Marine Structures最新文献

{"title":"Accelerated fully coupled hydro-elastic analysis of ships using a combined full and modal-reduced FEM approach","authors":"Julio García-Espinosa ,&nbsp;Antonio José Lorente-López ,&nbsp;Borja Serván-Camas ,&nbsp;José Enrique Gutierrez-Romero","doi":"10.1016/j.marstruc.2026.104011","DOIUrl":"10.1016/j.marstruc.2026.104011","url":null,"abstract":"<div><div>The numerical simulation of a ship’s hydroelastic structural response is typically carried out using simplified modelling approaches. The main reason can be found in the computational cost of the structural solver when solving the fully coupled hydro-elastic problems. In this work, a two-way coupled fluid-structure interaction model capable of efficiently and accurately computing the hydro-elastic response of a ship using a detailed full-length structural representation is proposed. To reduce the computational cost of the structural solver, a reduced-order method based on modal matrix reduction is applied. The main idea is to largely reduce the number of degrees of freedom of the structural system by retaining only those modes with significant energy. Furthermore, to improve the accuracy of the model, this work proposes a combined methodology in which a residual finite element (FE) solution is computed alongside the reduced model, while still achieving a reduction in the overall computational effort.</div><div>The seakeeping hydrodynamics is solved using the computational framework SeaFEM. And the structural particulars are introduced into this framework to fully integrate the fluid-structure interaction.</div><div>An application case of the proposed model strategy is presented for a detailed structural design of a ship. The consistency of the modal approximation and methodology is verified against the full FE structural solution. It shows the capabilities of the proposed framework to perform a fully coupled and detailed structural analysis, instead of at component level, with a significant reduction in computational time.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104011"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191730","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":"Effects of variable amplitude loading and random loading sequence on fatigue of welded joints made of high-strength steel in ship structural details","authors":"Kiia Grönlund ,&nbsp;Antti Ahola ,&nbsp;Shahriar Afkhami ,&nbsp;Tuomas Skriko","doi":"10.1016/j.marstruc.2026.104028","DOIUrl":"10.1016/j.marstruc.2026.104028","url":null,"abstract":"<div><div>The aim of this study was to validate a local stress-based fatigue assessment approach, the 4R method, for assessing the fatigue strength of common welded ship structural details subjected to variable amplitude (VA) loads. The objective was to provide increased accuracy in fatigue strength estimations through the consideration of local elastic-plastic material behaviour, possible residual stress relaxation, and sequential effects of loading conditions. The VA load effects on fatigue strength of welded joints made of high-strength steel (690QT) were investigated by means of analytical calculations and experimental testing. Random VA load spectra were created for the fatigue tests based on different mean stress levels according to a two-parameter Weibull distribution. Additionally, a 3D scan-based solid finite element model of the longitudinal double-sided gusset joint was employed within the notch-based local fatigue assessments. The use of the scanned geometry reduced the scatter of the fatigue test results among specimens in the local approaches highlighting the importance of accurate consideration of real weld geometry in the determination of fatigue notch factors. Furthermore, the 4R method provided additional accuracy by considering the loading sequence and mean stress via mean-stress correction.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104028"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191733","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":"Multi-mode response of a flexible catenary cable under oscillating shear flows","authors":"Shuai Wang ,&nbsp;Hongjie Wen ,&nbsp;Jingchang Zhang ,&nbsp;Yi Zheng ,&nbsp;Junjie Zhu","doi":"10.1016/j.marstruc.2026.104038","DOIUrl":"10.1016/j.marstruc.2026.104038","url":null,"abstract":"<div><div>Flexible catenary cables serve as critical components in offshore power transmission systems; however, their long-span configuration renders them highly susceptible to complex vortex-induced vibrations (VIV) when subjected to platform-induced oscillatory flows. This study develops and validates a coupled finite element–finite volume method (FEM–FVM) computational framework to investigate the VIV of a flexible catenary cable exposed to parallel (PA) and perpendicular (PP) nonlinear oscillating shear flows. The cable’s structural dynamics are modeled using an Euler–Bernoulli tensioned beam formulation, while the surrounding unsteady flow is resolved via large-eddy simulation. Model predictions are systematically compared with experimental measurements, demonstrating the framework’s capability to accurately reproduce phase-dependent characteristics of VIV under oscillatory flow conditions. The results reveal that PA flows induce an asymmetric hyperbolic static deflection with a curvature inflection point, whereas PP flows lead to symmetric deformation patterns. Dynamic responses exhibit velocity-gradient-dependent modal transitions, with PP flows preferentially exciting hybrid standing–traveling wave modes through phase-sensitive energy transfer mechanisms. Vortex evolution analysis identifies distinct phase-dependent behaviors, including a classical “2S” shedding mode during forward flow phases, vortex core dissipation at flow stagnation, and vortex reorganization during flow reversal. Three-dimensional vorticity analysis further uncovers spatially heterogeneous flow structures arising from continuous variations in cable curvature and inflow velocity gradient—manifested as quasi-two-dimensional ordered vortex tubes in the upper span and fully turbulent three-dimensional vortical patterns in the lower span. These findings advance the fundamental understanding of VIV mechanisms in long-span flexible structures under nonlinear oscillatory shear flows and offer valuable guidance for the fatigue-resistant design and installation of subsea power transmission systems in complex marine environments.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104038"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191732","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":"Wave slamming load inversion investigation of air cushion vehicle skirt airbags based on impulse-space superposition method","authors":"Yuchao Yuan ,&nbsp;Shengjie Xu ,&nbsp;Junhong Wei ,&nbsp;Li Guo ,&nbsp;Wenyong Tang","doi":"10.1016/j.marstruc.2026.104040","DOIUrl":"10.1016/j.marstruc.2026.104040","url":null,"abstract":"<div><div>The flexible skirt airbag is the core component of air cushion vehicle, and the external load it bears under wave slamming directly affects the safety and stability of the structure. Due to the non-uniformity of wave slamming load in time and space, accurately inverting the dynamic load has become an important challenge in current research. This paper proposes a multi-region load inversion model based on impulse-space superposition method to address the inversion of spatial non-uniformly wave slamming load. The construction of the load-response relationship and the solution process of dynamic load inversion are explained. The response characteristics under unit load in a single sub-region are analyzed, and a preferred arrangement of monitoring points along the Y-direction is determined for subsequent inversion. The effects of wave slamming load duration, wave slamming load distribution and wave slamming load area on the inversion precision are discussed. As the load distribution becomes more complex and the areas are larger, the inversion error increases. Properly increasing the number of monitoring points can significantly improve inversion accuracy, especially in more complex asymmetric load scenarios. This inversion method is easy to implement and can provide valuable insights for subsequent research on load identification of air cushion vehicle flexible airbags in actual marine environments.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104040"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191306","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":"Probabilistic-based collapse failure mechanism analysis and ultimate bearing capacity evaluation for deep-sea pipelines with random combined defects of geometrical imperfections and corrosion","authors":"Fengyuan Jiang ,&nbsp;Zhenkun Liao ,&nbsp;Hongchao Lu ,&nbsp;Enjin Zhao ,&nbsp;Yijie Gong","doi":"10.1016/j.marstruc.2026.104018","DOIUrl":"10.1016/j.marstruc.2026.104018","url":null,"abstract":"<div><div>Combined defects of initial geometrical imperfections and corrosion are critically responsible for collapse failures of deep-sea pipelines under external pressures. Besides, inherent randomness of combined defects (ovality, spatial locations and dimensions of corrosion defects) remarkably affects the failure development, introducing variabilities and non-linerites into structural responses, under which challenges in evaluating the collapse strength <em>p</em>_clc are posed. A stochastic finite element analysis (SFEA) model is developed to investigate the failure mechanisms of pipelines with random combined defects. Various failure behaviours and collapse modes dominated by corrosion defect, ovality and their combinations are identified, causing pronounced diversities in the <em>p</em>_clps. Probabilistic characteristics of <em>p</em>_clps are quantified, and their correlations with the random influential factors and the collapse failure evolutions are discussed, where the competition and transformation mechanisms among failure modes dominated by different factors are revealed. Further, core failure mechanisms are extracted and formalized into physical constraints to develop a physics-informed neural network (PINN) for forecasting the <em>p</em>_clps. The PINN models show reliable performance in the prediction accuracy, uncertainty quantification and transfer learning. Mutual dependencies among model performance, prediction mechanism and structural failure behaviours in different cases are analyzed, exploring the propagation rules of physical information between physical and digital spaces.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104018"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191307","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":"A method for validating loads and responses of large floating wind turbines using nacelle-mounted lidar","authors":"Feng Guo ,&nbsp;David Schlipf ,&nbsp;Zhen Gao","doi":"10.1016/j.marstruc.2026.104019","DOIUrl":"10.1016/j.marstruc.2026.104019","url":null,"abstract":"<div><div>For large-scale floating wind turbines, load and response validation enables a closed-loop design process, which helps to validate the simulation models and algorithms and provides a basis for improving subsequent designs. For this purpose, the characteristics of the freestream inflow wind are vital. The nacelle lidar system is easy to install, cost-effective, and capable of measuring the freestream wind in front of the rotor of a floating turbine. However, compared to bottom-fixed turbines, measurement errors in nacelle lidar caused by the motion of the floating platform require accurate motion measurements and complex reconstruction algorithms for motion compensation. In this paper, we investigate the potential of using nacelle lidar for load and response validation of floating turbines through numerical simulations. We propose a method for generating turbulent wind fields considering rotor-averaged wind speed estimated by simulated-lidar system as a constraint. This method does not require motion velocity measurements and allows for simplified wind field reconstruction. Based on aero-hydro-servo-elastic integrated simulations, this study demonstrates the potential of a nine-beam nacelle lidar system for load validation, including both sample-averaged statistical properties and one-to-one comparisons.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104019"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081951","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":"An aero-hydro-servo-elastic coupled frequency-domain method for dynamic analysis of floating wind turbines","authors":"Wenxi Shao ,&nbsp;Zhengshun Cheng ,&nbsp;Wenbin Zhou ,&nbsp;Minghao Cui ,&nbsp;Peng Chen ,&nbsp;Zhen Gao","doi":"10.1016/j.marstruc.2026.104016","DOIUrl":"10.1016/j.marstruc.2026.104016","url":null,"abstract":"<div><div>Compared with time-domain fully coupled methods for dynamic analysis of floating wind turbines, frequency-domain methods offer higher efficiency but rely on proper representation of nonlinear behaviors. Existing frequency-domain methods usually neglect substantial nonlinearities in aerodynamics, control strategies, as well as blade elasticity, which leads to significant discrepancies against time-domain results, particularly in the prediction of low-frequency and 3P responses. Therefore, this study develops an aero-hydro-servo-elastic coupled frequency-domain model, Pywind-FD, which enhances existing frequency-domain methods by accounting for blade and tower elasticity, advanced control dynamics, mooring line dynamics, and linearized floater and tower drag forces. Moreover, to address the nonlinearities of aerodynamics and control dynamics near rated condition, a hybrid time–frequency module is further integrated, in which the thrust spectrum is obtained based on time-domain simulations. Verifications against the time-domain simulations of 5 MW and 15 MW three-column FWTs confirm that the developed frequency-domain method performs well under high-wind conditions, while the hybrid method, by capturing nonlinear excitation forces, delivers reliable low-frequency predictions across all operating conditions. The inclusion of elastic blade dynamics allows accurate calculation of 3P responses. Overall, the proposed method agrees well with time-domain simulations and could serve as a reliable basis for FWT design and optimization.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104016"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191731","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":"Mitigating load responses of high-speed catamarans via ride control systems: An experimental study in irregular waves, part2: Slamming kinematics and energy transfer","authors":"Ehsan Javanmard ,&nbsp;Javad A. Mehr ,&nbsp;Damien S. Holloway ,&nbsp;Michael R. Davis ,&nbsp;Jason Ali-Lavroff","doi":"10.1016/j.marstruc.2026.104035","DOIUrl":"10.1016/j.marstruc.2026.104035","url":null,"abstract":"<div><div>This study investigates the influence of a Ride Control System (RCS) with stern-mounted trim tabs and a bow-fitted T-Foil on slam kinematics and energy transfer during slamming, using a 2.5 m scale model of a 112 m Incat Tasmania high-speed catamaran in irregular waves. Towing tank tests were conducted at a forward speed of 2.89 m/s (37 knots at full-scale) in irregular head seas with significant wave heights of 60 mm and 90 mm, corresponding to 2.7 m and 4 m at full-scale, respectively. It was demonstrated that relative bow immersion is the kinematic parameter most strongly correlated with slam severity and is associated with a higher likelihood of severe slamming. In contrast, slam magnitude (quantified as peak integrated centre bow force derived from strain measurements) showed no strong correlation with either the relative bow velocity at the instant of slamming or the maximum pre-slam relative bow velocity. While these velocity factors showed weaker correlation with slam magnitude reduction compared to relative bow immersion, their importance increases when evaluating the effectiveness of control algorithms that similarly reduce relative bow immersion. The nonlinear pitch control algorithm was found to be the most effective in reducing relative bow immersion, reducing it by 17% and 21% in 60 mm and 90 mm wave heights, respectively, compared to the No RCS condition. Strain energy analysis revealed that this control algorithm reduced overall slam-induced strain energy of the model by 96% in 60 mm waves and 68% in 90 mm waves over a 54-second model test period compared to the No RCS mode. Furthermore, this algorithm mitigated the maximum peak strain energy in the centre bow by 70% in 60 mm waves and 47% in 90 mm waves, highlighting its potential to reduce slam-induced loads and improve the structural design of high-speed catamarans operating in challenging sea conditions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104035"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191305","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":"Optimization of lifespan extension design for complex systems: degradation modeling, maintenance strategies and cost control","authors":"Xiaoyan Shao ,&nbsp;Baoping Cai ,&nbsp;Lei Gao ,&nbsp;Zhongfei Sui","doi":"10.1016/j.marstruc.2026.104017","DOIUrl":"10.1016/j.marstruc.2026.104017","url":null,"abstract":"<div><div>In complex systems, degradation processes are often intricate, and failures can result in high repair costs. Therefore, extending the system’s lifespan to enhance economic benefits is crucial. To address this challenge, this paper develops a system lifespan extension optimization method based on lifecycle revenue. First, the expectation-maximization algorithm is used to model component performance degradation and estimate the Wiener process degradation parameters based on component degradation data. Next, an overall system performance degradation model is established based on the functional relationships between components and the system, and an initial remaining useful life (RUL) prediction is performed. Subsequently, maintenance models, including no maintenance, partial maintenance, and complete maintenance, along with the corresponding cost and effectiveness models, are developed. The revenue model before and after maintenance is calculated, focusing on system performance. The ant colony optimization is used to optimize the system’s lifespan extension design, determining the optimal maintenance time and strategy. Finally, based on the optimal maintenance strategy, the post-extension system performance degradation model is reconstructed and the system’s RUL is re-predicted. In the case study, the method is validated using a subsea Christmas tree system. The results show that this method effectively extends the lifespan of complex systems, enhances reliability and economic benefits, and provides a theoretical basis and methodological reference for the lifespan extension of other complex systems.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"108 ","pages":"Article 104017"},"PeriodicalIF":5.1,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191734","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":"Field study on installation characteristics of bucket foundation for offshore wind turbine in marine clay","authors":"Sen Li ,&nbsp;Kun Fu ,&nbsp;Wenbo Tu ,&nbsp;Lixiang Wei ,&nbsp;Xiaoqiang Gu ,&nbsp;Kanmin Shen ,&nbsp;Wei Guo ,&nbsp;Yaoyu Jia","doi":"10.1016/j.marstruc.2025.104002","DOIUrl":"10.1016/j.marstruc.2025.104002","url":null,"abstract":"<div><div>The installation of the bucket foundation is critical to the long-term service performance of offshore wind turbines. To understand the stress changes of the bucket foundation and the surrounding soil during the installation process, a field test of the installation of the bucket foundation was carried out at the Pinghai Bay offshore wind farm in Fujian, China. The internal pressure of the bucket foundation, the pore water pressure, the soil pressure along the bucket foundation skirt, the structural stress of the bucket foundation and the inclination angle of the bucket foundation were monitored in real-time during the field test. The results show that the attitude of the bucket foundation can be well controlled by using a pumping system during the installation process. The pore water pressure on the external side of the bucket foundation can be used to determine the penetration depth of the foundation, and the cone tip resistance obtained by CPT can be used to approximately determine the penetration resistance of the foundation. In addition, the magnitude of the structural stress of the bucket foundation is directly proportional to the magnitude of the differential pressure. The top plate and skirts of the bucket foundation mainly experience deformation toward the internal part of the foundation under differential penetration pressure, however, the soil stresses along the skirts of the foundation and the stresses of the bucket foundation skirt show an evident flexural deformation of the foundation skirts due to the excessive differential penetration pressure. The results of the study can offer guidance for the installation of bucket foundations in marine clay.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"107 ","pages":"Article 104002"},"PeriodicalIF":5.1,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839887","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}