bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Non-Linear Finite Element Analysis to Analyze the Effects of Connection Designs on the Ice Strength of a Vessel
Authors: Gosse Joshua , Quinton Bruce , Daley Claude , Kendrick Andrew , Bond James 
Published: September 2023

Abstract
As global temperatures rise, ice clears in the Arctic Ocean and the demand for Canadian Coast Guard presence in the Canadian Arctic increases. The Canadian government intends to acquire two new heavy icebreakers as part of the “Polar Icebreaker Project”. These icebreakers are to be built to IACS Polar Class 2 standards. Some classification societies require fully welded collars to support stiffener penetrations through deeper hull structure in the ice-strengthened region of the ship. This, however, is a labour-intensive, material-heavy, and thus costly way to manufacture these vessels. This study analyzes hull structural response for three alternative penetration support details and compares these with the base case for a fully welded collar. The goal is to determine if there is a more cost-effective and less material-intensive way to implement these penetrations while maintaining the stiffness of a fully welded collar. A three-dimensional model of the port side ice strengthened structure of a Polar Class 2 vessel was investigated. A design ice load pressure patch based on the International Association of Classification Society’s unified rules for polar class was applied to the structure using finite element analysis. Results show that two of the three alternative connection designs gave unsatisfactory performance but that alternative connection designs with less steel and less welding can maintain acceptable structural strength.
Frequency Domain Analysis and Machine Learning Technique in Field Fatigue Monitoring of Flexible Risers
Authors: Yuan Jiabei , Zhu Linfa , Hou Yucheng , Tan Zhimin , Wilson Eric 
Published: September 2023

Abstract
Field fatigue monitoring of flexible risers has been gaining more interests in the offshore industry. Traditionally, monitoring is based on time domain simulation, where real-time loading data (environmental and functional) are collected and converted into time history stress and strain results of the strength components of the pipe and the subsequent accumulative damage. The time domain approach, with real-time input data, does produce more realistic fatigue results but at the cost of time-consuming simulations which may cause a lag between input data (realtime) and the fatigue results (computed).
This paper presents an application of the frequency domain approach in online fatigue monitoring of flexible risers to reduce computational effort. The study is focused on the tensile wire as these layers usually exhibit larger fatigue damage than other layers. The frequency domain method was implemented in fatigue analysis with an Artificial Intelligence (AI) technique, where guided machine learning is used to establish the responses pattern of the tensile armour wire along its configuration. With enough data captured, the field analysis can reduce the calculation to certain locations to speed up the computation and reduce the lag. Fatigue damage accumulation at other locations can be predicted by the trained model.
A Roadmap for Replacing Legacy Assets Using Metal Additive Manufacturing and Rapid Casting: A Case Study From the NCS
Authors: Karlsen Jon Erik , Mudiyanselage Chandima Ratnayake 
Published: September 2023

Abstract
Legacy, obsolete, or undocumented assets are an increasing liability for ageing offshore installations on the Norwegian Continental Shelf (NCS). It has become an untapped resource for suppliers that aim to provide a one-to-one replacement or original component modification by Metal Additive Manufacturing (MAM) and Rapid Casting (RC). Acquiring MAM assets for the Norwegian Energy, Oil & Gas (EO&G) industry with an on-demand solution requires a comprehensive understanding of standardization, manufacturing, and digitalization. However, the overall awareness and integration of the aforementioned areas are diffuse. The study focuses on the literature review, investigating the requirements and challenges of providing the framework for an on-demand solution and developing a roadmap for NCS stakeholders. The roadmap enables users to improve their understanding of the overall on-demand supply chain and the decision-making capabilities that enable using MAM and RC to replace legacy assets on request. This manuscript also demonstrates the criticality level selection for MAM of items proposed based on the committee “F42 on Additive Manufacturing Technologies” and load-bearing components in aviation. The roadmap includes a flow chart indicating the activities governing the manufacturing of legacy assets. The findings in this study are helpful for EO&G stakeholders and practicing engineers in developing internal work processes for providing on-demand spare parts solutions to the EO&G industry on the NCS, where the identified roadmap would replace legacy assets through a reverse engineering process in a digital warehouse environment.
Offset-Free Tracking Control for a Marine Autonomous Surface Ship
Authors: Islam Tanjil , Imtiaz Syed , Ahmed Salim , Islam Mohammad , Zaman Hasanat , Gash Robert 
Published: September 2023

Abstract
The importance of autonomous surface vessels is increasing day by day because of more and more missions and safety concerns. An offset-free control system is essential for a Marine Autonomous Surface Ship (MASS) to follow its desired trajectory. The position, yaw angles, and desired velocity are the main parameters that need to be controlled precisely to keep the ship on course in the presence of environmental disturbances. In this current research, we propose an advanced control system for surface vessels that is versatile and can achieve a broad range of operational objectives while obeying safety constraints. A Nonlinear Model Predictive Control (NMPC) is the heart of our proposed system. The NMPC solves a quadratic optimization problem and dynamically calculates the control actions considering the safety constraints of the vessel. The conventional way of calculating the yaw angle and the line-of-sight guidance method for the same are compared when the trajectory tracking results are simulated in the presence of disturbances to test the performance of the controller. Such controllers are expected to provide substantial benefits by providing less operational cost, enhanced safety, and efficiency.
Preparation of a Synthetic Geo-Polymer Based LCM Utilizing Saudi Arabian Volcanic Ash for a Sustainable Development: Method, Lab Testing and Applications
Authors: Alanqari Khawlah , Al-Yami Abdullah , Wagle Vikrant 
Published: September 2023

Abstract
We successfully developed a novel geo-polymer based LCM to treat moderate to severe losses. Geopolymers can be prepared utilizing waste materials such as fly ash. In Saudi Arabia, we have enough volcanic ash to sustain the development of the geo-polymer based LCM. This novel LCM was prepared by utilizing a Saudi Arabian volcanic ash. The volcanic ash particles were activated with an alkali solution to undergo a geo-polymerization reaction. The geo-polymerization was designed to delay and successfully controlled to gel up and form the target geo-polymer barrier after the fluid goes inside the wellbore. This is very important to avoid an early setting of the fluid. The objective of this paper is to discuss the formulation and preparation of the geopolymer barrier as a lost circulation material. Also, to investigate the effect of both the addition amounts and concentration of the activating solution on the final geopolymer physical properties as well as to detail lab testing.
Saudi Arabian volcanic ash particles were activated by a mixture of NaOH, sodium silicate and water to develop a geopolymer barrier. In this study, we prepared four different activating solutions by varying the alkali concertation and the addition amounts based on the volcanic ash chemical composition. The effect of these variations on the geo-polymerization in terms of setting time and rheological properties of the final geopolymer barrier were investigated. This was done to develop a geo-polymer barrier with a delayed and controlled setting to assure a right placement inside the wellbore. In addition, the chemical conditions were evaluated to simulate a variety of downhole conditions to prove the effectiveness of this novel geo-polymer composition as an LCM to treat moderate to severe losses. The lab testing includes thickening time, rheology, compressive strength and a chemical analysis of the Saudi Arabian volcanic ash. We found that thickening time and rheological properties of the final geo-polymer barrier are strongly affected by the alkali concentration and the addition amounts of the activating solution. This novel geo-polymer barrier can remain in a liquid phase from a few minutes to several hours based on the desired conditions. The final and target geo-polymer barrier will appear and gel as a solid thereby preventing loss circulation.
Manufacturing Method Selection for Mechanical Legacy Assets Aimed at the Norwegian Continental Shelf
Authors: Karlsen Jon Erik , Mudiyanselage Chandima Ratnayake 
Published: September 2023

Abstract
Introducing disruptive manufacturing technologies such as Metal Additive Manufacturing (MAM) and Rapid Casting (RC) for legacy assets to the Norwegian supply chain for energy, oil, and gas is challenging without a track record. Therefore, it becomes a requirement to re-engineer and manufacture parts “just-in-time” (or on-demand) that are currently not produced by the original equipment manufacturers (e.g., offshore facility components made in the 1970s and 1980s, etc.). This study demonstrates the selection of a just-in-time manufacturing method for a critical asset (i.e., a valve body) that needs to be manufactured for the offshore facility Statfjord-A, built in the late 1970s. The technical experts have concluded that MAM and RC are potential methods for critical asset manufacturing. The two benchmarking manufacturing options have been evaluated using the Analytic Hierarchy Process (AHP) to select the most suitable method for the asset. Furthermore, the AHP outlines the options for MAM and RC that involve essential criteria for manufacturing method selection based on feedback from industry experts (i.e., asset owners and suppliers). Expert Choice was used to compile the developed manufacturing method criteria hierarchy and is presented together with a criteria sensitivity analysis. The findings displayed that the criteria for environmental impact must increase by 32.5% relative to the other criteria to make RC and MAM equally selectable. In comparison, the criteria for cost and volume of material must decrease by 46% and 6.8%, respectively, for RC and MAM to be equally competitive. The outcome of the overall AHP analysis reveals that RC (63%) scored higher than MAM (37%).
An Efficient Three-Dimensional CFD-Based Numerical Wave Tank for a Wave Energy Converter in Extreme Irregular Waves
Authors: Wiley Will , Tran Thanh Toan , Boerner Thomas , Weston Collin , Wang Lu 
Published: September 2023

Abstract
A numerical wave tank approach for computational fluid dynamics (CFD) modelling of an extreme irregular seastate is presented. The technique couples a potential flow solution with a CFD solver for more efficient numerical predictions. This method has recently become attractive both for the research community and the industry working with offshore structures. The model is used to determine the response of a submerged pressure differential wave energy converter (WEC) in a fully nonlinear irregular wave condition using the high-fidelity CFD code, STAR-CCM+. Potential flow based numerical models are commonly used to predict motions and performance of wave energy converters. Wave kinematics can deviate from potential flow predictions for extreme wave conditions; the excitation loads on an absorber can also be increasingly influenced by viscous effects, not predicted by potential flow engineering level models. In these extreme conditions, a Reynolds-averaged Navier-Stokes CFD model can better predict motions and loads for a WEC. Long time series with varying random seed numbers can be used to identify singular extreme wave events from a stochastic irregular sea state. This approach simulates a more realistic wave series for a given sea state than a regular wave or a focused wave. However, it is computationally infeasible to run these long time series for three-dimensional (3D) CFD simulations. In this work, two-dimensional (2D) CFD simulations with a long domain allow the full development of an extreme nonlinear wave condition. The results are used to identify extreme events from a 50-year storm condition for the PacWave site off the coast of Oregon. A relatively short time window including this extreme event is then mapped to a 3D simulation using a user defined wave methodology. Convergence studies for domain length, wave forcing lengths, and time before the extreme event were conducted.
Wave-Current Interaction With Floating Objects With Square and Circular Waterplane Areas
Authors: Lamei Azin , Li Shuijin , Hayatdavoodi Masoud , Riggs H. Ronald 
Published: September 2023

Abstract
Floating pontoons of different shapes are used commonly as the base of floating offshore wind turbines, and as wave breakers to mitigate severity of incoming waves. The pontoons are typically attached to catenary mooring lines and often operate in areas subject to large environmental loads, including waves, current and wind. It is of interest to analyse the wave-current interaction with pontoons of various shapes, and assess the effect of the shape of the body, wave-current direction, and the mooring lines on the loads and responses. In this study, attention is confined to wave-current interaction with floating objects with square and circular waterplane areas. A range of wave conditions is considered and the solution is obtained by the Green-function method for small forward speeds within the context of the linear wave diffraction theory. Results include the wave-current-induced forces, and the motion of the body. Both conditions of freely floating and objects attached to catenary mooring lines are considered, subject to various wave-current directions. Computations are carried out in frequency domain and results of the two models are compared with each other. Discussion is provided on the effect of the mooring lines and the wave-current direction on the responses of the objects.
Comparison Study of Shallow Water and Deepwater Mooring Systems for Floating Offshore Wind Turbine
Authors: Kim Hyoungchul , Koo Bonjun , Sablok Anil , Lim Ho-Joon , Laihomäki Tapio 
Published: September 2023

Abstract
The offshore wind industry trend is towards larger wind turbines to lower the Levelized Cost of Energy (LCOE). The water depth plays an important role in Floating Offshore Wind Turbine (FOWT) project viability due to mooring system cost. In the present study, a comparison of shallow water and deep water mooring systems is performed for the offshore US West Coast.
To perform the comparison, two mooring systems for 150m and 1300m water depths are designed for a 15MW semi-submersible type FOWT. For comprehensive mooring system performance comparison, a response-based direct time domain simulation method is applied using MLTSIM-OpenFAST in conjunction with High Performance Computing (HPC). MLTSIM-OpenFAST is a time domain aero-hydro-servo-elastic solver for a FOWT and has been validated through OC3 DeepCwind model tests.
For metocean conditions, 1-year hindcast wind, wave and current data with 3-hour intervals from WAVEWATCH III® hindcast data and HYCOM (Hybrid Coordinate Ocean Model) are used. Based on simulation results, aero-hydro-servo-elastic fully coupled responses of the 15MW FOWT with two different mooring systems are systematically compared. In addition, high-level mooring system cost comparisons are performed. The platform motions other than the platform offset and yaw are similar in both cases along with the Tower Base loads. Similarly, the probability distributions of power generation are similar for both cases. In terms of mooring cost, a deepwater mooring system can be competitive compared to a shallow water mooring system.
A Feasibility Study on Green Energy Production at the Location of Offshore Oil and Gas Platforms in Australia
Authors: Aryai Vahid , Abdussamie Nagi , Abbassi Rouzbeh , Penesis Irene , Wang Chien-Ming , Garaniya Vikram 
Published: September 2023

Abstract
An important aim of the offshore energy sector is to replace oil and gas production with sustainable and environmentally friendly energy production. The public expectations and the international environmental agreements enforced all sectors of the governments to encourage the transition from fossil fuel production to renewable energy production. Green energy production alternatives by transforming/repurposing available offshore oil and gas platforms in Australia is essential for a successful blue economy. This research aims to explore the potential for generating green energy at the location of offshore oil and gas platforms that exist in different oil and gas basins around Australia. To this aim, the locations of seven platforms, one from each basin, are selected as case studies, and the potential energy production by using wind, wave, and solar energy conversion systems in the vicinity of the existing platforms is estimated. Furthermore, the green hydrogen production alternative is investigated in the case of repurposing the existing platforms as a storage, distribution and export multipurpose offshore platform. Finally, discussions on the other requirements for selecting target options for repurposing offshore oil and gas platforms are presented.
Offshore Oil Wells: Indicators for Configuration Selection
Authors: dos Santos Joaquim Rocha , Taverna Martins Pereira de Abreu Danilo , Colombo Danilo , Ramos Martins Marcelo 
Published: September 2023

Abstract
Brazil’s most productive oil fields are found in the pre-salt cluster, located at approximately 7,000 meters, with a water depth of around 2,000 meters. Offshore operations under these conditions represent a major technological challenge. If, on the one hand, the production of these wells is very attractive, generating significant revenue, on the other hand, maintenance costs and the risk of accidents are also high. In order to operate under these conditions, operators must make every effort to operate wells with a reliable integrated set of barriers and high oil and gas production availability. An important phase of the oil well’s life cycle is the design. Several competing configurations are presented during this phase, and the decision-makers (DM) must choose the best option. A decision support software is under development to assist DM in this challenging task. A module of this software is intended to quantitatively assess three aspects: the integrity of the barrier elements; the reliability of production functions; and a financial indicator. This article deals with the financial indicator. The financial indicator is calculated from two sets of variables. The first set is informed by the oil and gas operator, such as the planning price of an oil barrel; the second set is from values calculated from a simulation module that uses the Monte Carlo simulation. To calculate the financial indicator, a System Dynamics model was developed. The article shows the DS model in detail, explores the model, and presents the results of an actual case used for testing, resulting in a difference of 8.9 million dollars between the two configurations. The conclusions comment on the assumption that oil and gas companies give great importance both in safety and operations continuity; also, that the result obtained for a single well may be relevant when considering a large number of wells, which is the case of great oil and gas operators; also, it is commented on the expandability of the model.
State-of-the-Art Methodologies for Upheaval Buckling Design of Flexible Pipes
Authors: Amdal Lars Wist , Pettersen Sune , Skeie Geir , Røneid Sigbjørn , Collberg Leif 
Published: September 2023

Abstract
Upheaval buckling (UHB) of flexible pipes has recently been identified as an area of concern for the Oil and Gas industry in the North Sea. The concern is related to non-conservative design practice and the possibility of pipe leakage. The phenomenon of UHB means that covered pipeline experience buckling in the vertical plane that may lead to exposure of the pipeline, and in worse case, pipe leakage.
Up until now there has been a lack of guidance and requirements that cover UHB design of flexible pipes. For guidance, the industry has been using DNV-RP-F110 ‘Global buckling of submarine pipelines’ to design flexible pipelines even though this document is written for rigid pipelines. Although the basic principles of DNV-RP-F110 should be applicable also to flexibles, the Recommended Practice (RP) does not account for particularities in flexibles pipes that are important to consider, e.g., the difference in bending stiffness between rigid and flexible pipes.
A Joint industry project (JIP) led by DNV was established to provide guidance on the required modifications when applying DNV-RP-F110 for UHB design of flexible pipes. The main deliverable of this work is a guideline. This paper will summarise the work performed in this JIP, thereby providing state-of-the art methodologies for UHB design of flexible pipes.
Energy Storage and Direct Air Carbon Capture Solution for Offshore Sources of Energy
Authors: Hands Graydon , Truong Kevin , Unico Yvan , Ashar Areeb , Al-Saiedy Ali , Shor Roman J. 
Published: September 2023

Abstract
Power intermittency associated with many forms of renewable energy has been a significant challenge to overcome since its increased contribution to our grids. Additionally, the global climate crisis driven by increased greenhouse gasses in the atmosphere has driven innovations into Direct Air Capture (DAC) technology which removes carbon dioxide directly from the air. The present report outlines a theoretical design for an offshore energy storage system which seeks to provide solutions to both of these challenges in a consolidated system.
The proposed system involves a motorized cable system built around an offshore wind turbine. Attached to the cable is a series of air balloons or “gondolas”. During times of excess energy production by the turbine, these gondolas are driven to a depth of 400 meters below the ocean surface. When energy demand increases, gondolas are released back up to the surface wherein a net upwards buoyant force recovers a portion of the energy input. Additionally, at maximum depth, hydrostatic pressure is large enough to condense the carbon dioxide content in the air, and the system is designed to separate and store it.
Iterative analysis indicates a system efficiency of 92.83% with a storage capability of 16.29MWh and a carbon recovery rate of 17.95 kg per cycle. Through cost analysis, the NPV of the system is found to vary dependent on implementation location and governmental incentives for a set payback period, ranging between $1.1 million and $3.1 million across Vancouver, Canada and Oslo, Norway. This technology has the potential to be very competitive with conventional Battery Energy Storage Systems (BESS) and Flywheel Energy Storage Systems (FESS).
In addition to this system design, our team has designed and will construct a prototype for one gondola which is planned to be field tested in the Summer of 2023.