Journal of Marine Science and Engineering

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3 pages, 139 KiB

Open AccessEditorial

Advanced Analysis of Marine Structures—Edition II

by Bin Liu, Chenfeng Li and Kun Liu

J. Mar. Sci. Eng. 2024, 12(10), 1763; https://doi.org/10.3390/jmse12101763 - 5 Oct 2024

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Abstract

One of the key issues in the design of modern ship and offshore structures is the accurate prediction of strength under various load conditions, especially impact, ultimate and fatigue strength [...] Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

Research

Jump to: Editorial

15 pages, 9046 KiB

Open AccessArticle

Numerical Modelling of the Hydrodynamic Performance of Biodegradable Drifting Fish Aggregating Devices in Currents

by Tongzheng Zhang, Junbo Zhang, Qinglian Hou, Gangyi Yu, Ao Chen, Zhiqiang Liu and Rong Wan

J. Mar. Sci. Eng. 2024, 12(7), 1059; https://doi.org/10.3390/jmse12071059 - 24 Jun 2024

Cited by 2 | Viewed by 824

Abstract

Fish Aggregating Devices (FADs) are essential supplementary structures used in tropical tuna purse-seine fishing. They are strategically placed to attract tuna species and enhance fishing productivity. The hydrodynamic performance of FADs has a direct effect on their structural and environmental safety in the [...] Read more.

Fish Aggregating Devices (FADs) are essential supplementary structures used in tropical tuna purse-seine fishing. They are strategically placed to attract tuna species and enhance fishing productivity. The hydrodynamic performance of FADs has a direct effect on their structural and environmental safety in the harsh marine environment. Conventional FADs are composed of materials that do not break down naturally, leading to the accumulation of waste in the ocean and potential negative effects on marine ecosystems. Therefore, this work aimed to examine the hydrodynamic performance of biodegradable drifting FADs (Bio-DFADs) in oceanic currents by numerical modelling. The Reynolds-averaged Navier–Stokes equation was used to solve the flow field and discretized based on the realizable k-ε turbulence model, employing the finite volume method. A set of Bio-DFADs was developed to assess the hydrodynamic performance under varying current velocities and attack angles, as well as different balsa wood diameters and sinker weights. The results indicated that the relative current velocity significantly affected the relative velocity of Bio-DFADs. The relative length of the raft significantly affected both the relative velocity and the relative wetted area in a pure stream. Finally, the diameter of the balsa wood affected the drift velocity, and the sinker’s relative weight affected the hydrodynamic performance of the Bio-DFADs. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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17 pages, 9123 KiB

Open AccessArticle

Fully Buried Pipeline Floatation in Poro-Elastoplastic Seabed under Combined Wave and Current Loadings

by Jian Leng, Libin Liu, Chencong Liao and Guanlin Ye

J. Mar. Sci. Eng. 2024, 12(6), 995; https://doi.org/10.3390/jmse12060995 - 14 Jun 2024

Viewed by 824

Abstract

The floatation capacity of seabed pipelines has long been considered a key risk element during design, especially with the combined loading of waves and currents. This paper presents a two-dimensional coupled approach with a poro-elastoplastic theory to study the floatation of pipelines with [...] Read more.

The floatation capacity of seabed pipelines has long been considered a key risk element during design, especially with the combined loading of waves and currents. This paper presents a two-dimensional coupled approach with a poro-elastoplastic theory to study the floatation of pipelines with the combined loading of waves and currents. The findings suggest that the proposed method is able to capture the mechanical performance of pipeline floatation. Pipeline floatation occurs in two distinct phases. In the initial phases, the pipelines float slowly with the cyclic loadings. In the second stage, when the backfill soil in the middle position of the pipelines begins to liquefy, the floating displacement increases obviously. The boundary constraints provided by the pipelines strengthen the backfill soil as well as accelerate the release of excessive pore water pressure. Meanwhile, a nonliquefiable region is formed under the pipelines. The floating displacement of the pipelines increases as well as current velocity, wave height, and wave period, and reduces with increased backfill soil permeability. Increasing the permeability coefficient of backfill soil can obviously restrain the floatation of pipelines. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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15 pages, 4910 KiB

Open AccessArticle

Experimental Investigation of Ice Loads on Structures during Quasi-Static Compression Tests

by Jinsong Xia, Tongqiang Yu, Kun Liu, Junji Xiang, Nan Zhao and Junjie Liu

J. Mar. Sci. Eng. 2024, 12(6), 924; https://doi.org/10.3390/jmse12060924 - 31 May 2024

Viewed by 559

Abstract

In polar ship hull structural designs, methods based on regulations are considered the most authoritative; however, they tend to be conservative and often exhibit a notable degree of redundancy. This study aims to evaluate the applicability of the empirical formula for ice load [...] Read more.

In polar ship hull structural designs, methods based on regulations are considered the most authoritative; however, they tend to be conservative and often exhibit a notable degree of redundancy. This study aims to evaluate the applicability of the empirical formula for ice load assessments by conducting a series of quasi-static indentation tests on scaled hull plates under laboratory-made ice blocks of different scales. The obtained data include ice loads, structural responses, and characteristics of ice pressure distribution. A detailed comparison of various formulas is provided, along with an examination of their differences and errors in comparison to experimental results. The objective of this paper is to offer technical support for ice load forecasting and assessment. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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13 pages, 6693 KiB

Open AccessArticle

Dynamic Stability Analysis of Subsea Tunnel Crossing Active Fault Zone: A Case Study

by Zhiqiang Li, Qiushi Liu, Shian Liu, Xueying Liu, Yongqiang Zhang, Shixiang Jia, Guoliang Song and Yuting Zhao

J. Mar. Sci. Eng. 2024, 12(5), 839; https://doi.org/10.3390/jmse12050839 - 17 May 2024

Viewed by 1102

Abstract

The rock strength in an active fault zone is low and the surrounding rock is fractured and has poor stability, making any subsea tunnel crossing the active fault zone extremely susceptible to disasters such as tunnel collapse, sudden water ingress, and mud inrush. [...] Read more.

The rock strength in an active fault zone is low and the surrounding rock is fractured and has poor stability, making any subsea tunnel crossing the active fault zone extremely susceptible to disasters such as tunnel collapse, sudden water ingress, and mud inrush. This poses a potential threat to the construction project, making the dynamic stability analysis of a subsea tunnel crossing an active fault zone of great significance. This study takes the second subsea tunnel crossing the Cangkou Fault in Jiaozhou Bay as the engineering background and conducts numerical simulations by employing different lining stiffnesses for tunnel excavation, as well as applying dynamic loads. The dynamic stability of the subsea tunnel crossing the active fault zone is evaluated by comparing and analyzing the lining’s displacement, peak acceleration, and stress characteristics. This study explores the disaster-causing mechanisms of active fractures, determining that the hazard of orthogonal misalignment in an active fault zone is the least severe, while the hazard of opposite misalignment is the most severe. This research provides a basis for disaster prevention and mitigation in active fracture zones. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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24 pages, 13787 KiB

Open AccessArticle

Calibration of the Modified Mohr–Coulomb Failure Criterion and Its Application in the Study of Collision Response of Ship Hull Plate Frame Structures

by Shiye Liu, Kun Liu, Hewei Liu, Shuai Zong, Yue Lu and Chuhao Liu

J. Mar. Sci. Eng. 2024, 12(5), 805; https://doi.org/10.3390/jmse12050805 - 12 May 2024

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Abstract

Within the lifecycle of a ship’s hull structure, damage due to collisions has been a focal point of research for researchers both domestically and internationally. To enhance the predictive accuracy of failure criteria in the simulation of ship hull collisions, this paper focuses [...] Read more.

Within the lifecycle of a ship’s hull structure, damage due to collisions has been a focal point of research for researchers both domestically and internationally. To enhance the predictive accuracy of failure criteria in the simulation of ship hull collisions, this paper focuses on the modified Mohr–Coulomb (MMC) failure criterion for metals, utilizing a hybrid experimental–numerical method for parameter calibration. Consideration of stress-state-dependent mesh size sensitivity has been amended, and the approach is integrated into the comprehensive nonlinear finite element software Abaqus 2020. Finite element tensile simulations were conducted to validate the effectiveness of the MMC criterion. Simulation analyses were conducted based on drop hammer collision experiments with various failure criteria and grid sizes. The comparative validation highlighted the superiority of the mesh size sensitivity-corrected MMC failure criterion. The outcomes of this research provide a foundation for assessing the structural safety of ship hulls. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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21 pages, 33618 KiB

Open AccessArticle

Research on a Real-Time Prediction Method of Hull Girder Loads Based on Different Recurrent Neural Network Models

by Qiang Wang, Lihong Wu, Chenfeng Li, Xin Chang and Boran Zhang

J. Mar. Sci. Eng. 2024, 12(5), 746; https://doi.org/10.3390/jmse12050746 - 29 Apr 2024

Viewed by 936

Abstract

Real-time prediction of hull girder loads is of great significance for the safety of ship structures. Some scholars have used neural network technology to investigate hull girder load real-time prediction methods based on motion monitoring data. With the development of deep learning technology, [...] Read more.

Real-time prediction of hull girder loads is of great significance for the safety of ship structures. Some scholars have used neural network technology to investigate hull girder load real-time prediction methods based on motion monitoring data. With the development of deep learning technology, a variety of recurrent neural networks have been proposed; however, there is still a lack of systematic comparative analysis on the prediction performance of different networks. In addition, the real motion monitoring data inevitably contains noise, and the effect of data noise has not been fully considered in previous studies. In this paper, four different recurrent neural network models are comparatively investigated, and the effect of different levels of noise on the prediction accuracy of various load components is systematically analyzed. It is found that the GRU network is suitable for predicting the torsional moment and horizontal bending moment, and the LSTM network is suitable for predicting the vertical bending moment. Although filtering has been applied to the original noise data, the prediction accuracy still decreased as the noise level increased. The prediction accuracy of the vertical bending moment and horizontal bending moment is higher than that of the torsional moment. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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24 pages, 7759 KiB

Open AccessArticle

Experimental and Numerical Prediction of Slamming Impact Loads Considering Fluid–Structure Interactions

by Tao Lu, Jiaxia Wang, Kun Liu and Xiaochao Zhao

J. Mar. Sci. Eng. 2024, 12(5), 733; https://doi.org/10.3390/jmse12050733 - 28 Apr 2024

Cited by 2 | Viewed by 1077

Abstract

Slamming impacts on water are common occurrences, and the whipping induced by slamming can significantly increase the structural load. This paper carries out an experimental study of the water entry of rigid wedges with various deadrise angles. The drop height and deadrise angle [...] Read more.

Slamming impacts on water are common occurrences, and the whipping induced by slamming can significantly increase the structural load. This paper carries out an experimental study of the water entry of rigid wedges with various deadrise angles. The drop height and deadrise angle are parametrically varied to investigate the effect of the entry velocity and wedge shape on the impact dynamics. A two-way coupled approach combing CFD method software STAR-CCM+12.02.011-R8 and the FEM method software Abaqus 6.14 is presented to analyze the effect of structural flexibility on the slamming phenomenon for a wedge and a ship model. The numerical method is validated through the comparison between the numerical simulation and experimental data. The slamming pressure, free surface elevation, and dynamic structural response, including stress and strain, in particular, are presented and discussed. The results show that the smaller the inclined angle at the bottom of the wedge-shaped body, the faster the entry speed into the water, resulting in greater impact pressure and greater structural deformation. Meanwhile, studies have shown that the bottom of the bow is an area of concern for wave impact problems, providing a basis for the assessment of ship safety design. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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21 pages, 14444 KiB

Open AccessArticle

Experimental and Numerical Studies on the Ultimate Bending Strength of Welded Plated Grillage with Combined Openings

by Chen Chen, Hong Zhou, Zhengda Lv and Ziqiu Li

J. Mar. Sci. Eng. 2024, 12(2), 295; https://doi.org/10.3390/jmse12020295 - 7 Feb 2024

Viewed by 809

Abstract

Plated grillage with combined openings was susceptible to complex failure behaviors as the main load-bearing structure of the superstructure on passenger ships subjected to deck loads. Additionally, the deformation and stresses generated during the welding of the plated grillage complicated the prediction of [...] Read more.

Plated grillage with combined openings was susceptible to complex failure behaviors as the main load-bearing structure of the superstructure on passenger ships subjected to deck loads. Additionally, the deformation and stresses generated during the welding of the plated grillage complicated the prediction of its failure behavior. In this case, a new partitioned inherent strain method and nonlinear finite element method were used to simulate the welding and loading process, and experiments were designed and carried out to make comparisons, unveiling the influence regulations between the failure behavior of the structure and the loading condition, the initial welding state. This research on the failure mode analysis of plated grillages could provide references for the optimization of the structural form of plated grillages and the cargo loading scheme on the deck of a real ship. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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18 pages, 9116 KiB

Open AccessArticle

Real-Time Digital Twin of Ship Structure Deformation Field Based on the Inverse Finite Element Method

by Pengyu Wei, Chuntong Li, Ze Jiang and Deyu Wang

J. Mar. Sci. Eng. 2024, 12(2), 257; https://doi.org/10.3390/jmse12020257 - 31 Jan 2024

Cited by 2 | Viewed by 1734

Abstract

Digital twins, an innovative technology propelled by data and models, play a seminal role in the digital transformation and intelligent upgrade of ships. This study introduces a digital twin methodology for the real-time monitoring of ship structure deformation fields, based on finite discrete [...] Read more.

Digital twins, an innovative technology propelled by data and models, play a seminal role in the digital transformation and intelligent upgrade of ships. This study introduces a digital twin methodology for the real-time monitoring of ship structure deformation fields, based on finite discrete strain data, and a visualization tool framework is developed using virtual reality technology. First, the inverse Finite Element Method (iFEM) is employed to derive the deformation field of the ship structure in real time using sensor strain data. Secondly, the deformation field data obtained based on the iFEM algorithm is converted into general visualization data conducive to interpretation within virtual reality (VR) applications. Lastly, a digital twin software tool is built to enable synchronous responses and interactions between the virtual scene and the physical scene, directly superposing particular virtual objects (data acquired by sensors, computer-aided design (CAD) virtual models, and deformation field cloud images) onto the physical scene in real time. The digital twin tool embodies a virtual reality visualization system framework integrating the physical data measurement, reconstruction, analysis, expression, storage, rendering, and interaction of deformation field data. Through practical application, the flexibility, effectiveness, and compatibility of the developed prototype tool are verified. According to the results, the system can enhance the efficiency of scientific communication, model validation, and interdisciplinary sharing during the analysis and evaluation of the mechanical properties of ship structures. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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17 pages, 4944 KiB

Open AccessArticle

Stress Concentration Factors Due to Misalignment at Girth Welds in Bi-Layer Pipes

by Ruili Guo, Hongyang Hu, Haisheng Zhao and Yao Zhang

J. Mar. Sci. Eng. 2024, 12(2), 231; https://doi.org/10.3390/jmse12020231 - 28 Jan 2024

Viewed by 1162

Abstract

In recent years, bi-layer pipes, composed of an inner layer and an outer layer, have been widely used in offshore engineering. In this study, the governing equation for a bi-layer pipe subjected to axisymmetric loadings is derived based on classical shell theory. Then, [...] Read more.

In recent years, bi-layer pipes, composed of an inner layer and an outer layer, have been widely used in offshore engineering. In this study, the governing equation for a bi-layer pipe subjected to axisymmetric loadings is derived based on classical shell theory. Then, the equation is used to develop stress concentration factor formulations for girth welds in bi-layer pipes with fabrication tolerances and thickness transitions. Axisymmetric finite element analysis is carried out to verify the accuracy of the proposed formulations. It is noted that these formulations can be well suited for determining the stress concentration factors for a wide range of thickness ratios (ratio of the inner layer thickness to the total thickness in a bi-layer pipe) varying from 0.0 to 1.0. They can also obtain accurate stress concentration factors whether the elastic modulus of the inner layer is smaller or larger than that of the outer layer. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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24 pages, 28071 KiB

Open AccessArticle

A Two-Step Approach for Evaluating the Dynamic Ultimate Load Capacity of Ship Structures

by Weilong Zhang, Jinju Cui and Deyu Wang

J. Mar. Sci. Eng. 2024, 12(2), 219; https://doi.org/10.3390/jmse12020219 - 25 Jan 2024

Viewed by 1093

Abstract

One important parameter for evaluating the safety and reliability of a ship is o the dynamic ultimate load capacity of ship structures. Because of the importance of this parameter, its determination is essential. In this paper, a novel “two-step” approach for determining the [...] Read more.

One important parameter for evaluating the safety and reliability of a ship is o the dynamic ultimate load capacity of ship structures. Because of the importance of this parameter, its determination is essential. In this paper, a novel “two-step” approach for determining the dynamic ultimate load capacity of ship structures is proposed. The main idea of two-step approach is to determine the dynamic ultimate load capacity based on the static ultimate load capacity after accounting for impacts that cause strain on the ship structures. This approach is based on nonlinear finite element method. Here, taking stiffened plate as a case study, the practical application of thus two-step approach is discussed in detail. The results of this approach reveal that the static ultimate load capacity decreases by less than 3% after a stiffened plate is subjected to an impact load whose amplitude corresponds to the dynamic ultimate load capacity. Then, the influence of the impact duration on the failure mode and the effect of the impact load cycles and the impact load sequence on the dynamic ultimate load capacity of the stiffened plate were investigated. Finally, the applicability of the two-step approach to a hull girder is demonstrated. The two-step approach and the conclusions presented in this paper can provide guidance for the evaluation of dynamic ultimate load capacity. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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16 pages, 6885 KiB

Open AccessArticle

XFEM-Based Study of Fatigue Crack Propagation in Rocket Deflector Troughs under Coupled High-Temperature and Impact Conditions

by Zhixin Xiong, Chengyuan Zhu, Yue Yang, Tong Lin and Ruoxuan Li

J. Mar. Sci. Eng. 2024, 12(2), 207; https://doi.org/10.3390/jmse12020207 - 23 Jan 2024

Cited by 2 | Viewed by 1226

Abstract

This research investigated fatigue crack propagation on the lower surface of rocket deflector troughs in offshore rocket launch platforms. Initially, a numerical model of an offshore rocket launch platform was established using ABAQUS based on the Extended Finite Element Method (XFEM). Subsequently, two [...] Read more.

This research investigated fatigue crack propagation on the lower surface of rocket deflector troughs in offshore rocket launch platforms. Initially, a numerical model of an offshore rocket launch platform was established using ABAQUS based on the Extended Finite Element Method (XFEM). Subsequently, two variable parameters—the initial crack length and initial tilt angle—were introduced. This research systematically analysed the impact of these parameters on the fatigue crack propagation patterns in both the maximum stress and maximum deformation regions of the deflector channels under the combined conditions of high temperature and impact. Finally, the research indicated that the propagation length of surface cracks in the deflector trough exhibited an initial increase followed by a decrease with the rise in the pre-set inclination angle. Notably, the stable propagation rate of the crack in the region of maximum deformation surpassed that observed in the region of maximum stress. Through meticulous comparative analysis, it was evident that temperature loading significantly exacerbated the initiation and propagation of cracks, particularly in the upper region of the deflector channel’s lower surface. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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23 pages, 15187 KiB

Open AccessArticle

Experimental and Numerical Analysis of Supporting Forces and Lashing Forces in a Ship Cargo Securing Scheme

by Mengxiang Li, Guo Wang, Kun Liu, Yue Lu and Jiaxia Wang

J. Mar. Sci. Eng. 2024, 12(1), 158; https://doi.org/10.3390/jmse12010158 - 12 Jan 2024

Viewed by 1173

Abstract

The safety assessment of ship cargo securing systems is of significant importance in preventing casualties, vessel instability, and economic losses resulting from the failure of securing systems during transportation in adverse sea conditions. In this study, an independently designed cylindrical cargo securing scheme [...] Read more.

The safety assessment of ship cargo securing systems is of significant importance in preventing casualties, vessel instability, and economic losses resulting from the failure of securing systems during transportation in adverse sea conditions. In this study, an independently designed cylindrical cargo securing scheme with supporting structures was adopted for investigation. Utilizing a sway device, three-degree-of-freedom coupled motion encountered during ship transportation was obtained, and data regarding changes in the support forces at the foundations and tension forces in the lashing ropes were collected. Subsequently, numerical simulations were conducted using the multibody dynamics software ADAMS 2020. The results obtained from the simulations were compared with the experimental data. The overall tendencies were accurately predicted in the numerical analysis. It was observed that the difference of the peak support forces between the numerical simulation results and the experimental data were within a 10% margin. In terms of the lashing ropes, the difference was limited, within 9%. These findings demonstrate that numerical simulation techniques can provide valuable insights for verifying the safety of practical cargo securing systems. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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23 pages, 20731 KiB

Open AccessArticle

Experimental and Numerical Analysis of Ultimate Carrying Capacity of a Funnel Structure with Opening under Wind Pressure

by Lei Ao, Ziqi Ding, Bin Liu, Zhiyong Pei, Qin Tang and Weiguo Wu

J. Mar. Sci. Eng. 2024, 12(1), 41; https://doi.org/10.3390/jmse12010041 - 23 Dec 2023

Viewed by 1073

Abstract

This study presents experimental and finite element investigations on the ultimate strength of the funnel structure of a large passenger ship subjected to wind pressure. An experimental test is conducted using a similar model to analyze the failure characteristics of the funnel structure. [...] Read more.

This study presents experimental and finite element investigations on the ultimate strength of the funnel structure of a large passenger ship subjected to wind pressure. An experimental test is conducted using a similar model to analyze the failure characteristics of the funnel structure. The model is designed based on similar theories to simulate the progressive collapse behavior of an actual ship’s funnel under wind load. Additionally, a simplified wind loading device is also developed to apply large wind loads. Practical insights are provided in the research to assess the opening’s influence on reducing the ultimate strength of funnel structures when suffering wind pressure. Results represent the failure initiated at the edges of the large opening, with stress concentration primarily occurring at the stiffener end, showing good agreement with the simulated results performed using the finite element method. Furthermore, the effects of different parameters on the ultimate strength of the funnel structure are discussed by using the numerical method. This analysis provides an important guide for the design of funnel structures of passenger ships with openings. Full article

(This article belongs to the Special Issue Advanced Analysis of Marine Structures—Edition II)

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