bluuebunny/crossref_metadata_2025_split huggingface dataset:
Petro-AIMS: Implementation of Muhlbauer and El Reedy Method for Integrated Subsea Pipeline and Offshore Platform Integrity Management System
Authors: Pravi Maulidiyah , Putra Bakti Farid , Surjadi Frederick Gavin 
Published: August 2024

Abstract
This study investigates the implementation of combining two risk assessment methods that was developed for two distinct types of assets: the Muhlbauer and El Reedy techniques. The Muhlbauer method was developed for pipeline assets, while the El Reedy method was developed for offshore jacket platform assets. Even though they were developed for different type of assets, both Muhlbauer and El Reedy method uses the same straight-forward semi-quantitative risk assessment framework. The implementation of combining the two method is done within a web-based asset integrity management system: Petro-AIMS environment. To demonstrate a real-world case application of the proposed method, the data from four offshore platforms that are connected to ∼70 km offshore subsea pipeline is investigated. By implementing the same Likelihood of Failure (LoF) and Consequence of Failure (CoF) assessment framework for two different asset type, it is shown that Petro-AIMS is projected to be a practical and effective tool to perform asset integrity management function.
Optimization for Buoyancy Modules Attachment on Riser System for the Production of Polymetallic Nodules
Authors: Yamamoto Marcio , Yamamoto Joji , Masanobu Sotaro 
Published: August 2024

Abstract
The exploitation of polymetallic nodules will require the use of riser systems longer than 4,000 m. The main issue of such riser systems is that the effective tension increases linearly with length and overcomes the riser material’s yield strength at its top portion. Thus, buoys must be attached along the riser to reduce this effective tension. In this article, we apply a classic Genetic Algorithm to optimize the number and position of these buoys. The algorithm was set to minimize the failure criterion defined in a standard of riser pipes. This failure criterion considers the effective tension and bending moment. The evaluation function was calculated using only the static result of the riser simulation. However, the Genetic Algorithm minimized the failure criterion by reducing the riser’s effective tension with attached buoys. The dynamic simulation results show that this reduced effective tension raised other issues, such as large amplitudes of the effective tension and bending moment; even axial compression was observed. A large effective tension variation may result in the Mathieu Instability. The large bending moment variation may result in cumulative fatigue damage. At the same time, axial compression may cause the riser to buckle.
A Study on Route and Fuel Oil Consumption of Ships Considering Change of Weather Derived From Climate Change
Authors: Sogihara Naoto , Tsujimoto Masaru 
Published: August 2024

Abstract
Climate change brings significant impacts on various industrial sectors. In shipping sector, it is expected in future that weather condition such as winds and waves at sea will be different from current one. This makes significant influence on ships in service. As a ship navigates in winds and waves, the fuel oil consumption changes by the encounter weather condition. Accordingly, even though the ship route is not changed, the amount of the fuel oil consumption in future is different from the current one due to the effect of the climate change. Besides, an oceangoing ship navigates on an optimized route based on the weather routing system, generally. Therefore, in future the optimized route will be changed, which is affected on the climate change.
At Intergovernmental Panel on Climate Change (IPCC), Representative Concentration Pathways (RCP) scenarios are indicated in the fifth assessment report. In the report four concentration scenarios of greenhouse gases (GHG) are used for the prediction of the climate change. There are some investigations on weather condition in future based on RCP scenarios.
This paper addresses the climate change impact on the fuel oil consumption of ships in service and focuses on the fuel oil consumption of an oceangoing container ship in North Pacific Ocean. The fuel oil consumption in the great circle route and the optimized route are calculated under the present weather condition and future one based on RCP2.6 and RCP 8.5. Finally, the climate change impact on the fuel oil consumption is discussed.
One-Way Fluid-Structure Interaction of Submerged Floating Tunnel Under Current Action
Authors: Pathak Keshav , Saha Nilanjan 
Published: August 2024

Abstract
The submerged floating tunnel (SFT) is a long tunnel that remains suspended below the water surface at a considerable depth of around 100–150 m and connects to land masses separated by ‘deep’ and vast water bodies. The present study aims to characterize the flow dynamics around an excessive buoyant type SFT with a circular cross-section. In this paper, one-way fluid-structure interaction analysis is carried out to analyze the dynamic behavior of SFT under current action. Computational Fluid Dynamics (CFD) is implemented to perform a 2D numerical simulation of flow around the SFT cross-section. The k-ω SST turbulence model is implemented to capture the turbulence flow around the structure. The hydrodynamic load from the CFD solver is then sequentially transferred as a uniformly distributed transient load to a structural solver to study the dynamic behavior of the SFT tube segment. In structural solver, only a part of the structure separated by mooring lines at two ends (or SFT tube segment) is considered. Here, the structure is modelled as a Euler-Bernoulli’s beam, discretized as line body elements, and supported by linear vertical springs equivalent to mooring lines at two ends. The structural response of the SFT tube segment and the flow pattern around the structure are discussed and validated from the literature.
Self-Righting Characteristic of Autonomous Surface Vehicle Under Intact and Damage Conditions
Authors: Yanyun Yu , Kai Li , Yunlong Wang 
Published: August 2024

Abstract
In this paper, the concept of self-righting characteristic is introduced into stability analysis of Autonomous Surface Vehicles (ASVs) in order to improve their safety in rough sea. Firstly, the requirements of self-righting characteristic are discussed with the extended GZ curve that covers heeling angle range from 0 to 180 degree, based on the boundary-representation (B-Rep) solid floating body. Then an iteration process is proposed to calculate the righting lever at any heeling angle. With the extended GZ curve for different height of Center of Gravity (CG), the stability surface is created, and applied to compute the curve of extreme height of CG, which is the height limit of CG for ASVs if self-righting characteristic is required. Finally, the damage stability of ASVs is discussed, including how to make ASVs unsinkable, how to treat damage tank/room, how to compute floating state and GZ curve with B-Rep model in damage conditions, and how to analysis the self-righting performances of ASVs with the extended GZ curve etc. An ASV with self-righting hull form is taken as example to illustrate the principles and methods proposed in this study.
Full-Scale Measurements of Offshore Monopile Foundations and Numerical Benchmark
Authors: Winkler Kristof , Sastre Jurado Carlos , Stuyts Bruno , Weijtjens Wout , Devriendt Christof 
Published: August 2024

Abstract
In offshore wind, the modelled structural dynamics used in design do not fully describe the reality of build structures. For monopile supported turbines, previous work and other publications show an underestimation of eigenfrequencies. As fatigue and lifetime of a foundation is strongly dependent on using these eigenfrequencies, better models that more accurately predict reality are needed. This paper will present eigenfrequency measurements taken at two monopile foundation locations with a sandy topsoil layer and one with a clay topsoil layer within the same windfarm in the Belgian North Sea. The three datasets span a timeframe of around eight months, during which a rock armor scour protection was installed and the structures consisted of monopile foundations including a transition piece. Analyzing these measured eigenfrequencies we can see correlations with variable sea state, specifically with tidal level and wave height and period. Also the moment of scour protection installation is detectable by a consistent increase in eigenfrequency at all three locations. An integrated finite element model was then constructed using Timoschenko beam elements and lumped mass formulation to model the transition piece capped monopiles. The importance of the soil-structure interaction was studied by benchmarking the measurements against numerical results from API method and API method corrected for large diameter monopiles.
Shear Thinning Fluid for Shallow Fracture Formation
Authors: Al-Rashead Mohammed , Al-Yami Abdullah , Al-Arfaj Mohammad , Ba Hamdan Abdulaziz , Khan Majad , Tahir Muhammad Nawaz 
Published: August 2024

Abstract
Drilling fluids (water based or oil based) are used to drill wells. Water based drilling fluid utilize fresh water, seawater, or brines. Selection of optimum chemicals are critical to maximize well’s productivity and reduces drilling cost without damaging equipment or the surrounding environment. Drilling fluids need to be evaluated prior to drilling to ensure technical and environmental requirements. There is always a strong relation between the performance of wells to the chemicals used in drilling and completion. Different polymers are used to control filtration loss, viscosity and shale stabilization.
The objective of this study is to formulate low temperature water-based fluid that develop thixotropic properties at static conditions. The thixotropic conditions at static conditions is achieved at low temperature, which help in mitigating losses when drilling operations is suspended. Inorganic cross linkers trigger the thixotropic performance at static conditions. Inorganic trivalent metals cross linkers have been used since 1970. Cross linkers such as Cr (III) and Al (III) are used in operations such as fracturing. However, the issue with the inorganic cross linkers is the stability under high temperature (more than 90 °C). Such temperature limitation makes such thixotropic fluids ideal to drill through fractured shallow formation. A different study will address required modification to extend the temperature stability to be used in higher temperature formations.
Standard performance for drilling fluids include: fluids preparation, density and rheological properties, HT/HP filtration, pH measurement, thermal stability and contamination testing. Different types of salts were tested for additional compatibility testing. The resulted formulations have shown outstanding rheology and fluid loss control at low temperature at low-density ranges.
Enhancing Subsea Ball Valve Performance: A Material and Design Approach
Authors: Ahmadli Mehman , Gjersvik Tor Berge Stray , Sangesland Sigbjørn , Reynes Christian 
Published: August 2024

Abstract
Subsea field development is an important aspect of offshore oil and gas operations. One of the key components in the production system is the subsea actuated valves, installed on Christmas trees and manifolds to control the produced fluid flow from the well to the manifold, and then to onshore facilities or vessels. With the shift towards All Electric Control Systems (AES) in subsea operations, ball type subsea valves could be seen as a better fit for electric actuation since they operate with rotational movement, which aligns well with electric actuation mechanisms, eliminating the need to convert rotational movement to axial movement as in rising stem gate type valves. However, with the current use of tungsten carbide (WC) based coatings on the contact surfaces and sealings, the friction forces, and consequently the required power for actuation, are quite high. This leads to an extended valve opening duration which exposes the internal parts, especially the seals, to solid particles in the fluid. This results in a high wear and damage rate of the valve components over time and eventually the risk of sealing failure.
Initial lab tests from ongoing research activity on enhancing the material and coatings of the contact surfaces have shown a promising coefficient of friction of 0.08. To quantify the possible force and power reduction through material innovation, a 3D model of the 12-inch subsea ball valve is created, and the model includes different variations of the valve designs depending on the seat type. The models are exposed to different pressurizing scenarios and the maximum torque values are determined through finite element analysis. Considering the safety margins, the results show that with the material enhancement the design torque is expected to be reduced by around 25–35% depending on the valve design. This optimization contributes to the transition to AES in subsea operations by addressing the challenges resulted by high power requirements of subsea ball valves.
A Critical Review of the Correlations Used for Predicting the Onset of the Transition Flow Regime in Pipe Flow of Yield Stress Fluids
Authors: Abou-Kassem A. J. , Jing S. , Ghaemi S. , Kuru E. 
Published: August 2024

Abstract
In this paper, we present a critical review of the models used for predicting onset of the transition flow regime in pipe flow of yield stress fluids. Using the experimental data obtained by the Particle Image Velocimetry (PIV) technique, we developed a new methodology to identify the beginning of the transition flow regime in pipe flow of yield stress fluids. The new method was then used to evaluate the accuracy of the existing transition flow regime model predictions. The proposed approach relies on the boundary layer theory to classify flow into laminar and turbulent. The boundary layer theory enables microscopic characterization of the flow transition that translates into a more in-depth fundamental understanding of the transition phenomena. The corresponding literature, experimental validation, and proof of the concept are presented. We investigated 36 possible permutations of Reynolds number (Re) and critical Reynolds number (Recrit.) definitions (i.e., six Re definitions combined with six critical Re definitions), and in none of these cases, the onset of the transition regime was accurately and consistently predicted. It was noted that the percentage difference between the maximum and minimum values of Re, for the same flow rate and fluid properties, ranged between 27% to 58%, based on fluid properties and flow rate combination, mainly because of the subjectivity of the Re definitions. In order to ensure an accurate prediction of the transition zone, test fluids were designed to have a wide range of generalized Reynolds numbers (i.e., 20 to 9000, as defined by the API-RP:13D) within the physical capacity of the experimental facility (i.e. for a given pipe diameter, maximum pressure capacity of the flow loop and maximum available pump flow rate). The yield stress of the test fluids varied from 0.10 to 0.95 Pa (determined by using the nonlinear curve fitting technique recommended by the API RP:13-D). Results indicated that most of the current transition criteria for the pipe flow of yield power law (YPL) fluids have low accuracy and lack of consistency to predict the onset of the actual transition regime as compared to the data measured by using the PIV technique. This was regardless of the Reynolds number definition used. The proposed PIV measurement-based criterion provides an objective measure that can be used to develop more accurate future transition models or improve the accuracy of existing transition criteria.
Truncation Analysis of Mooring System and Physical Model Test Validation
Authors: Li Ying , Xie Dongxu 
Published: August 2024

Abstract
For a newly designed platform, performing experiments to investigate its motion performances is of significant importance. However, due to the dimension limitation of wave basins, mooring systems in deep waters cannot be modeled in the wave basin with a reasonable model scale. To overcome this limitation, hybrid model tests are carried out with truncated mooring systems. Truncation designs for mooring system are generally based on optimization algorithms as they can improve the accuracy of truncation. An effective dynamic truncation method based on golden-sine dynamic marine predator algorithm (GDMPA) is proposed in this work. A truncated design for the mooring system was conducted on a conceptual semi-submersible platform located in the South China Sea at a water depth of 1500 m, and experiments were carried out according to the truncated mooring system. The results are compared with those obtained from the truncated design based on the NSGA-II. It is found that the proposed method based on GDMPA is accurate and robust.
Hydroelastic Responses of Submersible Seaweed Cultivation Platforms With Single-Point Mooring Systems
Authors: Nguyen H. P. , Wang C. M. , von Herzen B. , Huang C. 
Published: August 2024

Abstract
This paper presents simulated and realized designs for a submersible seaweed platform capable of deep cycling to water depths beyond 100 meters. The platform is composed of a bundle of two ring structures made of high-density polyethylene (HDPE) pipes filled with seawater to support seaweed grow-out lines. The platform is kept in position by a single-point mooring system. Winches attached to supporting buoys are used to lower weights that help lower the HDPE ring structure to the desired water depth. The platforms responses under wave action in floating and submerged states are investigated by using the software AquaSim. The numerical results show that the deformed shapes of the simulated seaweed platform are similar to those of physical seaweed platform trialed in Cebu waters in the Philippines by the Climate Foundation. The numerical analysis also indicates that at least three lowering lines held by supporting buoys are needed to prevent excessive deformation and stress concentrations in the platform.
Engineering the Best Storm in a Teacup – Bespoke Metocean Criteria Improve STABLEpipe Outcomes for Offshore Wind Array and Export Cables
Authors: Oliver Isla , Thwaites Jack , Williams Benjamin , Pistani Fabrizio , McGrath Nicholas , Griffiths Terry , Brand Folkert 
Published: August 2024

Abstract
It has been found that for many offshore windfarm projects the STABLEpipe design methodology offers substantial benefits to demonstrating enhanced cable stability compared to conventional methods inherited from the oil and gas industry. It has also been shown that the behavior of subsea pipelines and cables can be quite sensitive to the local ambient and storm ramp-up conditions. On a number of recent offshore windfarm projects, Aurora Offshore Engineering has had the opportunity to develop a bespoke set of ambient and storm metocean design criteria through reanalysis of the project metocean hindcast dataset. This paper undertakes a comparative analysis of the outcomes of the STABLEpipe analysis with both bespoke and DNV-generic metocean timeseries in order to investigate the relative impact of these different approaches on cable stability outcomes.
Computational Performance of IB-LBM Based VIV Simulation Using Python With JAX
Authors: Zhu Haiming , Du Zunfeng , Yang Yuan , Han Muxuan 
Published: August 2024

Abstract
Vortex-induced vibration (VIV) of offshore cylindrical structures is a complex fluid-structure interaction (FSI) phenomenon that needs to be carefully considered in the design of subsea pipelines and risers. Computational fluid dynamics (CFD) methods have been recognized as useful tools for investigating VIV. However, the extensive computational time remains a major barrier to practical applications. This paper presents an ongoing effort to develop an efficient vortex-induced vibration (VIV) simulation model based on the immersed boundary lattice Boltzmann method (IB-LBM). We implemented the method in Python with the JAX framework, which offers a user-friendly interface similar to NumPy while delivering performance comparable to low-level programming languages, especially on GPU platforms. The current defects are discussed. Particularly, we highlight the computational inefficiencies associated with the immersed boundary method. The confined immersed boundary approach is proposed to mitigate this issue, which is found to be effective in reducing the time cost by about 25%.
The Influence of Structural Stiffness and Ice Shape on Impact Loads in Ice-Structure Interaction Experiments
Authors: Müller Franciska , von Bock und Polach Franz , Ehlers Sören 
Published: August 2024

Abstract
Ships that are navigating in waters with ice occurrence are prone to the risk of damage due to ice impact. For assessing the safety of ships it is crucial to predict these loads accurately. Ship hulls have varying structural stiffness due to differences in structural design. The stiffness influences the deformation of the structure during ice impact, which in turn affects both the failure behavior of the ice and the loads experienced by the structure. The aim of this study is to understand how ice responds to variations in structural stiffness in an impact scenario and how the structure is affected by impacting with different ice shapes as well as the interplay of both. Research on this topic is very limited, therefore we seek to address this knowledge gap. This paper presents controlled drop tower experiments with freshwater granular ice of varying shapes impacting structures with different levels of stiffness. Drawing upon prior experience,five different ice shapes were investigated: dome, 10° cone, 30° cone, 30° truncated cone and cylinder. Each of these ice shapes impacted both a quasi-rigid plate and a 3 mm steel plate.The 3 mm plate underwent plastic deformation and was measured before and after the ice impact. The data analysis showcased a significant reliance of the peak load on both the structural stiffness and the shape of the impacting ice. Additionally, the analysis highlighted the considerable impact of ice shape on the magnitude of the maximum plastic deformation in experiments involving ice specimens colliding with the 3 mm plates. Among the ice shapes investigated, the dome-shaped and truncated cone specimens stand out, producing the most pronounced plastic deformation in the plate. The results of this study contribute to the development of predictive numerical models for ice impacts on structures by providing a robust set of validation data.