bluuebunny/crossref_metadata_2025_split huggingface dataset:
Static and Fatigue Strength Assessment of Composite Patch Repair
Authors: Paboeuf Stéphane , Deydier Maxime , Sourisseau Quentin , Leprêtre Emilie , Chataigner Sylvain , Chapeleau Xavier 
Published: August 2024

Abstract
Marine and Offshore industries are looking for rapid, efficient and qualified repair solutions for damaged or corroded structures. Patch made in composite materials can offer such qualities as confirmed by the Joint Industry Project StrengthBond Offshore (JIP SBO) led by Bureau Veritas. Indeed, since 2019, Bureau Veritas, in collaboration with its partners, studied and analyzed the strength behaviour of composite patch repairs based on a large numerical and experimental testing campaign.
The JIP SBO consortium designed a layered composite patch composed of an epoxy resin with glass and carbon fibres, and proposed an installation procedure. Small-scale and large-scale specimens were tested in static and fatigue, and numerical simulations were done in order to develop a robust methodology for the strength assessment of composite patch repairs.
This paper first presents the comparison of two patch designs, one with a long scarf at the ends of the bonded composite patch, and the other one with a short scarf. In addition, two manufacturing processes, infusion and hand lay-up, are compared for long scarf specimens. The static resistance of the two patch designs and manufacturing processes is determined by tensile and bending tests. The results show that long scarf specimens have a higher resistance and that the manufacturing process has little influence. Finally, fatigue tests on long scarf specimens, and for the two studied manufacturing processes, are detailed and compared with a FPSO (Floating Production Storage Offloading) histogram.
Torpedo Piles and Suction Piles: Geotechnical Analysis and Installation Experiences in Seek for Optimal Anchoring System in Deepwater Clay Soils
Authors: Castillo Garcia Pablo , Branco L. Fernandes Bernardo , Tsetoulidis Charilaos , Mader Marcello , Orejuela Daniel , Serra Edy , Panayides Stylianos 
Published: August 2024

Abstract
Torpedo piles have emerged as a compelling alternative to conventional suction piles for anchoring floating facilities in deepwater developments. Gaining momentum in the offshore industry over the last decade, their design has been enhanced through specialised laboratory tests and the application of analytical and numerical tools. However, compared to suction piles, there is limited field data on torpedo piles, as their primary use has been in offshore Brazil.
This study is the first step of a series of analysis on torpedo piles aiming at further developing design and installation. Various aspects of the torpedo pile solution need to be thoroughly studied, should this concept prove pivotal in competing with conventional suction piles in offshore frontier acreage. Elements such as anchor dimensions and thus holding capacity, fabrication, transportation and installation costs need to be evaluated in search of the most optimal solution.
Leveraging recent installation feedback from Subsea7 on torpedo piles T-120 and existing literature, this paper presents an interdisciplinary assessment and comparison of suction and torpedo piles. It also includes an analysis of the novel finned pile design, currently applied in an ongoing Subsea7 project in Brazil.
The paper comprises finite element analysis (FEA) to compare holding capacities and offers insights into installation, transportation and fabrication costs of both anchoring systems.
Dynamic Simulations of Influence of Ship Rolling Motion on Aerodynamic Flow Field and Helicopter Loading Under Helicopter-Ship Coupling
Authors: Guo Daming , Chen Zhanyang , Duan Fang 
Published: August 2024

Abstract
The six degrees of freedom (6-DOF) motions of the ship is an important factor for helicopter landing on a ship safely, especially the rolling motion of ships has a short period and large magnitude. This study aims to investigate the changes in the aerodynamic flow field and the influence on the helicopter loading when landing on a ship under rolling motion conditions. In previous studies, the coupled aerodynamic flow field and helicopter loading during helicopter hover on a ship have been analyzed, however, the dynamic process of helicopter landing on a ship has not been adequately analyzed. Hence, a dynamic simulation scheme for the entire landing process of the helicopter is proposed in this study. By comparing the existing static research scheme with the proposed dynamic simulation scheme, the differences between the two methods will be analyzed, and the optimal scheme will be selected to study the coupling between ship and dynamic helicopter landing. The aim is to gain a comprehensive understanding of the landing issues of helicopters on ships under rolling conditions, and to explore the variations in helicopter loading caused by rolling motion. This study will contribute to enhancing the safety and stability of helicopter landing on ships, providing crucial guidance and reference for the design and operation of shipborne helicopters.
Ship As a Buoy: RAO-Driven Heading Adjustment Strategy Based on Restricted Isometry Property
Authors: Zhang Taiyu , Chen Shangyuan , Ma Can , Ren Zhengru 
Published: August 2024

Abstract
The safety and efficiency of marine operations heavily rely on external environmental conditions. Waves emerge as the most crucial factor influencing floating structures, which can be described by the directional wave spectrum. However, real-time in situ wave spectrum measurement are often lacking due to limitations involve in traditional approaches. To address this, estimating the sea state using ship motion responses has emerged as a cost-effective and viable method, known as the wave buoy analogy (WBA). Nevertheless, the performance of WBA varies due to ship’s inherent hydrodynamic properties, i.e., response amplitude operators (RAOs). The performance deterioration can lead to inaccurate estimations of the current sea state, potentially resulting in severe consequences. In this study, an adaptive ship heading adjustment strategy was proposed to circumvent inaccurate ship estimates in certain sea states and ascertain the optimal heading angle. The restricted isometry property was employed to determine the direction where ship can offer a better estimate. The involvement of heading adjustment strategy improved the accuracy and robustness of sea state estimation. Numerical simulations were conducted to validate the effectiveness of the proposed algorithm.
Analysis of the Dynamic Responses of a Barge-Type Platform With Multiple Wind Turbines
Authors: S. A. Vighneshwar , Saha Nilanjan , Rajendran Suresh 
Published: August 2024

Abstract
In recent years, there has been significant growth in ocean exploration. Energy production is an essential component of a multi-purpose platform. Wind turbines are the most space-efficient power-generating systems. This work proposes a barge-type VLFS (Very Large Floating Structure) with multiple wind turbines for the bays or breakwater-protected regions. The current project uses two 1.5 MW WindPACT NREL (National Renewable Energy Laboratory) wind turbines and VLFS utilized in the planning phase of Tokyo’s floating airport. Here, the length of the VLFS is sufficient to hold two wind turbines in cross-wind directions. Developing a fully coupled code that works with multiple wind turbines is difficult, as the modelling of wake interactions is challenging. As a result, this study uses a partially coupled methodology. This method uses a fully coupled code for a single wind turbine to estimate the loads at the tower bottom of the wind turbine. As a preliminary step, the fully coupled and partially coupled methods are verified for various load cases. Different ways of placement of wind turbines on the platform are studied for the two wind turbines. Three such configurations are proposed in the study, highlighting their various advantages over one another. These configurations are examined for their hydrodynamic performance.
A New Approach to Evaluate the Inflow Profile Heterogeneity of Lower Completion Horizontal Well in N Oilfield Middle East
Authors: Shi Shuzhe , Wu Bohong , Nie Zhen , Li Yong , Meng Lei , Zhang Yanna , Cui Weixiang , Zhang Lufeng 
Published: August 2024

Abstract
Horizontal well is one of the main technologies applied in carbonate reservoir development, and open-hole completion is widely adopted in the horizontal wells of Oilfields Middle East. However, the open-hole completion faces several challenges during the well production life. For example, the water or gas breakthrough caused by the uneven production profile will decrease the oil production, increase the surface equipment cost to transport produced gas/water and have a negative influence on the final recovery factor. Therefore, the well-designed lower completion configuration and evaluation for the inflow profiles need to be studied for the purpose of a higher cumulative oil production and a higher recovery factor.
In the present work, the inflow profile heterogeneity calculation approach is proposed, including two coefficients, inflow variation coefficient Cv and inflow Lorenz coefficient CL. Then, coupled model simulation is carried out to determine the optimal lower completion configurations with high efficiency. A production well case with a heterogeneity profile is presented, using the new approach to calculate the inflow variation coefficient Cv and inflow Lorenz coefficient CL between open-hole completion and well-designed lower completion under the coupled-model simulation, the result shows the inflow profile heterogeneity of open-hole completion is larger than the heterogeneity of well-designed lower completion. Therefore, by adopting the optimal lower completion configuration, the homogeneous profile can be achieved and will result in better production performance and a higher oil recovery factor.
This approach was successfully verified by the simulation case, which makes a quantitative evaluation of the inflow profile heterogeneity and provides guidance to the lower completion configuration design and reservoir development.
Statistical Uncertainty of Ship Response to Waves As a Function of Test Duration
Authors: van Essen Sanne , Bunnik Tim , Scharnke Jule 
Published: August 2024

Abstract
Wave-induced ship responses have a natural statistical variability, due to the nature of the ocean waves. This needs to be accounted for in ship design. The uncertainty and extreme values of the ship motions and loads depend on the test or simulation duration. This paper presents the experimental relation between uncertainty of root-mean-square (RMS) and most probable maximum (MPM) response values and the test duration, for a sailing ferry in steep bow-quartering waves. The RMSE uncertainty of the RMS of heave, pitch and relative wave elevation was 2–3% after 0.5 h test duration, reducing to 1% after 1 h. The uncertainty of the measured significant wave height was similar. For MPM values with a low uncertainty you need to perform longer tests. The RMSE uncertainty of the MPM of heave and pitch motions was 12% after 2 h, reducing to 5% after 5 h. This uncertainty is lower for relative wave elevation (2–6% after 2 h; 1–3% after 5 h), and higher for green water force on the accommodation (55–65% after 2 h; 20–40% after 5 h). We cannot use linear simulations to predict the RMS or MPM response values themselves, but we can use them to predict the required experimental duration for a given error tolerance of the RMS of (relative) motions.
Simple Estimation for Extreme Value Distribution of Nonlinear Roll Motion of Ship by RTP Method
Authors: Matsui Sadaoki 
Published: August 2024

Abstract
In a previous study, the author proposed a new RAO-based Translation Process (RTP) method for simple estimation of extreme value distribution (EVD) of narrowband nonlinear responses, and the method can estimate the EVD of wave-induced hull girder sectional forces (including body nonlinearity) with sufficient accuracy.
This paper confirms the applicability of the RTP method to a nonlinear roll motion of ships with nonlinear damping. The RTP method transforms a linear response into a nonlinear response based on the wave height-dependent RAO, and it is important to determine (A) what is considered as a linear response and (B) how to determine the correspondence between a linear and a nonlinear response. Regarding the former (A), if the response at small wave height is regarded as a linear response as in the case of wave loads, the linear response may be overestimated because there can be cases where the linear damping force is close to zero. Therefore, in this paper, the equivalent linearized response of the roll motion in irregular waves is considered as the linear response. For the latter (B), the linear-nonlinear relationship was determined based on the peaks of wave height-dependent RAO in the previous study, but it was found that applying this to the roll motion overestimates the nonlinear effect too strongly. Therefore, the author newly proposes a method to determine the linear-nonlinear relationship based on the standard deviation of the wave height-dependent response spectrum. This method was confirmed to be in good agreement with the time domain simulation results for both high and low damping cases, and for both blunt and sharp exciting moment spectrum cases.
Engineering Critical Assessment for Alternative Materials to IGC Code for LCO2 Carriers Type-C Tanks
Authors: Conti Fabien , Aubert Jean-Michel 
Published: August 2024

Abstract
With the developing market of Carbon Capture, Utilisation and Storage (CCUS), large volumes of CO2 need to be transported over large distances. To this end, a cost-effective solution is to consider the maritime transportation of liquefied CO2 (LCO2). Within the LCO2 carriers, the LCO2 can be contained in large diameter type-C tanks under high pressure / low temperature conditions, typically 19bara at −30°C but with now considering alternates with lower pressures (10bara @−50°C). The consideration of such pressures together with the intended tank diameter leads to the use of high strength steel grades, which are not covered by the International Maritime Organization regulations (IGC Code) governing the design of type-C tanks in liquefied gas carriers. Furthermore, the high strength steel grades intended for this application are known to exhibit a ductile to brittle transition at moderately low temperature, contrary to the materials usually used for transport of liquefied gases which can exhibit a ductile behaviour at very low temperatures. Therefore, in order to quantify the toughness requirements of these high strength steel grades for application on type-C tanks on LCO2 carriers, engineering critical assessment (ECA) have been carried out taking into account various design parameters such as the design pressure, the plate thickness or the stress relief method. In order to allow a continuity with the IGC Code requirements and maintain its inherent safety level, the IGC Code building assumptions were kept whenever possible and complemented otherwise with guidance from BS7910 standard. The analyses allowed defining minimum required CTOD toughness levels and provide useful guidance for steel manufacturers and construction yards for the material selection, the welding procedures and associated NonDestructive Testing procedures.
Numerical Investigation on the Cavitation Evolution and Trajectory Behaviors of High-Speed Oblique Water Entry of Projectiles
Authors: Chang Xing , Xin Jianjian , Chen Weimin 
Published: August 2024

Abstract
The high-speed water entry is of great significance in the development of the cross-media equipment. In this paper, the high-speed oblique water entry of a conical projectile is numerically investigated with particular emphasis on the local fluid field and trajectory behaviors. The numerical model is based on the Reynolds average Navier-Stokes (RANS) method with the Volume of Fluid (VOF) approach for capturing complicated multiphase flow characteristics. The present method is validated against the published experimental data by simulating a case of high-speed oblique water entry. The highspeed oblique water entry of the conical projectile under different impact velocities are investigated. The comprehensive process of the water entry, including the initial impact, formation, development, contraction, closure and collapse of the open cavity, have been reproduced. The flow evolution process of the high-speed water entry, which involves the cavity shape and the cavitation evolution, is analyzed comprehensively. Furthermore, the variation trends of the impulsive load, the projectile attitude and the trajectory stability are examined. The study is expected to enhance the understanding of the cavitation evolution, and is helpful for the design of the cross-media equipment.
Wave Loads on a Hollow Circular Cylinder in Open and Icy Waters
Authors: Li Hongtao , Gedikli Ersegun Deniz , Cheng Zhengshun , Sawamura Junji , Lubbad Raed 
Published: August 2024

Abstract
Arctic offshore structures are subject to combined wave-ice actions. However, the underlying mechanisms governing the interaction between waves ice and these structures remain inadequately understood. Performing well-controlled laboratory experiments is a fundamental approach to acquiring insights into such complicated physical processes.
This paper builds on analyzing the laboratory data that were obtained from the HYDRALAB+ Transnational Access project: Loads on Structure and Waves in Ice (LS-WICE), and studies the inline wave forces on a model-scale, stationary, vertical, semi-submerged, bottomless circular cylindrical shell structure, both with and without the presence of ice. In the experiment, the structure was exposed to unidirectional monochromatic waves with increasing heights at prescribed periods under open-water and ice-infested conditions. In the latter case, the ice field comprised uniformly sized and densely packed rectangular ice floes.
Various data analysis techniques, including Prony, dynamic mode decomposition, fast Fourier transform, Tikhonov regularization-based denoising, and Singular Spectrum Analysis, are applied to obtain a reliable estimate of wave amplitudes and the magnitudes of wave loads.
The experimental results suggest that the wave loads on the hollow cylinder, when surrounded by a fragmented ice cover, decrease by up to 27% in comparison to the ice-free water condition. This reduction results primarily from the attenuation of waves in an ice field.
The Influence of Wave Diffraction on the Motion of a Crew Transfer Vessel Behind a Monopile
Authors: Meyer Jannik , Grotebrune Thilo , Wynants Mareile , Hildebrandt Arndt , Schlurmann Torsten 
Published: August 2024

Abstract
In this experimental study, the incidence of wave diffraction behind monopile foundations and their influence on the motion response of a CTV are investigated. The model tests were conducted in the wave flume Schneiderberg (German: Wellenkanal Schneiderberg, WKS) in a scale of 1/40. The water depth was fixed to 40 m (all following quantities are given in prototype scale). Four sets of tests were conducted: (i) Wave-only tests without vessel or monopile to measure the undisturbed wave, (ii) Vessel-only tests without monopile to measure the reference motion response of the vessel, (iii) monopile-only tests without the vessel to measure the wave field behind the monopile, which will subsequently cause the motion response of the vessel behind the monopile. This is investigated in test set (iv): monopile-vessel tests to measure the motion response of the vessel behind the monopile. Monopiles with different diameters D of 6.4 m, 8 m and 10 m were tested, while the distance between vessel bow and monopile had three fixed values of 10 m, 18 m and 40 m as well. Regular waves with wave periods T between 5 s and 10 s were generated, while the wave height H was set to 1 m, 2 m, and 3 m. The results show that the expected diffraction effects occur behind the monopiles, especially for short period waves and large diameter monopiles, leading to a large diffraction parameter ka. These diffraction effects have a significant influence on the vessel’s motion response. However, further analyses indicate that other hydrodynamic interactions (e.g., vessel’s radiated wave interacts with monopile’s diffracted wave) are important for an accurate prediction of vessel motion during CTV-based maintenance operations. The incorporation of these hydromechanic coupling effects in planning tools as well as real-time systems could lead to an significant increase in technician safety as well as maintenance efficiency.
Validation of a Mooring System With Clump Weights for a Spar Floating Wind Turbine Model Using OpenFAST
Authors: Lopez-Olocco Tomas , González Gutiérrez Leo M. , Thiagarajan Krish 
Published: August 2024

Abstract
This research focuses on analyzing three different mooring systems for a FWT mounted on a spar-buoy platform. Building on an initial realistic two-segment catenary mooring system, we introduce two innovative mooring configurations that incorporate the use of a clump weight at two different locations: one close to the seabed and the other close to the fairlead. The mooring configurations are evaluated under wave-only conditions. To assess these different mooring systems, we conducted 1:47 scale model experiments at the CEHIPAR ocean basin. These experiments are compared with a set of OpenFAST numerical simulations, where MoorDyn is implemented to model the mooring dynamics. The results demonstrate a good agreement of OpenFAST with MoorDyn compared to the experimental data in terms of platform motions, but small differences are found when comparing the mooring tensions. A discussion of the difficulty of scaling the axial stiffness of the line material is presented. With the inclusion of clump weights, the maximum tension in the lines under extreme conditions decreases by around 6% while maximum allowable motion limits remain acceptable. This research contributes significantly to the estimation of the change in FWT sea-keeping performance when these devices are attached to mooring lines.
Embracing Uncertainties: Stochastic Decision-Making in Subsea Pipeline Decommissioning
Authors: Da Silva Távora Giselle , Durange De Carvalho Infante Carlos Eduardo , Ribeiro Nicolosi Eduardo , Violante Ferreira Claudio , Lourenço de Souza Marcelo Igor , Caprace Jean-David 
Published: August 2024

Abstract
As Brazil’s offshore fields age, the need for decommissioning subsea structures is intensifying. While the importance of decommissioning is well understood, the current literature lacks a detailed stochastic approach for the decommissioning of subsea pipelines. This paper fills the gap by presenting a stochastic multi-criteria decision analysis (MCDA) to aid in determining the most appropriate decommissioning option. The method includes a way to handle data variability and incorporates decision-makers’ preferences using MCDA techniques. Through a case study of a rigid pipeline in Brazil’s Cação field, various decommissioning strategies are evaluated against criteria like safety, social, environmental impact, and cost. The study considers various decommissioning alternatives, including leaving the pipeline in place, rock deposition at the pipeline ends, total removal by cutting and lifting sections, and complete removal by reverse reel lay. The study, using Monte Carlo simulations to account for data uncertainties, concludes that leaving the pipeline in place is the preferable choice. This research provides a comprehensive tool for transparent decommissioning decision making in the face of uncertainties, demonstrating its effectiveness in practical scenarios.