bluuebunny/crossref_metadata_2025_split huggingface dataset:
Escarpment Crossing Design and Analyses of Large Diameter Offshore Pipelines
Authors: Qi Xinhai , Kvist Orjan , Chen Jian , Duan Gang , Ren Lan , Wang Howard , Lan Jundong 
Published: August 2024

Abstract
Subsea pipeline design for escarpment crossings proves complicated and time-consuming, primarily attributable to the excessive plastic strains encountered at the overbend and the extraordinary fatigue damage over long spans, exacerbated by the steep seabed conditions.
Due to substantial uncertainties, the design approach for pipeline escarpment crossings leans towards conservatism by limiting pipeline bending moment/strain and span length. Consequently, the implementation of mitigation measures becomes a common necessity. In pursuit of a straightforward and cost-effective crossing design, this paper offers a comprehensive insight into the in-place behavior of large diameter pipeline crossing over escarpments.
This study investigates a 24-in gas export pipeline in an African field from a water depth of 25m to 250m. The pipeline strength assessment employs the displacement-controlled condition (DCC) at the escarpment top and load-controlled condition (LCC) for the remaining pipeline, aligning with DNV offshore pipeline design standards. The numerical model, utilizing Abaqus elbow elements, simulates the S-lay, pre-commissioning, and operating processes. The mitigations of the strain and DCC utilization are then examined. This involves optimizing pipeline route, wall thickness, lay tension, and crossing protection.
Seismic Vulnerability Analysis of Pile Foundations in Liquefiable Sites
Authors: Tao Xiaosan , Wang Zhekai , Tan Huiming 
Published: August 2024

Abstract
Pile foundations of structures like offshore wind farms and bridges are often located in potentially liquefiable sites. In order to study the seismic vulnerability of pile foundations in liquefiable sites and analyze the seismic response of pile foundation structures in such conditions, a numerical model of pile foundations was established using OpenSees platform. Subsequently, by conducting nonlinear time history analysis using representative seismic waves, seismic vulnerability curves for various components were plotted with the peak ground acceleration (PGA) as a parameter. The results indicate that the failure probability of the piers is related to both PGA and the damage state. A higher PGA leads to a higher failure probability of the piers. With a constant PGA, the more severe the damage state of the piers, the lower the failure probability. As PGA increases from 0.1g to 0.5g, the probability of slight and moderate damage states of the piers shows a rapid increase, indicating a significant response of the piers to the change in seismic intensity from 0.1g to 0.5g, making them highly susceptible to damage during this stage. As for the vulnerability curve under complete damage state, the damage probability starts to change only after PGA reaches 0.5g, and the magnitude of change is small. When PGA reaches 0.8g, the damage exceedance probability is also less than 10%, demonstrating the structural safety.
Numerical Investigation of the Vertical Settlement of Seabed Pipelines Under Lateral Cyclic Loading in Clay
Authors: Jia Xu , Liu Yi , Jia Lusheng , Cheng Li , Wang Qi , Shen Zhichao 
Published: August 2024

Abstract
As exploration moves into deeper water, offshore pipelines, generally laid on the seabed, are an increasingly significant component of offshore hydrocarbon developments. Seabed pipelines are mainly subjected to the wave loading, which causes vertical settlement of pipelines. In this study, the vertical settlement of seabed pipelines under lateral cyclic loading in normally consolidated clay is investigated through the large deformation finite element (LDFE) analysis with the Coupled Eulerian Lagrangian (CEL) technique. The effects of strain rate dependency of the undrained shear strength and soil remoulding are considered by adopting an extended Tresca clay model during lateral cyclic loadings. Firstly, the LDFE results are compared with centrifuge test results and published LDFE data, showing a good agreement. Then, a series of LDFE cases are conducted to investigate the effects of pipe weight, lateral load amplitude, soil sensitivity, and the initial trench depth on the accumulated vertical settlement of pipelines under lateral cyclic loading. The LDFE results show that the affected clay zone around the pipeline due to the lateral cyclic loading is highly remoulded, and the initial trench depth has a great effect on the accumulated vertical settlement of pipelines. With the increasing number of lateral load cycles, the accumulated vertical settlement of pipelines first increases and then decreases. A modified expression is proposed to estimate the ultimate vertical settlement of pipelines in clay.
Ultimate Strength Test of Typical Joint of Composite Ship
Authors: Feng Guoqing , Li Kaiyan 
Published: August 2024

Abstract
Compared to metal materials, composite materials possess favorable properties such as high strength-to-weight ratio and high stiffness-to-weight ratio. They allow for a reduction in the overall weight of a ship while still meeting the requirements of ship design, aligning with the principles of energy efficiency and emission reduction. However, due to the anisotropy of composite materials, some components of composite ships are easily damaged in complex marine environment, which affects the safety and reliability of the entire hull structure. To understand the ultimate load-carrying capacity of vulnerable structures of composite ships under the influence of wave loads, structural response calculations for the target ship was conducted based on the design wave method in this paper. In cases where the target ship experiences overall longitudinal bending, areas with high compressive stress were identified. After screening, the box bracket structure at the joint of deck and transverse bulkhead was selected as the research object, and a typical joint specimen composed of transverse bulkhead, deck, cap girder and bracket was designed. Standard specimens of 0° uniorientational layering and 90° uniorientational layering were designed according to the relevant specifications, and tensile and compression tests were carried out, and the stiffness and strength data of the materials were measured for numerical analysis. In order to carry out the model test, the compressive ultimate strength test of typical joint specimens was carried out, and the displacement-loading force curve during the test was recorded. A shell element model was used to simulate the compression process of the ship typical joint specimen based on the 2D Hashin criterion as the failure criterion. By comparing numerical simulation results with experimental data, the accuracy of the numerical simulation method was validated.
CFD-DEM Modelling of Cuttings Transport With Power-Law Fluids in Horizontal Annulus
Authors: Sun Yi , Zhou Mengmeng , Song Xianzhi , Xu Zhengming , Ping Wanzhuo , Zhu Zhaopeng , Qi Yiqun , Jing Silin , Yao Xuezhe 
Published: August 2024

Abstract
For the horizontal wells, the cuttings deposition becomes a general question, as the cuttings are easy to deposit at the bottom of the wellbore to form a thick cuttings bed, which can easily cause drilling stuck and pumping accidents. Accurately characterizing the flow regimes and their transition of cuttings in complex multiphase flow in the wellbore becomes an important consideration, as the flow regimes and their transport directly affect the distribution of cuttings concentration. The drilling fluids exhibit typical power-law rheological properties, so it is necessary to study the influence of power-law rheological parameters on the flow characteristics of cuttings. A coupled Computational Fluid Dynamics (CFD) with Discrete Element Method (DEM) is applied here to describe the different flow regimes and their transition. The influences of power-law fluids’ rheological parameters on flow field characteristics and cuttings distribution are also discussed here. Based on these, the pressure gradient change in the wellbore is further described. The research results will lay a theoretical foundation for improving hole-cleaning efficiency and have practical significance for guiding the field construction of extended-reach horizontal wells.
The Load Bearing Mechanism and Holding Capacity of Helical Piles Subjected to Uplifting
Authors: Li Zeliang , Tian Yinghui , Maitra Shubhrajit , Cassidy Mark , Gaudin Christophe 
Published: August 2024

Abstract
Helical piles have been widely used onshore which can withstand compressive and tensile loads. As a promising foundation for offshore wind developments in deep water, helical pile has advantages of quiet installation and significant uplift capacity. In this paper, numerical analyses are conducted to investigate the load bearing mechanism considering the contributions from shaft and helical plate. The effects of helical plate embedment depth, interface roughness and shaft diameter ratio are studied. A discussion is presented on the terminology adoption depending on the contribution from the helical plate and the shaft.
Restoring Time Computation in Self-righting Process
Authors: Liu Jinbang , Hou Guoxiang 
Published: August 2024

Abstract
The excellent self-righting performance is important to guarantee the normal navigation of boats after overturning, and the restoring time is an important index in design requirements. Traditionally, the static stability method and experiments of full-scale vehicles were used to analyze the large angle stability of boats. However, when it comes to the analysis of self-righting performance, the traditional static stability method will cause improper integration, and experiments are not convenient. To solve these two problems, two new methods are proposed. An improved static stability method is proposed and a numerical simulation method is adopted. Firstly, a midpoint average method based on the static stability theory is proposed to compute the static restoring time, which has the advantage of convenience and can avoid improper integration. The results are compared with the references, which verifies the effectiveness of the midpoint average method. Then, a numerical simulation of a physical model in static water was finished and an experiment of the physical model in a towing tank was conducted. Comparing the restoring time of the midpoint average method, the numerical simulation and the experiment, the results show that the numerical simulation has high accuracy.
Numerical Investigation of Hydrogen Fuel Tank Skid Leakage on a Hydrogen-Powered Vessel
Authors: Fan Hongjun , Abdussamie Nagi , Harris Andrew , Chen Peggy Shu-Ling 
Published: August 2024

Abstract
Green hydrogen as a marine fuel can be crucial in decarbonising the maritime sector. More than 40 hydrogen-powered demonstration vessels are in operation worldwide, and numerous hydrogen-powered vessel projects are under development. Hydrogen gas exhibits a lower minimum ignition energy and a broader flammability range compared to other alternative fuels. In the event of a leak, there is a risk of fire and explosion, posing challenges for the safe design of hydrogen-powered vessels. Presently, rules and regulations for hydrogen-powered vessels are not yet fully developed. In many cases, classification societies recommend using risk-based design for such vessels. This paper is centered on the conceptual design of a hydrogen-powered offshore windfarm crew transfer vessel. It utilises the computational fluid dynamics (CFD) approach to simulate the dispersion behaviour of leaked hydrogen gas, taking into account environmental factors, vessel navigation speed, onboard obstacles, and other relevant parameters. Based on the CFD modelling results, this paper provides safety design recommendations for arranging hydrogen gas tanks on board the vessel.
Impacts of Vessel Motion on the Dynamic Response of ROV System in The Processes of Deployment and Recovery
Authors: Guo Yucheng , Yu Xiaoqi , Guo Shuangxi , Liu Xiangxu , Kong Yue , Chen Weimin 
Published: August 2024

Abstract
Remotely operated vehicles (ROVs) are frequently used in subsea explorations and exploitations, aiming to obtain not only traditional ocean oil and gas, but also other mineral resources, such as manganese, polymetallic nodules and sulfides. However, due to the interactions between ocean environmental loads, ROV, suspending cable and top-end vessel, the dynamic responses of ROV system have strong coupling and nonlinear characteristics. Especially, during the initial deployment and the final recovery stages, the cable length might be so short that the relative motion between the ROV and the vessel may cause a severe collision and even structural damage. In this study, based on the structural and dynamic characteristics of the ROV system during the initial deployment and the final recovery stages, numerical simulation and analytical method are employed to investigate the impacts of the top-end vessel motion on the ROV system. In the numerical simulations, vessel surge and hydrodynamic force on ROV, are considered, and the ROV responses and cable tensions under different vessel motion amplitudes and frequencies are presented. It is found that the ROV responses are larger than the vessel motion amplitudes in some cases owing to vessel surge. And, the governing equation of ROV with a horizontal moving boundary is developed. Then, in order to have a deeper understand of the behaviors of the ROV system and the mechanisms of our simulation results, the analytical method is used.
The Impact of Controller Parameters on the Maneuvering of Two Ships at Different Water Depths
Authors: Xu Chen , Zhou Xueqian , Ren Huilong , Guedes Soares C. , Sutulo Serge 
Published: August 2024

Abstract
This paper aims to investigate the impact of controller parameters on the performance of a PID controller in the maneuvering of two ships. In present work, a maneuvering model, which accounts the hydrodynamic interactions, is established using the MMG model. The shallow water effects on hydrodynamic derivatives are estimated by empirical formulas, and the hydrodynamic interaction forces between ships are evaluated by a 3D potential flow code. In the prediction of hydrodynamic interaction, the influence of fluid viscosity and the variation of free surface on hydrodynamic interaction are both neglected, and the double body model and mirror image technique are used to model the free surface and bottom, respectively. A conventional PID controller is used for course keeping, with the desired heading angle is determined via Line-of-Sight (LOS) guidance. The simulations of two ships overtaking are conducted at different ship speeds, initial lateral distances, water depths, and impact of PID controller parameters, such as lookahead distance, relative damping ratio, control bandwidth, on the performance of PID controller is revealed.
Transient Hole Cleaning Behaviour: What Can We Learn From Flow Loop Experiments
Authors: Lund Bjørnar , Taghipour Ali , Saasen Arild , Ytrehus Jan David 
Published: August 2024

Abstract
Ensuring adequate hole cleaning is important for safe, efficient and economic drilling operations. Most models and flow loop experiments assume steady-state conditions. However, drilling is an inherently transient process. Even in the steadiest situation, the drill bit position advances continuously. When inserting a new stand of drill-pipe there are transients in both string rotation speed and flow rate. Additional transients occur when the drill-pipe is rotated and reciprocated to clean the wellbore. When drilling wells with a narrow pressure margin it is important to control and limit such pressure peaks.
We have conducted flow loop experiments in a drilling fluid rig with a 10 m long inclinable test section to investigate hole cleaning performance of field applied oil-based and water-based drilling fluids. While the focus of the experiments has been on steady-state performance, the experiments also provide quantitative information about transient performance. Such information can be used for model closure development. Field applications could include analysis of transient responses from Along-String Measurement instruments, and thus provide additional information on cuttings accumulation, both with respect to location and quantity.
Transient data have been analysed using simple physics-based models. We have shown that the pressure peak due to onset of string rotation can be correlated with the cuttings entrainment rate. We further showed that a large fraction of the cuttings can be transported in suspended mode, even for laminar flow without string rotation.
Mooring Chains Out of Plane Bending Fatigue Analysis Clarifications
Authors: Barros Pedro , Storesund Walter , Skretting Ådne , Rahman Md. M. , Lillestøl Dag-Børre 
Published: August 2024

Abstract
Out of Plane Bending (OPB) fatigue of mooring chains has been the subject of several studies, of which the most comprehensive was the “Chain Out of Plane Bending” JIP completed in 2013. The currently applied fatigue damage calculation procedures are derived from the mentioned JIP. Following practical use of those procedures, it has been found that alternative procedures and updates can be considered. This paper describes alternative OPB fatigue damage calculation procedures, and the work performed to demonstrate their applicability and safety level with respect the JIP results most common applications.
A detailed implementation of the JIP test results with focus on interlink stiffness for wide angle amplitude cycles (cycles with sliding events) is presented. The resultant safety levels based on this methodology compared with a simplified interpretation of JIP test results is presented.
Alternative simplified procedures, for OPB fatigue damage estimation for mooring systems using OPB mitigation devices or for which very low OPB fatigue damage is expected, are presented and compared with the currently accepted procedures. In these systems it is demonstrated that the complex mooring analysis dedicated to OPB fatigue estimations, requiring mooring line angle estimations, may be waived and an indication of the conservativeness of the calculation results is presented.
Comparative analysis of the different interlink stiffness and fatigue damage calculation procedures were performed on several representative environmental states, demonstrating for different levels of procedural simplification the increasing level of safety.
It is demonstrated that different OPB fatigue damage calculation procedures can be used with different levels of required calculation effort, and therefore cost, according to the system optimization objective level. Simplified and easier to perform procedures for OPB fatigue calculation are presented and verified.
Deep Reinforcement Learning for Ship Collision Avoidance and Path Tracking
Authors: Singh Amar Nath , Vijayakumar Akash , Balasubramaniyam Shankruth , Somayajula Abhilash 
Published: August 2024

Abstract
This research focuses on collision avoidance between ships in the maritime industry, addressing human decision errors as a significant contributor to ship-to-ship collision. Emphasizing the crucial role of automation in maritime operations, the study employs advanced algorithms, specifically Deep Q Network, to enhance dynamic collision avoidance capabilities. By automating decision-making processes, the research aims to significantly reduce collision occurrences between ships, highlighting these algorithms as promising within the realm of deep reinforcement learning. Utilizing a three-degree-of-freedom dynamic model and Krisco field ship as a benchmark hull, rigorous numerical simulations validate the proposed model’s accuracy. The reinforcement learning agent, trained on this dynamic model, strives to optimize collision avoidance and waypoint tracking, demonstrated through numerical simulations and model experiments with a scaled version for a comprehensive evaluation of its maritime safety efficacy.
Using 3-P Weibull Distribution Evaluate Reliability of DDV and SPM Valve Hydraulic System of BOP
Authors: Cao Yang , Zhang Yu , An Chen 
Published: August 2024

Abstract
The direct drive valve and subplate mounted valve are critical components of the blowout preventer’s hydraulic system. The reliability analysis theory is used to analyze the service life of direct drive valve valves and subplate mounted valve valves in order to improve their reliability. The fault data is analyzed and Weibull probability plot is fitted, which is determined to follow the Weibull distribution of three parameters. The Weibull parameters are estimated by maximum likelihood estimation, and the optimal solution is obtained by particle swarm optimization. The probability density function reliability function and failure rate function are obtained. The results show that the direct drive valve and subplate mounted valve fault data follow the three-parameter Weibull distribution, and the average direct drive valve fault time is 2700 times, for subplate mounted valve is 6000 times.
Cnoidal Wave on a Long Elastic Floating Plate at Shallow Water Depth
Authors: Iijima Kazuhiro , Kyaw Soe Sandar , Maeda Takeru , Akira Tatsumi 
Published: August 2024

Abstract
This paper addresses the nonlinear waves propagating along a thin elastic plate floating in shallow water by using a numerical approach and by comparing with the analytical cnoidal wave theory. A numerical approach to simulate the nonlinear wave behavior on a floating plate is developed by incorporating the plate stiffness and inertia effects in the existing numerical method for free-surface waves. The accuracy and reliability of the newly developed numerical approach have been verified through comparisons with theoretical or experimental data from the literature. An analytical cnoidal wave solution for the propagation of cnoidal nonlinear waves along a floating plate is discussed and derived, too. This analytical approach aims to provide a foundational understanding of the complex wave dynamics exhibited by the floating plate. It turns out that the predictions from the analytical approach agree well with the numerical results in many cases while it still needs improvement.
Application of Data Analytics and Machine Learning in Analysing Result of Numerical Ship Manoeuvring Study
Authors: Hassani Vahid , Ross Andrew , Aspelund Leiv 
Published: August 2024

Abstract
We present the results of applying basic data analytic tools to data collected through an extensive high fidelity numerical simulation study focused on a vessel steering towards and passing through an enclosed ship tunnel in diverse weather conditions. While a companion paper [1] describes the simulation study that incorporates innovative developments in a numerical simulation tool, utilising results from geospatial modelling of the fjords and tunnel, shallow-water and confined-water hydrodynamics, extended modelling of ship hydrodynamics, both seakeeping and manoeuvring, collision-dynamics, the current paper focuses on application of tools from machine learning and data analytics to analyse the results from the above mentioned simulation study.
Lateral Displacement Control Challenges for Installation of Floating HDPE Pipeline
Authors: Jiwa M. Z. 
Published: August 2024

Abstract
HDPE pipe for marine application is commonly used for water intake, effluent outfall or water abstraction. The main reasons for this are PE has very high resistance to corrosion, low surface roughness which improves the hydraulic behaviour and excellent performance against the environmental force due to its flexibility properties. HDPE pipeline is normally installed by float-and-sink method. During the initial stage of installation, the string of HDPE pipeline will be floating for some period. A floating pipeline will be exposed to the current velocity and cause the pipeline to displace laterally. Therefore, it is necessary to introduce a method to hold the pipe while it is being installed offshore. This study presents method to manage the HDPE pipeline displacement during the float-and-sink method installation utilising the support boats.