Ocean EngineeringPub Date : 2025-03-26DOI: 10.1016/j.oceaneng.2025.121013
Minghao Li, Xiaowei Tang, Kaiwei Wang, Chengxiang Song, Shuai Li
{"title":"Seismic performance assessment of composite breakwater on liquefiable seabed foundations with various reinforcement schemes","authors":"Minghao Li, Xiaowei Tang, Kaiwei Wang, Chengxiang Song, Shuai Li","doi":"10.1016/j.oceaneng.2025.121013","DOIUrl":"10.1016/j.oceaneng.2025.121013","url":null,"abstract":"<div><div>As an important coastal protective structure, the breakwater is prone to failure due to foundation damage under seismic actions. However, the seismic performance evaluation of breakwaters has received little attention. This study conducts a seismic fragility analysis of composite breakwaters constructed on liquefiable foundations. By adopting a performance-based seismic design (PBSD) approach and considering the record-to-record (RTR) variability of ground motions, the seismic performance of the breakwaters is assessed over their entire lifecycle. Based on the results of the parameter sensitivity analysis, the reinforcement schemes were proposed in terms of delaying foundation liquefaction and limiting the lateral displacement of liquefied soil. The results of the seismic intensity measure (IM) parameter selection indicate that the commonly used peak ground acceleration (PGA) exhibits a weak correlation with the seismic response of the breakwater, whereas the cumulative absolute velocity (CAV) has a strong correlation. The comparison of the reinforcement schemes shows that the Dense Sand Column (DC) scheme provides significant reinforcement effects, while the Concrete Sheet Pile (CSP) scheme is more suitable for reinforcing existing breakwaters. The seismic performance assessment framework can also be applied to other structures where structural damage is closely related to foundation deformation, such as caisson quays and embankments.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121013"},"PeriodicalIF":4.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704442","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}
Ocean EngineeringPub Date : 2025-03-26DOI: 10.1016/j.oceaneng.2025.121030
Guangxi Cui , Zhongya Cai , Xiaofeng Yang
{"title":"IWResNet-MA: A deep learning framework for extracting internal wave stripe and propagation direction from SAR imagery","authors":"Guangxi Cui , Zhongya Cai , Xiaofeng Yang","doi":"10.1016/j.oceaneng.2025.121030","DOIUrl":"10.1016/j.oceaneng.2025.121030","url":null,"abstract":"<div><div>Internal waves play a critical role in the transport of oceanic matter, momentum, and energy in the ocean. Using Synthetic Aperture Radar (SAR) images, this study developed a deep learning-based method (IWResNet-MA) to extract the IW's stripes and propagation direction. In this method, the stripes extraction model (IWResNet) incorporates the Binary Cross Entropy (BCE) and Matthews Correlation Coefficient (MCC) loss functions. Additionally, the IW propagation direction was extracted by the morphological analysis (MA) of IW stripes based on convex hull of wave crests. The developed IWResNet-MA model was then tested in the Northern South China Sea (NSCS), where is one of the most active regions for IWs. Compared with the previous detection methods, the IWResNet model achieved a much better performance with the mean precision, recall, and F1-score of 89.14 %, 90.22 %, and 89.26 %, respectively. The mean absolute error of new MA method was 2.43 %, indicating its accurate extraction of the propagation directions of IWs. The statistical results further indicate that IWs are primarily distributed along the upper branch of the slope current. From Luzon Strait to the east of Hainan Island, the propagation angle gradually increases from 276° to 304°, aligning with the topographical variations.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121030"},"PeriodicalIF":4.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704444","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}
Ocean EngineeringPub Date : 2025-03-26DOI: 10.1016/j.oceaneng.2025.121007
Ho-Seong Yang , Ali Alkhabbaz , Young-Ho Lee
{"title":"Integrated CFD and hydrodynamic correction approach for load response analysis of floating offshore wind turbine","authors":"Ho-Seong Yang , Ali Alkhabbaz , Young-Ho Lee","doi":"10.1016/j.oceaneng.2025.121007","DOIUrl":"10.1016/j.oceaneng.2025.121007","url":null,"abstract":"<div><div>This study investigates the load response of a 10 MW FOWT mounted on a semi-submersible platform using CFD and hydrodynamic correction methods. The primary objective is to derive generalized correction coefficients through free decay simulations and evaluate the load response under regular wave conditions. To achieve this, three correction approaches, damping coefficient-based, drag coefficient-based, and a hybrid combining both were compared. A newly designed 10 MW semi-submersible substructure connected by pontoons was employed instead of the extensively studied OC4 DeepCwind model. The analysis revealed that the correction method relying solely on damping coefficients failed to capture critical load responses under regular wave conditions and demonstrated inaccuracies. In contrast, the hybrid correction method, which incorporates both drag and damping coefficients, better captured viscous effects and improved damping accuracy, leading to more accurate load response predictions for the 10 MW semi-submersible FOWT. These findings highlight the necessity of considering both free decay results and real-world environmental conditions when determining correction coefficients to enhance prediction accuracy. This study evaluates various correction approaches to enhance hydrodynamic modeling accuracy of FOWTs.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121007"},"PeriodicalIF":4.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704443","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}
Ocean EngineeringPub Date : 2025-03-25DOI: 10.1016/j.oceaneng.2025.121065
Chaodong Hu , Yu Wang , Xu Han , Hui Liu , Qun Sun , Bo Zhou
{"title":"Research on speed optimization of fixed route ship with low data dependence","authors":"Chaodong Hu , Yu Wang , Xu Han , Hui Liu , Qun Sun , Bo Zhou","doi":"10.1016/j.oceaneng.2025.121065","DOIUrl":"10.1016/j.oceaneng.2025.121065","url":null,"abstract":"<div><div>A low data demand long-term fuel consumption prediction model suitable for variable pitch propeller ships has been established for the first time, and a segmented route speed optimization method has been provided. The event triggered Informer (ET-Informer) algorithm has the ability to predict long-term high-precision sequences and capture key data to reduce data redundancy and improve computational efficiency. The event triggering mechanism allows for data loss at a certain stage, improving the algorithm's fault tolerance and reducing communication requirements. An ordered sample clustering algorithm based on the weighted event-triggered mechanism is introduced, enabling the adjustment of clustering weights according to demand. The threshold for dynamically adjusting similarity measures triggered by events can solve the problem of uneven clustering distribution. This study reduces data dependency and improves the fault tolerance and accuracy of speed optimization through two aspects: fuel consumption model prediction and route segment speed optimization. The proposed algorithm was validated using real-world data from 24 passenger ferry voyages on major international routes in 2021, achieving a fuel consumption prediction accuracy of 98.4 % and a 4.4 % reduction in fuel consumption, while maintaining travel time. The results confirm the effectiveness, robustness, and practical applicability of the fixed-route speed optimization algorithm.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679224","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}
{"title":"Distributed fixed-time formation control for UAV-USV multiagent systems based on the FEWNN with prescribed performance","authors":"Haitao Liu , Huiting Huang , Xuehong Tian , Jing Zhang","doi":"10.1016/j.oceaneng.2025.120996","DOIUrl":"10.1016/j.oceaneng.2025.120996","url":null,"abstract":"<div><div>This paper investigates the problem of formation trajectory tracking control for heterogeneous multiagent systems with error time-varying constraints, prescribed performance and external disturbances. The multiagent system consists of multiple unmanned aerial vehicles (UAVs) and multiple unmanned surface vessels (USVs). First, a distributed fixed-time adaptive state observer is designed for each agent to obtain the virtual leader's state accurately, which is important for accomplishing a specific formation. Second, a funnel function is introduced as the prescribed performance function to constrain the tracking error, and a formation tracking control protocol with error time-varying constraints is proposed to ensure that all followers quickly achieve formation tracking and the specific formation. Third, a fixed-time fuzzy Elman wavelet neural network (FEWNN) is proposed to approximate the external disturbances for UAV-USV systems to improve robustness. Through the Lyapunov function theorem, the proposed distributed fixed-time formation control approach can ensure that the closed-loop system is stable within a fixed time. Finally, the simulation results demonstrate the feasibility and flexibility of the proposed approach.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 120996"},"PeriodicalIF":4.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679225","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}
Ocean EngineeringPub Date : 2025-03-25DOI: 10.1016/j.oceaneng.2025.121052
Xin Chen , Naiwei Kuai , Wenwei Fu , Zhiqiang Zhang , Tong Guo , Tao Liu , Cong Liu
{"title":"Automated physics parameter identification of tuned vibration absorber in offshore wind turbines based on unsupervised spectral clustering and SSI","authors":"Xin Chen , Naiwei Kuai , Wenwei Fu , Zhiqiang Zhang , Tong Guo , Tao Liu , Cong Liu","doi":"10.1016/j.oceaneng.2025.121052","DOIUrl":"10.1016/j.oceaneng.2025.121052","url":null,"abstract":"<div><div>Tuned vibration absorbers (TVBs) are essential for vibration control in offshore wind turbines (OWTs), which are subjected to noticeable vibrations caused by environmental loads. The complex dynamic characteristics of OWT with TVBs pose challenges for traditional methods to accurately identify modal parameters. This paper presents an automated parameter identification method based on spectral clustering and stochastic subspace identification (SSI). This method takes into account the contributions of modal information, with the weighted distance function ensuring the accurate calculation of modal parameter contributions. It effectively improves the accuracy of identifying closely spaced modes. For the numerical simulations, the identification results show high accuracy for the damper when the noise level is below 5.0 %. For the testing model, the average relative deviation in the physics parameters (stiffness and liquid height) of dampers is 2.52 %. This method effectively identifies the physics parameters of TVB, offering theoretical support for the vibration control of OWTs.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121052"},"PeriodicalIF":4.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696068","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}
Ocean EngineeringPub Date : 2025-03-25DOI: 10.1016/j.oceaneng.2025.121029
Wei Shi , Yuxin Zeng , Zaibin Lin , Qing Xiao , Constantine Michailides , Zhiqiang Hu , Xin Li
{"title":"CFD numerical simulation of wave interaction for a TLP floating offshore wind turbine with porous structural members","authors":"Wei Shi , Yuxin Zeng , Zaibin Lin , Qing Xiao , Constantine Michailides , Zhiqiang Hu , Xin Li","doi":"10.1016/j.oceaneng.2025.121029","DOIUrl":"10.1016/j.oceaneng.2025.121029","url":null,"abstract":"<div><div>Designing stable floating support structures for offshore wind turbines in energetic environments is crucial to reducing the cost of energy. Porous structural members are commonly employed in offshore structures to passively attenuate wave reflection. Using a Computational Fluid Dynamics (CFD) numerical model, this paper investigates the motion response of a Tension Leg Platform (TLP) with porous outer structural members. It is further extended to study the hydrodynamic loads and flow fields with various wave conditions, Numerical validation was performed with data from physical model tests conducted at Dalian University of Technology. The results demonstrate that incorporating porous outer structural members significantly reduces the surge response and mooring line tension of the TLP platform. Notably, the fundamental frequency of the surge motion undergoes a significant shift. The mechanism behind this phenomena is analyzed through wave-structure interaction modeling, revealing that the opposite velocity phase of water particles on either side of the porous members leads to a decrease in horizontal hydrodynamic loads. Additionally, the porous elements increase the viscous damping ratio of platform motions, achieving a 43.1 % reduction in peak tendon tension. These findings highlight the potential benefits using porous structural components to enhance the performance and economic viability of floating offshore wind turbine (OWT) systems.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121029"},"PeriodicalIF":4.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696067","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}
Ocean EngineeringPub Date : 2025-03-24DOI: 10.1016/j.oceaneng.2025.121031
Xiangcheng Lyu , Chenhao Mi , Stan Collions , Wenchuang Chen , Danlei Yang , Luofeng Huang
{"title":"Design and experimental tests for novel shapes of floating OWC wave energy converters with the additional purpose of breakwater","authors":"Xiangcheng Lyu , Chenhao Mi , Stan Collions , Wenchuang Chen , Danlei Yang , Luofeng Huang","doi":"10.1016/j.oceaneng.2025.121031","DOIUrl":"10.1016/j.oceaneng.2025.121031","url":null,"abstract":"<div><div>The oscillating water column (OWC) is a type of wave energy converter (WEC) that captures the energy of incoming waves. As waves reach the structure, their movement causes the water within an enclosed chamber to oscillate, creating airflow that powers a turbine, generating electricity. This principle can be applied to the design of breakwaters, which can protect marine structures such as floating solar farms and wind turbines. This study involved designing two types of buoyancy chambers for the OWC-WEC and two underneath baffles with adjustable spacing. These configurations were tested in a wave tank to assess wave energy capture, wave attenuation, hydrodynamics, and mooring forces. The experimental results demonstrate that a baffle spacing of 1 m, combined with a V-type buoyancy chamber, significantly enhances the wave energy capture and wave attenuation performance of the OWC. This configuration achieves up to a 57.09 % increase in the capture width ratio and a maximum reduction of 20.88 % in the wave transmission coefficient. Furthermore, mooring line forces are reduced by 21.86 %, while the baffles effectively mitigate pitch motion. Notably, greater pitch reduction improves the capture width ratio. In conclusion, this study introduces a novel wave energy converter, providing key insights for future marine energy development.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121031"},"PeriodicalIF":4.6,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ocean EngineeringPub Date : 2025-03-24DOI: 10.1016/j.oceaneng.2025.121034
Zaiwei Li , Long-yuan Li
{"title":"Analytical modelling of chloride diffusion in circular section concrete columns with binding effects","authors":"Zaiwei Li , Long-yuan Li","doi":"10.1016/j.oceaneng.2025.121034","DOIUrl":"10.1016/j.oceaneng.2025.121034","url":null,"abstract":"<div><div>– Reinforced concrete structures in marine environments face significant durability challenges due to chloride-induced corrosion of the steel reinforcement. Understanding and modelling chloride ingress are critical for the prediction of the service life of these structures. This study presents an analytical model for chloride diffusion in circular section concrete columns, addressing a critical gap in existing research by incorporating the effects of chloride binding. The model employs a bilinear chloride binding isotherm to derive an analytical solution in cylindrical coordinates, which captures the nonlinear interaction between free and bound chlorides. Validation is performed by comparing the model's predictions with numerical and experimental solutions from one-dimensional cylindrical and slab coordinate systems, demonstrating high accuracy. The results show that the diffusion front advances more rapidly in the cylindrical model than in the slab model. For instance, chloride ingress reaches approximately 90 mm in a circular section column after 10-year diffusion time, whereas in a corresponding concrete slab, it extends only to about 80 mm. The present model offers engineers a valuable tool for designing and maintaining durable reinforced concrete columns in chloride-rich environments, contributing to enhanced service life predictions and more resilient infrastructure.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121034"},"PeriodicalIF":4.6,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ocean EngineeringPub Date : 2025-03-24DOI: 10.1016/j.oceaneng.2025.121024
Muhammed Fatih Gulen , Ozcan Arslan
{"title":"Holistic risk assessment approach for seafarers’ adaptation to digital transformation","authors":"Muhammed Fatih Gulen , Ozcan Arslan","doi":"10.1016/j.oceaneng.2025.121024","DOIUrl":"10.1016/j.oceaneng.2025.121024","url":null,"abstract":"<div><div>The maritime industry is experiencing a significant digital transformation that brings both opportunities and challenges for seafarers. This study presents a holistic risk assessment for seafarers’ adaptation to digital transformation using an integrated methodology that combines Failure Modes, Effects, and Criticality Analysis (FMECA), Dempster–Shafer (D-S) evidence theory, and a rule-based Bayesian network (RBN). The approach identifies and quantifies twenty-two failure modes across five critical components: human-related, technological, operational, organizational & regulatory, and cybersecurity. The findings reveal that operational failures and human-related failures are the most critical components, with “over-reliance on digitalization” being the highest-risk failure mode. Other significant failure modes include “insufficient digital competency and skill gaps” and “inadequate cybersecurity awareness and training.” Consequently, the study offers short and long-term actions to mitigate risks and provides valuable insights for effective human-technology interaction.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"328 ","pages":"Article 121024"},"PeriodicalIF":4.6,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679216","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}