bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrodynamic Characteristic of the “ChangJiangKou II” Wreck Salvage: A Coupled Time Domain Model
Authors: Wang Yiting , Wang Lei 
Published: August 2024

Abstract
This paper reports an integral salvage solution for an ancient vessel “Chang Jiang Kou II” wreck salvage. To ensure the safety of the whole salvage operation and reduce the damage to the historical relic, especially in the off-bottom and lifting process, a novel coupled time-domain model is developed to evaluate the safety of the moored salvage system in Yangtze River. The wreck-soil interaction module, lifting module and mooring module are coupled into the conventional potential flow time domain numerical simulation code. The finite element method, potential flow method and lumped mass method are adopted and integrated for considering the influence of the wreck-soil interaction, lifting and mooring system. The coupled model is preliminary validated by similar mature software in our previous study and is further validated by a model-scale experiment in present paper. The safety assessment is quantitatively conducted by using a three-parameters safety assessment methodology. Case studies with different sea states are numerically performed and quantitatively assessed. The results of the numerical simulation and experiments found that there is a special breakout phenomenon, where the displacements increase abruptly, and uneven distributions of the lifting tensions are observed. The outcome of present coupled model can give an important reference in real salvage operation.
Development of Hanwha Ocean Liquefied CO2 Carrier
Authors: Jun In-Jae , Koh Teuk-Jin , Kang Byoung-Chul 
Published: August 2024

Abstract
The interest in carbon neutrality is growing around the world as human faces the climate crisis caused mainly by greenhouse gas emission. The methodologies for carbon reduction are being introduced in every industry and carbon reduction through Carbon Capture Utilization & Storage (hereafter “CCUS”) is being recognized as one of the most feasible carbon reduction plan at the moment. CCUS is defined as a system of technologies that intergrates three stages: CO2 capture, transportation and utilization & geological storage. The transportation sector is a major part in CCUS value chain to link the capture sector and utilization & storage sector. Transportation methods of trucks, trains, pipelines, ships, etc. are being considered in the CCUS value chain and pipelines and ships are applicable in ocean transportation field. As the transportation distance of CCUS projects under development becomes longer and the total transportation volume is increased, ocean transportation using a dedicated liquefied CO2 (LCO2) carrier is expected to play a key role in carbon transportation of CCUS chain. In these market trends, Hanwha Ocean began developing a new vessel that can transfer liquid CO2 safely. This paper is to introduce the design development of Hanwha Ocean LCO2 carrier such as ship & cargo tank design, tank material, CHS (Cargo Handling System) test facility, etc.
Monte Carlo Dropout Based Active Learning for Deep Learning in Structural Simulation
Authors: Jiang Chunhao , Chen Nian-Zhong , Zhao Zhimin 
Published: August 2024

Abstract
In recent years, deep learning (DL) has been widely used in the realm of maritime technology and engineering, particularly in the domain of structural simulation. However, one of the significant challenges in this context is the requirement for extensive training data, which is cost-prohibitive. To mitigate the expensive cost of generating training data, an active learning (AL) model is proposed to reduce the required number of labeled samples for deep learning. Within this active learning model, a predefined acquisition function is used to query an unlabeled sample pool. It focuses on selecting highly informative samples for labeling and subsequent inclusion into the training dataset. The predefined oracle in the proposed active learning model is developed based on the Monte Carlo dropout technique, which is used to quantify the aleatory uncertainty and epistemic uncertainty inherent in the deep learning model. Consequently, samples characterized by maximal uncertainty are identified and subsequently integrated into the training dataset. A comparative study with random sampling is conducted to demonstrate the effectiveness and advantage of the proposed active learning model. This model can be generalized to improve other deep learning models used in the maritime technology and engineering domain, as it offers a computationally efficient way of sampling additional data.
Global Response Performance of HDPE Based Offshore Floating Solar Farm by Using Beam-Floater Model
Authors: Gavin Surjadi Frederick , Bakti Farid Putra , Jin Chungkuk , Simamora Pandu Kristian Prayoga 
Published: August 2024

Abstract
This study investigates the hydrodynamic and structural behavior of floating photovoltaics (FPV) equipped with floaters made of high-density polyethylene (HDPE) in marine environments. A comprehensive time-domain dynamics simulation of coupled FPV is executed to analyze the interactions among floaters, connectors, mooring lines, and PV modules. The HDPE floater is represented by a 6-degree-of-freedom (6DOF) non-diffracting buoy, interconnected by beam elements to capture elastic behavior. The PV module is positioned on the floater and modeled as a wing component with consideration for wind drag and lift forces. Multiple mooring lines, strategically placed on all sides of the FPV, serve the purpose of station-keeping. The study evaluates the tension in mooring lines and the bending moments of floaters using statistical values, response amplitude operators (RAOs), time histories, and spectra. The findings indicate that low-frequency excitation emerges as a pivotal factor influencing structural dynamics, primarily due to significant flexibility. The proposed design demonstrates superior performance in low-sea states.
Time-Varying Model for Scour Evolution Around Pile Foundations in Clay Soils
Authors: Zhao Pei-Qing , Wang Shun-Yi , Qi Wen-Gang , Gao Fu-Ping 
Published: August 2024

Abstract
The determination of the equilibrium value and time-dependent development of the scour depth around pile foundations has been a fundamental concern in hydraulic and coastal engineering. While significant progress has been made in understanding local scour around pile foundations in non-cohesive soils in recent years, the study of scour in clay soils remains less developed. Traditional methods for predicting scour in non-cohesive soils have been inappropriately applied to clay soils. Therefore, there is a pressing need to establish an accurate prediction model for scour depth in clay soils to enhance foundation designs. Current formulas for predicting scour development in clay soils around pile foundations are often empirical fittings to experimental data, making them susceptible to data ranges and scale effects. To fill this gap, a time-varying model for the evolution of scour around pile foundations in clay soils under a steady flow is proposed in this paper. This model utilizes a scaling expression for shear stress based on the phenomenological theory of turbulence (PTT) and integrates a general sediment transport model with sediment mass conservation principles to derive an ordinary differential equation (ODE) representing temporal variations in scour depth. By comprehensively considering all dimensional parameters affecting the scouring process, the model overcomes scale issues. The proposed model’s predictions closely align with previously observed scour depth development curves, demonstrating its effectiveness.
The Effect of Boundary Condition on Predicting the Thrust Loss of Azimuth Thruster in Ship-Type Offshore Structures
Authors: Woo Jaehong , Song Gisu , Kim Joo-Sung 
Published: August 2024

Abstract
For various offshore structures including ship types such as drillship, Wind Turbine Installation Vessel (WTIV), Floating Production Storage and Off-loading (FPSO), and Floating Liquefied Natural Gas (FLNG), the dynamic positioning (DP) is a fundamental function. For effective DP operation, the special propulsor, for example, azimuth thruster was chosen in general. It is well known that several azimuth thrusters are installed in offshore structures, the thrust loss might be induced by various interaction phenomena. In this study, the influence of boundary conditions is mainly examined for predicting thrust loss on numerical simulation. WTIV and FPSO were chosen as a target vessel, respectively. Two different types of boundaries were defined. The first consideration is that the boundary condition was assigned with the direction of the azimuth angle of the thruster whereas it is fixed regardless azimuth angle of the thruster. The predicted thrust loss according to these boundary conditions showed a difference and this is originated from the current load of the vessel. The current load on the ship depends on the ship type, draft, and inflow direction, the magnitude of the current load is affected by those conditions. Since the current load might be induced unintentionally in numerical simulation, the boundary condition is important to obtain a realistic thrust loss.
Numerical Study of Motion Responses of a New Combined Floating Wind Turbine and Wave Energy Converters
Authors: Lu Shunhang , He Fang , Cai Yuanlang , Yang Xiaolong , Zhang Guanglei 
Published: August 2024

Abstract
Improving power generation efficiency and reducing development costs is one of the main challenges for the floating offshore wind turbine (FOWT). A similar set of challenges is encountered in wave energy converter (WEC) systems. In response, this paper proposes a novel hybrid concept that combines FOWT and oscillating water columns (OWC) to capitalize on their respective advantages, as substantiated through a comprehensive numerical comparison with a purely FOWT system. The hybrid concept’s advantages are underscored by a rigorous analysis that incorporates wave-induced loads on the semi-submersible floating foundation and OWC using the potential theory, encompassing the 1st and 2nd order excitation forces as well as radiating added mass and damping, all integrated within the AQWA code. Viscous effects are approximated via the empirical Morison equation. Furthermore, the aerodynamic impact of the turbine blades is meticulously simulated using the blade element momentum method within the FAST code. Pitch and Nacelle horizontal acceleration of system are identified as the primary criterion for illustrating the advantages of the hybrid concept. In addition, this paper conducts a comparative study that explores the impact of sizing OWC in hybrid systems, shedding light on the potential for optimizing system motion performance and improving cost efficiency while maintaining constant structural weight. The paper culminates in a proposed arrangement plan, serving as a fundamental reference for the design of future offshore wind turbine systems.
Dynamic Analysis of a Novel Floating Wind Turbine and Fish Cage Combined System
Authors: Chen Feng , Li Jinghui , Deng Shi , Liu Xuping , Zhang Fafu 
Published: August 2024

Abstract
In recent years, the combined floating offshore wind turbine and fish cage has garnered significant attention as a novel form of clean energy infrastructure. In this study, a novel combined floating offshore wind turbine and fish cage structure was proposed. A three-dimensional diffraction/radiation analysis was performed in the frequency-domain using the WADAM program to compute hydrodynamic coefficients, such as added mass, radiation damping, first-order wave exciting forces, wave drift force coefficients, and motion. Additionally, second-order difference-frequency wave forces were calculated using the Newman approximation method. Time domain analysis was carried out using ORCAFLEX. The results of frequency domain analysis, including hydrodynamic coefficients (potential added mass and damping), transfer functions of the 1st and 2nd order wave loads. were substituted into the time domain model. In the ORCAFLEX program, full coupled motion analysis was conducted for wind-wave-current operation and extreme environmental conditions of the combined system. For the wind loads, a decoupled analysis method was applied, with the wind turbine tower base loads as input loads for the lower floating foundation. The analysis also included an assessment of the global motion, accelerations, and heel angles for the semi-submersible platform. The results indicate that the floating offshore wind turbine meets the requirements with a maximum inclination of less than 9 deg under extreme conditions, the maximum inclination in the operation condition meets the requirement less than 5 deg. the maximum acceleration in the extreme condition meets the requirement less than 0.6 g. The maximum acceleration in the operation condition meets the requirement less than 0.3 g. There is no green water phenomenon on the floating wind turbine system. The novel combined system exhibits favorable motion performance and can serve as a reference for engineering practice.
Position Loss Incidents on DP Class 3 Mobile Offshore Drilling Units on the Norwegian Continental Shelf
Authors: Chen Haibo , Reinås Lorents , Garlid Stian , Nygård Bjørn , Hasund Nils 
Published: August 2024

Abstract
This paper presents a study to collect and analyze position loss incidents on dynamically positioned (DP) mobile offshore drilling units (MODUs) on the Norwegian Continental Shelf (NCS). These MODUs are of DP class 3 according to the requirements from the Norwegian Petroleum Safety Authority (PSA) and perform offshore operations with major accident risk potentials if position loss occurs. A definition of position loss is formulated in this study with considerations of capability and excursion. A method for position loss incident data collection and analyses is developed. Twenty-six (26) DP class 3 MODUs have worked on the NCS from 2000 to 2022. Among them, 31 position loss incidents were reported. Position loss incidents and associated DP operational time data are collected and estimated from multiple public sources and several databases in Equinor. Position loss scenarios and their common patterns of event development are analyzed. A historical frequency of position loss for DP class 3 MODUs on the NCS is derived, and uncertainties are discussed. The results in this paper provide useful knowledge of position loss incidents and insight into the safety of DP operations on MODUs on the NCS.
Study on Failure Modes and Ultimate Strength of Stiffened Panels in Large Cruise Ships
Authors: Zhang Zheng , Wu Haolong , Liu Xiang , Deng Hui , Gan Jin , Wu Weiguo 
Published: August 2024

Abstract
In response to the demand for structural lightweight design in large cruise ships, the geometric parameters of the materials used in their construction differ significantly from those used in traditional vessels. Traditional empirical formulas offer limited accuracy in assessing the ultimate strength of stiffened panels. As a result, there is a need to investigate the impact of failure modes on the ultimate load-carrying capacity of such stiffened panels and to propose a predictive method for evaluating their ultimate load-carrying capacity. To explore the influence of failure modes on the ultimate strength of stiffened panels, and to propose a method for predicting the ultimate strength of stiffened panels. Using the nonlinear finite element method, the model of a typical hull stiffened panel is analyzed. Considering the two main influencing factors of reinforcement slenderness ratio and deck slenderness ratio, the failure mechanism of the stiffened panel is analyzed, and the influence rules of the deck slenderness ratio and reinforcement compliance on the ultimate strength of the stiffened panel under different failure modes are clarified, and different failure modes are proposed. Empirical formulas for the ultimate load-carrying capacity of stiffened panels under failure modes. When the slenderness ratio of the deck is constant, with the increase of the slenderness ratio of the reinforcement, the failure mode of the stiffened panel changes from the local buckling of the panel and the reinforcement to the local buckling of the panel, and finally to the overall beam-column of the stiffened panel buckling. When the panel width is low, the failure mode of the stiffened panel will change from beam-column buckling to panel buckling with the increase of the reinforcement height, and when the panel width is large, the failure mode of the stiffened panel with different reinforcement heights Both are panel buckling. At the same time, under different failure modes, the load-displacement curves of the stiffened panels also show different trends. The quantitative relationship between the slenderness ratio of the stiffener and the slenderness ratio of the deck will lead to different failure modes of the stiffened panels. At this point, the impact of these two factors on the ultimate strength of the stiffened panels will diverge. During the design phase, it is imperative to align the stiffness of the reinforcement with that of the deck, thus preventing a scenario where material utilization becomes excessively inefficient.
Research on Failure Modes Converting Method and Identification Method of Autonomous Navigation Equipments Based on Knowledge Graphs
Authors: Kang Jichuan , Zhang Weijie , Zhang Zizhao , Li Mingxin 
Published: August 2024

Abstract
To solve the problem of insufficient real data of autonomous navigation equipment, this paper extracts the failure causes of equipment by constructing a knowledge graph and converting human errors into equipment errors. Firstly, this paper searches relevant websites to obtain the collision accident investigation reports as source data. Web crawlers are applied to get the report that compliance with keywords is efficient. After conversion and filtering operations, the target files are filtered out and they are then transformed into structured data. Text annotation is introduced to process data for entity extraction and relation extraction, and to get an exact data set. A knowledge graph in terms of failure modes of normal vessels is established based on the extracting results, which serves as a knowledge base to support the subsequent work. This step takes failure cases in plain text form and organizes them into a structured, visual form that can be easily retrieved to summarize the main human errors of conventional ships’ collisions. A convert model is created to convert human errors to device errors of autonomous vessels. Typical failure modes identification of the autonomous navigation equipment is performed through FMEA to clarify the critical components and their potential failure modes.
The Field Test of a Shallow-Water Mooring System for FOWT Using Nylon Synthetic Fiber Ropes
Authors: Kamizawa Ken , Yoshimoto Haruki , Chujo Toshiki 
Published: August 2024

Abstract
Japan Marine United Corporation (JMU) are currently developing substructures and mooring systems for floating offshore wind turbines (FOWT) With the cooperation of National Maritime Research Institute. Cost reduction technology is very important for the large-scale commercialization of FOWTs, and a low-cost mooring system as well as a floating foundation are required.
Among these, mooring systems using nylon ropes have been attracting attention in recent years because they can reduce mooring costs in shallow waters. However, nylon rope has little experience in mooring large offshore structures. Therefore, there is insufficient durability data of nylon ropes under actual sea conditions.
The authors conducted a field test of a mooring system using nylon ropes in shallow water to verify the durability of nylon ropes. The 1/9th scale semi-submersible floating structure designed for FOWT is moored, and the mooring system consists of two taut mooring lines and two catenary mooring lines, totaling four lines, was set up at a depth of about 20 m off Akita Prefecture in Japan for about one-year test. This paper introduces the field tests conducted and presents the results of the comparison between the design and measured values, as well as the results of the evaluation of the durability of the nylon rope.
The Spatiotemporal Distribution of Heavy Metals and Their Response to Physicochemical Parameters of Water Quality in the Yangtze River Estuary
Authors: Zou Yuwen , Lou Sha , Zhang Zhirui , Liu Shuguang , Zhou Feng 
Published: August 2024

Abstract
Heavy metals present a significant risk to the safety of water environments and aquatic ecosystems due to their resistance to degradation and high levels of toxicity. Field investigations were conducted in this study in Yangtze River Estuary in July, 2021 and February, 2022. Seven sampling locations were selected at Liu He Kou (LHK), Shi Dong Kou (SDK), Wu Song Kou (WSK), Zhu Yuan (ZY), San Jia Gang (SJG), Chao Yang Nong Chang (CYNC), Da Zhi He (DZH). Fourteen sediment samples and fourteen water samples were collected. The heavy metal concentrations (Cr, Ni, Cu, Pb, Zn, Cd) and physicochemical parameters of water quality including Temperature (Temp), pH, Oxygen redox potential (ORP), Dissolved oxygen (DO), Electrical conductivity (EC), Electrical resistivity (RES), Total dissolved solids (TDS), Salinity (SAL) and turbidity (NTU) were investigated. The concentrations of most heavy metals were higher in July compared to February, and exhibited spatial heterogeneity. Principal component analysis (PCA) was used to determine the sources of heavy metals. Steel industry wastewater, domestic and industrial sewage, shipping and vessel emissions were the main sources of heavy metals. Spearman correlation analysis identified Temp, pH, and DO as the key physicochemical parameters of water quality, exhibiting the strongest correlation with heavy metal concentrations in sediment and water samples. These results can provide scientific basis and guidance for the water environmental management of the Yangtze River estuary, making a significant contribution to the protection of water quality and health in this region.
Load Mapping Algorithm of Submerged Floating Tunnels Under Different Wave Conditions
Authors: Liao Haiyan , Wang Baoxuan , Sheng Fangyuan , Liang Xu 
Published: August 2024

Abstract
The submerged floating tunnel is a new type of traffic structure that can cross the deep as well as long channels. Most of the current studies on submerged floating tunnels are based on highly simplified beam models. Although the use of beam element modeling is convenient for analysis, the beam model of submerged floating tunnels is limited to longitudinal. In order to design the sections reasonably, it is required to provide information about the member forces in the transverse direction. So, it needs to conduct a more detailed three-dimensional finite element analysis of the submerged floating tunnels’ structure system under the action of waves and currents. This paper proposes a set of load mapping algorithms for submerged floating tunnels, which maps the load from the beam finite element model to the shell finite element model, to analyze the three-dimensional structure of submerged floating tunnels in the time domain. In this study, it is the first time to realize full load mapping in the field of submerged floating tunnels. According to the load mapping algorithm, this paper calculates the response of a submerged floating tunnel under different wave conditions, which provides a reference for the actual design of submerged floating tunnels.