devices, with lower costs and simpler construction than grouting methods, empirically validating its enhanced scour mitigation capabilities.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103956"},"PeriodicalIF":5.1,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study evaluates an efficient time-domain fatigue analysis approach for welded joints in semi-submersible floating wind turbine (FWT) hulls. A fully coupled, time domain approach serves as reference for comparing simplified methods. In particular, a simplified decoupled method in which the global load effects due to wind and waves are determined separately and the corresponding hot spot stress for estimating the fatigue damage in representative points is determined by superimposing the time series of the stress due to global wave and wind effects. A 10-MW semi-submersible FWT at various North Sea and China offshore locations, is analyzed employing a multi-segment floater model to capture global structural responses. Fatigue damage of various positions of the hull is estimated using the rainflow cycle counting method and the SN-curve approach. The results indicate that the fully coupled method, while highly accurate in capturing real-time wind-wave interactions, implies significant computational costs. The decoupled approach enhances the efficiency and reduces the simulation requirements by over 80 %, while maintaining a reasonable accuracy, particularly for wind turbines in the Northern North Sea, i.e., with a deviation of <12 %. In addition, a highly simplified method is proposed, which is based on considering only the most probable wave conditions at different wind speeds. This method shows good agreement with fully coupled fatigue assessments in the Northern North Sea, but it leads to notable underestimation in the South China Sea. However, further investigations of this approach are needed to document its feasibility. The findings in this study highlight the trade-offs between computational cost and accuracy, and especially shows the potential of the decoupled method for an efficient long-term fatigue assessment of floating wind turbines. Future research should be carried out to document its applicability for various floating wind turbine designs and offshore locations.
{"title":"An efficient approach for time-domain fatigue analysis for semi-submersible hulls of floating wind turbines","authors":"Shuaishuai Wang , Torgeir Moan , Zhen Gao , Shan Gao","doi":"10.1016/j.marstruc.2025.103955","DOIUrl":"10.1016/j.marstruc.2025.103955","url":null,"abstract":"<div><div>This study evaluates an efficient time-domain fatigue analysis approach for welded joints in semi-submersible floating wind turbine (FWT) hulls. A fully coupled, time domain approach serves as reference for comparing simplified methods. In particular, a simplified decoupled method in which the global load effects due to wind and waves are determined separately and the corresponding hot spot stress for estimating the fatigue damage in representative points is determined by superimposing the time series of the stress due to global wave and wind effects. A 10-MW semi-submersible FWT at various North Sea and China offshore locations, is analyzed employing a multi-segment floater model to capture global structural responses. Fatigue damage of various positions of the hull is estimated using the rainflow cycle counting method and the SN-curve approach. The results indicate that the fully coupled method, while highly accurate in capturing real-time wind-wave interactions, implies significant computational costs. The decoupled approach enhances the efficiency and reduces the simulation requirements by over 80 %, while maintaining a reasonable accuracy, particularly for wind turbines in the Northern North Sea, i.e., with a deviation of <12 %. In addition, a highly simplified method is proposed, which is based on considering only the most probable wave conditions at different wind speeds. This method shows good agreement with fully coupled fatigue assessments in the Northern North Sea, but it leads to notable underestimation in the South China Sea. However, further investigations of this approach are needed to document its feasibility. The findings in this study highlight the trade-offs between computational cost and accuracy, and especially shows the potential of the decoupled method for an efficient long-term fatigue assessment of floating wind turbines. Future research should be carried out to document its applicability for various floating wind turbine designs and offshore locations.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103955"},"PeriodicalIF":5.1,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.marstruc.2025.103950
Malcolm Smith , Ken Nahshon , Teresa Magoga , Joel Hogan , Rachel Markert , Joel Higgins
A deck grillage structure was extracted from a decommissioned warship (ex-HMCS IROQUOIS) and damaged as the result of a dynamic pressure loading test, resulting in overall permanent multi-bay deformation of the plating and attached members. The damaged grillage was then re-configured for residual ultimate strength testing under longitudinal loading. The test article spanned three complete frame bays plus half-bays at each end and four continuous longitudinals of the original structure. In addition to thickness and material property measurements, Light Detection and Ranging (LiDAR) measurement of the damaged panel was carried out after re-configuration. The residual strength testing consisted of compressive loading to collapse and post-collapse, followed by two tension-compression cycles. Numerical assessments of the residual strength were performed using nonlinear finite element analysis (FEA) and material models based on measured material properties from material recovered from the ship. Excellent agreement is achieved between the measured and predicted load-shortening behaviour through progressive adjustment of the material modelling parameters. The deformation damage is estimated to result in a 20.7% loss of ultimate strength. The modelling approach developed here is then extended to the analysis of four previously-studied grillage structures recovered from the same vessel.
{"title":"Residual ultimate strength of a damaged deck grillage structure","authors":"Malcolm Smith , Ken Nahshon , Teresa Magoga , Joel Hogan , Rachel Markert , Joel Higgins","doi":"10.1016/j.marstruc.2025.103950","DOIUrl":"10.1016/j.marstruc.2025.103950","url":null,"abstract":"<div><div>A deck grillage structure was extracted from a decommissioned warship (ex-HMCS IROQUOIS) and damaged as the result of a dynamic pressure loading test, resulting in overall permanent multi-bay deformation of the plating and attached members. The damaged grillage was then re-configured for residual ultimate strength testing under longitudinal loading. The test article spanned three complete frame bays plus half-bays at each end and four continuous longitudinals of the original structure. In addition to thickness and material property measurements, Light Detection and Ranging (LiDAR) measurement of the damaged panel was carried out after re-configuration. The residual strength testing consisted of compressive loading to collapse and post-collapse, followed by two tension-compression cycles. Numerical assessments of the residual strength were performed using nonlinear finite element analysis (FEA) and material models based on measured material properties from material recovered from the ship. Excellent agreement is achieved between the measured and predicted load-shortening behaviour through progressive adjustment of the material modelling parameters. The deformation damage is estimated to result in a 20.7% loss of ultimate strength. The modelling approach developed here is then extended to the analysis of four previously-studied grillage structures recovered from the same vessel.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103950"},"PeriodicalIF":5.1,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.marstruc.2025.103953
Zhiquan Zhou , Jiasong Wang
The stability of wake oscillator model prediction accuracy across varying conditions is a critical and widely studied topic. This study developed a wake oscillator model incorporating newly fitted Van der Pol parameters, derived through mathematical derivation coupled with experimental fitting. The model comprises structural dynamic equations and Van der Pol oscillators in the in-line and cross-flow directions, solved numerically via the central difference method. Comparison with several classical experimental data and other numerical studies illustrates the enhanced comprehensive accuracy of the model. Particularly, this modification effectively addresses the common underestimation of in-line amplitudes and maintains consistent performance across diverse operating conditions. Investigation of the vortex-induced vibrations in the deep-sea mining riser reveals that the application of the new parameters magnifies the vibration amplitude, especially the peaks. The phenomenon arises from localized energy accumulation and reduced phase velocity. The model effectively enhances the higher-order frequency components and modifies the sidelobe width of the dominant vibration frequency, preventing the occurrence of unforeseen resonance. Those variations are amplified as the flow velocity increases. The static displacement of the riser, governed by the mean drag coefficient, remains unaffected. This improvement establishes a foundation for predicting vortex-induced vibrations responses and ensuring operational safety of deep-sea mining risers.
{"title":"Newly fitted Van der Pol parameters for vortex-induced vibration and their application to a deep-sea mining riser","authors":"Zhiquan Zhou , Jiasong Wang","doi":"10.1016/j.marstruc.2025.103953","DOIUrl":"10.1016/j.marstruc.2025.103953","url":null,"abstract":"<div><div>The stability of wake oscillator model prediction accuracy across varying conditions is a critical and widely studied topic. This study developed a wake oscillator model incorporating newly fitted Van der Pol parameters, derived through mathematical derivation coupled with experimental fitting. The model comprises structural dynamic equations and Van der Pol oscillators in the in-line and cross-flow directions, solved numerically via the central difference method. Comparison with several classical experimental data and other numerical studies illustrates the enhanced comprehensive accuracy of the model. Particularly, this modification effectively addresses the common underestimation of in-line amplitudes and maintains consistent performance across diverse operating conditions. Investigation of the vortex-induced vibrations in the deep-sea mining riser reveals that the application of the new parameters magnifies the vibration amplitude, especially the peaks. The phenomenon arises from localized energy accumulation and reduced phase velocity. The model effectively enhances the higher-order frequency components and modifies the sidelobe width of the dominant vibration frequency, preventing the occurrence of unforeseen resonance. Those variations are amplified as the flow velocity increases. The static displacement of the riser, governed by the mean drag coefficient, remains unaffected. This improvement establishes a foundation for predicting vortex-induced vibrations responses and ensuring operational safety of deep-sea mining risers.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103953"},"PeriodicalIF":5.1,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-09DOI: 10.1016/j.marstruc.2025.103949
Hongyan Ding , Tingyuan Wang , Conghuan Le , Yunlong Xu , Puyang Zhang
To address the challenges of penetration attitude control caused by eccentric loads during the integrated penetration of composite bucket foundations for offshore wind power, this study combines model tests and numerical simulations to systematically investigate the penetration characteristics, seepage field evolution, and critical suction mechanism under eccentric loads. The effects of different eccentric load magnitudes and positions on penetration characteristics were analyzed. Results show that increasing eccentric loads reduces penetration resistance (about 15 % lower than the non-eccentric case), and applying the load directly above a single compartment enhances installation stability through a three-compartment compensation strategy. The study reveals the asymmetric distribution of excess pore water pressure in the soil under eccentric loads, with the negative pore pressure loss at the outer wall of the compensation compartment reduced by approximately 20 % compared to the non-compensation compartment. Critical seepage failure occurs at the interface between the non-compensation compartments and the partition plates. Based on the relationship between seepage paths and pressure differences, a critical suction formula is derived, considering the number of compensation compartments, pressure differences, and penetration depth. The results show that eccentric loads lead to a maximum reduction of 17.56 % in critical suction. This study provides theoretical support and engineering guidance for efficiently installing composite bucket foundations in offshore wind power applications.
{"title":"Penetration characteristics of composite bucket foundations under eccentric loads during integrated offshore wind turbine installation","authors":"Hongyan Ding , Tingyuan Wang , Conghuan Le , Yunlong Xu , Puyang Zhang","doi":"10.1016/j.marstruc.2025.103949","DOIUrl":"10.1016/j.marstruc.2025.103949","url":null,"abstract":"<div><div>To address the challenges of penetration attitude control caused by eccentric loads during the integrated penetration of composite bucket foundations for offshore wind power, this study combines model tests and numerical simulations to systematically investigate the penetration characteristics, seepage field evolution, and critical suction mechanism under eccentric loads. The effects of different eccentric load magnitudes and positions on penetration characteristics were analyzed. Results show that increasing eccentric loads reduces penetration resistance (about 15 % lower than the non-eccentric case), and applying the load directly above a single compartment enhances installation stability through a three-compartment compensation strategy. The study reveals the asymmetric distribution of excess pore water pressure in the soil under eccentric loads, with the negative pore pressure loss at the outer wall of the compensation compartment reduced by approximately 20 % compared to the non-compensation compartment. Critical seepage failure occurs at the interface between the non-compensation compartments and the partition plates. Based on the relationship between seepage paths and pressure differences, a critical suction formula is derived, considering the number of compensation compartments, pressure differences, and penetration depth. The results show that eccentric loads lead to a maximum reduction of 17.56 % in critical suction. This study provides theoretical support and engineering guidance for efficiently installing composite bucket foundations in offshore wind power applications.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103949"},"PeriodicalIF":5.1,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.marstruc.2025.103948
Haonan Tian , Mohsen N. Soltani , Oriol Colomés
Mooring failures significantly threaten the stability of Floating Offshore Wind Turbines (FOWT) under extreme environmental conditions. This study presents an innovative integrated damping mooring system incorporating Seaflex dampers to improve structural stability and operational reliability. Dynamic simulations under 1-year and 50-year return period sea states demonstrate the system’s effectiveness. Under Ultimate Limit State (ULS) conditions, the system reduces surge displacement by 59%, pitch angle by 47%, and mooring line tension by 72%. Under Accidental Limit State (ALS) conditions, it mitigates load spikes, reduces drift displacement by 60%, and improves safety factors by 50%. The comparison shows chain and wire rope configurations have better load reduction performance in the integrated damping scheme. Lightweight and adaptable, the Seaflex dampers enhance broad-spectrum damping without affecting platform buoyancy. This study offers a robust solution for enhancing FOWT safety and durability in harsh marine environments, thereby enabling large-scale offshore wind energy development.
{"title":"Innovative integrated damping mooring technology for floating wind turbines under extreme sea conditions","authors":"Haonan Tian , Mohsen N. Soltani , Oriol Colomés","doi":"10.1016/j.marstruc.2025.103948","DOIUrl":"10.1016/j.marstruc.2025.103948","url":null,"abstract":"<div><div>Mooring failures significantly threaten the stability of Floating Offshore Wind Turbines (FOWT) under extreme environmental conditions. This study presents an innovative integrated damping mooring system incorporating Seaflex dampers to improve structural stability and operational reliability. Dynamic simulations under 1-year and 50-year return period sea states demonstrate the system’s effectiveness. Under Ultimate Limit State (ULS) conditions, the system reduces surge displacement by 59%, pitch angle by 47%, and mooring line tension by 72%. Under Accidental Limit State (ALS) conditions, it mitigates load spikes, reduces drift displacement by 60%, and improves safety factors by 50%. The comparison shows chain and wire rope configurations have better load reduction performance in the integrated damping scheme. Lightweight and adaptable, the Seaflex dampers enhance broad-spectrum damping without affecting platform buoyancy. This study offers a robust solution for enhancing FOWT safety and durability in harsh marine environments, thereby enabling large-scale offshore wind energy development.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103948"},"PeriodicalIF":5.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.marstruc.2025.103951
Peter J. Rohrer , Erin E. Bachynski-Polić , John Marius Hegseth
A wide variety of semi-submersible floating wind turbine designs have been proposed, though few studies have attempted design optimization with more than a handful of design variables. Gradient-based design optimization can enable optimization with many design variables to define the tower, substructure, and structural scantling design and allow for the inclusion of increasingly realistic design constraints based on ultimate and fatigue limit states of the structure. A surrogate-assisted optimization model centered around a linearized frequency-domain aero-hydro-servo-elastic model of a semi-submersible wind turbine was developed and applied to find optimal designs in three hypothetical locations. The optimal designs vary significantly based on the environmental conditions, and show the potential for significant cost-savings by employing site-specific design for floating wind turbines. For all of the hypothetical locations considered here, the tower design is driven by fatigue damage in near-rated wind speed conditions at the tower base and top, and buckling utilization in the rated-wind speed extreme condition for the remaining tower sections. The substructure design is driven by fatigue damage in near-rated wind speed conditions for the central column and above-rated wind speed conditions for the pontoons. Rules-based buckling constraints in the rated-wind speed condition drive the outer column and scantling design. The optimization model has also been used to investigate the impact of the bounds on tower design variables on the integrated tower-substructure structural design, and has the potential to be adapted to help answer a range of other concept-level design questions.
{"title":"Gradient-based design optimization of semi-submersible floating wind turbines","authors":"Peter J. Rohrer , Erin E. Bachynski-Polić , John Marius Hegseth","doi":"10.1016/j.marstruc.2025.103951","DOIUrl":"10.1016/j.marstruc.2025.103951","url":null,"abstract":"<div><div>A wide variety of semi-submersible floating wind turbine designs have been proposed, though few studies have attempted design optimization with more than a handful of design variables. Gradient-based design optimization can enable optimization with many design variables to define the tower, substructure, and structural scantling design and allow for the inclusion of increasingly realistic design constraints based on ultimate and fatigue limit states of the structure. A surrogate-assisted optimization model centered around a linearized frequency-domain aero-hydro-servo-elastic model of a semi-submersible wind turbine was developed and applied to find optimal designs in three hypothetical locations. The optimal designs vary significantly based on the environmental conditions, and show the potential for significant cost-savings by employing site-specific design for floating wind turbines. For all of the hypothetical locations considered here, the tower design is driven by fatigue damage in near-rated wind speed conditions at the tower base and top, and buckling utilization in the rated-wind speed extreme condition for the remaining tower sections. The substructure design is driven by fatigue damage in near-rated wind speed conditions for the central column and above-rated wind speed conditions for the pontoons. Rules-based buckling constraints in the rated-wind speed condition drive the outer column and scantling design. The optimization model has also been used to investigate the impact of the bounds on tower design variables on the integrated tower-substructure structural design, and has the potential to be adapted to help answer a range of other concept-level design questions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103951"},"PeriodicalIF":5.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-07DOI: 10.1016/j.marstruc.2025.103952
Jinming Tu , Fan Yang , Donghua Liu , Yunsong Ji , Chengchao Guo , Fuming Wang
Local scour around the semiconical structure of a monopile was systematically studied considering the side slope angle (α = 0°–60°), protruding height (E/d = 0–2), and flow intensity (clear-water or live-bed flow conditions). The three-dimensional scour profiles and features were meticulously explored using flow visualizations through large-eddy simulations. As the semiconical structure was buried in the seabed (E/d = 0), increasing side slope angle α from 0° to 60° reduced the maximum scour depth Smax by 53 % compared with the results of the monopile without the countermeasure. At E/d = 2, the maximum scour depth occurred at the downstream edge for α ≥ 30°, while the scour upstream was significantly diminished. Smax decreased significantly with an increase in α. At α = 60°, the reduction of Smax is up to 100 %. Vortex shedding also diminished owing to the semiconical structure. An increase in E led to a reduction in Smax, while the flow intensity had a limited impact. An equation for predicting scour-protection efficiency was derived from experimental results; it shows good predictive performance, with errors within 20 %.
{"title":"Local scour around a monopile using semiconical protection in a steady current","authors":"Jinming Tu , Fan Yang , Donghua Liu , Yunsong Ji , Chengchao Guo , Fuming Wang","doi":"10.1016/j.marstruc.2025.103952","DOIUrl":"10.1016/j.marstruc.2025.103952","url":null,"abstract":"<div><div>Local scour around the semiconical structure of a monopile was systematically studied considering the side slope angle (<em>α</em> = 0°–60°), protruding height (<em>E/d</em> = 0–2), and flow intensity (clear-water or live-bed flow conditions). The three-dimensional scour profiles and features were meticulously explored using flow visualizations through large-eddy simulations. As the semiconical structure was buried in the seabed (<em>E/d</em> = 0), increasing side slope angle α from 0° to 60° reduced the maximum scour depth <em>S<sub>max</sub></em> by 53 % compared with the results of the monopile without the countermeasure. At <em>E/d</em> = 2, the maximum scour depth occurred at the downstream edge for <em>α</em> ≥ 30°, while the scour upstream was significantly diminished. <em>S<sub>max</sub></em> decreased significantly with an increase in <em>α</em>. At <em>α</em> = 60°, the reduction of <em>S<sub>max</sub></em> is up to 100 %. Vortex shedding also diminished owing to the semiconical structure. An increase in <em>E</em> led to a reduction in <em>S<sub>max</sub></em>, while the flow intensity had a limited impact. An equation for predicting scour-protection efficiency was derived from experimental results; it shows good predictive performance, with errors within 20 %.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103952"},"PeriodicalIF":5.1,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.marstruc.2025.103946
Limin Huang , Hangyu Chen , Yejia Feng , Gaoxiang Sun , Hao Jiang , Xuewen Ma
Real-time prediction of the ship motion in advance can effectively enhance the safety and efficiency of maritime operations. However, the current prediction methods mainly focus on the motion time series forecasting without considering the uncertainty existing in measured motions. In this paper, a novel prediction method combined with the confidence interval forecasting of the motion is proposed. The method integrates the probability prediction module into the time-series prediction model. The normal distribution and student’s T-distribution are considered and the long short-term memory (LSTM) neural network is selected as the time-series prediction model. A set of measured full-scale ship roll motion of Yukun Ship is used to verify the prediction performance. The results demonstrate that the proposed method can effectively predict the confidence intervals of future ship motions, especially for extreme motions. This approach circumvents the issue of reduced accuracy over longer prediction periods, which is commonly existed in traditional time-series prediction models due to the influence of non-stationary characteristics of the data. Particularly, at the confidence level of 99 %, the prediction results could cover >90 % of the motion time series for future 12 s, which can significantly ensure the safety of offshore operations.
{"title":"Deterministic real-time prediction of ship roll motion with quantified uncertainty based on machine learning","authors":"Limin Huang , Hangyu Chen , Yejia Feng , Gaoxiang Sun , Hao Jiang , Xuewen Ma","doi":"10.1016/j.marstruc.2025.103946","DOIUrl":"10.1016/j.marstruc.2025.103946","url":null,"abstract":"<div><div>Real-time prediction of the ship motion in advance can effectively enhance the safety and efficiency of maritime operations. However, the current prediction methods mainly focus on the motion time series forecasting without considering the uncertainty existing in measured motions. In this paper, a novel prediction method combined with the confidence interval forecasting of the motion is proposed. The method integrates the probability prediction module into the time-series prediction model. The normal distribution and student’s T-distribution are considered and the long short-term memory (LSTM) neural network is selected as the time-series prediction model. A set of measured full-scale ship roll motion of Yukun Ship is used to verify the prediction performance. The results demonstrate that the proposed method can effectively predict the confidence intervals of future ship motions, especially for extreme motions. This approach circumvents the issue of reduced accuracy over longer prediction periods, which is commonly existed in traditional time-series prediction models due to the influence of non-stationary characteristics of the data. Particularly, at the confidence level of 99 %, the prediction results could cover >90 % of the motion time series for future 12 s, which can significantly ensure the safety of offshore operations.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103946"},"PeriodicalIF":5.1,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-26DOI: 10.1016/j.marstruc.2025.103947
Jianxing Yu , Zihang Jin , Yang Yu , Zhongzhen Sun , Ruilong Gao , Ruoke Sun
To enhance the performance of deep-sea pipeline CFRP-winding buckle arrestors, this paper innovatively proposes a CFRP arrestor through joint topology-fiber shape optimization (TFSO). For the high cost of traditional joint optimization, a Multi-Generator conditional Generative Adversarial Network (MG-cGAN) is proposed to enable rapid TFSO prediction without iteration under limited high-cost TFSO dataset. Considering CFRP arrestor’s structural characteristics, the Bi-directional Evolutionary Structural Optimization (BESO) and Nondominated Sorting Genetic Algorithm III (NSGA-III) methods are sequentially employed for topology optimization (TO) and fiber shape optimization (FSO) to yield an improved structure form. Next, MG-cGAN method is used to construct a TFSO prediction model. In offline phase, TO and FSO prediction models are developed using Enhanced Structural Optimization Prediction Residual Network (ESOP-ResNet) based on single-form optimization results. In online phase, a TFSO prediction model is developed by combining TO and FSO predictions, with the model outputs treated as fake and limited serial TFSO results treated as real for adversarial training. Case studies demonstrate that the jointed optimized CFRP arrestor achieves a 25 % increase in arresting efficiency while reducing 40 % volume. Furthermore, MG-cGAN, coupled with ESOP-ResNet, significantly enhances optimization efficiency while maintaining high prediction accuracy, avoiding the substantial cost of constructing large TFSO result datasets.
{"title":"Data-driven topology-fiber shape optimization method for CFRP-winding buckle arrestor based on MG-cGAN","authors":"Jianxing Yu , Zihang Jin , Yang Yu , Zhongzhen Sun , Ruilong Gao , Ruoke Sun","doi":"10.1016/j.marstruc.2025.103947","DOIUrl":"10.1016/j.marstruc.2025.103947","url":null,"abstract":"<div><div>To enhance the performance of deep-sea pipeline CFRP-winding buckle arrestors, this paper innovatively proposes a CFRP arrestor through joint topology-fiber shape optimization (TFSO). For the high cost of traditional joint optimization, a Multi-Generator conditional Generative Adversarial Network (MG-cGAN) is proposed to enable rapid TFSO prediction without iteration under limited high-cost TFSO dataset. Considering CFRP arrestor’s structural characteristics, the Bi-directional Evolutionary Structural Optimization (BESO) and Nondominated Sorting Genetic Algorithm III (NSGA-III) methods are sequentially employed for topology optimization (TO) and fiber shape optimization (FSO) to yield an improved structure form. Next, MG-cGAN method is used to construct a TFSO prediction model. In offline phase, TO and FSO prediction models are developed using Enhanced Structural Optimization Prediction Residual Network (ESOP-ResNet) based on single-form optimization results. In online phase, a TFSO prediction model is developed by combining TO and FSO predictions, with the model outputs treated as fake and limited serial TFSO results treated as real for adversarial training. Case studies demonstrate that the jointed optimized CFRP arrestor achieves a 25 % increase in arresting efficiency while reducing 40 % volume. Furthermore, MG-cGAN, coupled with ESOP-ResNet, significantly enhances optimization efficiency while maintaining high prediction accuracy, avoiding the substantial cost of constructing large TFSO result datasets.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103947"},"PeriodicalIF":5.1,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号