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Theory, Method and Engineering Application of Computational Mechanics in Offshore...
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Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Ocean Engineering".

Deadline for manuscript submissions: closed (20 December 2022) | Viewed by 28922

Special Issue Editors

Prof. Dr. Jun Yan

grade E-Mail Website
Guest Editor
School of Mechanics and Aerospace Engineering, Dalian University of Technology, Dalian, China
Interests: structure optimization; marine composite flexible pipes and cables; artificial intelligence; software development; topological optimization; multiscale analysis
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Wanhai Xu

E-Mail Website
Guest Editor
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300350, China
Interests: dynamics and control of marine structures; wave energy conversion; vortex-induced vibration; fluid mechanics
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Zhiqiang Hu

E-Mail Website
Guest Editor
School of Engineering, Newcastle University, Newcastle, UK
Interests: offshore renewable energy; hydrodynamic theoretical research on the potential flow theory and complex nonlinear responses for ships and offshore floating units; basin model experimental investigations for ships and offshore structures; interaction analysis between ice and marine structures
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Min Lou

E-Mail Website
Guest Editor
School of Petroleum Engineering, China University of Petroleum, Qingdao, China
Interests: response research and optimization design of marine riser; the safety and reliability of submarine pipelines/underwater production systems; the safety and reliability of offshore platforms
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Marine energy development is the trend of energy development in the world. The development of marine energy is inseparable from the design, manufacture and application of offshore structures. In order to systematically report the theoretical calculation methods of offshore structures in the process of design, manufacturing, testing and application in the process of marine energy development, this Special Issue aims to collect the research work related to the theory, method and engineering application of computational mechanics in offshore structures. Through this Special Issue, the application scope, frontier, innovative research results and key technical achievements of computational mechanics in ocean engineering will be presented.

This is based on the great success of our previous Special Issue with the same title: Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures. We sincerely invite researchers from enterprises or research institutes to submit innovative and advanced scientific research work, show their research results and serve the development of marine energy. 

Prof. Dr. Jun Yan
Prof. Dr. Wanhai Xu
Prof. Dr. Zhiqiang Hu
Prof. Dr. Min Lou
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • offshore oil engineering
  • subsea production system
  • offshore platform
  • marine risers and pipelines
  • intelligent design and manufacture of marine equipment
  • structural safety and reliability
  • intelligent monitoring and operation

Published Papers (17 papers)

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Editorial

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4 pages, 174 KiB  
Editorial
Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures
by Jun Yan, Wanhai Xu, Zhiqiang Hu and Min Lou
J. Mar. Sci. Eng. 2023, 11(6), 1105; https://doi.org/10.3390/jmse11061105 - 23 May 2023
Viewed by 886
Abstract
Oceans cover approximately 71% of the planet’s surface, and 97% of the Earth’s water is contained within the ocean [...] Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)

Research

Jump to: Editorial

21 pages, 8456 KiB  
Article
Mechanical Characteristics of Fiber-Reinforced Flexible Pipe Subjected to Axial Tensile Load
by Zhenwen Sun, Weiping Huang, Hailong Lu, Yufeng Bu, Yuanchao Yin, Shichao Wang and Yimeng Fan
J. Mar. Sci. Eng. 2023, 11(3), 586; https://doi.org/10.3390/jmse11030586 - 9 Mar 2023
Cited by 2 | Viewed by 1874
Abstract
Fiber-reinforced flexible pipes are subjected to large axial tension loads in deep-water applications, which may result in the excessive deformation of the pipes. Owing to the anisotropy of the composite materials, accurately describing the tensile behavior of these pipes is difficult. Theoretical, numerical, [...] Read more.
Fiber-reinforced flexible pipes are subjected to large axial tension loads in deep-water applications, which may result in the excessive deformation of the pipes. Owing to the anisotropy of the composite materials, accurately describing the tensile behavior of these pipes is difficult. Theoretical, numerical, and experimental methods are employed in this study to investigate the mechanical characteristics of a glass fiber-reinforced unbonded flexible pipe under axial tensile loads. Based on the load–strain relationship of each pipe layer, analytical equations considering the effect of anisotropy and radial deformation are first proposed to calculate the axial tensile stiffness of the pipe. A detailed numerical model is established to simulate the tensile behavior of the pipe. A prototype test is performed on a 4500 mm long sample using a tensile testing machine. The leading roles of outer tensile reinforcement layers in axial tensile capacity are illustrated by the strain energy of the pipe layers obtained by the numerical model. Subsequently, a comparison analysis of the mean fiber direction strains of the selected sections are performed between numerical and experimental results, which validates the numerical model. Additionally, the stress distributions of different pipe layers are discussed based on the results of the numerical analysis. Finally, the comparison of axial tensile stiffness results validates the accuracy of the analytical model considering radial deformation. This study proposes effective theoretical and numerical models to predict the tensile behavior of a fiber-reinforced flexible pipe, which provides useful references for the design and structural analysis of these pipes. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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17 pages, 6585 KiB  
Article
Numerical Study on Flexible Pipe End Fitting Progressive Failure Behavior Based on Cohesive Zone Model
by Tao Zhang, Qingzhen Lu, Jun Yan, Shichao Wang, Qianjin Yue, Shanghua Wu, Hailong Lu and Jinlong Chen
J. Mar. Sci. Eng. 2023, 11(1), 116; https://doi.org/10.3390/jmse11010116 - 5 Jan 2023
Cited by 4 | Viewed by 1651
Abstract
Flexible pipes are extensively used to connect seabed and floating production systems for the development of deep-water oil and gas. In the top connection area, end fitting (EF) is the connector between the flexible pipe and floating platform, as a critical component for [...] Read more.
Flexible pipes are extensively used to connect seabed and floating production systems for the development of deep-water oil and gas. In the top connection area, end fitting (EF) is the connector between the flexible pipe and floating platform, as a critical component for structural failure. To address this issue, a combined numerical and experimental prediction method is proposed in this paper to investigate the failure behavior of flexible pipes EF considering tensile armor and epoxy resin debonding. In order to analyze the stress distribution of the tensile armor and the damage state of the bonding interface as the tensile load increases, a finite element model of the EF anchorage system is established based on the cohesive zone model (CZM). Additionally, the effects of the epoxy resin shear strength (ss) and the steel wire yield strength (ys) on the structural load-bearing capacity are discussed in detail. The results indicate that wire strength and interface bonding have a substantial effect on the anchorage system’s failure behavior, and the low-strength wire anchorage system has a three-stage failure behavior with wire yielding as the predominant failure mode, while the high-strength wire anchorage system has a two-stage failure behavior with interface debonding as the predominant failure mode. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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13 pages, 5122 KiB  
Article
Experimental and Numerical Study of Lateral Indentation for Pipe-in-Pipe Structures
by Yi Wang, Jun Huang, Menglan Duan, Chengong Sun and Xiongfei Wang
J. Mar. Sci. Eng. 2023, 11(1), 98; https://doi.org/10.3390/jmse11010098 - 4 Jan 2023
Cited by 1 | Viewed by 1136
Abstract
Pipe-in-pipe (PIP) flowlines have been widely arranged in offshore oil and gas fields for transportation, to achieve a significant thermal insulation capacity and outstanding resistance to external loads. However, the lateral indentation mechanisms of these multilayer pipelines are more complicated than those of [...] Read more.
Pipe-in-pipe (PIP) flowlines have been widely arranged in offshore oil and gas fields for transportation, to achieve a significant thermal insulation capacity and outstanding resistance to external loads. However, the lateral indentation mechanisms of these multilayer pipelines are more complicated than those of single-layer pipelines. In this paper, the change and deformation laws of lateral indentation in the PIP structure were studied by experimental and numerical methods, and three stages of deformation behavior for PIP during lateral indentation were observed. The effects of the diameter and wall thickness of inner and outer pipes on the relationship between the indentation load and lateral indentation were also studied, which provided a reference for the design and analysis of PIP structures. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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17 pages, 4933 KiB  
Article
Short-Term Trajectory Prediction of Maritime Vessel Using k-Nearest Neighbor Points
by Minglong Zhang, Liang Huang, Yuanqiao Wen, Jinfen Zhang, Yamin Huang and Man Zhu
J. Mar. Sci. Eng. 2022, 10(12), 1939; https://doi.org/10.3390/jmse10121939 - 7 Dec 2022
Cited by 2 | Viewed by 1627
Abstract
The prediction of ship location has become an increasingly popular research hotspot in the field of maritime transportation engineering, which benefits maritime safety supervision and security. Existing methods of ship location prediction based on motion characteristics have a large uncertainty and cannot guarantee [...] Read more.
The prediction of ship location has become an increasingly popular research hotspot in the field of maritime transportation engineering, which benefits maritime safety supervision and security. Existing methods of ship location prediction based on motion characteristics have a large uncertainty and cannot guarantee trajectory prediction accuracy of the target ship. An improved method of location prediction using k-nearest neighbor (KNN) is proposed in this paper. An expanded circle area of the latest point of the target ship is first generated to find the reference points with similar movement characteristics in the constraints of distance and time intervals. Then, the top k-nearest neighbors are determined based on the degree of similarity. Relationships between the reference point of each neighbor and the latest points of the target ship are calculated. The predicted location of the target ship can then be determined by a weighted calculation of the locations of all neighbors at the predicted time and their relationships with the target ship. Experiments of ship location prediction in 10 min, 20 min, and 30 min were conducted. The correlation coefficient of the location prediction error for the three experiments was 0.992, 0.99, and 0.9875, respectively. The results show that ship location prediction with reference to multiple nearest neighbors with similar movements can provide better accuracy. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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14 pages, 3513 KiB  
Article
Anchor Chain Optimization Design of a Catenary Anchor Leg Mooring System Based on Adaptive Sampling
by Qiang Sun, Wenbo Li, Rundong Li, Dongsheng Peng, Qiang Guo, Yan Zhao, Qianjin Yue and Wanxie Zhong
J. Mar. Sci. Eng. 2022, 10(11), 1739; https://doi.org/10.3390/jmse10111739 - 13 Nov 2022
Cited by 4 | Viewed by 2228
Abstract
A catenary anchor leg mooring system (CALM) is one of the main kinds of offshore transport terminals. Its buoyancy is connected by multiple anchor chains fixed on the seabed. Because a large deformation characterizes the anchor chain, it is prone to fatigue failure [...] Read more.
A catenary anchor leg mooring system (CALM) is one of the main kinds of offshore transport terminals. Its buoyancy is connected by multiple anchor chains fixed on the seabed. Because a large deformation characterizes the anchor chain, it is prone to fatigue failure under dynamic loads in marine environments. These factors lead to many challenges in the design optimization of anchor chains. This study aims to develop a rapid optimization design framework for a mooring anchor chain with cost minimization as the design objective. In this framework, an approximation model of the mooring analysis is built based on an adaptive sampling method, and a combination of a genetic algorithm and a sequential quadratic programming method is utilized to optimize the established approximation model. The results show that the framework significantly reduces the computation time, and the error of the final optimization result obtained by adaptive sampling is significantly reduced. We found that using a quadratic or elliptic function as an adaptive function is good enough to obtain the optimization result. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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10 pages, 50987 KiB  
Article
Test Study on Vortex-Induced Vibration of Deep-Sea Riser under Bidirectional Shear Flow
by Weiwei Zhou, Menglan Duan, Rongqi Chen, Shisheng Wang and Huiming Li
J. Mar. Sci. Eng. 2022, 10(11), 1689; https://doi.org/10.3390/jmse10111689 - 7 Nov 2022
Cited by 2 | Viewed by 1125
Abstract
A model test was carried out to reveal the vortex-induced vibration characteristics of a deep-sea riser under bidirectional shear flow. Bandpass filtering and modal analysis were used to process the test strain data, and the amplitude and frequency response characteristics of the vortex-induced [...] Read more.
A model test was carried out to reveal the vortex-induced vibration characteristics of a deep-sea riser under bidirectional shear flow. Bandpass filtering and modal analysis were used to process the test strain data, and the amplitude and frequency response characteristics of the vortex-induced vibration of the riser in the bidirectional shear flow field were obtained. The results of the test data analysis show that the dominant frequency of the vortex-induced vibration of the riser model under bidirectional shear flow is locked in the natural frequency of the riser and does not increase with the increase in flow velocity, that the average resistance coefficient of the riser model has little change under different flow velocities because of the distribution characteristics of the “bidirectional shear” flow field, that there is an extreme value of the shear force in the middle of the riser model, and that the Strouhal number in the transverse direction of the vortex-induced vibration under bidirectional shear flow is less than the recommended value of the current vortex-induced vibration prediction software. The obtained results provide basic data for the prediction of vortex-induced vibration and research into the fatigue analysis method of a riser under an internal wave flow field. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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22 pages, 4251 KiB  
Article
A Combined Measurement Method for the Seafloor Positioning, Navigation, and Timing Network
by Jinye Ma and Jianhu Zhao
J. Mar. Sci. Eng. 2022, 10(11), 1664; https://doi.org/10.3390/jmse10111664 - 4 Nov 2022
Cited by 3 | Viewed by 1282
Abstract
The idea of constructing the “GNSS-like” seafloor geodetic network for underwater positioning, navigation, and timing (PNT) has been proposed by many countries. Based on this idea, this paper introduces the principle of the seafloor PNT network and provides a combined measurement method, including [...] Read more.
The idea of constructing the “GNSS-like” seafloor geodetic network for underwater positioning, navigation, and timing (PNT) has been proposed by many countries. Based on this idea, this paper introduces the principle of the seafloor PNT network and provides a combined measurement method, including the absolute positioning and the relative positioning. Experimental results show that the positioning difference between the proposed method and circle-sailing positioning is approximately 10 cm, and the observation efficiency is higher than the existing measurement in the seafloor PNT network. In addition, a model is derived to determine the optimal configuration of the unit network (the basic component of the seafloor PNT network), considering the ranging capability of acoustic beacons, which is helpful to balance the side length of the unit network and the number of observation sessions in the relative positioning. Finally, a chain coordinate transfer strategy in the whole seafloor PNT network is proposed, and the positions where the absolute positioning should be carried out in the whole network are derived based on the conditional adjustment model. Based on this strategy, the design schemes of a seafloor PNT network with centimeter, decimeter, and meter positioning accuracy when the acoustic velocity measuring accuracy is 0.02 m/s and the time measuring accuracy is 10−5 s, are given in the experimental section. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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19 pages, 5375 KiB  
Article
Probability Prediction Approach of Fatigue Failure for the Subsea Wellhead Using Bayesian Regularization Artificial Neural Network
by Jiayi Li, Yuanjiang Chang, Jihao Shi, Xiuquan Liu, Guoming Chen, Nan Zhang, Qingtao Guan and Yongguo Dai
J. Mar. Sci. Eng. 2022, 10(11), 1627; https://doi.org/10.3390/jmse10111627 - 2 Nov 2022
Cited by 5 | Viewed by 1929
Abstract
The subsea wellhead (SW) system is a crucial connection between blowout preventors (BOPs) and subsea oil and gas wells. Excited by cyclical fatigue dynamic loadings, the SW is prone to fatigue failure, which would lead to the loss of well integrity and catastrophic [...] Read more.
The subsea wellhead (SW) system is a crucial connection between blowout preventors (BOPs) and subsea oil and gas wells. Excited by cyclical fatigue dynamic loadings, the SW is prone to fatigue failure, which would lead to the loss of well integrity and catastrophic accidents. Based on the Bayesian Regularization Artificial Neuron Network (BRANN), this paper proposes an efficient probability approach to predict the fatigue failure probability of SW during its entire life. In the proposed method, the BRANN fatigue damage (BRANN-FD) model reflecting the non-linear relationship between the input and output data was developed by the limited fatigue damage analysis data, which was utilized to generate thousands of non-numerical fatigue damage data of SW rapidly. Combining parametric and non-parametric estimation methods, the probability density function (PDF) of SW fatigue damage was determined to calculate the accumulation fatigue damage during service life. Using the logistic regression, the fatigue failure probability of SW was predicted. The application of the proposed approach was demonstrated by a case study. The results illustrated that the fatigue damage of SW would be viewed as obeying the Lognormal distribution, which could be used to obtain the accumulation fatigue damage in operation conveniently. Furthermore, the fatigue failure probability of SW nonlinearly increased with the increment in the accumulation fatigue damage of SW, which could be helpful to ensure the operation safety of SW in deepwater oil and gas development, especially for aged wellhead. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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12 pages, 2382 KiB  
Article
On Cubic Spudcan Deep Penetration in Dense Sand Overlying Non-Uniform Clay
by Jun Zhao, Yang Zhang and Luyu Liu
J. Mar. Sci. Eng. 2022, 10(11), 1607; https://doi.org/10.3390/jmse10111607 - 31 Oct 2022
Cited by 3 | Viewed by 1208
Abstract
Installing spudcans for jack-up rigs in a layered seabed with an interbedded strong-over-soft layer is challenging in the offshore industry due to possible punch-through failure. The methods currently used to predict punch-through failure mainly focus on generic spudcans, usually ignoring the geometric features [...] Read more.
Installing spudcans for jack-up rigs in a layered seabed with an interbedded strong-over-soft layer is challenging in the offshore industry due to possible punch-through failure. The methods currently used to predict punch-through failure mainly focus on generic spudcans, usually ignoring the geometric features of the spudcan. The aim of this study is to determine whether the punch-through potential of a generic spudcan is applicable to a cubic spudcan of a BH12# jack-up rig installed in dense sand overlying non-uniform clay. We conducted a series of large deformation finite element (LDFE) analyses on dense sand overlying non-uniform clay using a generic spudcan and a cubic spudcan. The thickness of the sand layer was also varied to cover a range of practical interest. The special cubic spudcan was found to be less likely to induce punch-through failure on sand-over-clay sediments compared with the corresponding generic spudcan. Herein, we propose a method to predict the degree of post-peak bearing reduction, which is a key measure of the severity of punch-through failure. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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14 pages, 7108 KiB  
Article
Numerical Simulation Analysis on the Lateral Dynamic Characteristics of Deepwater Conductor Considering the Pile-Soil Contact Models
by Yanbin Wang, Deli Gao and Chenyu Meng
J. Mar. Sci. Eng. 2022, 10(10), 1540; https://doi.org/10.3390/jmse10101540 - 19 Oct 2022
Cited by 2 | Viewed by 1455
Abstract
It is important to accurately assess the interaction between the conductor and the soil to ensure the stability of the subsea wellheads during deepwater drilling. In this paper, numerical simulations were carried out to study the lateral dynamic bearing capacity of the conductor [...] Read more.
It is important to accurately assess the interaction between the conductor and the soil to ensure the stability of the subsea wellheads during deepwater drilling. In this paper, numerical simulations were carried out to study the lateral dynamic bearing capacity of the conductor considering different contact models between the conductor and the soil. In particular, the contact surface model and contact element model were selected to study the dynamic behavior of pile–soil under a transverse periodic load. On this basis, the influence of the bending moment, the wellhead stick-up, the outer diameter (O.D.) of the conductor and the wall thickness (W.T.) of the conductor, as well as the physical parameters of the soil on the dynamic bearing capacity are discussed in detail. Analysis results show that the lateral deformation, deflection angle and von Mises stress calculated by the contact element model are greater than those calculated by the contact surface model. The maximum value of the lateral deformation and bending moment of the conductor decrease with the O.D. and W.T. of the conductor, and the cohesion and internal friction angle of the soil. However, the maximum value of the lateral deformation and bending moment of the conductor increase with the wellhead stick-up. Both the vertical force and the soil density have a negligible effect on the lateral behavior of the conductor. This study has reference value for the design and stability assessment of subsea wellheads. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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19 pages, 4659 KiB  
Article
Quantitative Risk Analysis of Disconnect Operations in a Marine Nuclear Power Platform Using Fuzzy Bayesian Network
by Chongchong Guo and Wenhua Wu
J. Mar. Sci. Eng. 2022, 10(10), 1479; https://doi.org/10.3390/jmse10101479 - 11 Oct 2022
Cited by 4 | Viewed by 1394
Abstract
Marine nuclear power platforms can continuously supply electricity and fresh water for marine resource exploration and surrounding islands. China’s first marine nuclear power platform uses a soft yoke multi-joint connect mode as the mooring positioning device. When the marine nuclear power platform needs [...] Read more.
Marine nuclear power platforms can continuously supply electricity and fresh water for marine resource exploration and surrounding islands. China’s first marine nuclear power platform uses a soft yoke multi-joint connect mode as the mooring positioning device. When the marine nuclear power platform needs repair, maintenance, nuclear fuel replacement, or a different operation area, a mooring disconnect operation must be carried out. The traditional mooring disconnect process consists of four stages: cable limiting, yoke offloading, yoke dropping, and equipment recovery stages. The entire disconnect process is a high-risk nuclear-related operation that could result in a collision accident between the yoke and hull structure, resulting in nuclear fuel leaks and casualties. Therefore, it is necessary to evaluate the risk factors of the disconnect process and to assess the risk level together with the consequence of each risk. In this paper, a quantitative risk analysis of nuclear power platform disconnect operations is carried out based on a fuzzy Bayesian network approach for risk events in each stage of the disconnect operations. Based on the forward fuzzy Bayesian inference, the criticality of each risk event to the disconnect process is evaluated and compared. The main risk factors that may cause a disconnect accident are then determined based on the reverse Bayesian inference rule. The results indicate that human error is the most likely factor leading to the failure of the disconnect process, requiring strict control of personnel operation procedures during this process. The yoke colliding with the hull and stern antifriction chain-breaking are the most significant hazards caused by the disconnect failing. Thus, the distance between the yoke and hull, stern tug tensile force, and maintenance of the antifriction chain should receive particular attention. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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16 pages, 2764 KiB  
Article
Three-to-One Internal Resonance of L-Shaped Multi-Beam Structure with Nonlinear Joints
by Yunxu Shi, Zhe Wu, Wei Liu and Jin Wei
J. Mar. Sci. Eng. 2022, 10(10), 1461; https://doi.org/10.3390/jmse10101461 - 9 Oct 2022
Cited by 3 | Viewed by 1097
Abstract
In this paper, a reduced-order analytical model for an L-shaped multi-beam structure with nonlinear joints is presented to investigate the nonlinear responses of the system with three-to-one internal resonances conditions. Firstly, the global mode shapes are used to obtain an explicit set of [...] Read more.
In this paper, a reduced-order analytical model for an L-shaped multi-beam structure with nonlinear joints is presented to investigate the nonlinear responses of the system with three-to-one internal resonances conditions. Firstly, the global mode shapes are used to obtain an explicit set of nonlinear ordinary differential equations of motion for the system. Then, the first two natural frequencies of the system are calculated to determine the specific tip mass that results in three-to-one internal resonance. Subsequently, an approximation of the analytical solution of the dynamic model with two-degree-of-freedom is derived by using the multi-scale method. The accuracy of the approximation solution is verified by comparing it with the numerical solution obtained from the original motion equations. Based on the nonlinear dynamical model obtained by this paper, the frequency response curves are given to investigate the nonlinear dynamic characteristic of the L-shaped multi-beam structure with nonlinear joints. The results show that the nonlinear stiffness of the joints has a great influence on the nonlinear response of the system with three-to-one internal resonance conditions. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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14 pages, 15076 KiB  
Article
Development and Field Testing of a Smart Support System for ROV Operators
by Alexander Konoplin, Nikita Konoplin and Alexander Yurmanov
J. Mar. Sci. Eng. 2022, 10(10), 1439; https://doi.org/10.3390/jmse10101439 - 5 Oct 2022
Cited by 6 | Viewed by 1740
Abstract
The article considers the issues of development of a smart system for supporting activities of ROV operators and its practical implementation for the efficient operation a ROV Comanche 18 that is based on the R/V Akademik M.A. Lavrentiev. The system uses algorithms that [...] Read more.
The article considers the issues of development of a smart system for supporting activities of ROV operators and its practical implementation for the efficient operation a ROV Comanche 18 that is based on the R/V Akademik M.A. Lavrentiev. The system uses algorithms that provide coordinated movements of the ROV and its depressor unit. These algorithms are designed for ROVs to make synchronous, accurate, and accident-free movements along long-distance routes even when launched from a support vessel without dynamic positioning (DP). For this, the operator receives real-time visual recommendations and warnings generated on the basis of the expert evaluation of information coming from various sensors and positioning systems. The ability to plan routes of the ROV and its mothership, inputting target points, saving maps, tracks, and locations of the detected underwater objects are also implemented in the designed system. The article presents the results of successful tests carried out during a deep-sea research expedition of the A.V. Zhirmunsky National Scientific Center of Marine Biology FEB RAS in the Bering Sea and Pacific Ocean. The created smart support system for ROV operators significantly extends the range of capabilities of ROVs performing many unique underwater operations, while significantly reducing their operating time. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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19 pages, 6339 KiB  
Article
Mechanism of Mechanical Analysis on Torsional Buckling of U-Shaped Bellows in FLNG Cryogenic Hoses
by Jun Yan, Xipeng Ying, Huixin Cao, Feiyu Xiong, Kailun Zhang and Zhixun Yang
J. Mar. Sci. Eng. 2022, 10(10), 1405; https://doi.org/10.3390/jmse10101405 - 1 Oct 2022
Cited by 4 | Viewed by 1889
Abstract
Floating liquefied natural gas (FLNG) cryogenic hoses can be employed for the transmission of liquefied natural gas (LNG). Usually, U-shaped metal bellows can be applied as the inner lining of FLNG cryogenic hoses. In installation, positioning and other working conditions, torsion is one [...] Read more.
Floating liquefied natural gas (FLNG) cryogenic hoses can be employed for the transmission of liquefied natural gas (LNG). Usually, U-shaped metal bellows can be applied as the inner lining of FLNG cryogenic hoses. In installation, positioning and other working conditions, torsion is one of the main loads, and torsional buckling instability is a major failure mode of U-shaped metal bellows of FLNG cryogenic hoses. In the current research, the buckling instability of bellows under torsional loads has been investigated in detail, the mechanical mechanism of deformation in torsional buckling mode of bellows has been analyzed and the influence of the structural design parameters on the stability performance has been summarized. It was seen that the axis of the bellows was presented as a spiral line shape during the torsional buckling stage. At the same time, the torsional buckling properties of toroid and spiral bellows were analyzed. The obtained results showed that the torsional buckling stability of the spiral bellows was weaker than that of the toroid bellows and increase of the spiral angle of the spiral bellows intensified this trend. In addition, the post-buckling analysis of U-shaped bellows under torsional loads was carried out by means of experiments and finite element simulation. It was shown that the results obtained from finite element (FE) analysis in this research presented a relatively accurate critical torque value and a consistent buckling instability mode, compared with the experimental results. On this basis, the effects of common defects such as thickness thinning on the torsional stability of bellows were investigated. Considering the geometric defect of thickness thinning, the error of FE analysis was reduced further, and it was found that the defect could significantly decrease the stability of the bellows. The above analysis results could provide a reference for structural design and post-buckling analysis of bellows. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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20 pages, 8361 KiB  
Article
Effect of Winding Steel Wire on the Collapse Pressure of Submarine Hose
by Daifeng Wei, Chen An, Jixiang Zhang, Yixuan Huang and Chenwang Gu
J. Mar. Sci. Eng. 2022, 10(10), 1365; https://doi.org/10.3390/jmse10101365 - 23 Sep 2022
Cited by 6 | Viewed by 1859
Abstract
The submarine hose plays a vital role in the single-point mooring system and is a necessary channel for medium transportation. Once crushed under the load of the seawater external pressure, it will cause oil and gas leakage and major safety accidents. It is [...] Read more.
The submarine hose plays a vital role in the single-point mooring system and is a necessary channel for medium transportation. Once crushed under the load of the seawater external pressure, it will cause oil and gas leakage and major safety accidents. It is a composite hose composed of a rubber layer, cord layer and steel helix wire, of which the steel helix wire plays an important part in bearing mechanical properties. In this work, python language was used to model the submarine hose parametrically, the finite element (FE) analysis software ABAQUS was utilized to analyze the ultimate bearing capacity of the hose under uniformly distributed external pressure loads and the influence of the initial ovality of the submarine hose, the diameter and pitch of the helix wire, the yield strength of the helix wire material on the ultimate bearing capacity of the submarine hose were studied. Through a large number of FE results, the ultimate bearing capacity of the hose was obtained by fitting the prediction formula. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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15 pages, 4368 KiB  
Article
A Recognition Algorithm of Seismic Signals Based on Wavelet Analysis
by Wensheng Jiang, Weiwei Ding, Xinke Zhu and Fei Hou
J. Mar. Sci. Eng. 2022, 10(8), 1093; https://doi.org/10.3390/jmse10081093 - 10 Aug 2022
Cited by 3 | Viewed by 1787
Abstract
In order to meet the requirements of mobile marine seismometers to observe and record seismic signals, a study of fast and accurate seismic signal recognition was carried out. This paper introduces the use of the wavelet analysis method for seismic signal processing and [...] Read more.
In order to meet the requirements of mobile marine seismometers to observe and record seismic signals, a study of fast and accurate seismic signal recognition was carried out. This paper introduces the use of the wavelet analysis method for seismic signal processing and recognition, and compares and analyzes the abilities of different wavelet basis functions to detect the seismic signal. By denoising and reconstructing the signal, the distribution law of the wavelet coefficients of seismic signal at different scales was obtained. On this basis, this paper proposes an identification model of seismic signals based on wavelet analysis and thereby solves the conflict between high speed and high accuracy of seismic signal recognition methods. In this study, the simulation was carried out in the Matlab2020b environment, and the feasibility of wavelet recognition algorithm was proven by applying this algorithm to the seismic signal database for experimental verification. Full article
(This article belongs to the Special Issue Theory, Method and Engineering Application of Computational Mechanics in Offshore Structures)
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