Marine Structures最新文献

{"title":"A CPT-based p-y model for laterally loaded monopiles in sand","authors":"Zhentao Liu,&nbsp;Youhu Zhang,&nbsp;Peng Guo","doi":"10.1016/j.marstruc.2024.103767","DOIUrl":"10.1016/j.marstruc.2024.103767","url":null,"abstract":"<div><div>Large-diameter monopiles are currently the dominant foundation solution for supporting offshore wind turbines (OWTs). Monopiles exhibit a rigid response with significant rotation under lateral load and overturning moment. There is some debate regarding the applicability of <em>p-y</em> models derived from tests on small-diameter slender piles (such as the sand <em>p-y</em> model recommended by the API standard) to monopiles. To address this issue, this study gathered existing field pile load tests and finite element analysis results for large-diameter monopiles in sand and established a database incorporating the CPT results from each testing site. Through a comprehensive analysis of the collected database, a CPT-based <em>p-y</em> model with a modified hyperbolic formulation is proposed. The model has four parameters, which are the initial soil-pile interaction stiffness (<em>k</em>_ini), the ultimate soil resistance (<em>p</em>_u), the stiffness degradation coefficient (<em>m</em>), and the ultimate soil resistance adjustment coefficient (<em>A</em>). All of them are functions of the CPT cone tip resistance (<em>q</em>_c), thus avoiding potential uncertainties with the determination of input soil parameters, such as the peak friction angle, which is necessary for the conventional API <em>p-y</em> model. The model is demonstrated to provide satisfactory performance in predicting the lateral response of monopiles in sand.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103767"},"PeriodicalIF":4.0,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147714","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":"Risk assessment of the erosive process in the production pipeline of an Wet Christmas Tree as an indicator for inspection request","authors":"Vinícius Bellincanta Hercos,&nbsp;Miguel Luiz Ribeiro Ferreira","doi":"10.1016/j.marstruc.2024.103765","DOIUrl":"10.1016/j.marstruc.2024.103765","url":null,"abstract":"<div><div>Wet Christmas Trees (WCTs) pipes are susceptible to erosion owing to the presence of solid particles in the oil. The thickness measurements of these pipes are performed using remotely operated vehicles (ROVs). This study aims to assess the risk of leakage caused only by erosion, specifically for curved sections, based on the Det Norske Veritas (DNV) methodology. Data processing was performed using the Monte Carlo method by utilizing the operational and design data from a WCT with the aid of @Risk 8.2 software. The results demonstrate that the risk of leakage is too low, mainly because the design of the pipes of this WCT is conservative. However, the operator is responsible for determining their tolerance level and scheduling inspections accordingly. Through sensitivity analysis, was observed that an increase in sand content, water, oil, and gas flow rates most significantly impacted thickness reduction due to erosion.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103765"},"PeriodicalIF":4.0,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147713","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":"Water impact damage considering hydro-plastic interactions: Extensive experimental and numerical validation, and structural design recommendations","authors":"Zhaolong Yu","doi":"10.1016/j.marstruc.2024.103766","DOIUrl":"10.1016/j.marstruc.2024.103766","url":null,"abstract":"<div><div>Water impact damage can occur for ocean structures subjected to extreme waves as well as aeronautical vehicles during emergency water landing. The problem involves complicated fluid structure interaction (FSI) effects between large plastic structural deformations and fluid flow pressures, known as hydro-plasticity, and is not well understood. In 2019, we (Yu et al. [1]) derived a novel hydroplastic solution for water impact damage of beams and stiffened panels considering the mutual coupling effect. This paper utilizes results from model tests, real world wave impact accidents and coupled FSI numerical simulations to verify comprehensively the accuracy of the hydroplastic model in terms of the predicted structural damage and pressure histories. As most design standards use suggested pressure curves for designing against extreme wave impacts in the maritime and offshore industries, the pressure histories predicted by the hydroplastic model are reapplied to the structures to calculate the structural responses using nonlinear finite element analysis (NLFEA). This is to test if the generated pressure histories can reproduce the water impact damage and be used as suggested design pressure curves. Finally, a new design method is suggested based on the hydroplastic slamming model for the design of ocean structures against extreme wave impacts. The proposed design approach suggests using impact velocities rather than design pressures in current design standards, as the main design parameter, the value of which should meet required annual exceedance probability levels. The proposed design approach represents clear improvement and is useful for reliable and cost-effective design of structures against extreme water impacts.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103766"},"PeriodicalIF":4.0,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highlights and future research areas from ISSC 2022","authors":"Xiaozhi Wang ,&nbsp;Ole Andreas Hermundstad ,&nbsp;James Underwood ,&nbsp;Yordan Garbatov ,&nbsp;Sören Ehlers ,&nbsp;B Lennart Josefson ,&nbsp;Athanasios Kolios ,&nbsp;Iraklis Lazakis ,&nbsp;Agnes Marie Horn ,&nbsp;Neil Pegg","doi":"10.1016/j.marstruc.2024.103746","DOIUrl":"10.1016/j.marstruc.2024.103746","url":null,"abstract":"<div><div>The International Ship and Offshore Structures Congress 2022 (ISSC 2022) held in September 2022 covered most of the essential topics related to marine and offshore structures. The proceedings of ISSC 2022 include Committee Reports for Environment, Loads, Quasi-Static Response, Dynamic Response, Ultimate strength, Fatigue and Fracture, Design Principles and Criteria, Design Methods, Accidental Limit States, Experiment Methods, Materials and Fabrication Technology, Offshore Renewable Energy, Special Vessels, Ocean Space Utilization, Structural Longevity and Subsea Technology [<span><span>1</span></span>,<span><span>2</span></span>,<span><span>3</span></span>]. While the nature of ISSC Committee work is focused on state-of-the-art review based on the latest publications, the future work and research areas, which are most relevant to stimulate more R&amp;D effort, are presented here, focusing on Loads, Quasi-static response, Fatigue and fracture, Experimental method, Material and fabrication technology, Offshore renewable energy, Structural longevity, and Subsea technology.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103746"},"PeriodicalIF":4.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of flow-induced vibrations in two tandem circular cylinders at low gap ratios with considering collisions","authors":"Guosheng Qi ,&nbsp;Xiangxi Han ,&nbsp;Junlong Su ,&nbsp;Di Ren ,&nbsp;Zhanbin Meng ,&nbsp;Jian Gu ,&nbsp;Youhong Tang ,&nbsp;Zekun Hu ,&nbsp;Weidong Ruan","doi":"10.1016/j.marstruc.2024.103758","DOIUrl":"10.1016/j.marstruc.2024.103758","url":null,"abstract":"<div><div>In this study, two tandem elastically supported cylinders with the same parameters undergo numerical simulations using the overset grid method to analyze flow-induced vibrations (FIVs) with two degrees of freedom (2DOF). This study presents a model that can consider the collision of two tandem circular cylinders with FIVs in order to systematically analyze the FIV response, hydrodynamic characteristics, and wake vortex shedding patterns of two tandem circular cylinders with varying gaps of 0.5<em>D</em>, 1.0<em>D</em>, and 1.5<em>D</em>. The critical collision gap was found to be 1.6<em>D</em> for the 2 DOF FIV of two tandem circular cylinders. ​At each initial gap ratio, the streamwise amplitude of the upstream cylinder closely matches that of the isolated cylinder at lower reduced velocities (<em>U_r</em> ≤8.0), but increases significantly at higher reduced velocities (<em>U_r</em> &gt;8.3). Furthermore, the reduced velocity at which the downstream cylinder reaches its maximum transverse amplitude exceeds that of the isolated cylinder. For the large initial gap ratios (<em>G</em> = 1.0<em>D</em>, 1.5<em>D</em>), the transverse vibration frequency ratios of the upstream and downstream cylinders are close to those of the isolated cylinder. However, the reduced velocity at frequency ratio <em>f_y</em>/<em>f_n</em> equal to 1.3 is larger compared to the isolated cylinder case, and the delay effect becomes more noticeable as the initial gap ratio decreases. The upstream cylinder presents a figure 8 vibration trajectory only for small reduced velocities (<em>U_r</em> ≤7.0) and large gap ratios (<em>G</em>/<em>D</em> = 1.0, 1.5). However, in the range of reduced velocity and gap ratio considered in this study, the downstream cylinder exhibits chaotic vibration trajectories. For an initial gap of <em>G</em> = 0.5<em>D</em>, both the collision frequency and collision force between the upstream and downstream cylinders increase with increasing reduced velocities. As the initial gap ratio increases, the collision frequency and the collision force of the two cylinders decrease. The flow patterns of the two cylinders are mainly the shear layer reattachment flow pattern and the shear layer embedding flow pattern at small initial gap ratio. With the increase of the initial gap ratio, the synchronized gap vortex shedding flow pattern gradually occupies the dominant position. When the initial gap <em>G</em> = 0.5<em>D</em>, the wake vortex shedding patterns of the upstream and downstream cylinders are essentially 2S. When the initial gap <em>G</em> = 1.5<em>D</em>, both upstream and downstream cylinders can form super upper branches with 2T wake vortex shedding pattern, and the maximum transverse amplitude of the downstream cylinder reaches 1.73<em>D</em>.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103758"},"PeriodicalIF":4.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147711","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":"Methods for the local mechanical analysis of submarine power cables: A systematic literature review","authors":"Pan Fang ,&nbsp;Xiao Li ,&nbsp;Xiaoli Jiang ,&nbsp;Hans Hopman ,&nbsp;Yong Bai","doi":"10.1016/j.marstruc.2024.103763","DOIUrl":"10.1016/j.marstruc.2024.103763","url":null,"abstract":"<div><div>As the wind industry expands into remoter and deeper areas of the open sea with abundant wind energy, environmental loadings become harsher. This increases the requirements for submarine power cables (SPCs), which serve as the ‘lifeline’ for transporting electricity. Consequently, a more advanced design based on a thorough understanding of this structure is needed. However, the complex configuration and intensive contact issues within SPCs limit our understanding and make them black boxes for cable engineers. To gain more insights, methods for performing local mechanical analysis of SPCs are necessary. Despite this need, a comprehensive review of existing methods for local mechanical analysis of SPC is still lacking. Therefore, it is essential to review the available methods and provide guidelines for utilizing and developing these methods.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103763"},"PeriodicalIF":4.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PSO-based design and optimization of jacket substructures for offshore wind turbines","authors":"Borja Benítez-Suárez,&nbsp;Román Quevedo-Reina,&nbsp;Guillermo M. Álamo,&nbsp;Luis A. Padrón","doi":"10.1016/j.marstruc.2024.103759","DOIUrl":"10.1016/j.marstruc.2024.103759","url":null,"abstract":"<div><div>The search for more and better wind resources pushes offshore wind farms further into deeper waters, where jacket support structures become a competitive alternative to monopiles for bottom-fixed offshore wind turbines. In this context, this paper proposes a cost-effective methodology for the autonomous design that facilitates the generation of preliminary candidate designs of jacket substructures, reaching a level of detail suitable for the initial design phase. A Particle Swarm Optimization algorithm, with precomputed initial swarms, is used as a search and optimization tool. The proposed strategy is able to find candidate designs that satisfy, with a minimum use of material, a wide range of Ultimate Limit States, Fatigue Limit States and Geometrical Restrictions. It is shown that the use of a precomputed initial swarm generated taking into account a starting concept design of the structures with a low computational cost, instead of a standard random population, significantly improves the efficacy and efficiency of the algorithm. A reference case, based on the NREL-5MW wind turbine and its OC4 reference jacket support structure, is used for studying and illustrating the capabilities of the proposal.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103759"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147709","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":"Ultimate strength of deck grillages recovered from a decommissioned warship","authors":"Malcolm Smith ,&nbsp;Ken Nahshon ,&nbsp;Teresa Magoga ,&nbsp;Radu Chiritoiu ,&nbsp;Prahshanth Sivapalan","doi":"10.1016/j.marstruc.2024.103764","DOIUrl":"10.1016/j.marstruc.2024.103764","url":null,"abstract":"<div><div>Cyclic ultimate strength testing of four deck grillage structures recovered from a decommissioned naval destroyer was conducted at Naval Surface Warfare Center Carderock Division to explore the behavior of in-service ship structure and generate data for modeling and simulation comparisons. The test articles spanned 3 or 4 complete frame bays of the original structure and included features typical of ship construction such as non-uniform thickness and frame spacing, hatch openings, and weld seams. Prior to strength testing, thickness and shape measurements were conducted on all test specimens, including full LiDAR scanning, and material properties were measured from coupons recovered from each grillage. Measured ultimate strength, post-collapse strength, load-shortening response collapse mode and location are compared with nonlinear FEA and Smith's method predictions. Numerical assessments were performed in two modelling configurations: nominal configuration, using design scantlings and material properties; and the actual configuration, using all pre-test measured data. Nonlinear FEA predictions indicate interframe collapse modes in a central frame bay, consistent with the test results, although differences in the collapse location and collapse mode of individual stiffeners are observed. Prediction of ultimate and post-collapse strength is shown to be greatly improved in the actual configuration, in particular when using measured material properties. Agreement between predictions and measured ultimate strengths is good, and Smith's method strength predictions are found to be comparable to FEA predictions.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103764"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143146727","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":"Flow past two tandem cylinders with a slight misalignment angle between them","authors":"Qin Zhang ,&nbsp;Xinyu Wang ,&nbsp;Ming Zhao ,&nbsp;Tianyuan Wang","doi":"10.1016/j.marstruc.2024.103762","DOIUrl":"10.1016/j.marstruc.2024.103762","url":null,"abstract":"<div><div>This paper investigates the flow past two tandem cylinders with a slight misalignment angle between them. Unlike previous studies of flow past two parallel cylinders, the two cylinders are not on a same plane as the downstream cylinder is rotated slightly along an axis that is in the flow direction. Simulations are conducted for a cylinder length equal to 100 diameters, Reynolds numbers of 100 and 500 and the gap ratios of 0.5, 1, 2 and 4. If <em>Re</em>=100 and the gap ratio is 0.5, 1 and 2, intermittent vortex dislocation occurs, but the location of vortex dislocation varies between 15 and 35 diameters from the midsection. At gap ratios of 1 and 2, another vortex dislocation always occurs at the midsection because there is not vortex shedding at this location. This vortex dislocation at the midsection was not observed at <em>Re</em>=500 because there is vortex shedding at this position. The sectional drag coefficients of the two cylinders are nearly the same as those of two parallel cylinders with the same staggered distance. The standard derivation of the sectional lift coefficients of two cylinders at a section near the cylinder centres is smaller than those of two parallel cylinders with the same staggered distance.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103762"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147548","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 study on vibration responses of flexible riser transporting spiral flow in deep sea mining: Part II - solid-liquid two-phase transportation","authors":"Jiayu Zhang ,&nbsp;Nian-Zhong Chen ,&nbsp;Svein Sævik ,&nbsp;Aichun Feng","doi":"10.1016/j.marstruc.2024.103757","DOIUrl":"10.1016/j.marstruc.2024.103757","url":null,"abstract":"<div><div>An experimental study is carried out to investigate the responses of flow-induced vibration (FIV) on a flexible riser within a large-scale particle mixing transport device utilized in deep-sea mining, in which both spiral and straight solid-liquid flows are examined. The three-dimensional displacement field of the flexible riser is measured using a non-contact optical measurement system in time domain. The influence of fluid dynamic effects on the FIV responses of the riser, including velocity of straight flow, circumferential velocity of spiral flow, average concentration of solid-liquid two-phase flow, and internal flow density waves are investigated. For the mode of straight flow transport, the presence of internal flow density wave leads to the variation of dynamic load inside the riser, manifesting as periodic, significantly large-amplitude flutter of the riser, and noticeable bending deformation of the riser. Conversely, the flow pattern of the spiral flow results in a relatively uniform distribution of dynamic pressure, suppressing riser bending deformation, reducing the pulsation effects induced by internal flow density fluctuations. It is observed in frequency domain analysis that the riser vibration system transporting spiral flow exhibits multiple vibration modes, with higher-order frequencies being dominated and strong nonlinear characteristics.</div></div>","PeriodicalId":49879,"journal":{"name":"Marine Structures","volume":"101 ","pages":"Article 103757"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143147549","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}