Pub Date : 2026-01-07DOI: 10.1016/j.marstruc.2025.104005
Arun Rajput , Harikrishna Chavhan
The elastic properties of honeycomb structures are determined by the foil thickness (FT) and cell size (CS), which significantly influence their mechanical behavior. In present study, comparison of energy absorption capacity and specific energy absorption of different shapes of honeycombs (Hexagonal, Square and Triangular) sandwich composites has been presented. Initially, experiments were performed on a pair of hexagonal honeycomb sandwich composites using a Charpy impact testing machine in accordance with ASTM E23 standards. The experimental results were validated through numerical simulations conducted using the commercially available software Abaqus, showing good agreement. Subsequently, numerical simulations were extended to various honeycomb sandwich structure geometries. Energy absorption and specific energy absorption (SEA) values were extracted at the time steps corresponding to the detachment of the specimen from the supports. A comparison of the energy absorbed by different honeycomb shapes was carried out. Furthermore, the influence of FT, CS, and core height (CH) on the SEA of various honeycomb geometries was examined through detailed numerical analysis.
{"title":"Effect of honeycomb shape and parameters on specific energy absorption of aluminium honeycomb sandwich composites","authors":"Arun Rajput , Harikrishna Chavhan","doi":"10.1016/j.marstruc.2025.104005","DOIUrl":"10.1016/j.marstruc.2025.104005","url":null,"abstract":"<div><div>The elastic properties of honeycomb structures are determined by the foil thickness (FT) and cell size (CS), which significantly influence their mechanical behavior. In present study, comparison of energy absorption capacity and specific energy absorption of different shapes of honeycombs (Hexagonal, Square and Triangular) sandwich composites has been presented. Initially, experiments were performed on a pair of hexagonal honeycomb sandwich composites using a Charpy impact testing machine in accordance with ASTM E23 standards. The experimental results were validated through numerical simulations conducted using the commercially available software Abaqus, showing good agreement. Subsequently, numerical simulations were extended to various honeycomb sandwich structure geometries. Energy absorption and specific energy absorption (SEA) values were extracted at the time steps corresponding to the detachment of the specimen from the supports. A comparison of the energy absorbed by different honeycomb shapes was carried out. Furthermore, the influence of FT, CS, and core height (CH) on the SEA of various honeycomb geometries was examined through detailed numerical analysis.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104005"},"PeriodicalIF":5.1,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938794","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}
Ships can suffer impact injuries when they are impacted by underwater explosions. Currently, the impact injury studies of seated crew members are mostly focused on lumbar-pelvic and neck whiplash injuries, and there is a lack of analysis of secondary collision injuries in the absence of seatbelt restraints. In this paper, an impact injury analysis of seated shipmates was carried out based on a multibody dynamics human model, and the accuracy of the model was verified by experimental comparison. Head Injury Criterion (HIC), Neck Injury (NIJ), Dynamic Response Index (DRI) and other injury guidelines were used to evaluate the impact damage in various parts of the human body. Sensitivity analysis was conducted for two parameters, namely impact factor and angle of attack, comparing the damage patterns of the human body with and without seat belt restraints. The results showed that the crew with a seatbelt produced a four-cycle whiplash motion, and the crew without a seatbelt would produce three phases: flight phase, deck-head collision phase, and deck-torso collision phase. These findings can guide the development of impact injury protection strategies for shipmates.
当船只受到水下爆炸的冲击时，可能会受到撞击伤。目前，对坐式乘员的碰撞损伤研究多集中在腰骨盆和颈部颈部鞭打伤，缺乏对无安全带约束的二次碰撞损伤的分析。本文基于多体动力学人体模型对坐式船友的碰撞损伤进行了分析，并通过实验对比验证了模型的准确性。采用Head Injury Criterion （HIC）、Neck Injury （NIJ）、Dynamic Response Index （DRI）等损伤指南对人体各部位的冲击损伤进行评价。对冲击系数和迎角两个参数进行敏感性分析，比较有无安全带约束时人体的损伤模式。结果表明，系安全带的机组人员产生了4个周期的鞭动，而不系安全带的机组人员产生了3个周期的鞭动：飞行阶段、甲板头部碰撞阶段和甲板躯干碰撞阶段。这些发现可以指导船员碰撞伤害保护策略的制定。
{"title":"Research on impact damage of ship crew with sitting posture","authors":"Wenqi Zhang , Shenhe Zhang , Zhifan Zhang , Guiyong Zhang , Ying Li","doi":"10.1016/j.marstruc.2025.103996","DOIUrl":"10.1016/j.marstruc.2025.103996","url":null,"abstract":"<div><div>Ships can suffer impact injuries when they are impacted by underwater explosions. Currently, the impact injury studies of seated crew members are mostly focused on lumbar-pelvic and neck whiplash injuries, and there is a lack of analysis of secondary collision injuries in the absence of seatbelt restraints. In this paper, an impact injury analysis of seated shipmates was carried out based on a multibody dynamics human model, and the accuracy of the model was verified by experimental comparison. Head Injury Criterion (HIC), Neck Injury (NIJ), Dynamic Response Index (DRI) and other injury guidelines were used to evaluate the impact damage in various parts of the human body. Sensitivity analysis was conducted for two parameters, namely impact factor and angle of attack, comparing the damage patterns of the human body with and without seat belt restraints. The results showed that the crew with a seatbelt produced a four-cycle whiplash motion, and the crew without a seatbelt would produce three phases: flight phase, deck-head collision phase, and deck-torso collision phase. These findings can guide the development of impact injury protection strategies for shipmates.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 103996"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884568","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 : 2025-12-31DOI: 10.1016/j.marstruc.2025.104001
Chenyu Wang, Fulian Li , Binbin Li
The growing demand for renewable energy has driven focus toward floating offshore wind turbines (FOWTs), although their economic viability remains hindered by high costs. While shared mooring designs employ shared lines among multiple FOWTs as a coupled multibody system, their safety redundancy under extreme conditions, including mooring line failure scenarios, still requires extensive validations. This study aims to evaluate the dynamic behaviors of a grand trine shared mooring system for floating offshore wind farms under mooring line failure scenarios in 50-year return period storm conditions. Both damaged and transient analyses are conducted for a 3-FOWT grand trine shared mooring floating offshore wind farm in different mooring line failure scenarios by the in-house software Kraken to investigate the dynamic behaviors and transient effects. Results indicate the failure of a shared mooring line significantly affects the offset and line tension of the connected FOWTs, while having a minimal impact on other FOWTs unconnected with the shared line. The FOWT motions exhibit significant transient effects when the line failure deviates from the environmental load direction, while mooring line tensions exhibit negligible transient effects. The static and dynamic tension of shared lines in failure scenarios is significantly lower than upstream anchored lines, which exhibit minimal differences compared to those in intact conditions.
{"title":"Study of damaged and transient effects of the grand trine shared mooring system for floating offshore wind farms","authors":"Chenyu Wang, Fulian Li , Binbin Li","doi":"10.1016/j.marstruc.2025.104001","DOIUrl":"10.1016/j.marstruc.2025.104001","url":null,"abstract":"<div><div>The growing demand for renewable energy has driven focus toward floating offshore wind turbines (FOWTs), although their economic viability remains hindered by high costs. While shared mooring designs employ shared lines among multiple FOWTs as a coupled multibody system, their safety redundancy under extreme conditions, including mooring line failure scenarios, still requires extensive validations. This study aims to evaluate the dynamic behaviors of a grand trine shared mooring system for floating offshore wind farms under mooring line failure scenarios in 50-year return period storm conditions. Both damaged and transient analyses are conducted for a 3-FOWT grand trine shared mooring floating offshore wind farm in different mooring line failure scenarios by the in-house software Kraken to investigate the dynamic behaviors and transient effects. Results indicate the failure of a shared mooring line significantly affects the offset and line tension of the connected FOWTs, while having a minimal impact on other FOWTs unconnected with the shared line. The FOWT motions exhibit significant transient effects when the line failure deviates from the environmental load direction, while mooring line tensions exhibit negligible transient effects. The static and dynamic tension of shared lines in failure scenarios is significantly lower than upstream anchored lines, which exhibit minimal differences compared to those in intact conditions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104001"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884567","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 : 2025-12-31DOI: 10.1016/j.marstruc.2025.104000
Alastair Ramsay , Vahid Vaziri , Sean Snee , Marcin Kapitaniak
The growing deployment of floating offshore wind turbines (FOWTs) presents new challenges in maintenance operations, particularly concerning in-situ component replacement. This study builds upon prior research into the feasibility of using a floating crane for generator exchange on a semi-submersible FOWT, specifically the UMaine VolturnUS-S supporting a 15 MW reference turbine. Utilising a marine simulation environment at NDC, the dynamic responses of the generator, nacelle, and crane barge were evaluated under various sea states. The results highlight that while generator accelerations are a significant operational factor, the primary constraint is the risk of collision between the generator and turbine structure during lifting operations. Parametric studies revealed critical wave periods that exacerbate generator motions and collisions, and while modifications to the lifting methodology proved ineffective, reorienting the crane barge parallel to incoming waves showed a modest reduction in collisions. These findings underline the importance of vessel selection, wave direction, and sea state limitations in ensuring the viability of in-situ maintenance using floating cranes for FOWTs.
{"title":"De-risking utilising a floating crane for floating offshore wind turbine maintenance","authors":"Alastair Ramsay , Vahid Vaziri , Sean Snee , Marcin Kapitaniak","doi":"10.1016/j.marstruc.2025.104000","DOIUrl":"10.1016/j.marstruc.2025.104000","url":null,"abstract":"<div><div>The growing deployment of floating offshore wind turbines (FOWTs) presents new challenges in maintenance operations, particularly concerning in-situ component replacement. This study builds upon prior research into the feasibility of using a floating crane for generator exchange on a semi-submersible FOWT, specifically the UMaine VolturnUS-S supporting a 15 MW reference turbine. Utilising a marine simulation environment at NDC, the dynamic responses of the generator, nacelle, and crane barge were evaluated under various sea states. The results highlight that while generator accelerations are a significant operational factor, the primary constraint is the risk of collision between the generator and turbine structure during lifting operations. Parametric studies revealed critical wave periods that exacerbate generator motions and collisions, and while modifications to the lifting methodology proved ineffective, reorienting the crane barge parallel to incoming waves showed a modest reduction in collisions. These findings underline the importance of vessel selection, wave direction, and sea state limitations in ensuring the viability of in-situ maintenance using floating cranes for FOWTs.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104000"},"PeriodicalIF":5.1,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884569","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 : 2025-12-30DOI: 10.1016/j.marstruc.2025.104003
Xiaofeng Dong , Honghao Peng , Zekun Shi , Jijian Lian , Yang Gao , Yan Li
Ensuring the operational safety of offshore wind turbine (OWT) structures during their service period requires accurate identification on the operational modal parameters (OMPs), which are not only a crucial parameter which reflect the structure’s vibration characteristics, but also a key index for evaluating the structural healthy status. However, due to the complex and unpredictable ocean environmental circumstances, the measured signals obtained from the actual OWT structures are frequently accompanied by a huge amount of low-frequency, high-energy noise, which has a significant influence on the identification accuracy of OMPs. Therefore, one called CSVS (CEEMDAN-SSA-VMD-SSI) modal identification process, which combined the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), sparrow search algorithm (SSA), variational modal decomposition (VMD) and stochastic subspace identification (SSI) method, was proposed for identifying modal parameters of OWT structures under operational conditions. It aims to mitigate the influence on the identification accuracy resulted from the low-frequency, high-energy noise and investigates the variations of modal parameters based on measured data. Firstly, the CEEMDAN method and VMD process optimized by the SSA were used to decompose the signal and remove the low-frequency, high-energy noises, and then the SSI method was following applied to identify and extract the OMPs from the measured data. Secondly, the efficiency of the proposed CSVS approach to identify OMPs of one 3.3 MW OWT operating in Yellow sea of China, was confirmed based on the measured vibration displacement signals under various operational conditions by comparing the results identified from the classic method. Finally, the distribution characteristics of the natural modal frequency, impeller rotation frequency (1P) and blade sweeping frequency (3P) were furtherly investigated, and the change regulations of identified OMPs with the operational factors including wind speed and rotational speed were also provided. It is indicated that the CSVS method shows the strong resistance to modal aliasing and effectiveness on noise reduction compared to the traditional methods so that it can accurately identify and distinguish the natural modal frequency, 1P frequency and 3P frequency of the OWT structure. Further, it may provide the essential technical support for identifying the OMPs and evaluating the operational safety of OWT structures.
{"title":"One operational modal parameter identification approach for offshore wind turbine structure resisting low-frequency and high-energy noise interference","authors":"Xiaofeng Dong , Honghao Peng , Zekun Shi , Jijian Lian , Yang Gao , Yan Li","doi":"10.1016/j.marstruc.2025.104003","DOIUrl":"10.1016/j.marstruc.2025.104003","url":null,"abstract":"<div><div>Ensuring the operational safety of offshore wind turbine (OWT) structures during their service period requires accurate identification on the operational modal parameters (OMPs), which are not only a crucial parameter which reflect the structure’s vibration characteristics, but also a key index for evaluating the structural healthy status. However, due to the complex and unpredictable ocean environmental circumstances, the measured signals obtained from the actual OWT structures are frequently accompanied by a huge amount of low-frequency, high-energy noise, which has a significant influence on the identification accuracy of OMPs. Therefore, one called CSVS (CEEMDAN-SSA-VMD-SSI) modal identification process, which combined the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), sparrow search algorithm (SSA), variational modal decomposition (VMD) and stochastic subspace identification (SSI) method, was proposed for identifying modal parameters of OWT structures under operational conditions. It aims to mitigate the influence on the identification accuracy resulted from the low-frequency, high-energy noise and investigates the variations of modal parameters based on measured data. Firstly, the CEEMDAN method and VMD process optimized by the SSA were used to decompose the signal and remove the low-frequency, high-energy noises, and then the SSI method was following applied to identify and extract the OMPs from the measured data. Secondly, the efficiency of the proposed CSVS approach to identify OMPs of one 3.3 MW OWT operating in Yellow sea of China, was confirmed based on the measured vibration displacement signals under various operational conditions by comparing the results identified from the classic method. Finally, the distribution characteristics of the natural modal frequency, impeller rotation frequency (1P) and blade sweeping frequency (3P) were furtherly investigated, and the change regulations of identified OMPs with the operational factors including wind speed and rotational speed were also provided. It is indicated that the CSVS method shows the strong resistance to modal aliasing and effectiveness on noise reduction compared to the traditional methods so that it can accurately identify and distinguish the natural modal frequency, 1P frequency and 3P frequency of the OWT structure. Further, it may provide the essential technical support for identifying the OMPs and evaluating the operational safety of OWT structures.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104003"},"PeriodicalIF":5.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884564","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 : 2025-12-30DOI: 10.1016/j.marstruc.2025.104006
Ling-Yu Chen, Tiao-Jian Xu
Wind-fishery integration, a novel development model combining offshore wind power and marine aquaculture, effectively addresses marine resource conflicts. This study presents an innovative marine integrated structure (JOWT+AC), combining jacket-foundation offshore wind turbines (JOWT) with aquaculture cages (AC). The numerical simulation method was first validated using data from physical model experiments, and then used to analyze the dynamic response of the structure. Results indicate that pile loads, leg stresses, and displacements are most affected by wave period, along with wave height and incidence angle. Bottom rope tensions in AC are significantly higher than top ones, with JOWT+AC-M2 (with a total of 12 mooring points) and M3 (with a total of 20 mooring points) showing about 32 % of M1’s (with a total of 8 mooring points) bottom rope tension, while top tensions remain similar. A middle rope section aids in load redistribution, while different mooring configurations influence load paths and structural stiffness. The AC’s damping effect reduces the JOWT+AC dynamic response compared to standalone JOWT. This study offers theoretical guidance for sustainable JOWT+AC design through combined physical and numerical modelling.
{"title":"Dynamic response analysis of integrated jacket offshore wind turbine foundation and aquaculture cage structure under regular waves","authors":"Ling-Yu Chen, Tiao-Jian Xu","doi":"10.1016/j.marstruc.2025.104006","DOIUrl":"10.1016/j.marstruc.2025.104006","url":null,"abstract":"<div><div>Wind-fishery integration, a novel development model combining offshore wind power and marine aquaculture, effectively addresses marine resource conflicts. This study presents an innovative marine integrated structure (JOWT+AC), combining jacket-foundation offshore wind turbines (JOWT) with aquaculture cages (AC). The numerical simulation method was first validated using data from physical model experiments, and then used to analyze the dynamic response of the structure. Results indicate that pile loads, leg stresses, and displacements are most affected by wave period, along with wave height and incidence angle. Bottom rope tensions in AC are significantly higher than top ones, with JOWT+AC-M2 (with a total of 12 mooring points) and M3 (with a total of 20 mooring points) showing about 32 % of M1’s (with a total of 8 mooring points) bottom rope tension, while top tensions remain similar. A middle rope section aids in load redistribution, while different mooring configurations influence load paths and structural stiffness. The AC’s damping effect reduces the JOWT+AC dynamic response compared to standalone JOWT. This study offers theoretical guidance for sustainable JOWT+AC design through combined physical and numerical modelling.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104006"},"PeriodicalIF":5.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884565","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 : 2025-12-29DOI: 10.1016/j.marstruc.2025.103994
M. Gomis , S. Fernández-Ruano , J.J. Viadero , R. Guanche , M. Redon , M. Sirera , E. Pons-Puig
In this study, the hydrodynamic behaviour of a floating photovoltaic (FPV) platform designed by ISIGENERE was evaluated through 107 experimental tests conducted in a wave tank at Cantabria Coastal and Ocean Basin (CCOB, IHCantabria). The system, composed of interconnected floating units joined using nylon plates reinforce with fiberglass, was tested under regular and irregular wave conditions to understand the interactions between waves and the floating structure. The results highlight that the dynamic regime of the platform is primarily determined by the wave period. For longer periods, the platform behaves as a wave follower, whereas shorter periods induce higher motion amplitudes of the windward floats because of increased energy dissipation. In terms of wave direction, energy dissipation is most efficient under perpendicular waves (90°). In this study, the mooring system was also assessed, revealing that surge and heave motions dominate its response, with energy concentrated at frequencies matching those of the waves. These findings are critical for optimizing the design of FPV platforms and enhancing their energy dissipation capacity and mooring resilience under various marine conditions. This study provides empirical data and design insights to support the development and global integration of efficient, scalable floating photovoltaic systems.
{"title":"Floating solar PV response to wave action","authors":"M. Gomis , S. Fernández-Ruano , J.J. Viadero , R. Guanche , M. Redon , M. Sirera , E. Pons-Puig","doi":"10.1016/j.marstruc.2025.103994","DOIUrl":"10.1016/j.marstruc.2025.103994","url":null,"abstract":"<div><div>In this study, the hydrodynamic behaviour of a floating photovoltaic (FPV) platform designed by ISIGENERE was evaluated through 107 experimental tests conducted in a wave tank at Cantabria Coastal and Ocean Basin (CCOB, IHCantabria). The system, composed of interconnected floating units joined using nylon plates reinforce with fiberglass, was tested under regular and irregular wave conditions to understand the interactions between waves and the floating structure. The results highlight that the dynamic regime of the platform is primarily determined by the wave period. For longer periods, the platform behaves as a wave follower, whereas shorter periods induce higher motion amplitudes of the windward floats because of increased energy dissipation. In terms of wave direction, energy dissipation is most efficient under perpendicular waves (90°). In this study, the mooring system was also assessed, revealing that surge and heave motions dominate its response, with energy concentrated at frequencies matching those of the waves. These findings are critical for optimizing the design of FPV platforms and enhancing their energy dissipation capacity and mooring resilience under various marine conditions. This study provides empirical data and design insights to support the development and global integration of efficient, scalable floating photovoltaic systems.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 103994"},"PeriodicalIF":5.1,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884563","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 : 2025-12-29DOI: 10.1016/j.marstruc.2025.103995
Rinor Lubovci , İlyas Kacar
An autonomous catamaran is designed, optimized, and implemented. Its structural parameters are optimized to achieve a cost-effective operating and a lightweight and safe structure. An optimization technique based on the genetic algorithm method and finite element simulation are employed. Besides, computational fluid dynamics is utilized to determine the hydromechanics characteristics of the catamaran. Lastly, the response to random vibrations is investigated. Due to industrialization in recent years, environmental degradation has become one of the main issues for the world. Regulations are the only protection mechanism against this issue, but they are not enough yet. In addition, present water surface cleaning techniques are far from autonomy and low energy consumption. The proposed design has lightweight structure with lower energy consumption, making it suitable for autonomous operations. By integrating computational fluid dynamics simulation, genetic algorithms, random vibration analysis, and structural optimization, this study presents a novel approach that improves energy efficiency and operational stability, addressing gaps in existing autonomous water-cleaning technologies. The findings indicate that the catamaran operates safely for lifting 350.75 N. It holds potential for various applications, including marine, area near moored ferries, and trading ports with high human population and pollution levels.
{"title":"Design and optimization of an autonomous catamaran for water surface cleaning","authors":"Rinor Lubovci , İlyas Kacar","doi":"10.1016/j.marstruc.2025.103995","DOIUrl":"10.1016/j.marstruc.2025.103995","url":null,"abstract":"<div><div>An autonomous catamaran is designed, optimized, and implemented. Its structural parameters are optimized to achieve a cost-effective operating and a lightweight and safe structure. An optimization technique based on the genetic algorithm method and finite element simulation are employed. Besides, computational fluid dynamics is utilized to determine the hydromechanics characteristics of the catamaran. Lastly, the response to random vibrations is investigated. Due to industrialization in recent years, environmental degradation has become one of the main issues for the world. Regulations are the only protection mechanism against this issue, but they are not enough yet. In addition, present water surface cleaning techniques are far from autonomy and low energy consumption. The proposed design has lightweight structure with lower energy consumption, making it suitable for autonomous operations. By integrating computational fluid dynamics simulation, genetic algorithms, random vibration analysis, and structural optimization, this study presents a novel approach that improves energy efficiency and operational stability, addressing gaps in existing autonomous water-cleaning technologies. The findings indicate that the catamaran operates safely for lifting 350.75 N. It holds potential for various applications, including marine, area near moored ferries, and trading ports with high human population and pollution levels.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 103995"},"PeriodicalIF":5.1,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884570","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 : 2025-12-29DOI: 10.1016/j.marstruc.2025.103998
Jiahao Bian , Ling Wan , Kai Chen , Naiquan Ye , Svein Sævik , Torgeir Moan
As floating wind turbines develop toward deeper waters, and turbine power capacity continues to increase, the design of dynamic power cables for floating wind turbines faces significant challenges. This study systematically analyzes the response characteristics and configuration optimization of dynamic cables under various underwater configurations, i.e., catenary, lazy wave, lazy S, steep wave and steep S configurations, and under four different water depth conditions, i.e., 50 m, 100 m, 150 m and 200 m, based on a 15MW semi-submersible floating wind turbine platform. Firstly, a fully coupled time-domain numerical model considering mooring system and dynamic power cable is established; then, taking lazy-wave configuration under 100 m water depth as a base model, axial forces and displacement of the cable at various locations along the cable length are comprehensively analyzed under different environmental conditions, revealing the cable dynamic characteristics; Furthermore, under shallow water condition, various cable underwater configurations are investigated, showing problems of the catenary configuration, and indicating the necessity of applying bend stiffeners and bend restrictors; In addition, under medium and deep water conditions, dynamic power cable responses including underwater configurations, key mechanical properties (axial force, bending moment, and curvature) at critical locations along the cable length are comprehensively studied for various configurations, highlighting critical locations that may suffer larger dynamic responses. This work provides a theoretical basis and engineering reference for the design and optimization of dynamic cables for large-capacity floating wind turbines under different environmental conditions.
{"title":"Power cable underwater configurations and dynamics for a 15MW floating wind turbine at different water depths","authors":"Jiahao Bian , Ling Wan , Kai Chen , Naiquan Ye , Svein Sævik , Torgeir Moan","doi":"10.1016/j.marstruc.2025.103998","DOIUrl":"10.1016/j.marstruc.2025.103998","url":null,"abstract":"<div><div>As floating wind turbines develop toward deeper waters, and turbine power capacity continues to increase, the design of dynamic power cables for floating wind turbines faces significant challenges. This study systematically analyzes the response characteristics and configuration optimization of dynamic cables under various underwater configurations, i.e., catenary, lazy wave, lazy S, steep wave and steep S configurations, and under four different water depth conditions, i.e., 50 m, 100 m, 150 m and 200 m, based on a 15MW semi-submersible floating wind turbine platform. Firstly, a fully coupled time-domain numerical model considering mooring system and dynamic power cable is established; then, taking lazy-wave configuration under 100 m water depth as a base model, axial forces and displacement of the cable at various locations along the cable length are comprehensively analyzed under different environmental conditions, revealing the cable dynamic characteristics; Furthermore, under shallow water condition, various cable underwater configurations are investigated, showing problems of the catenary configuration, and indicating the necessity of applying bend stiffeners and bend restrictors; In addition, under medium and deep water conditions, dynamic power cable responses including underwater configurations, key mechanical properties (axial force, bending moment, and curvature) at critical locations along the cable length are comprehensively studied for various configurations, highlighting critical locations that may suffer larger dynamic responses. This work provides a theoretical basis and engineering reference for the design and optimization of dynamic cables for large-capacity floating wind turbines under different environmental conditions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 103998"},"PeriodicalIF":5.1,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884566","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 : 2025-12-26DOI: 10.1016/j.marstruc.2025.103999
Qingxin Li , Guangsi Chen , Jijian Lian , Run Liu , Huaicheng Liu
Offshore wind turbines are subjected to long-term vertical deadweight load during service life. Before experiencing extreme conditions, the vertical dead load accelerates the drainage and consolidation of the ground, leading to strength enhancement of the soil. This paper quantitatively evaluates the effects of vertical dead load on the uniaxial consolidated bearing capacity of composite bucket foundations. First, centrifuge tests are conducted on the torsional consolidated bearing capacity of composite bucket foundations, and then a finite element model is established. Significant differences in consolidated bearing characteristics among the composite bucket foundation, shallow foundation and mono-bucket foundation are revealed. The necessity to investigate the bearing characteristics of composite bucket foundation affected by soil consolidation is clarified. Next, a framework is established as a unified analysis tool for calculating the different uniaxial consolidated bearing capacities of composite bucket foundations. Considering changes in bearing mechanism, theoretical prediction formulae for uniaxial consolidated bearing capacity are proposed for the first time. Finally, the development of partially consolidated bearing capacity over time is analysed, and the influence of key factors on partially consolidated bearing capacity is evaluated. The simulation results indicate the proposed methods can effectively evaluate the gain of consolidation effect caused by vertical dead load on the uniaxial bearing capacity, and provide practical design guidance for consolidation engineering of composite bucket foundations under vertical dead load.
{"title":"Quantitative evaluation method for uniaxial consolidated bearing capacity of composite bucket foundation under vertical dead load","authors":"Qingxin Li , Guangsi Chen , Jijian Lian , Run Liu , Huaicheng Liu","doi":"10.1016/j.marstruc.2025.103999","DOIUrl":"10.1016/j.marstruc.2025.103999","url":null,"abstract":"<div><div>Offshore wind turbines are subjected to long-term vertical deadweight load during service life. Before experiencing extreme conditions, the vertical dead load accelerates the drainage and consolidation of the ground, leading to strength enhancement of the soil. This paper quantitatively evaluates the effects of vertical dead load on the uniaxial consolidated bearing capacity of composite bucket foundations. First, centrifuge tests are conducted on the torsional consolidated bearing capacity of composite bucket foundations, and then a finite element model is established. Significant differences in consolidated bearing characteristics among the composite bucket foundation, shallow foundation and mono-bucket foundation are revealed. The necessity to investigate the bearing characteristics of composite bucket foundation affected by soil consolidation is clarified. Next, a framework is established as a unified analysis tool for calculating the different uniaxial consolidated bearing capacities of composite bucket foundations. Considering changes in bearing mechanism, theoretical prediction formulae for uniaxial consolidated bearing capacity are proposed for the first time. Finally, the development of partially consolidated bearing capacity over time is analysed, and the influence of key factors on partially consolidated bearing capacity is evaluated. The simulation results indicate the proposed methods can effectively evaluate the gain of consolidation effect caused by vertical dead load on the uniaxial bearing capacity, and provide practical design guidance for consolidation engineering of composite bucket foundations under vertical dead load.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 103999"},"PeriodicalIF":5.1,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839971","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}
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