Marine Structures最新文献

{"title":"Long-term validation of a model-based virtual sensing method for fatigue monitoring of offshore wind turbine support structures: Comparing as-designed with state-of-the-art foundation models","authors":"Dominik Fallais ,&nbsp;Carlos Sastre Jurado ,&nbsp;Wout Weijtjens ,&nbsp;Christof Devriendt","doi":"10.1016/j.marstruc.2025.103841","DOIUrl":"10.1016/j.marstruc.2025.103841","url":null,"abstract":"<div><div>Model-based virtual sensing offers a viable approach for monitoring fatigue loads on operational offshore wind turbines. These methods combine response measurements with first-principle, or data-informed models, to estimate load time series at hard-to-access locations. However, their accuracy depends on the fidelity of the underlying model, which is largely influenced by uncertainties in the soil–structure interaction (SSI) models.</div><div>This study evaluates the impact of different SSI modelling approaches in terms of a virtual sensing validation study targeting strain estimation above and below the mudline of a bottom-founded offshore wind turbine. To this end, different numerical models derived from, and validated against, design documentation serve as input to a dual-band modal decomposition and expansion (MDE) method. The considered SSI models range from an API/DNV-based foundation model to a PISA-based model including scour protection. Virtual sensing results are generated for two-year equivalent datasets, obtained for three operational offshore wind turbines, each equipped with extensive load monitoring systems. One turbine is used to assess the effect of the model updates, while two additional turbines are used to assess the across-site consistency. The estimated strains are directly compared against available strain validation data, in terms of damage-equivalent stress, and are accumulated to give a single comparative metric representative for the two-year periods.</div><div>Results show that PISA-based soil reaction curves significantly improve agreement with measured strains while adding a scour protection model has a relatively smaller impact. These findings highlight the importance of accurate foundation modelling in virtual sensing and demonstrate the feasibility of fatigue monitoring at hard-to-access locations.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103841"},"PeriodicalIF":4.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322651","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":"Experimental and numerical studies on dynamic performances of the hybrid modular floating structure system","authors":"Yaqiong Liu ,&nbsp;Nianxin Ren ,&nbsp;Jinping Ou ,&nbsp;Yanwei Li","doi":"10.1016/j.marstruc.2025.103878","DOIUrl":"10.1016/j.marstruc.2025.103878","url":null,"abstract":"<div><div>The present work mainly reports experimental and numerical studies on dynamic performances of the chain-type hybrid multi-module floating structure (HMFS) system under typical wave conditions. For the HMFS system, box-type modules are arranged outermost with functions of floating breakwaters for better anti-wave effect, and semi-sub modules are arranged internally for functions of production and living due to superior hydrodynamic performance. The outermost module is hinged with its adjacent module with an additional Wave Energy Converter (WEC), and semi-sub modules are mutually connected by hinges with torsional stiffness. Numerical analysis has been conducted through ANSYS AQWA based on potential flow theory and structural dynamic method, and scaled physical model tests have been conducted in a wave-current flume laboratory. WECs driven by parallel-shaft gears and hinge connectors with additional linear torsional stiffness are specially designed. The effect of the WEC on the main dynamic performances of the chain-type HMFS system has been studied, and results reveal that it is reasonable and feasible to attach a WEC to the outermost connector for reducing module motion responses and generating wave energy. In addition, the main experimental and numerical results have been compared systematically, which verifies the effectiveness of the coupling dynamic numerical method to a certain extent. Test results of dynamic responses under the survival sea condition demonstrate good motion performance of the system, and the extremum of connector loads can provide an experimental data basis for the design of connectors.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103878"},"PeriodicalIF":4.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330395","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":"Seismic fragility and vulnerability assessment of multi-megawatt jacket-supported offshore wind turbines","authors":"Upasana Nath,&nbsp;Sumanta Haldar","doi":"10.1016/j.marstruc.2025.103882","DOIUrl":"10.1016/j.marstruc.2025.103882","url":null,"abstract":"<div><div>Offshore wind turbines (OWTs) are increasingly installed in earthquake-prone regions, thus it is essential to determine the seismic risks associated with these structures. To ensure structural integrity of OWT, seismic fragility and vulnerability needs to be studied to evaluate structural performance and determine earthquake damage risk. This study investigates the seismic risk associated with the multi-megawatt OWTs supported by jacketed foundation. Three-dimensional numerical modelling of jacket, pile, and tower is developed in SAP2000 using non-linear beam elements. The soil-pile interaction is modelled by using American Petroleum Institute (API) based <em>p-y</em> springs. Different damage states were defined for various subsystems of tower, nacelle and substructure to develop the fragility curves of 5, 10, and 15 MW OWTs for near-field and far-field earthquake motions, considering ground motion directionality. The fragility of 15 MW OWTs are more sensitive in case of both near-field and far-field motions. Finally, the vulnerability models of the multi-megawatt OWTs are also developed to evaluate the expected loss of the structures.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103882"},"PeriodicalIF":4.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330396","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":"Behaviour of vertically loaded spudcan foundations under sustained uplift","authors":"Zhen Wang ,&nbsp;Jiang Tao Yi ,&nbsp;Shi Jie Xu ,&nbsp;Shuai Yin ,&nbsp;Fei Liu ,&nbsp;Yu Tao Pan","doi":"10.1016/j.marstruc.2025.103871","DOIUrl":"10.1016/j.marstruc.2025.103871","url":null,"abstract":"<div><div>Extracting a spudcan foundation in clay is frequently challenging and time-consuming due to the substantial pull-out force needed to overcome the soil breakout resistance. The actual mode of spudcan extraction in the field is that the spudcan is extracted under a constant force provided by the buoyancy of the hull rather than the undrained displacement uplift. This paper investigates the behaviour of the vertically loaded spudcan foundations under sustained uplift through centrifuge experiments and coupled pore fluid-effective stress large deformation finite element simulations. The finding indicates that the threshold sustained load of spudcan failure is approximately 60% of the undrained breakout resistance. When the sustained load is higher than this threshold, the uplift displacement of the spudcan is similar to the soil creep curve, characterised as accelerating at the beginning, then entering a stable stage, and finally tending to accelerate uplift until the spudcan pull-out failure. The failure mechanisms under different uplift modes are also revealed. Under sustained loading, the soil disturbance area increases with the sustained load, gradually manifesting local circulation around the spudcan. Total stress and pore pressure responses lie in the sustained consolidation status under various levels of sustained force.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103871"},"PeriodicalIF":4.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313870","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":"Sand-coated hybrid FRP tubes for marine applications: Bond performance with seawater-sea sand concrete under seawater","authors":"Jivan Subedi ,&nbsp;Milad Bazli ,&nbsp;Shalik Dhungana ,&nbsp;Ali Rajabipour ,&nbsp;Reza Hassanli ,&nbsp;Mehrdad Arashpour","doi":"10.1016/j.marstruc.2025.103872","DOIUrl":"10.1016/j.marstruc.2025.103872","url":null,"abstract":"<div><div>This study investigates the durability of the bond between sand-coated hybrid carbon-glass fibre-reinforced polymer (HFRP) tubes and seawater-sea sand concrete (SWSSC) under simulated marine conditions. Concrete-filled filament-wound HFRP tubes were immersed in seawater at temperatures of 25 °C, 40 °C, and 60 °C for durations of 30, 90, and 120 days. Push-out tests were conducted to evaluate the bond performance of the concrete-filled FRP tubes (CFFTs), focusing on failure modes, bond strength, and bond-slip characteristics. Results revealed an initial enhancement in bond strength for all conditioned samples after 30 days compared to unconditioned references, followed by a gradual decline, culminating in a maximum bond strength reduction of 9 % after 120 days. The primary failure mode for conditioned specimens occurred at the interface between the HFRP tube and the sand-coated layer, while unconditioned specimens failed at the interface of the tube and the concrete. The study found that post-peak bond behaviour varied, with bond strength either maintained or gradually reduced, mainly due to the loss of chemical adhesion and friction. Using the fib Bulletin 40 approach, a knock-down factor of 0.5 is recommended for bond strength durability over a 50-year service life in seawater environments. This research stresses the potential of sand-coated HFRP tubes and SWSSC as sustainable, marine-compatible construction materials that meet structural durability requirements.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103872"},"PeriodicalIF":4.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306793","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":"Analysis of mooring system for floating wind turbine based on macro-model of chain-seabed interaction","authors":"Shengjie Rui ,&nbsp;Hans Petter Jostad ,&nbsp;Zefeng Zhou ,&nbsp;Erin Bachynski-Polić ,&nbsp;Svein Sævik ,&nbsp;Lizhong Wang ,&nbsp;Zhen Guo","doi":"10.1016/j.marstruc.2025.103877","DOIUrl":"10.1016/j.marstruc.2025.103877","url":null,"abstract":"<div><div>Traditional fully integrated analyses of floating wind turbines (FTWs) assume a fixed mooring point on the seabed, overlooking the effects of the embedded mooring line within the seabed. This simplification introduces inconsistency and uncertainty in mooring system design. In this study, a macro-model was proposed to simulate the interaction between the mooring line and seabed soil, and it was implemented into SIMA (a fully coupled aero-hydro-servo-elastic engineering tool). The macro-model captures the coupled non-linear relationship between incremental displacement and resultant soil reaction force in three-dimensional space. After verifying the model, effects of seabed friction and embedded chain on the mooring line were evaluated. Subsequently, mooring analyses of the VolturnUS-S floater supporting the IEA 15MW floating wind turbine were performed using the macro-model to assess key parameters in mooring line design. Then, three representative cases under dynamic conditions are designed to investigate the influence of the embedded line on mooring system response. The study demonstrated that the macro-model of chain-seabed interaction effectively captures the response of the mooring chain considering gradual mobilization of soil reaction forces and effective width parameters due to the chain geometry. Without modelling the embedded line, mooring lines have larger tension due to smaller displacement near the padeye on the seabed, emphasizing the importance of embedded line on seabed friction mobilization under both static and dynamic conditions. The seabed friction shares the load transferred from the floater, and significantly affects the anchor load. This study develops a crucial tool for mooring design of floating wind turbines considering the embedded chain.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103877"},"PeriodicalIF":4.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144279510","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":"Degradation mechanisms of axial compressive performance in defective unbonded flexible pipes","authors":"Yu Liu,&nbsp;Yanfei Chen,&nbsp;Keyang Tan,&nbsp;Mingchang He,&nbsp;Rongfeng Zhong,&nbsp;Xin Wang,&nbsp;Ruihao Liu,&nbsp;Rui Li","doi":"10.1016/j.marstruc.2025.103862","DOIUrl":"10.1016/j.marstruc.2025.103862","url":null,"abstract":"<div><div>As a critical conduit connecting offshore oil and gas fields to marine platforms, the unbonded flexible pipe plays a vital role in offshore production. The tensile armor, as one of the primary load-bearing components of the flexible pipe, is crucial to the structural integrity of the pipeline system, and its failure poses a significant threat. Therefore, investigating the influence mechanisms of various defects on the mechanical properties of the tensile armor and analyzing its mechanical behavior are of great theoretical and engineering significance. A numerical simulation approach was employed to study the axial compression performance of the tensile armor in unbonded flexible pipes with defects. A five-layer finite element model of the unbonded flexible pipe under axial compression was established to examine the effects of defects in the non-metallic layer, interlayer friction coefficient, and wires fracture on the axial compression stiffness and critical buckling load. The results indicate that a decrease in the friction coefficient due to increased annular water content significantly reduces the critical buckling load, while defects in the non-metallic layer and fracture of the wires substantially decrease both axial compression stiffness and critical buckling load. These findings emphasize the necessity of monitoring annular water content and ensuring the structural integrity of each layer in engineering applications. By constructing a critical buckling load degradation model and a nonlinear axial stiffness degradation model considering defects in both non-metallic and metallic layers, as well as a degradation model for the critical buckling load and stiffness that accounts for the differences between internal and external fracture of the metal layer, this study reveals the scale-separation characteristics of interlayer mechanical transmission in unbonded flexible pipes. A key innovation of this work is the development of a dual-scale coupled axial compression degradation model. By introducing a novel degradation factor (<span><math><mrow><mi>β</mi><mo>(</mo><mi>θ</mi><mo>,</mo><mi>L</mi><mo>)</mo></mrow></math></span>) linking non-metallic defect severity to metallic layer buckling sensitivity and a nonlinear weighted degradation term (<span><math><mrow><mi>ψ</mi><mo>(</mo><msub><mi>n</mi><mrow><mi>o</mi><mi>u</mi><mi>t</mi></mrow></msub><mo>,</mo><msub><mi>n</mi><mtext>int</mtext></msub><mo>)</mo></mrow></math></span>) capturing the accelerated stiffness loss due to wire fracture interactions, this model explicitly quantifies the synergistic effects between non-metallic and metallic defects, which have largely been treated in isolation previously. This provides a more comprehensive and physically grounded framework for evaluating the axial compression performance of unbonded flexible pipes with complex, co-existing defects.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103862"},"PeriodicalIF":4.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242154","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":"Thermal buckling of aluminum conductors in submarine cables","authors":"Haolin Li ,&nbsp;Zhenkui Wang ,&nbsp;Yifan Wang ,&nbsp;Hongyu Wang ,&nbsp;Xiaowei Huang ,&nbsp;Zhen Guo","doi":"10.1016/j.marstruc.2025.103860","DOIUrl":"10.1016/j.marstruc.2025.103860","url":null,"abstract":"<div><div>The conductor is a key component in submarine cables for power transmission. During the operation of the cable, the transmission of current results in an increase in the conductor's temperature. Due to initial imperfections caused by welding, the aluminum conductor at the joint may experience buckling failure under the compressive load induced by thermal loading. In this study, a finite element model is developed to investigate the thermal buckling of the wire in the conductor, and the model is validated against theoretical formulas within the elastic stage. The welding effect is considered in the finite element model, including the mechanical strength reduction, length, and initial deformation of the heat-affected zone (HAZ). The typical buckling mechanism of the conductor wire is analyzed, and a sensitivity analysis of the welding effect on the buckling behavior is also conducted. The results indicate that the conductor wire in the HAZ undergoes snap-through buckling under thermal loading during the plastic stage. This buckling behavior causes a sudden and significant increase in displacement and stress in the HAZ, which may lead to structural failure. Moreover, both the critical buckling temperature and critical buckling axial force are negatively correlated with the magnitude of the mechanical strength reduction, length, and out-of-straightness of the HAZ.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103860"},"PeriodicalIF":4.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144223252","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":"Numerical simulation of ship hydroelastic responses in short-crested irregular waves","authors":"Zhenwei Chen ,&nbsp;Jialong Jiao ,&nbsp;Wenhua Xu ,&nbsp;Caixia Jiang ,&nbsp;Shuai Chen","doi":"10.1016/j.marstruc.2025.103858","DOIUrl":"10.1016/j.marstruc.2025.103858","url":null,"abstract":"<div><div>In this paper a two-way CFD-FEM fluid-structure coupled method is developed to simulate ship motions and wave load responses in short-crested irregular waves. First, a segmented ship model is established in FEM solver, and a numerical tank is established in CFD solver to reproduce short-crested irregular waves. Then, the simulation of 3D irregular waves is illustrated, and the time series of simulated waves and the estimated directional spectra are analyzed. The simulation results of ship motions and sectional loads in 3D waves are illustrated and analyzed. The asymmetric motions and loads for ship with and without forward speed are comprehensively analyzed and cross-spectral method is used for correlation analysis between different signals. This paper has potential application values in the prediction of ship seakeeping and hydroelastic responses in realistic sea states.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"103 ","pages":"Article 103858"},"PeriodicalIF":4.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204367","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":"Theoretical and data-driven methods to predict the mechanical response of flexible pipe carcass under radial compression","authors":"Wenbo Li ,&nbsp;Hailong Lu ,&nbsp;Murilo Augusto Vaz ,&nbsp;Jun Yan","doi":"10.1016/j.marstruc.2025.103857","DOIUrl":"10.1016/j.marstruc.2025.103857","url":null,"abstract":"<div><div>The carcass layer is the innermost structure of flexible pipes and is primarily designed to resist radial loads. Flexible pipes are subjected to compression by tensioners during installation, and excessive radial loads can lead to plastic deformation and premature material yielding, consequently diminishing the structural load-bearing capacity. Despite the critical role of the carcass layer, limited research has been performed on the plastic analysis of its complex cross-section under symmetric radial compression. This study applied the plastic-hinge theory to a planar circular ring, considering factors such as ellipticity and material hardening, and introduced the concept of equivalent radial stiffness for the carcass layer to predict the load-displacement curve during the plastic phase of the carcass layer under radial compression. Simultaneously, owing to the challenge of uneven stress distribution caused by a complex cross-section, this study adopts a combined approach of the attention mechanism and Long Short-Term Memory (LSTM) neural network. By inputting the structural ellipticity, inner diameter, and load–displacement response, the method aims to accurately predict the stress in the carcass layer. This conclusion indicates that the theoretical model exhibits a higher prediction accuracy when material hardening is considered. Errors arise when material hardening is ignored, as the theoretical model fails to account for the deformation of nonuniform cross-sections. By contrast, the data-driven models demonstrated high precision in predicting both radial and circumferential stresses in the carcass layer under radial compression.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"104 ","pages":"Article 103857"},"PeriodicalIF":4.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213255","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}