Pub Date : 2025-11-13DOI: 10.1016/j.marstruc.2025.103962
Nan Gu , Xueqian Zhou , Lei Li , Huilong Ren
The large multi-body floating offshore platform is a new type of offshore structure with a rectangular, long and flat shape. Traditional CFD-FEA methods, that use one backbone beam to simulate the stiffness of the whole floating offshore platform, is only applicable to symmetric response problems of floating offshore structure, specifically to vertical bending issues under head sea conditions, thus limiting its scope of application. In quartering seas, waves not only vary along the length of the offshore platform but also in the beam direction. The large multi-body floating offshore platform has a large breadth, resulting in a modest overall torsional stiffness. Under severe quartering sea conditions, the large multi-body floating offshore platform may undergo significant torsional deformation due to the substantial torsional moment induced by waves, presenting an asymmetric response problem. In the present paper, an improved CFD-FEA method based on backbone beam grid model composed of Timoshenko beams that can be used to simulate the vertical bending, horizontal bending, and longitudinal torsional motion of the offshore platform is developed for the analysis of asymmetric responses of large multi-body floating offshore platform. The hydrodynamic and structural response characteristics of the large multi-body floating offshore platform are studied experimental via a segmented model test, and also numerically using an improved CFD-FEA method. Comparisons of numerical results with experimental results show the validity of the proposed numerical simulation approach.
{"title":"Asymmetric response analysis of large multi-body floating offshore platform in waves based on an improved CFD-FEA method","authors":"Nan Gu , Xueqian Zhou , Lei Li , Huilong Ren","doi":"10.1016/j.marstruc.2025.103962","DOIUrl":"10.1016/j.marstruc.2025.103962","url":null,"abstract":"<div><div>The large multi-body floating offshore platform is a new type of offshore structure with a rectangular, long and flat shape. Traditional CFD-FEA methods, that use one backbone beam to simulate the stiffness of the whole floating offshore platform, is only applicable to symmetric response problems of floating offshore structure, specifically to vertical bending issues under head sea conditions, thus limiting its scope of application. In quartering seas, waves not only vary along the length of the offshore platform but also in the beam direction. The large multi-body floating offshore platform has a large breadth, resulting in a modest overall torsional stiffness. Under severe quartering sea conditions, the large multi-body floating offshore platform may undergo significant torsional deformation due to the substantial torsional moment induced by waves, presenting an asymmetric response problem. In the present paper, an improved CFD-FEA method based on backbone beam grid model composed of Timoshenko beams that can be used to simulate the vertical bending, horizontal bending, and longitudinal torsional motion of the offshore platform is developed for the analysis of asymmetric responses of large multi-body floating offshore platform. The hydrodynamic and structural response characteristics of the large multi-body floating offshore platform are studied experimental via a segmented model test, and also numerically using an improved CFD-FEA method. Comparisons of numerical results with experimental results show the validity of the proposed numerical simulation approach.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103962"},"PeriodicalIF":5.1,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528177","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 : 2025-11-12DOI: 10.1016/j.marstruc.2025.103966
Marco Gaiotti Ph.D. , Lars Brubak , Bai-Qiao Chen , Ionel Darie , Dimitris Georgiadis , Daisuke Shiomitsu , Mihkel Kõrgesaar , Yining Lv , Ken Nahshon , Marcelo Paredes , Jani Romanoff , Ingrid Schipperen , Akira Tatsumi , Murilo Vaz , Yikun Wang , Albert Zamarin , Zhihu Zhan , Jonas W. Ringsberg
The demand for sustainable ship design has driven the use of high-strength steel to reduce structural weight, although this introduces buckling challenges due to unchanged elastic properties. Supported by the ISSC 2025 Ultimate Strength Committee, this study evaluated the ability of numerical simulations to predict the nonlinear response and ultimate strength of stiffened panels subjected to transverse compression. The benchmark consisted of full-scale blinded experimental tests that were conducted in parallel using a deck-like structure with thin plating prone to elastic buckling. The finite element models produced by participating researchers were compared, focusing on the complete end-shortening curve rather than just ultimate strength. Despite identical input geometry and minimal modeling guidance, results varied widely, revealing the significant influence of user-defined assumptions. The inclusion of additional data on material properties in the second study phase led to greater result dispersion due to the different strategies adopted for the hardening model. Key variability sources included the modeling of initial imperfections, material constitutive laws, and residual stresses from welding. The study highlights the need for consistent modeling and improved experimental data collection, particularly regarding boundary conditions and residual stress effects. While including welding stresses improved stiffness predictions, uncertainty in boundary behavior limited the assessment of ultimate strength impacts. The study also evaluated compliance with classification society rules (e.g., CSR, DNV, UR-S35), offering insights into how nonlinear numerical analyses complement or challenge regulatory frameworks based on closed-form expressions. Recommendations are made for improving simulation reliability and result validation.
{"title":"Evaluating numerical simulation accuracy for full-scale high-strength steel ship structures: Insights from the ISSC 2025 Ultimate Strength Committee benchmark on transversely stiffened panels","authors":"Marco Gaiotti Ph.D. , Lars Brubak , Bai-Qiao Chen , Ionel Darie , Dimitris Georgiadis , Daisuke Shiomitsu , Mihkel Kõrgesaar , Yining Lv , Ken Nahshon , Marcelo Paredes , Jani Romanoff , Ingrid Schipperen , Akira Tatsumi , Murilo Vaz , Yikun Wang , Albert Zamarin , Zhihu Zhan , Jonas W. Ringsberg","doi":"10.1016/j.marstruc.2025.103966","DOIUrl":"10.1016/j.marstruc.2025.103966","url":null,"abstract":"<div><div>The demand for sustainable ship design has driven the use of high-strength steel to reduce structural weight, although this introduces buckling challenges due to unchanged elastic properties. Supported by the ISSC 2025 Ultimate Strength Committee, this study evaluated the ability of numerical simulations to predict the nonlinear response and ultimate strength of stiffened panels subjected to transverse compression. The benchmark consisted of full-scale blinded experimental tests that were conducted in parallel using a deck-like structure with thin plating prone to elastic buckling. The finite element models produced by participating researchers were compared, focusing on the complete end-shortening curve rather than just ultimate strength. Despite identical input geometry and minimal modeling guidance, results varied widely, revealing the significant influence of user-defined assumptions. The inclusion of additional data on material properties in the second study phase led to greater result dispersion due to the different strategies adopted for the hardening model. Key variability sources included the modeling of initial imperfections, material constitutive laws, and residual stresses from welding. The study highlights the need for consistent modeling and improved experimental data collection, particularly regarding boundary conditions and residual stress effects. While including welding stresses improved stiffness predictions, uncertainty in boundary behavior limited the assessment of ultimate strength impacts. The study also evaluated compliance with classification society rules (e.g., CSR, DNV, UR-S35), offering insights into how nonlinear numerical analyses complement or challenge regulatory frameworks based on closed-form expressions. Recommendations are made for improving simulation reliability and result validation.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103966"},"PeriodicalIF":5.1,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528178","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 : 2025-11-10DOI: 10.1016/j.marstruc.2025.103963
Dongyang Li , Zhen Chen
Ship structures are normally assembled by a large number of structural components using welding technology which causes inevitable welding residual stress (WRS). Over the life span of a ship, the hull girder may be subjected to potential extreme cyclic bending in rough sea conditions. Cumulative plastic damage (CPD) induced by the repeated load reversals, coupled with the inherent WRS, may lead to significant deterioration of the ultimate hull girder strength. The current paper proposes an extended incremental-iterative approach to efficiently assess the residual ultimate strength of ship hull girders under the coupling effect of these two factors as well as material hardening. The developed approach follows the theoretical framework of traditional Smith’s method but extends its capability. A practical expression is suggested to analytically reformulate the load-shortening curves of structural elements by means of machine learning (ML). Influence of stiffener type, geometric dimension, WRS, load amplitude and cycle is considered in the modified curves. Experimental data, Common Structural Rules (CSR) formulae and numerical results by parametric nonlinear finite element analysis (FEA) are used to validate the extended incremental-iterative approach. It is found that this approach can predict the ultimate strength of simplified and real hull girders under different curvature amplitudes, loading sequences and cycle numbers. In addition, characteristics of the cyclic collapse responses of stiffener elements and hull girders are reported to provide novel insights into ship structural design.
{"title":"An extended incremental-iterative approach to evaluate the residual ultimate strength of ship hull girders with welding residual stress subjected to cumulative plastic damage","authors":"Dongyang Li , Zhen Chen","doi":"10.1016/j.marstruc.2025.103963","DOIUrl":"10.1016/j.marstruc.2025.103963","url":null,"abstract":"<div><div>Ship structures are normally assembled by a large number of structural components using welding technology which causes inevitable welding residual stress (WRS). Over the life span of a ship, the hull girder may be subjected to potential extreme cyclic bending in rough sea conditions. Cumulative plastic damage (CPD) induced by the repeated load reversals, coupled with the inherent WRS, may lead to significant deterioration of the ultimate hull girder strength. The current paper proposes an extended incremental-iterative approach to efficiently assess the residual ultimate strength of ship hull girders under the coupling effect of these two factors as well as material hardening. The developed approach follows the theoretical framework of traditional Smith’s method but extends its capability. A practical expression is suggested to analytically reformulate the load-shortening curves of structural elements by means of machine learning (ML). Influence of stiffener type, geometric dimension, WRS, load amplitude and cycle is considered in the modified curves. Experimental data, Common Structural Rules (CSR) formulae and numerical results by parametric nonlinear finite element analysis (FEA) are used to validate the extended incremental-iterative approach. It is found that this approach can predict the ultimate strength of simplified and real hull girders under different curvature amplitudes, loading sequences and cycle numbers. In addition, characteristics of the cyclic collapse responses of stiffener elements and hull girders are reported to provide novel insights into ship structural design.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103963"},"PeriodicalIF":5.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528176","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 : 2025-11-10DOI: 10.1016/j.marstruc.2025.103965
Xinyan Yu , Bowen Zhao
Aiming to address the deficiencies of existing ship-ice collision theoretical models in characterizing ice failure mechanisms, construct complete impact processes, and unify ice load parameters, this paper establishes a unified theoretical model for ice load determination in ship-ice collisions considering ice crushing. A rigid body-ice layer interaction model is employed to describe the hull impact process, with oblique non-central asymmetric collisions simplified to central symmetric collisions through mass and velocity reduction coefficients, establishing momentum and angular momentum change equation sets. Combined with Reynolds equations describing viscoplastic fluid motion in the interlayer, an ice layer ultimate contact force coefficient is introduced to characterize the limiting effect of ice fracture on ice loads, constructing a unified calculation framework for contact pressure, line loads, resultant forces, and contact zone geometric parameters. Through structural strength curves and ice resistance strength surface concepts, the correlation between navigation condition parameters and structural design standards is established. Verification analysis using the “Lena” ice navigation vessel demonstrates that the model can effectively calculate ice load parameters under different ice thicknesses, navigation speeds, and structural design conditions, providing a theoretical foundation for bow structure design of various ice class transport vessels and achieving a unified calculation method for integrated ice load determination under multiple working conditions.
{"title":"Development of а unified theoretical model for ice load determination in ship - ice collisions considering ice crushing","authors":"Xinyan Yu , Bowen Zhao","doi":"10.1016/j.marstruc.2025.103965","DOIUrl":"10.1016/j.marstruc.2025.103965","url":null,"abstract":"<div><div>Aiming to address the deficiencies of existing ship-ice collision theoretical models in characterizing ice failure mechanisms, construct complete impact processes, and unify ice load parameters, this paper establishes a unified theoretical model for ice load determination in ship-ice collisions considering ice crushing. A rigid body-ice layer interaction model is employed to describe the hull impact process, with oblique non-central asymmetric collisions simplified to central symmetric collisions through mass and velocity reduction coefficients, establishing momentum and angular momentum change equation sets. Combined with Reynolds equations describing viscoplastic fluid motion in the interlayer, an ice layer ultimate contact force coefficient is introduced to characterize the limiting effect of ice fracture on ice loads, constructing a unified calculation framework for contact pressure, line loads, resultant forces, and contact zone geometric parameters. Through structural strength curves and ice resistance strength surface concepts, the correlation between navigation condition parameters and structural design standards is established. Verification analysis using the “Lena” ice navigation vessel demonstrates that the model can effectively calculate ice load parameters under different ice thicknesses, navigation speeds, and structural design conditions, providing a theoretical foundation for bow structure design of various ice class transport vessels and achieving a unified calculation method for integrated ice load determination under multiple working conditions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103965"},"PeriodicalIF":5.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528179","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 : 2025-11-06DOI: 10.1016/j.marstruc.2025.103964
Libei Zhou , Shunfeng Gong , Lin Yuan , Junwei Ren , Xipeng Wang
During long-term service, offshore pipelines may simultaneously experience axial tension coupled with external pressure in the complex marine environment. Under these combined loadings, subsea pipes are prone to local collapse and even propagation, especially in the presence of corrosion. This paper deals with the collapse response of outer corroded pipes subjected to both axial tension and external pressure using theoretical and numerical methods, aiming to determine their ultimate load-bearing capacity. A theoretical model is developed for a preliminary assessment of collapse pressure. Then, a numerical framework, incorporating either longitudinally continuous rectangular defects or localized elliptical defects, is established, and its accuracy is validated against the theoretical results and available experimental data, respectively. With the verified numerical models, the collapse responses are investigated parametrically, including different geometric features, material properties, 3D defect sizes, and defect distribution. Finally, a set of optimized empirical expressions is proposed based upon the comprehensive finite element (FE) results to evaluate the ultimate pressure of pipelines with elliptical corrosion defects subjected to axial tension and external pressure.
{"title":"Theoretical and numerical studies on collapse of corroded subsea pipelines under combined external pressure and axial tension","authors":"Libei Zhou , Shunfeng Gong , Lin Yuan , Junwei Ren , Xipeng Wang","doi":"10.1016/j.marstruc.2025.103964","DOIUrl":"10.1016/j.marstruc.2025.103964","url":null,"abstract":"<div><div>During long-term service, offshore pipelines may simultaneously experience axial tension coupled with external pressure in the complex marine environment. Under these combined loadings, subsea pipes are prone to local collapse and even propagation, especially in the presence of corrosion. This paper deals with the collapse response of outer corroded pipes subjected to both axial tension and external pressure using theoretical and numerical methods, aiming to determine their ultimate load-bearing capacity. A theoretical model is developed for a preliminary assessment of collapse pressure. Then, a numerical framework, incorporating either longitudinally continuous rectangular defects or localized elliptical defects, is established, and its accuracy is validated against the theoretical results and available experimental data, respectively. With the verified numerical models, the collapse responses are investigated parametrically, including different geometric features, material properties, 3<em>D</em> defect sizes, and defect distribution. Finally, a set of optimized empirical expressions is proposed based upon the comprehensive finite element (FE) results to evaluate the ultimate pressure of pipelines with elliptical corrosion defects subjected to axial tension and external pressure.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103964"},"PeriodicalIF":5.1,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465502","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 : 2025-11-06DOI: 10.1016/j.marstruc.2025.103960
Tianjiao Dai , Shuo Yang , Xing Jin , Svein Sævik , Jiaxuan Zhang , Jun Wu , Naiquan Ye
Subsea umbilical and power cables contain a large number of contact interfaces between different geometries and materials. These complex interactions rise significant challenges for accurately considering contact surface properties by using traditional analytical solutions or finite element methods. These properties have been identified as the most sensitive parameters when performing the numerical simulation for stress analysis. Therefore, it is essential to apply a novel approach for contact analysis which improves the accuracy and efficiency for predicting contact properties. This paper presents an isogeometric analysis (IGA) approach addressing contact problems in dynamic umbilicals and power cables. Firstly, this isogeometric contact algorithm is formulated in MATLAB as a tool including the geometry description, contact detection and penalty function. Secondly, the contact interface between a steel tube and an outer sheath in an dynamic umbilical is established by this IGA contact algorithm and validated against that in ABAQUS for proving the accuracy and efficiency of IGA. Finally, the effects of element refinement, geometrical description, penalty factor on the accuracy, efficiency and stability of IGA are discussed.
{"title":"Isogeometric contact analysis in subsea umbilical and power cables","authors":"Tianjiao Dai , Shuo Yang , Xing Jin , Svein Sævik , Jiaxuan Zhang , Jun Wu , Naiquan Ye","doi":"10.1016/j.marstruc.2025.103960","DOIUrl":"10.1016/j.marstruc.2025.103960","url":null,"abstract":"<div><div>Subsea umbilical and power cables contain a large number of contact interfaces between different geometries and materials. These complex interactions rise significant challenges for accurately considering contact surface properties by using traditional analytical solutions or finite element methods. These properties have been identified as the most sensitive parameters when performing the numerical simulation for stress analysis. Therefore, it is essential to apply a novel approach for contact analysis which improves the accuracy and efficiency for predicting contact properties. This paper presents an isogeometric analysis (IGA) approach addressing contact problems in dynamic umbilicals and power cables. Firstly, this isogeometric contact algorithm is formulated in MATLAB as a tool including the geometry description, contact detection and penalty function. Secondly, the contact interface between a steel tube and an outer sheath in an dynamic umbilical is established by this IGA contact algorithm and validated against that in ABAQUS for proving the accuracy and efficiency of IGA. Finally, the effects of element refinement, geometrical description, penalty factor on the accuracy, efficiency and stability of IGA are discussed.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103960"},"PeriodicalIF":5.1,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465503","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 : 2025-11-04DOI: 10.1016/j.marstruc.2025.103961
Junliang Gao , Yuntao Wu , Zhiwei Song , Ming He
Wave resonance phenomenon may occur in the narrow gap formed between adjacent marine structures, and the wave loads acting on the structures and the energy accumulated in the narrow gap may pose a huge threat to the safty operation of the structures. Via establishing a two-dimensional viscous wave-current flume based on the OpenFOAM® model, this article comprehensively investigates the influence of the direction and velocity of uniform current on the characteristics of gap resonance and the wave loads on the structures for a gap resonance system consisting of two fixed floating bodies. A wave analysis method based on the least squares principle is adopted to separate the incident and the reflected waves in the wave-current flume. The results show that both the following current and the opposing current increase the resonant frequency of the gap resonance. The opposing current increases the wave height amplification of the gap resonance system and the wave load on the structures, while the following current decreases them. In addition, the energy loss of the gap resonance system is slightly reduced by the following current, while the energy loss of the system is greatly increased by the opposing current.
{"title":"Influences of low velocity uniform current on characteristics of gap resonance occurring between two adjacent fixed bodies","authors":"Junliang Gao , Yuntao Wu , Zhiwei Song , Ming He","doi":"10.1016/j.marstruc.2025.103961","DOIUrl":"10.1016/j.marstruc.2025.103961","url":null,"abstract":"<div><div>Wave resonance phenomenon may occur in the narrow gap formed between adjacent marine structures, and the wave loads acting on the structures and the energy accumulated in the narrow gap may pose a huge threat to the safty operation of the structures. Via establishing a two-dimensional viscous wave-current flume based on the OpenFOAM® model, this article comprehensively investigates the influence of the direction and velocity of uniform current on the characteristics of gap resonance and the wave loads on the structures for a gap resonance system consisting of two fixed floating bodies. A wave analysis method based on the least squares principle is adopted to separate the incident and the reflected waves in the wave-current flume. The results show that both the following current and the opposing current increase the resonant frequency of the gap resonance. The opposing current increases the wave height amplification of the gap resonance system and the wave load on the structures, while the following current decreases them. In addition, the energy loss of the gap resonance system is slightly reduced by the following current, while the energy loss of the system is greatly increased by the opposing current.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103961"},"PeriodicalIF":5.1,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1016/j.marstruc.2025.103958
Waldemar Magda
The paper explores safe, efficient, and economic design of ship berthing dolphins. Focus is on the real, dual-elastic performance of a modern marine modular rubber fender and a tubular steel-pile substructure of a berthing dolphin. Assuming the simultaneous absorption of a vessel’s berthing kinetic energy by two elastic components of the pile-fender berthing system, an explicit procedure is given for the selection of a steel-pile cross-section geometry in relation to a given size of the rubber fender unit. The procedure uses an easily applicable method of geometrically overlaid energy-on-force contour maps. The contour maps contain isolines of the minimum required potential energy of the berthing dolphin steel-pile substructure and the maximum reaction force of the marine rubber fender. Four example cases of the overlaid contour maps are presented and discussed practically. The application of the overlaid contour maps method assumes a full (100%) efficiency of the fender unit in energy absorption and fulfils a condition of geotechnical stability of the embedded steel-pile dolphin substructure. A practical application of the overlaid contour maps is illustrated by means of a worked example, assuming an oil tanker of 70,000 deadweight tonnes, realistic geometries of large-diameter berthing dolphin steel-piles, and a family of widely used Sumitomo modular rubber fenders. It is shown that the proposed method can serve as a convenient and simple design technique for the optimum selection of the required geometry of steel pile cross-section in relation to the size of the fender unit.
{"title":"Overlaid energy-on-force contour maps method for safe, efficient, and economic design of dual-elastic ship berthing dolphins","authors":"Waldemar Magda","doi":"10.1016/j.marstruc.2025.103958","DOIUrl":"10.1016/j.marstruc.2025.103958","url":null,"abstract":"<div><div>The paper explores safe, efficient, and economic design of ship berthing dolphins. Focus is on the real, dual-elastic performance of a modern marine modular rubber fender and a tubular steel-pile substructure of a berthing dolphin. Assuming the simultaneous absorption of a vessel’s berthing kinetic energy by two elastic components of the pile-fender berthing system, an explicit procedure is given for the selection of a steel-pile cross-section geometry in relation to a given size of the rubber fender unit. The procedure uses an easily applicable method of geometrically overlaid energy-on-force contour maps. The contour maps contain isolines of the minimum required potential energy of the berthing dolphin steel-pile substructure and the maximum reaction force of the marine rubber fender. Four example cases of the overlaid contour maps are presented and discussed practically. The application of the overlaid contour maps method assumes a full (100%) efficiency of the fender unit in energy absorption and fulfils a condition of geotechnical stability of the embedded steel-pile dolphin substructure. A practical application of the overlaid contour maps is illustrated by means of a worked example, assuming an oil tanker of 70,000 deadweight tonnes, realistic geometries of large-diameter berthing dolphin steel-piles, and a family of widely used Sumitomo modular rubber fenders. It is shown that the proposed method can serve as a convenient and simple design technique for the optimum selection of the required geometry of steel pile cross-section in relation to the size of the fender unit.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103958"},"PeriodicalIF":5.1,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1016/j.marstruc.2025.103959
Guy McCauley, Hugh Wolgamot, Paul H. Taylor, Jana Orszaghova
The relationship between measured tower bending moments and motions of the TetraSpar Demonstrator floating offshore wind turbine is assessed using conditioning analysis techniques for an extreme storm event, and indicates that the motion to moment transfer function is linear, but dependent on turbine state and wind speed. Using measured motions and bending moments, a look-up table of linear transfer functions is generated for different turbine speed and wind speed bins. The look-up table is then used to predict tower bending moment from measured motions for a winter period, and the accuracy of the predictions is assessed. Finally, predicted stress from the linear transfer function method is used to calculate fatigue damage, which compares well to fatigue calculated using measured bending moments.
{"title":"From motion to moments: conditioning analysis of floating offshore wind turbine tower bending","authors":"Guy McCauley, Hugh Wolgamot, Paul H. Taylor, Jana Orszaghova","doi":"10.1016/j.marstruc.2025.103959","DOIUrl":"10.1016/j.marstruc.2025.103959","url":null,"abstract":"<div><div>The relationship between measured tower bending moments and motions of the TetraSpar Demonstrator floating offshore wind turbine is assessed using conditioning analysis techniques for an extreme storm event, and indicates that the motion to moment transfer function is linear, but dependent on turbine state and wind speed. Using measured motions and bending moments, a look-up table of linear transfer functions is generated for different turbine speed and wind speed bins. The look-up table is then used to predict tower bending moment from measured motions for a winter period, and the accuracy of the predictions is assessed. Finally, predicted stress from the linear transfer function method is used to calculate fatigue damage, which compares well to fatigue calculated using measured bending moments.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"106 ","pages":"Article 103959"},"PeriodicalIF":5.1,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-27DOI: 10.1016/j.marstruc.2025.103957
Wei Cheng , Yun Gao , Conghe Shi , Chen Shi
The dynamic response characteristics of a submerged floating tunnel (SFT) under pure wave loads, pure current loads, and combined wave-current loads were studied using the two-dimensional unsteady Reynolds-averaged Navier-Stokes equations and the shear stress transport k-ω model coupled with the fourth-order Runge-Kutta method. The hydrodynamic forces acting on the SFT, and its motion response characteristics, including vibration amplitude, displacement frequency, and vibration trajectory, were systematically analyzed and discussed. The numerical results showed that, for the design parameters of the SFT selected in this study, when only a wave load was considered, the vibration amplitude of the SFT tube increased as the wave height increased, however, it decreased as the wave period increased. The displacement frequency remained consistent with the wave frequency. When only a current load was considered, the motion response of the SFT tube in the sway direction displayed multi-frequency characteristics, with the dominant frequency in the sway direction being approximately twice that in the heave direction. When a combined wave-current load was considered, for a low current velocity, the displacement frequency response of the SFT body in the heave direction was dominated by the wave load, while for a high current velocity, it was dominated by the wave and current loads simultaneously. Furthermore, for a low current velocity, the coupling effect between the wave and current loads was slight. However, as the current velocity increased to 2.5 m s-1, the wave-current coupling effect became obviously pronounced and non-negligible.
采用二维非定常雷诺数-平均Navier-Stokes方程和四阶龙格-库塔方法耦合的剪切应力输运k-ω模型，研究了纯波浪荷载、纯电流荷载和波流复合荷载作用下沉浮隧道的动力响应特性。系统地分析和讨论了作用在SFT上的水动力力及其运动响应特性，包括振动幅值、位移频率和振动轨迹。数值结果表明，对于本研究选取的SFT设计参数，当仅考虑波浪荷载时，SFT管的振动幅值随波高的增加而增大，随波周期的增加而减小。位移频率与波浪频率保持一致。仅考虑电流载荷时，SFT管在摇摆方向的运动响应呈现多频特性，摇摆方向的主导频率约为升沉方向的两倍。考虑波流复合载荷时，当电流速度较低时，SFT体在升沉方向的位移频率响应以波浪载荷为主，而当电流速度较大时，SFT体在升沉方向的位移频率响应同时由波浪和电流载荷主导。此外，当电流速度较低时，波浪和电流负载之间的耦合效应较小。然而，当电流速度增加到2.5 m s-1时，波流耦合效应变得明显且不可忽略。
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