Pub Date : 2025-06-01DOI: 10.1016/j.joes.2024.05.002
Rongze Wang , Quan Shi , Xinliang Tian , Xiaoxian Guo , Xin Li , Jianmin Yang
The twin-barge float-over technique, incorporating a dynamic positioning (DP) system, has been increasingly utilized to enhance the installation capacity and efficiency of offshore platforms. But the DP system is not fully considered during the design stage at present. This study investigates the dynamic responses of a twin-barge float-over system integrating flexible connections and DP system. A numerical model is developed and combined with model-scale experiments to analyze the characteristics of the system. The findings reveal the significant influence of the DP system on the coupled system, leading to harsh oscillations in the roll and heave directions. To effectively address this oscillation, a method with eigenmodes analysis and filter adjusting is proposed. The robustness of this method is verified through sensitivity analysis, and further investigation is conducted to analyze the motion response characteristics of the coupled system under varying environmental conditions. The findings and the proposed method in this paper are also applicable to various multi-vessel cooperative transportation scenarios.
{"title":"Dynamic responses of a twin-DP-barge float-over installation system with flexible connections","authors":"Rongze Wang , Quan Shi , Xinliang Tian , Xiaoxian Guo , Xin Li , Jianmin Yang","doi":"10.1016/j.joes.2024.05.002","DOIUrl":"10.1016/j.joes.2024.05.002","url":null,"abstract":"<div><div>The twin-barge float-over technique, incorporating a dynamic positioning (DP) system, has been increasingly utilized to enhance the installation capacity and efficiency of offshore platforms. But the DP system is not fully considered during the design stage at present. This study investigates the dynamic responses of a twin-barge float-over system integrating flexible connections and DP system. A numerical model is developed and combined with model-scale experiments to analyze the characteristics of the system. The findings reveal the significant influence of the DP system on the coupled system, leading to harsh oscillations in the roll and heave directions. To effectively address this oscillation, a method with eigenmodes analysis and filter adjusting is proposed. The robustness of this method is verified through sensitivity analysis, and further investigation is conducted to analyze the motion response characteristics of the coupled system under varying environmental conditions. The findings and the proposed method in this paper are also applicable to various multi-vessel cooperative transportation scenarios.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 353-365"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141395683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-05-30DOI: 10.1016/j.joes.2025.05.005
Mudassir Iqbal , Xiao-Ling Zhao , Hui Li , Daxu Zhang , Pei-Fu Zhang , Xuan Zhao , Congshui Yu
The understanding of GFRP composites under hydrothermal conditions and sustained loading offers valuable insights into their performance in challenging environments such as coastal areas, deep-sea structures, and environmentally friendly and long-lasting infrastructure solutions. This study examined the mechanical response of GFRP composites subjected to synergic sustained loading and hydrothermal degradation. A prediction application based on the XGBoost machine learning model was developed to estimate the residual mechanical response. The developed model was used to calculate the conversion factor accounting for moisture and temperature-based degradation in FRP composites. The SHAP analysis corroborated the experimental findings such that GFRP-based composites experience an initial rapid decline in mechanical properties when exposed to harsh environments, followed by a slower degradation rate over time. The pultruded vinyl ester-based GFRP composites depict less degradation than polyester-based composites and composites made via vacuum infusion. It was inferred that sustained loading below 30 % has no negative impact on the mechanical characteristics of hydrothermal-aged GFRP composites. The degradation became worse for the sustained loading beyond 30% of the ultimate strength of the GFRP composite. Comments are also made on the current recommendations in technical specifications by the European Committee for Standardization CEN/TS 19101 related to moisture and temperature conversion factors. The current work is limited to the mechanical investigation of GFRP composites subjected to hydrothermal degradation. It needs to be extended to other composites such as CFRP and BFRP.
{"title":"Evaluating hydrothermal degradation of GFRP composites under sustained loading using explainable machine learning","authors":"Mudassir Iqbal , Xiao-Ling Zhao , Hui Li , Daxu Zhang , Pei-Fu Zhang , Xuan Zhao , Congshui Yu","doi":"10.1016/j.joes.2025.05.005","DOIUrl":"10.1016/j.joes.2025.05.005","url":null,"abstract":"<div><div>The understanding of GFRP composites under hydrothermal conditions and sustained loading offers valuable insights into their performance in challenging environments such as coastal areas, deep-sea structures, and environmentally friendly and long-lasting infrastructure solutions. This study examined the mechanical response of GFRP composites subjected to synergic sustained loading and hydrothermal degradation. A prediction application based on the XGBoost machine learning model was developed to estimate the residual mechanical response. The developed model was used to calculate the conversion factor accounting for moisture and temperature-based degradation in FRP composites. The SHAP analysis corroborated the experimental findings such that GFRP-based composites experience an initial rapid decline in mechanical properties when exposed to harsh environments, followed by a slower degradation rate over time. The pultruded vinyl ester-based GFRP composites depict less degradation than polyester-based composites and composites made via vacuum infusion. It was inferred that sustained loading below 30 % has no negative impact on the mechanical characteristics of hydrothermal-aged GFRP composites. The degradation became worse for the sustained loading beyond 30% of the ultimate strength of the GFRP composite. Comments are also made on the current recommendations in technical specifications by the European Committee for Standardization CEN/TS 19101 related to moisture and temperature conversion factors. The current work is limited to the mechanical investigation of GFRP composites subjected to hydrothermal degradation. It needs to be extended to other composites such as CFRP and BFRP.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 982-1001"},"PeriodicalIF":11.8,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-05-23DOI: 10.1016/j.joes.2025.05.003
Zeyu Zhang , Qi Su , Yarong Zhou , Ren Sun
The moving behaviors of a prolate spheroidal complex with the controllable rotation in an ideal fluid without vortex shedding are investigated to find out the self-propelled mechanism of a non-spherical swimmer via the self-controlled rotation coupled with shift of its internal mass. Based on the model, algebraic velocity vector equations for the complex are derived from the Kirchhoff equations. Several simple cases reveal that the single non-spherical body can push itself to move persistently forward to break the kinematic time-reversal symmetry through coupling the specially-appointed rotation with the corresponding cyclic shift of the internal mass, and some typical self-motion patterns such as trochoids in two dimensions and unidirectional spatial helical motions are identified. The study aims to provide a potential swimming manner of underwater vehicles.
{"title":"Self-motion of an ellipsoid with controllable rotation in potential flow","authors":"Zeyu Zhang , Qi Su , Yarong Zhou , Ren Sun","doi":"10.1016/j.joes.2025.05.003","DOIUrl":"10.1016/j.joes.2025.05.003","url":null,"abstract":"<div><div>The moving behaviors of a prolate spheroidal complex with the controllable rotation in an ideal fluid without vortex shedding are investigated to find out the self-propelled mechanism of a non-spherical swimmer via the self-controlled rotation coupled with shift of its internal mass. Based on the model, algebraic velocity vector equations for the complex are derived from the Kirchhoff equations. Several simple cases reveal that the single non-spherical body can push itself to move persistently forward to break the kinematic time-reversal symmetry through coupling the specially-appointed rotation with the corresponding cyclic shift of the internal mass, and some typical self-motion patterns such as trochoids in two dimensions and unidirectional spatial helical motions are identified. The study aims to provide a potential swimming manner of underwater vehicles.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 960-967"},"PeriodicalIF":11.8,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An innovative approach is proposed in this paper to develop a three-dimensional numerical model to simulate the wave-induced erosion of a floating iceberg. The simulation domain is divided into three zones, i.e., inside the iceberg, outside the iceberg, and the interface between the two zones. While computational fluid dynamics is used to model heat conduction inside the iceberg, a hydrodynamic analysis based on linear wave theory and potential flow theory is performed to account for wave effects. The main objective of this paper is to implement the developed numerical model and validate it against experimental data obtained from a wave flume. Three case studies are designed to compare the results of numerical simulations against experimental data: Case #1: the melting rate and mass loss rate of a bottom-fixed ice cylinder is studied under wave erosion; Case #2: focusing on the hydrodynamic part: the response amplitude operator of a free-heaving ice cylinder is analyzed; and Case #3: coupling both the hydrodynamic and thermodynamic processes, the mass loss rate of a heaving ice cylinder is investigated in different wave periods. Results indicate that the model can predict melting rates in the first case study near the still water level where wave-induced erosion is the dominant mechanism. In addition, the outputs of numerical modeling in terms of the mass loss rate of a heaving ice cylinder closely follow those of experimental data, particularly around the critical wave period where the mass loss rate significantly increases due to dramatic ice cylinder heave motion (resonance).
{"title":"A numerical model for the simulation of wave-induced erosion of floating icebergs: Implementation and validation against wave flume data","authors":"Behzad Forouzi Feshalami , Sveinung Løset , Raed Lubbad , Wenjun Lu , Henriette Skourup , Marat Kashafutdinov","doi":"10.1016/j.joes.2025.05.004","DOIUrl":"10.1016/j.joes.2025.05.004","url":null,"abstract":"<div><div>An innovative approach is proposed in this paper to develop a three-dimensional numerical model to simulate the wave-induced erosion of a floating iceberg. The simulation domain is divided into three zones, i.e., inside the iceberg, outside the iceberg, and the interface between the two zones. While computational fluid dynamics is used to model heat conduction inside the iceberg, a hydrodynamic analysis based on linear wave theory and potential flow theory is performed to account for wave effects. The main objective of this paper is to implement the developed numerical model and validate it against experimental data obtained from a wave flume. Three case studies are designed to compare the results of numerical simulations against experimental data: Case #1: the melting rate and mass loss rate of a bottom-fixed ice cylinder is studied under wave erosion; Case #2: focusing on the hydrodynamic part: the response amplitude operator of a free-heaving ice cylinder is analyzed; and Case #3: coupling both the hydrodynamic and thermodynamic processes, the mass loss rate of a heaving ice cylinder is investigated in different wave periods. Results indicate that the model can predict melting rates in the first case study near the still water level where wave-induced erosion is the dominant mechanism. In addition, the outputs of numerical modeling in terms of the mass loss rate of a heaving ice cylinder closely follow those of experimental data, particularly around the critical wave period where the mass loss rate significantly increases due to dramatic ice cylinder heave motion (resonance).</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 968-981"},"PeriodicalIF":11.8,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-05-14DOI: 10.1016/j.joes.2025.05.002
Rui Zhang , Lingyu Zhan , Limin Kuang , Redili Yushan , Yu Tu , Hongbo Zhu , Jie Su , Zhaolong Han , Dai Zhou
Vertical-axis wind turbines (VAWTs) are receiving growing interest in offshore wind energy exploitation. However, they often exhibit suboptimal energy conversion efficiency, particularly at low tip speed ratios (TSRs). One critical challenge is suppressing flow separation and dynamic stall on the blades. Passive flow control techniques have shown potential in improving blade aerodynamics, yet a simple and effective approach is still desired. This study proposes a novel leading-edge slot structure aimed at enhancing the power efficiency of VAWTs without additional energy input. The structure facilitates natural suction and blowing flows on the suction side of the blades. High-fidelity computational fluid dynamics simulations incorporating a transition shear stress transport model are employed to examine turbine aerodynamics. The power performance and aerodynamic loads of VAWTs with various slotted blade designs (different start locations, 0.02c ≤ xI ≤ 0.31c, and end locations, 0.1c ≤ xII ≤ 0.35c, where c denotes the blade chord length) are compared to identify the relatively optimal slot configuration. The analysis of blade boundary layer phenomena and flow state in the slot further elucidates the flow control mechanism. Results indicate that the leading-edge slot structure significantly enhances the power efficiency of the VAWT at low TSRs. The relatively optimal slot configuration (xI = 0.16c, xII = 0.2c) yields an average power increase of 38.33 % under studied operating conditions. Laminar separation bubble bursting is delayed or even eliminated for slotted blades at low and moderate TSRs. The leading-edge slot structure also delays trailing-edge separation, suppresses dynamic stall vortex formation, and reduces shedding vortex strength, thereby increasing the blade lift-to-drag ratio. This study would facilitate the blade design of VAWTs.
垂直轴风力涡轮机（VAWTs）在海上风能开发中受到越来越多的关注。然而，它们经常表现出次优的能量转换效率，特别是在低叶尖速比（tsr）下。一个关键的挑战是抑制流动分离和叶片的动态失速。被动流动控制技术在改善叶片空气动力学方面已经显示出潜力，但仍然需要一种简单有效的方法。本研究提出了一种新的前缘槽结构，旨在提高vawt的功率效率，而无需额外的能量输入。这种结构有利于叶片吸力侧的自然吸力和吹气流动。采用高保真计算流体动力学模拟，结合过渡剪应力输运模型对涡轮空气动力学进行了研究。对比不同开槽叶片设计（开始位置为0.02c≤xI≤0.31c，结束位置为0.1c≤xII≤0.35c，其中c为叶片弦长）的vawt的动力性能和气动载荷，确定相对最优的开槽构型。通过对叶片边界层现象和槽内流动状态的分析，进一步阐明了流动控制机理。结果表明，前缘槽结构显著提高了低tsr时VAWT的功率效率。在研究的工作条件下，相对最佳的槽位配置（xI = 0.16c, xII = 0.2c）的平均功率增加了38.33%。在中低tsr条件下，狭缝叶片可延迟甚至消除层流分离气泡的破裂。前缘槽结构还可以延缓尾缘分离，抑制动态失速涡的形成，降低脱落涡强度，从而提高叶片升阻比。本文的研究将为vawt叶片的设计提供参考。
{"title":"Passive flow control technique for enhancing power efficiency of vertical-axis wind turbines: Leading-edge slot structure","authors":"Rui Zhang , Lingyu Zhan , Limin Kuang , Redili Yushan , Yu Tu , Hongbo Zhu , Jie Su , Zhaolong Han , Dai Zhou","doi":"10.1016/j.joes.2025.05.002","DOIUrl":"10.1016/j.joes.2025.05.002","url":null,"abstract":"<div><div>Vertical-axis wind turbines (VAWTs) are receiving growing interest in offshore wind energy exploitation. However, they often exhibit suboptimal energy conversion efficiency, particularly at low tip speed ratios (TSRs). One critical challenge is suppressing flow separation and dynamic stall on the blades. Passive flow control techniques have shown potential in improving blade aerodynamics, yet a simple and effective approach is still desired. This study proposes a novel leading-edge slot structure aimed at enhancing the power efficiency of VAWTs without additional energy input. The structure facilitates natural suction and blowing flows on the suction side of the blades. High-fidelity computational fluid dynamics simulations incorporating a transition shear stress transport model are employed to examine turbine aerodynamics. The power performance and aerodynamic loads of VAWTs with various slotted blade designs (different start locations, 0.02<em>c</em> ≤ <em>x<sub>I</sub></em> ≤ 0.31<em>c</em>, and end locations, 0.1<em>c</em> ≤ <em>x<sub>II</sub></em> ≤ 0.35<em>c</em>, where <em>c</em> denotes the blade chord length) are compared to identify the relatively optimal slot configuration. The analysis of blade boundary layer phenomena and flow state in the slot further elucidates the flow control mechanism. Results indicate that the leading-edge slot structure significantly enhances the power efficiency of the VAWT at low TSRs. The relatively optimal slot configuration (<em>x<sub>I</sub></em> = 0.16<em>c, x<sub>II</sub></em> = 0.2<em>c</em>) yields an average power increase of 38.33 % under studied operating conditions. Laminar separation bubble bursting is delayed or even eliminated for slotted blades at low and moderate TSRs. The leading-edge slot structure also delays trailing-edge separation, suppresses dynamic stall vortex formation, and reduces shedding vortex strength, thereby increasing the blade lift-to-drag ratio. This study would facilitate the blade design of VAWTs.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 945-959"},"PeriodicalIF":11.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-05-06DOI: 10.1016/j.joes.2025.05.001
Liming Zhang , Deqing Yang , Qing Li , Jianghai Qiu
Applying distinctive designs to mechanical metamaterials is an effective way to achieve bandgap generation, widening and movement. In this paper, the bandgaps of metamaterials are tailored through the unique design of bending, folding, and twisting units and applied to the vibration-damping design of a marine water pump base. It is found that the bending operation generates a new complete bandgap and significantly enlarges the directional bandgap in the low-frequency region; the folding operation expands the directional bandgap in the high-frequency region; and the twisting operation generates and broadens the directional bandgap in the mid-frequency region. The application of the negative Poisson's ratio star-shaped metamaterial (NPRSM) cell, with a 60° bending angle, to vibration damping in a metamaterial ship pump base is presented. The new base achieved vibration attenuation of 43.435 dB and 60.282 dB over the bandgap ranges of 517.95 Hz - 668.36 Hz and 916.98 Hz - 965.03 Hz, respectively. In addition, the weight of the new base was reduced by 36.19 % compared to the conventional pump base, which is merely capable of bearing loads. This study provides an innovative design method for broadband vibration isolation and demonstrates the promising future of mechanical metamaterials in practical engineering applications.
{"title":"Tailor metamaterial bandgaps with bending, folding and twisting for the non-vibration ship pump base","authors":"Liming Zhang , Deqing Yang , Qing Li , Jianghai Qiu","doi":"10.1016/j.joes.2025.05.001","DOIUrl":"10.1016/j.joes.2025.05.001","url":null,"abstract":"<div><div>Applying distinctive designs to mechanical metamaterials is an effective way to achieve bandgap generation, widening and movement. In this paper, the bandgaps of metamaterials are tailored through the unique design of bending, folding, and twisting units and applied to the vibration-damping design of a marine water pump base. It is found that the bending operation generates a new complete bandgap and significantly enlarges the directional bandgap in the low-frequency region; the folding operation expands the directional bandgap in the high-frequency region; and the twisting operation generates and broadens the directional bandgap in the mid-frequency region. The application of the negative Poisson's ratio star-shaped metamaterial (NPRSM) cell, with a 60° bending angle, to vibration damping in a metamaterial ship pump base is presented. The new base achieved vibration attenuation of 43.435 dB and 60.282 dB over the bandgap ranges of 517.95 Hz - 668.36 Hz and 916.98 Hz - 965.03 Hz, respectively. In addition, the weight of the new base was reduced by 36.19 % compared to the conventional pump base, which is merely capable of bearing loads. This study provides an innovative design method for broadband vibration isolation and demonstrates the promising future of mechanical metamaterials in practical engineering applications.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 929-944"},"PeriodicalIF":11.8,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-04-26DOI: 10.1016/j.joes.2025.04.003
Zihan Liu , Yong Yang , Guocheng Zhao , Longfei Xiao
The Coandă-effect-based hydraulic collection, celebrated for its high pick-up efficiency, has become a focus in deep-sea mining. However, prevailing research mainly focused on the performance in clear water environments, overlooking the impact of seabed sediments. This experimental study aims to examine the dynamic characteristics of nodule particles within the "fluid-solid-soil" multi-field under Coandă-effect-based hydraulic collection. The sediments were simulated in the laboratory by mixing the bentonite and water in specific proportions to replicate the physical and mechanical properties of in-situ sediments. A detailed analysis was conducted on the mechanical and motion characteristics of particles under various jet parameters and sediment shear strengths. The results illuminated that the shear strength of the sediment predominantly influenced the soil adhesion force, exhibiting an approximately linear correlation. Subsequent to assessing the collection performance, a criterion for particle incipient motion was proposed, and an empirical formula was established for predicting the maximum lifting force and experimentally confirmed to possess a maximum error below 20%. The pick-up efficiency experiments further demonstrated that when the jet parameters aligned with the critical conditions delineated by using the empirical formula, there was a significant increase to nearly 100% in pick-up efficiency, underscoring the practicality and accuracy of the predictive model. The results can offer theoretical guidance for selecting optimal jet parameters, to ensure efficient collection while minimizing potential environmental impacts due to excessive hydrodynamic forces and sediment erosion.
{"title":"Experimental study on dynamic characteristics of nodule particles in multi-field coupling during the Coandă-effect-based hydraulic collection","authors":"Zihan Liu , Yong Yang , Guocheng Zhao , Longfei Xiao","doi":"10.1016/j.joes.2025.04.003","DOIUrl":"10.1016/j.joes.2025.04.003","url":null,"abstract":"<div><div>The Coandă-effect-based hydraulic collection, celebrated for its high pick-up efficiency, has become a focus in deep-sea mining. However, prevailing research mainly focused on the performance in clear water environments, overlooking the impact of seabed sediments. This experimental study aims to examine the dynamic characteristics of nodule particles within the \"fluid-solid-soil\" multi-field under Coandă-effect-based hydraulic collection. The sediments were simulated in the laboratory by mixing the bentonite and water in specific proportions to replicate the physical and mechanical properties of in-situ sediments. A detailed analysis was conducted on the mechanical and motion characteristics of particles under various jet parameters and sediment shear strengths. The results illuminated that the shear strength of the sediment predominantly influenced the soil adhesion force, exhibiting an approximately linear correlation. Subsequent to assessing the collection performance, a criterion for particle incipient motion was proposed, and an empirical formula was established for predicting the maximum lifting force and experimentally confirmed to possess a maximum error below 20%. The pick-up efficiency experiments further demonstrated that when the jet parameters aligned with the critical conditions delineated by using the empirical formula, there was a significant increase to nearly 100% in pick-up efficiency, underscoring the practicality and accuracy of the predictive model. The results can offer theoretical guidance for selecting optimal jet parameters, to ensure efficient collection while minimizing potential environmental impacts due to excessive hydrodynamic forces and sediment erosion.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 916-928"},"PeriodicalIF":11.8,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-04-15DOI: 10.1016/j.joes.2025.04.001
Qing-Hua Zhou , Hong-Xiang Xue , Ke-Yi Hu , Hong-Rui Liu , Wen-Ling Tu
Type B cargo tanks in Very Large Ethane Carriers (VLECs), constructed with 5 % Ni steel, exhibit non-negligible probability of cryogenic liquid leakage due to fatigue failure in welded joints under cyclic loads and the presence of pre-existing surface cracks. This study systematically investigates the fatigue and fracture behavior of 5 % Ni steel submerged arc welded (SAW) joints through tensile, fracture toughness, and fatigue crack propagation (FCP) tests at 23 °C and -110 °C. Results demonstrate the SAW joints exhibited superior cryogenic mechanical properties compared to those under ambient condition. A novel methodology integrating critical fatigue fracture location identification and FCP life analysis was developed, utilizing a Weibull-distributed random wave-induced load spectrum generated via Python to simulate operational stresses. FCP analysis using failure assessment diagram (FAD) and the Paris law model revealed critical crack sizes and remaining life at tank vertical support toes. Additionally, the influence of material properties and temperatures on FCP life was quantitatively evaluated. This study addresses the lack of fracture toughness and Paris parameters for 5 % Ni steel SAW joints, providing essential reference for damage tolerance design and safe operation of VLEC type B tanks under cryogenic conditions.
{"title":"Experimental and analytical investigation on cryogenic fatigue and fracture behavior of 5% Ni steel welded joints for LEG type B cargo tank","authors":"Qing-Hua Zhou , Hong-Xiang Xue , Ke-Yi Hu , Hong-Rui Liu , Wen-Ling Tu","doi":"10.1016/j.joes.2025.04.001","DOIUrl":"10.1016/j.joes.2025.04.001","url":null,"abstract":"<div><div>Type B cargo tanks in Very Large Ethane Carriers (VLECs), constructed with 5 % Ni steel, exhibit non-negligible probability of cryogenic liquid leakage due to fatigue failure in welded joints under cyclic loads and the presence of pre-existing surface cracks. This study systematically investigates the fatigue and fracture behavior of 5 % Ni steel submerged arc welded (SAW) joints through tensile, fracture toughness, and fatigue crack propagation (FCP) tests at 23 °C and -110 °C. Results demonstrate the SAW joints exhibited superior cryogenic mechanical properties compared to those under ambient condition. A novel methodology integrating critical fatigue fracture location identification and FCP life analysis was developed, utilizing a Weibull-distributed random wave-induced load spectrum generated via Python to simulate operational stresses. FCP analysis using failure assessment diagram (FAD) and the Paris law model revealed critical crack sizes and remaining life at tank vertical support toes. Additionally, the influence of material properties and temperatures on FCP life was quantitatively evaluated. This study addresses the lack of fracture toughness and Paris parameters for 5 % Ni steel SAW joints, providing essential reference for damage tolerance design and safe operation of VLEC type B tanks under cryogenic conditions.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 5","pages":"Pages 864-877"},"PeriodicalIF":11.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-04-01DOI: 10.1016/j.joes.2024.05.001
Fabian Thies, Jonas W. Ringsberg
Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods. Aero- and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically, but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials. This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations. The results show that sea trials have an uncertainty of 23 %, well above 100 % of the measured savings, if performed using normal onboard equipment. Model uncertainties were found to be between 6 % and 17 % of the predicted savings.
{"title":"Sea trials vs prediction by numerical models—Uncertainties in the measurements and prediction of WASP performance","authors":"Fabian Thies, Jonas W. Ringsberg","doi":"10.1016/j.joes.2024.05.001","DOIUrl":"10.1016/j.joes.2024.05.001","url":null,"abstract":"<div><div>Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods. Aero- and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically, but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials. This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations. The results show that sea trials have an uncertainty of 23 %, well above 100 % of the measured savings, if performed using normal onboard equipment. Model uncertainties were found to be between 6 % and 17 % of the predicted savings.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 239-245"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141032096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-04-01DOI: 10.1016/j.joes.2024.01.002
Isaac Slaughter , Jagir Laxmichand Charla , Martin Siderius , John Lipor
Maritime situational awareness tasks such as port management, collision avoidance, and search-and-rescue missions rely on accurate knowledge of vessel locations. The availability of historical vessel trajectory data through the Automatic Identification System (AIS) has enabled the development of prediction methods, with a recent focus on trajectory prediction via recurrent neural networks (RNNs) and other deep learning architectures. While these methods have shown promising performance benefits over kinematic and clustering-based models, comparing among RNN-based models remains difficult due to variations in evaluation datasets, region sizes, vessel types, and numerous other design choices. As a result, it is not clear whether recent methods based on highly-sophisticated network architectures are necessary to achieve strong prediction performance. In this work, we present a simple fusion-based RNN approach to vessel trajectory prediction that allows for easy incorporation of exogenous variables. We perform an extensive ablation study to measure the impact of various modeling choices, including preprocessing, loss functions, and the choice of features, as well as the first usage of surface current information in vessel trajectory prediction. We demonstrate that our approach achieves state-of-the-art performance on three large regions off the United States coast, obtaining an improvement of up to 0.88 km over competing methods when predicting three hours into the future. We conclude that our simple architecture can outperform more complicated architectures while incurring a lower memory cost. Further, we show that the choice of loss function and the inclusion of surface current information both have significant impact on prediction performance.
{"title":"Vessel trajectory prediction with recurrent neural networks: An evaluation of datasets, features, and architectures","authors":"Isaac Slaughter , Jagir Laxmichand Charla , Martin Siderius , John Lipor","doi":"10.1016/j.joes.2024.01.002","DOIUrl":"10.1016/j.joes.2024.01.002","url":null,"abstract":"<div><div>Maritime situational awareness tasks such as port management, collision avoidance, and search-and-rescue missions rely on accurate knowledge of vessel locations. The availability of historical vessel trajectory data through the Automatic Identification System (AIS) has enabled the development of prediction methods, with a recent focus on trajectory prediction via recurrent neural networks (RNNs) and other deep learning architectures. While these methods have shown promising performance benefits over kinematic and clustering-based models, comparing among RNN-based models remains difficult due to variations in evaluation datasets, region sizes, vessel types, and numerous other design choices. As a result, it is not clear whether recent methods based on highly-sophisticated network architectures are necessary to achieve strong prediction performance. In this work, we present a simple fusion-based RNN approach to vessel trajectory prediction that allows for easy incorporation of exogenous variables. We perform an extensive ablation study to measure the impact of various modeling choices, including preprocessing, loss functions, and the choice of features, as well as the first usage of surface current information in vessel trajectory prediction. We demonstrate that our approach achieves state-of-the-art performance on three large regions off the United States coast, obtaining an improvement of up to 0.88 km over competing methods when predicting three hours into the future. We conclude that our simple architecture can outperform more complicated architectures while incurring a lower memory cost. Further, we show that the choice of loss function and the inclusion of surface current information both have significant impact on prediction performance.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 229-238"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139637147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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