Journal of Marine Science and Engineering

Editorial

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3 pages, 172 KiB

Open AccessEditorial

Ship Collision Risk Assessment

by Sang Jin Kim

J. Mar. Sci. Eng. 2023, 11(7), 1355; https://doi.org/10.3390/jmse11071355 - 3 Jul 2023

Viewed by 1468

Abstract

Ship collision accidents are one of the most frequent events, and cause serious damages to health, structural safety and the environment [...] Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

Research

Jump to: Editorial

16 pages, 3356 KiB

Open AccessArticle

A Data-Driven Intelligent Prediction Approach for Collision Responses of Honeycomb Reinforced Pipe Pile of the Offshore Platform

by Lei Yang, Hong Lin, Chang Han, Hassan Karampour, Haochen Luan, Pingping Han, Hao Xu and Shuo Zhang

J. Mar. Sci. Eng. 2023, 11(3), 510; https://doi.org/10.3390/jmse11030510 - 26 Feb 2023

Cited by 2 | Viewed by 1315

Abstract

The potential collision between the ship and the pipe piles of the jacket structure brings huge risks to the safety of an offshore platform. Due to their high energy-absorbing capacity, honeycomb structures have been widely used as impact protectors in various engineering applications. [...] Read more.

The potential collision between the ship and the pipe piles of the jacket structure brings huge risks to the safety of an offshore platform. Due to their high energy-absorbing capacity, honeycomb structures have been widely used as impact protectors in various engineering applications. This paper proposes a data-driven intelligent approach for the prediction of the collision response of honeycomb-reinforced structures under ship collision. In the proposed model, the artificial neural network (ANN) is combined with the dynamic particle swarm optimization (DPSO) algorithm to predict the collision responses of honeycomb reinforced pipe piles, including the maximum collision depth (δ_max) and maximum absorption energy (E_max). Furthermore, a data-driven evaluation method, known as grey relational analysis (GRA), is proposed to evaluate the collision responses of the honeycomb-reinforced pipe piles of offshore platforms. Results of the case study demonstrate the accuracy of the DPSO-BP-ANN model, with measured mean-square-error (MSE) of 5.06 × 10⁻⁴ and 4.35 × 10⁻³ and R² of 0.9906 and 0.9963 for δ_max and E_max, respectively. It is shown that the GRA method can provide a comprehensive evaluation of the performance of a honeycomb structure under impact loads. The proposed model provides a robust and efficient assessment tool for the safe design of offshore platforms under ship collisions. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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15 pages, 6147 KiB

Open AccessArticle

Modelling Manoeuvrability in the Context of Ship Collision Analysis Using Non-Linear FEM

by Šimun Sviličić and Smiljko Rudan

J. Mar. Sci. Eng. 2023, 11(3), 497; https://doi.org/10.3390/jmse11030497 - 25 Feb 2023

Cited by 4 | Viewed by 1329

Abstract

Ship collisions are rare events that may have a significant impact on the safety of people, ships, and other marine structures, as well as on the environment. Because of this, they are extensively studied but events that just precede collision are often overlooked. [...] Read more.

Ship collisions are rare events that may have a significant impact on the safety of people, ships, and other marine structures, as well as on the environment. Because of this, they are extensively studied but events that just precede collision are often overlooked. To rationally assess collision risks and consequences, a ship’s trajectory, and consequently the velocity and collision angle, should be known. One way to achieve this is through accurate modelling of ship manoeuvrability in collision analysis using non-linear FEM (NFEM). The Abkowitz manoeuvring model is implemented in the LS-Dyna software code and is therefore coupled with FEM calculations. Hydrodynamic forces are calculated in each time step of the LS-Dyna calculation and added to the FE model continuously through calculation. The accuracy of the calculations depends on the choice of and values of hydrodynamic derivatives from the Abkowitz model. Abkowitz’s model derives hydrodynamic forces in the Taylor expansion series to provide hydrodynamic derivatives. The application of the procedure is sensitive on higher-order Taylor series members. This article reviews different sets of hydrodynamic derivatives available for the KVLCC2 ship. Each of them is incorporated into the LS-Dyna NFEM solver by a user-made Fortran subroutine, with standard Zigzag and turning manoeuvres simulated and results compared with the experimental tests. As a result, the optimal selection of hydrodynamic derivatives is determined, laying a foundation for assessing the risk of ship collision due to different ship manoeuvres prior to the collision itself. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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21 pages, 4930 KiB

Open AccessArticle

An Improved Bald Eagle Search Algorithm for Global Path Planning of Unmanned Vessel in Complicated Waterways

by Yongjun Chen, Wenhao Wu, Pengfei Jiang and Chengpeng Wan

J. Mar. Sci. Eng. 2023, 11(1), 118; https://doi.org/10.3390/jmse11010118 - 5 Jan 2023

Cited by 5 | Viewed by 1454

Abstract

The path planning of unmanned ships in complex waters using heuristics usually suffers from problems such as being prone to fall into the local optimum, slow convergence, and instability in global path planning. Given this, this paper proposes a Self-Adaptive Hybrid Bald Eagle [...] Read more.

The path planning of unmanned ships in complex waters using heuristics usually suffers from problems such as being prone to fall into the local optimum, slow convergence, and instability in global path planning. Given this, this paper proposes a Self-Adaptive Hybrid Bald Eagle Search (SAHBES) Algorithm by incorporating adaptive factors into the traditional BES in order to enhance the early global searching ability of the BES algorithm. Moreover, Pigeon-Inspired Optimization (PIO) is introduced to overcome the disadvantage of traditional BES algorithms: that it is easy for them to fall into local optimization. This study improves the fitness function by adding a distance between the ships’ path corners. The obstacle is based on the calculation of the path length. The curve optimization module is applied to smooth the obtained path to generate more rational path planning results, which means the path is the shortest and avoids collision successfully. A simulation test of the SAHBES algorithm on the path planning under different obstacle scenarios is conducted by using the MATLAB platform. The results show that SAHBES can generate the shortest safe, smooth path in different complex water environments, considering the limitations of fundamental ship maneuvering operations compared to other algorithms, thus verifying the feasibility and efficiency of the proposed SAHBES algorithm. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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26 pages, 11901 KiB

Open AccessArticle

Effects of Local Denting and Fracture Damage on the Residual Longitudinal Strength of Box Girders

by Sang-Hyun Park, Sang-Hoon Yoon, Teguh Muttaqie, Quang Thang Do and Sang-Rai Cho

J. Mar. Sci. Eng. 2023, 11(1), 76; https://doi.org/10.3390/jmse11010076 - 3 Jan 2023

Cited by 3 | Viewed by 1090

Abstract

The residual strength of denting- and fracture-damaged box girders were experimentally and numerically investigated. The experiments were conducted under a pure bending moment using the four-point bending test method. The load, deflection, and strain were measured. The strains of the extension structures were [...] Read more.

The residual strength of denting- and fracture-damaged box girders were experimentally and numerically investigated. The experiments were conducted under a pure bending moment using the four-point bending test method. The load, deflection, and strain were measured. The strains of the extension structures were also measured, and the frictional forces between the model and the supported round bar were estimated. Test models consisting of two groups were fabricated. These groups were designed to estimate the residual strength of denting- and fracture-damaged models. The damage was induced by releasing a striker using a drop-testing machine to consider the dynamic effect. Additionally, numerical analyses were performed via a nonlinear finite element analysis, where the measured initial imperfection data and welding residual stresses were considered. The ultimate longitudinal moments that considered the frictional force of the round bars were reduced by 12% (on average) compared with those obtained by neglecting the frictional forces. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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21 pages, 2760 KiB

Open AccessArticle

Requirements for Optimal Local Route Planning of Autonomous Ships

by Sung-Wook Ohn and Ho Namgung

J. Mar. Sci. Eng. 2023, 11(1), 17; https://doi.org/10.3390/jmse11010017 - 22 Dec 2022

Cited by 7 | Viewed by 1893

Abstract

Ships transport large volumes of cargo, and are therefore major contributors to the global economy. Ship collisions can cause significant economic losses. Path-planning algorithms can prevent such collisions by suggesting the optimal path for navigation. Conventional path-planning algorithms are disadvantageous, because they do [...] Read more.

Ships transport large volumes of cargo, and are therefore major contributors to the global economy. Ship collisions can cause significant economic losses. Path-planning algorithms can prevent such collisions by suggesting the optimal path for navigation. Conventional path-planning algorithms are disadvantageous, because they do not consider the navigation practices followed by experienced navigators. Therefore, in this study, we developed the requirements for optimal local path planning of autonomous ships by considering the open sea, restricted waters, and two-ship and multi-ship interactions, in addition to the navigation practices adopted by navigators and rules in COLREGs part B. First, the navigation practices under various scenarios were collected. Subsequently, these practices were linked to COLREGs part B to extract the key rules and keywords related to collision avoidance. Finally, the requirements for generating the optimal local path were drafted based on the rules and keywords. The utility of the requirements was demonstrated by applying them to representative path-planning algorithms for the timely and accurate evaluation of their effectiveness. The proposed requirements can be utilized to improve the existing path-planning algorithms and develop superior algorithms in the future. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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15 pages, 3028 KiB

Open AccessArticle

Double Broad Reinforcement Learning Based on Hindsight Experience Replay for Collision Avoidance of Unmanned Surface Vehicles

by Jiabao Yu, Jiawei Chen, Ying Chen, Zhiguo Zhou and Junwei Duan

J. Mar. Sci. Eng. 2022, 10(12), 2026; https://doi.org/10.3390/jmse10122026 - 18 Dec 2022

Cited by 1 | Viewed by 2023

Abstract

Although broad reinforcement learning (BRL) provides a more intelligent autonomous decision-making method for the collision avoidance problem of unmanned surface vehicles (USVs), the algorithm still has the problem of over-estimation and has difficulty converging quickly due to the sparse reward problem in a [...] Read more.

Although broad reinforcement learning (BRL) provides a more intelligent autonomous decision-making method for the collision avoidance problem of unmanned surface vehicles (USVs), the algorithm still has the problem of over-estimation and has difficulty converging quickly due to the sparse reward problem in a large area of sea. To overcome the dilemma, we propose a double broad reinforcement learning based on hindsight experience replay (DBRL-HER) for the collision avoidance system of USVs to improve the efficiency and accuracy of decision-making. The algorithm decouples the two steps of target action selection and target Q value calculation to form the double broad reinforcement learning method and then adopts hindsight experience replay to allow the agent to learn from the experience of failure in order to greatly improve the sample utilization efficiency. Through training in a grid environment, the collision avoidance success rate of the proposed algorithm was found to be 31.9 percentage points higher than that in the deep Q network (DQN) and 24.4 percentage points higher than that in BRL. A Unity 3D simulation platform with high fidelity was also designed to simulate the movement of USVs. An experiment on the platform fully verified the effectiveness of the proposed algorithm. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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16 pages, 6261 KiB

Open AccessArticle

Spatial and Statistical Analysis of Operational Conditions Contributing to Marine Accidents in the Singapore Strait

by Serdar Yildiz, Fatih Tonoğlu, Özkan Uğurlu, Sean Loughney and Jin Wang

J. Mar. Sci. Eng. 2022, 10(12), 2001; https://doi.org/10.3390/jmse10122001 - 15 Dec 2022

Cited by 5 | Viewed by 4843

Abstract

Narrow waterways are important connection hubs, also known as logistics transfer nodes, within maritime transport, where maritime traffic can become very dense and congested. Heavy traffic, unsuitable environmental conditions and human errors make narrow waterways risky areas for marine accident occurrence. Accidents in [...] Read more.

Narrow waterways are important connection hubs, also known as logistics transfer nodes, within maritime transport, where maritime traffic can become very dense and congested. Heavy traffic, unsuitable environmental conditions and human errors make narrow waterways risky areas for marine accident occurrence. Accidents in narrow waterways cause ship damage, loss of cargo, loss of life and environmental disasters, as well as interruption of maritime transport and negative impact on the economy. Thus, the sustainability of navigational safety in narrow waterways has been the focus of attention of all beneficiaries in the maritime industry. The Singapore Strait is one of the busiest narrow waterways in the world in terms of the number of ships transiting. Sustaining and safe maritime transport in the Singapore Strait is significantly important for the sustainability of the global trade. Therefore, it is vitally important to appropriately identify the threats to safety of navigation in the Singapore Strait. In this study, the operational conditions that have played a role in the occurrence of accidents in the Singapore Strait are examined. For this purpose, using the Geographical Information System (GIS), the areas where marine accidents are concentrated were determined by the Kernel Density Analysis method and a “Marine Accidents Density Map” was created for the Singapore Strait. The relationship between the dense areas in the marine accidents density map and the operational conditions that play a role in the accidents in the Singapore Strait were examined using the Chi-Square Test and expert opinions. The results of the study indicate that if there is a condition (e.g., turning, joining to the traffic stream, or failure in propulsion/steering systems) that directly or indirectly disturbs the normal flow of traffic in the Singapore Strait, the risk of having an accident increases. The results of this study can be used to determine the measures to be taken for the prevention of possible accidents, as well as to help manage the risks associated with the ships that pass through the region. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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17 pages, 7271 KiB

Open AccessArticle

The Effect of Dynamic Fracture Strain on the Structural Response of Ships in Collisions

by Sang Jin Kim and Jung Min Sohn

J. Mar. Sci. Eng. 2022, 10(11), 1674; https://doi.org/10.3390/jmse10111674 - 6 Nov 2022

Cited by 1 | Viewed by 1413

Abstract

As ship collisions and grounding accidents lead to human injury and damage to the environment and property, more accurate predictions of structural damage to ships under impact loads are needed. Currently, to determine structural behaviors, finite element analysis (FEA) is frequently adopted. However, [...] Read more.

As ship collisions and grounding accidents lead to human injury and damage to the environment and property, more accurate predictions of structural damage to ships under impact loads are needed. Currently, to determine structural behaviors, finite element analysis (FEA) is frequently adopted. However, it is recommended to pay attention to material properties in FEA because structural damage is sensitive to material properties such as yield strength, fracture strain, etc. While the strain rate (impact speed) is automatically considered for dynamic yield stress using the Cowper–Symonds equation or other methods, the pre-defined fracture strain is generally used as the dynamic fracture strain (DFS), which is not dependent on strain rate during the simulation. This assigned value of fracture strain may affect the extent of damage and structural response. In this study, the effect of the DFS on the structural damage from collisions was investigated to determine the relationship between the DFS and damage. Empirical formulas based on predictions of damage by various events were developed as a function of the DFS and initial impact speed. The results of this study explained the effect of the DFS on the structural damage and determined the upper and lower bounds of damage by collisions. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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17 pages, 5143 KiB

Open AccessArticle

Collision Risk Situation Clustering to Design Collision Avoidance Algorithms for Maritime Autonomous Surface Ships

by Taewoong Hwang and Ik-Hyun Youn

J. Mar. Sci. Eng. 2022, 10(10), 1381; https://doi.org/10.3390/jmse10101381 - 27 Sep 2022

Cited by 3 | Viewed by 1657

Abstract

The reliability of collision avoidance systems for Maritime Autonomous Surface Ships is one of the most critical factors for their safety. In particular, since many ship collisions occur in coastal areas, it is crucial to ensure the reliability of collision avoidance algorithms in [...] Read more.

The reliability of collision avoidance systems for Maritime Autonomous Surface Ships is one of the most critical factors for their safety. In particular, since many ship collisions occur in coastal areas, it is crucial to ensure the reliability of collision avoidance algorithms in geographically limited coastal waters. However, studies on maritime autonomous surface ships collision avoidance algorithms mainly focus on the traffic factor despite the importance of the geographic factor. Therefore, this study presents a methodology for establishing a practical collision avoidance system test bed, considering the geographic environment. The proposed methodology is a data-driven approach that objectively categorizes collision risk situations by extracting these risks using Automatic Identification System (AIS) and Electronic Navigational Chart (ENC) data, followed by clustering algorithms. Consequently, the research results present a direction for establishing test beds from the perspective of geographic and traffic factors. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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34 pages, 12019 KiB

Open AccessArticle

Consequence Analysis of Accidental LNG Release on the Collided Structure of 500 cbm LNG Bunkering Ship

by Haris Nubli, Jung-Min Sohn and Dongho Jung

J. Mar. Sci. Eng. 2022, 10(10), 1378; https://doi.org/10.3390/jmse10101378 - 26 Sep 2022

Cited by 6 | Viewed by 2481

Abstract

The growing demand for liquefied natural gas (LNG)-fueled ships necessitates the establishment of an LNG bunkering facility. Ship-to-ship (STS) is one of the most practical forms of LNG bunkering systems. Although there are benefits to the LNG bunkering of ships, risk and safety [...] Read more.

The growing demand for liquefied natural gas (LNG)-fueled ships necessitates the establishment of an LNG bunkering facility. Ship-to-ship (STS) is one of the most practical forms of LNG bunkering systems. Although there are benefits to the LNG bunkering of ships, risk and safety issues are a concern due to the volatile cargo. Ship collision could result in accidental LNG release. The purpose of this study was to build LNG leakage scenarios, establish critical zones based on gas concentrations, and estimate the temperature reduction in a bunkering ship’s structure resulting from the use of cryogenic fluid. The condition of a target ship’s structure, both intact and when damaged due to collision, was considered. Leak size, leak direction, leak position, release rate, and reservoir pressure were included as leak parameters, and environmental parameters, such as the wind direction, wind speed, and ambient temperature, were also included. The release duration was set based on the shutdown duration of the emergency shutdown valve (ESD). A total of 72 leakage scenarios were generated for the main CFD analysis. Convergence tests were conducted to determine the appropriate grid and iteration numbers for a computational fluid dynamics (CFD) simulation. The gas dispersion characteristics and the cryogenic flow impact on the LNG bunkering ship’s structure are discussed through a parametric study. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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17 pages, 3712 KiB

Open AccessArticle

Research on Ship Collision Probability Model Based on Monte Carlo Simulation and Bi-LSTM

by Srđan Vukša, Pero Vidan, Mihaela Bukljaš and Stjepan Pavić

J. Mar. Sci. Eng. 2022, 10(8), 1124; https://doi.org/10.3390/jmse10081124 - 15 Aug 2022

Cited by 8 | Viewed by 2555

Abstract

The efficiency and safety of maritime traffic in a given area can be measured by analyzing traffic density and ship collision probability. Maritime traffic density is the number of ships passing through a given area in a given period of time. It can [...] Read more.

The efficiency and safety of maritime traffic in a given area can be measured by analyzing traffic density and ship collision probability. Maritime traffic density is the number of ships passing through a given area in a given period of time. It can be measured using vessel tracking systems, such as the Automatic Identification System (AIS). The information provided by AIS is real-time data designed to improve maritime safety. However, the AIS data can also be used for scientific research purposes to improve maritime safety by developing predictive models for collisions in a research area. This article proposes a ship collision probability estimation model based on Monte Carlo simulation (MC) and bidirectional long short-term memory neural network (Bi-LSTM) for the maritime region of Split. The proposed model includes the processing of AIS data, the verification of AIS data, the determination of ports and ship routes, MC and the collision probability, the Bi-LSTM learning process based on MC, the ship collision probability for new or existing routes, and the traffic density. The results of MC, i.e., traffic/vessel route and density, and collision probability for the study area can be used for Bi-LSTM training with the aim of estimating ship collision probability. This article presents the first part of research that includes MC in detail, followed by a preliminary result based on one day of processed AIS data used to simulate MC and propose a model architecture that implements Bi-LSTM for ship collision probability estimation. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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16 pages, 3710 KiB

Open AccessArticle

SASD Modeling Using an ANFIS to Prevent the Collision of MASS in Restricted Areas

by Hee-Jin Lee and Deuk-Jin Park

J. Mar. Sci. Eng. 2022, 10(7), 961; https://doi.org/10.3390/jmse10070961 - 13 Jul 2022

Cited by 7 | Viewed by 1440

Abstract

This study aimed to present the criteria for the collision avoidance of maritime autonomous surface ships (MASS) in restricted areas. The criteria were presented via ship domains, and a seafarers’ awareness-based ship domain (SASD) that dynamically changes the existing SASD according [...] Read more.

This study aimed to present the criteria for the collision avoidance of maritime autonomous surface ships (MASS) in restricted areas. The criteria were presented via ship domains, and a seafarers’ awareness-based ship domain (SASD) that dynamically changes the existing SASD according to the external environment was used to develop a new domain model. For application, we have converged an adaptive neuro-fuzzy inference system with the existing model. The proposed SASD was applied to an actual marine restricted area and compared with automatic identification system (AIS) based ship domain models. Consequently, although there was a slight difference depending on the restricted area and domain design method applied, the SASD, (i.e., the minor axis of the elliptical domain) and the AIS-based ship domain were similar. Cross-validation of the seafarers’ awareness-based ship domain and the AIS-based ship domain could propose a reference lateral side passing distance for MASS in restricted areas. However, the major axis of the ellipse should be further studied since the domain design method differs between models. Full article

(This article belongs to the Special Issue Ship Collision Risk Assessment)

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