bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy Harvesting From Multiple Responses of an Elastically Mounted D-Section Prism
Authors: Chen Weilin , Li Yuzhu 
Published: September 2023

Abstract
Extracting mechanical energy from flow-induced vibration (FIV) of cylindrical structures has become a critical research subject. In this paper, we numerically investigate the FIV of a D-section prism with various angles of attack (α) and look into energy harness from the identified multiple FIV responses by using immersed boundary method (IBM). We found that as α increases, six distinct responses appear. At α = 0°–40°, typical vortex-induced vibration (VIV) occurs where the amplitude first increases and then decreases with reduced velocity, showing similar behaviour to that of VIV of a circular cylinder. At α = 50°–60°, the vibration amplitude becomes larger, with a third branch observed. At α = 70° and 165°–180°, galloping response dominates where the amplitude generally increases with increasing reduced velocity. At α = 80°, a combined VIV and galloping response occurs. At α = 90°–145°, a narrowed VIV is observed where large-amplitude vibration exists in a narrowed reduced velocity range. At α = 155°–160°, the response behaves like a transition from narrowed VIV to galloping. Examinations of the energy harness from these identified responses indicate that in the VIV, energy extraction, including harness power (Ph) and efficiency (ηh), shows a strong dependence on the amplitude, while in the galloping, its dependence on the amplitude becomes significantly weak.
Proposal for How to Assess the Load Reduction Efficiency of Wellhead Load Relief Systems
Authors: Sætre Stian , Muff Anthony , Hørte Torfinn , Macke Michael , Osen Per , Reinås Lorents 
Published: September 2023

Abstract
Managing the risk of subsea wellhead fatigue failure has been a concern in the offshore Oil & Gas industry in the last decade. Considerable efforts have been spent towards understanding the risk picture through improving underlying analysis methodology described in recommended practices such as DNV-RP-E104.
For wells where the likelihood and consequence of a fatigue failure is viewed as unacceptably high, it may be desirable to reduce the fatigue damage for upcoming operations. This may be achieved by reducing the loads from the MODU and drilling riser to the wellhead, by using a wellhead load relief (WLR) system to reduce BOP motions.
In addition to reducing fatigue damage, WLR systems can also be designed to reduce possible accidental loading on the subsea wellhead.
The design concept of a WLR system is to transfer a major part of the riser loads into subsea facility structures and seabed, thereby reducing the residual loads into the wellhead system.
Understanding which parameters that are of importance to the efficiency of the WLR system is of essence when designing and choosing compensating measures for reducing fatigue damage.
This paper presents how to calculate the wellhead load reduction efficiency and provide guidance on properties that are of importance for the efficiency for different wellhead load relief concepts. Further, the paper will illustrate that a WLR system of high stiffness (relative to the well/BOP stiffness) will achieve a high wellhead load reduction, while a softer system results in a lower load reduction. Conversely, the load reduction for a given WLR system is less for a stiff well than for a soft well. Thus, the performance of a WLR system is impacted by relative stiffness problem and not one of stress or forces.
A Physics-Informed Neural Operator for the Simulation of Surface Waves
Authors: Sproesser Mathias Marlon , Deberaldini Netto Caio Fabricio , Marino Moreno Felipe , Fialho Coelho Jefferson , Palmiro de Freitas Lucas , Rodrigues de Barros Marcel , Cardozo de Mello Pedro , Dottori Marcelo , Gagliardi Cozman Fábio , Reali Costa Anna Helena , Costa Nogueira Junior Alberto , Satoshi Gomi Edson , Aoun Tannuri Eduardo 
Published: September 2023

Abstract
We develop and implement a Neural Operator (NOp) to predict the evolution of waves on the surface of water. The NOp uses a Graph Neural Network (GNN) to connect randomly sampled points on the water surface and exchange information between them to make the prediction. Our main contribution is adding physical knowledge to the implementation, which allows the model to be to be more general and able to be used in domains of different geometries with no retraining. Our implementation also takes advantage of the fact that the governing equations are independent of rotation and translation to make training easier. In this work, the model is trained with data from a single domain with fixed dimensions and evaluated in domains of different dimensions with little impact to performance. We believe this technique could be extended to more complex problems, such as simulating water currents in environments with more complicated geometries. It may also be possible to use encoding models that are aware of temporal evolution to predict a full time series instead of just a snapshot.
Numerical Simulation of a Moored Wave-Buoy in Waves and Current by Smoothed Particle Hydrodynamics
Authors: Capasso Salvatore , Tagliafierro Bonaventura , González-Ávalos Raúl , Martínez-Estévez Iván , Domínguez José Manuel , Altomare Corrado , Crespo Alejandro J. C. , Viccione Giacomo 
Published: September 2023

Abstract
The behavior, safety and survivability of offshore moored systems is determined by the environmental conditions, which, along with the wave characteristics, usually include the presence of currents. Their effect modifies the wave pattern and the overall fluid behavior, and may cause inaccuracies in the estimated sea state parameters, which would eventually jeopardize the design of offshore structures. The present work provides the validation of the interaction of a moored floating sphere with the joint action of waves and current by means of the Smoothed Particle Hydrodynamics (SPH) method. An experimental campaign is carried out in a combined wave-current test tank to assess the dynamic behavior of the moored spherical buoy; the experimental data are eventually used to validate a newly developed wave-current flume in the SPH-based solver DualSPHysics. For this purpose, open boundary conditions are implemented to reproduce the fluid flow perceived by the buoy: third order wave-current theoretical flow velocity field and free surface are derived from Stokes wave theory and imposed at the inlet boundary. Thanks to the coupling with MoorDyn+, which solves the mechanics of anchoring systems, DualSPHysics is able to capture the flow-induced moored buoy motion. The results of this preliminary investigation show the feasibility of this approach for simulating moored structure subject to the joint action of waves and current. A useful and practical application for the numerical framework here developed is the high-fidelity simulation of Wave Energy Converters (WECs), for which the action of current could play a significant role in term of loads, motions and power output.
Effect of Polymer Latex and Cement Density in Wellbore Integrity
Authors: Al-Yami Abdullah S. , Al-Qahtani Hussam , Jaber Nizar , Khan Majad , Wagle Vikrant 
Published: September 2023

Abstract
Due to pressure and temperature changes during the life of the well (from drilling to production); globally many Casing-Casing Annular (CCA) leaks could be observed in the annuli between surface and intermediate casings. A new approach to well cementing had to be developed, and advanced cement technologies considered, taking into account both short- and long-term design parameters.
To assess the effect of pressure and temperature cycling on the long-term well integrity, intensive lab work was done to design cement polymer latex formulations at different densities to improve wellbore integrity.
Experimental work in this study contained short term testing and long-term testing. The short-term testing included thickening time and rheology. The long-term testing included curing for 30 days and mechanical properties measurements. Analytical techniques, such as nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared analysis (FTIR), differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA), were used to help with understanding the structures and physical properties of the latex and its interaction with cement matrix.
Conventional cements had values of static Young’s Modulus range between 3 and 3.5 million psi which indicated that the cement was too rigid to resist any type of pressure or temperature cycling. Adding polymer latex improved wellbore integrity by reducing Young’s Modulus. Reducing density resulted in reducing Young’s Modulus values. Combination of low densities and polymer latex should be investigated for future cementing for potential improved wellbore integrity.
Analytical Optimization Approach for Fatigue Analysis of Flexible Pipes Tensile Armors Inside End Fittings
Authors: Miyazaki Marcelo Noboro Ralim , da Silva Vinicius Ribeiro Machado , de Sousa José Renato Mendes , Ellwanger Gilberto Bruno 
Published: September 2023

Abstract
The assembly process makes flexible pipes susceptible to fatigue within the end fitting (EF). Notably, the tensile armors are folded and unfolded during this procedure to install the pipe’s inner sealing ring. This process induces a high level of plasticization at the tensile armors, which impacts their fatigue performance. Hence, initially, this work summarizes an analytical approach to assess the stress-strain loop in the tensile armors due to the assembling of the EF, the factory acceptance test (FAT) of the pipe, and its operation. Relying on this approach and employing optimization techniques, different design scenarios with distinct boundaries and criteria may be considered, leading to an optimized EF. A case study based on a 6” production riser in catenary configuration shows the different impacts of each variable in output (utilization factors, fatigue life, and EF cost).
Critical Review of the Literature on Curing Losses and Long-Term Shale Inhibition
Authors: Al-Yami Abdullah S. , Tahir Muhammad , Khan Majad , Wagle Vikrant 
Published: September 2023

Abstract
Lost circulation is one of the prevalent issues in drilling operations. It holds a negative impact on the oil and gas industry as it is a major source of non-productive time (NPT). Moreover, the process of elimination/control is timely and costly. Lost circulation is the loss of drilling fluids to geological formations rather than circulating back to the surface through the annulus. Lost circulation can be categorized based on the volume of fluid being lost to seepage, moderate, severe, or complete loss, and it occurs in the following types of formations: unconsolidated/highly permeable, induced or naturally-fractured, and vugular formations.
The consequences of lost circulation include, but are not limited to, well control incidents, damage of formation, abysmal zonal isolation, and stuck pipe. Therefore, as the vitality of the well affects the quality of both drilling and production, curing lost circulation is essential.
As the topic of lost circulation holds global significance in the oil and gas industry, huge amount of money is allocated to the research and development of solutions to the issue. Many researchers publish papers addressing different and innovative solutions to the ongoing challenge. Long term shale inhibition challenge will be detailed in the case of total losses. This paper will also show some experimental setup to test long term inhibition in the case of total losses.
Analysis of Offshore Helidecks Turbulence and Hot Gas Plumes – A Systematic Approach
Authors: e Silva Daniel Fonseca de Carvalho , Oliveira Allan Carre de , Chads Carlos Eduardo Holmes , Ferreira Marcos Donato Auler da Silva , Liang Denis Alvin , Dolinsky Mauro Cresta de Barros 
Published: September 2023

Abstract
The air flow surrounding offshore helidecks is subjected to many perturbations and obstacles that may represent additional risks to helicopter operations. There are some standards and recommendations for offshore helidecks that establish some thresholds in terms of turbulence and temperature levels that are acceptable for helideck location during early stages of offshore platforms design (e.g.: CAP437 and NORSOK C-004). Nowadays it is usual to perform such evaluations by using Computational Fluid Dynamics (CFD) techniques. Although the hot gas plume evaluation through simulations is done by the temperature field evaluation directly, the turbulence parameter suggested by the standards is not straightforward to obtain from traditional turbulence modelling approaches adopted in CFD. As already discussed in previous publications, the turbulence criteria can be obtained as a function of the turbulent kinetic energy, which is available in traditional RANS (Reynolds Average Navier Stokes) models. This paper illustrates a systematic approach of turbulence and hot gas plume evaluation around offshore helidecks using CFD. The simulations were performed using real case studies for three different offshore unit concepts, namely a semi-submersible, a spread moored and turret moored FPSO (Floating, Production Storage and Offloading). The results are interpreted in terms of the expected risk levels for each key variables threshold. The temperature evaluation method is based on NORSOK C-004 Temperature Gradient Matrix (TGM) and for turbulence, this paper presents a similar and novel approach, called Turbulence Kinetic Energy Gradient Matrix (KGM) according to the standard deviation of vertical velocity levels cited in CAP-437.
Dynamic Small-Scale Riser Model Experiments: A Physics-Based Algorithm to Recover Lost Measurements From Optical Tracking Systems
Authors: Vernizzi Guilherme J. , Schwenck Franco Maciel Vitor , Defensor Filho Wagner A. , Orsino Renato M. M. , Franzini Guilherme R. , Pesce Celso P. 
Published: September 2023

Abstract
While data acquisition to obtain structural displacement fields is traditionally made with the use of strain gauges and accelerometers, recent focus has been put on the use of optical tracking systems for this purpose. Amongst the advantages of this approach, the lack of interference with the investigated structure and the direct measurement of the displacements can be mentioned. However, in recent experimental efforts in which this approach was taken, two types of issues were observed, namely the presence of spurious measurements or the temporary loss of tracking for some targets. The present work focuses on a novel methodology aiming at pre-processing the raw data acquired using optical tracking systems, based on well known mathematical tools. Using a physics-based algorithm, the effects of spurious measurements is diminished and the missing data is adequately interpolated, thus generating a dataset which is much more adequate for subsequent analyses. Even in the case in which no issues occur, this dataset enhances the available measurements since it provides a continuous function for the displacement field, rather than a scatter of a limited amount of points. Both experimental and fabricated numerical sets of data are used to evaluate the capabilities of the algorithm. It is shown that the methodology herein presented leads to an enhanced dataset in which the limitations of optical tracking systems have remarkably less effect on subsequent analyses.
Optimized U-OWC Wave Energy Converter in the Mediterranean Sea
Authors: Romolo Alessandra , Arena Felice 
Published: September 2023

Abstract
The REWEC3 (Resonant Wave Energy Converter – realization 3) is a fixed oscillating water column (OWC) wave energy converter (WEC) based on a U-shaped collector (for this reason namely also U-OWC) aimed to be incorporated in breakwaters. The device is composed by a chamber containing a water column in its lower part and an air pocket in its upper part. The air pocket is connected to the atmosphere via a duct hosting a self-rectifying air turbine. In addition, a REWEC3 includes a vertical U-shaped duct for connecting the water column to the open sea. The working principle of the system is quite simple: by the action of the incident waves, the water inside the U-shaped duct is subject to a reciprocating motion, which induces alternately a compression and an expansion of the air pocket. The pressure difference between the air pocket and the atmosphere is used to drive an air turbine coupled to an off-the-shelf electrical generator connected to the grid.
The main feature of the REWEC3 is the possibility of tuning the natural period of the water column in order to match a desired wave period through the size of the U-duct.
This paper aims to provide an optimized configuration of the U-OWC pneumatic chambers in order to maximize the air power available to a possible PTO for the wave energy conversion. For this purpose, two different REWEC3 configurations are analysed: A) with independent cells, that is the REWEC3/3 or U-OWC/3; B) with adjacent connecting cells, that is the REWEC3/2 or U-OWC/2. Finally, a critical analysis of the performances in both configurations will be presented.
FAT Pressure Impact on Residual Stress in Flexible Pipe Pressure Armours
Authors: Sautreuil Dorine , Deheeger Antoine , Wang Howard 
Published: September 2023

Abstract
The manufacturing of flexible pipes involves the spiralling of carbon steel material wires, with high permanent deformation where significant residual stresses could remain in the wire. These residual stresses directly impact the service life of the flexible pipe. By application of hydrostatic internal pressure during the Factory Acceptance Test (FAT), residual stresses can be released. These residual manufacturing stresses and the relaxation due to the FAT shall be considered for an accurate pressure armour service life prediction.
A recent study was conducted on a flexible pipe riser to quantify the reduction of residual stresses due to FAT process on pressure armour wires. The residual stresses have been measured using X-Ray Diffraction (XRD) approach, a non-destructive methodology appropriated for shaped areas, contrary to the Hole Drilling methods. Two samples were manufactured and used for measurements: one sample that had not undergone FAT and another that had undergone FAT. The measured values were then compared to identify the FAT pressure impact on the wire residual stresses.
This paper presents the residual stress measurements and the results analyses. It also discusses the pressure impact on the residual stresses on the flexible pipe pressure armour wires.
Numerical Analysis of the Effect of Multidirectional Load on the Bearing Capacity of Suction Bucket Foundation
Authors: Yan Bin , Zhu Wenxuan , Gao Bin , Ye Guanlin , Tian Yinghui 
Published: September 2023

Abstract
With the development of clean energy, the development of offshore wind and tidal energy is being emphasized. In deeper waters, shared anchored foundations are becoming the preferred form of foundation for future energy development. Multiple floating structures are simultaneously anchored by a single anchor foundation, thereby reducing the number of anchor foundations used and saving construction costs. The anchor and the seabed form a coupled system that needs to withstand various loads, including wind, waves, currents and their combined effects. Under wind and wave loads, a foundation can be loaded in one direction and unloaded in another due to the phase difference of multi-directional loads or failure of one anchor system, which can have a great impact on the normal operation of the foundation. In this paper, a suction bucket foundation is investigated as an anchor of shared anchor foundations. The effect of the magnitude of the loads in two different directions and the angle between them on the load carrying capacity was investigated. The finite element software named DBLEAVES-X with an advanced constitutive model was used in the research. According to the results, when the suction bucket foundation is subjected to multidirectional loading, its bearing capacity decreases, and the decrease is influenced by the angle between two different directional loads, the load level, and the relative density of the soil.
An Improved Total Interpretive Structural Modeling Method for Constructing Indicator Systems in Multi-Criteria Decision-Making Problems: The Case of Ship Design Evaluation and Selection
Authors: Chen Cheng , Zhang Xiangrui , Zhang Pei , Feng Feng , Sun Cong , Zhang Xiuyuan 
Published: September 2023

Abstract
The inherent complexity of large ships makes it challenging to construct appropriate indicator systems for evaluating and selecting optimal ship designs. Knowledge-based expert systems can be reasonable solutions. However, this problem needs more rationality and better operability, especially in complicated multi-criteria decision-making (MCDM) problems with numerous indicators and complex structures. This paper aims to present a universal methodological approach for constructing indicator systems in MCDM problems using an improved total interpretive structural modeling (TISM) method. The classical TISM method is extended under group decision-making settings and interval type-2 fuzzy sets (IT2FS) environment to deal with the uncertainties and variances in expert knowledge. To ensure the rationality and operability of indicator system construction, two novel cardinal and ordinal indices are proposed to quantify the degree of group consensus, and an interactive group consensus improvement algorithm is further developed to assist experts in reviewing their opinions to achieve acceptable group consensus. Finally, a case study of constructing a ship-equipment environmental suitability indicator system is examined to illustrate the feasibility and effectiveness of the proposed method, with the results indicating that the improved TISM method can deal with the uncertainties and variances in expert knowledge, promote rationality and operability in indicator system construction, and can be applied to numerous group decision-making problems.
Monopile-Supported Offshore Wind Turbine Ultimate Limit State Design Format From a Structural Reliability Point’ of View – Impact of Uncertainties in Loads and Strength on the Implied Safety Level
Authors: Amlashi Hadi 
Published: September 2023

Abstract
Offshore wind turbines are complex systems which are subjected to complicated loads and load effects. This will demand comprehensive numerical modelling of the structure for both loads and resistance. Design by direct analysis and first principles of hydrodynamic and aerodynamic loads and their effects on offshore wind turbine structure are hence preferred to limit the uncertainty in modelling and prediction. Therefore, it is important to account for the uncertainties in load effect (responses) and resistance modelling in relation to the current design value. This paper deals with the monopile-supported offshore wind turbine ultimate limit state design format. The effect of model uncertainty in loads and resistance on the safety level are studied. Differences in safety levels due to such uncertainties show that the implied safety level is not properly harmonized. Impact of bias and random uncertainty in calculation of wind and wave nonlinearities and the correlation between nonlinear prediction and statistical predictions of both wave and wind loads on the implied safety level should carefully be accounted for.