bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of Crack Propagation in Defective X100 Line Pipes
Authors: Xue Lufeng , Paredes Marcelo , Nonn Aida , Wierzbicki Tomasz 
Published: December 2020

Abstract
A comprehensive experimental program is carried out to determine material parameters for fracture initiation and propagation in X100 pipeline steels. The quadratic Hill’48 yield function along with an isotropic hardening are used to describe plastic flow at large deformation and a phenomenological fracture criterion to predict fracture initiation. Fracture mechanics SENT specimens are used to calibrate post-initiation softening parameters necessary for ductile crack propagation in thick components. Once the material model parameters set is complete a final comparison is conducted with ring expansion test on same material.
Fast Riser Installation: A Field Proven, Safe and Efficient Riser Pull-in Technology
Authors: Tian Zhigang (Kevin) , Radanovic Branka , DaSilva Otto , Kirkland Blair , Mediamolle Glenn , Cruz Pete 
Published: December 2020

Abstract
A technical study of an innovative steel catenary riser (SCR) installation technology is presented in this paper. This installation technology maneuvers the hull through ballasting to align its riser porch with the riser, which is philosophically different from conventional riser installation that relies on an array of tugging winches to catch and pull riser into positions of the riser porches. The technology has been applied to the installation of eight SCRs on the Delta House production semi-submersible (second end) and, subsequently, five tieback SCRs (first end). We demonstrate that equipment arrangement, riser adaptor fabrication, and ballasting process remain the same for both first end and second end operations, resulting in a robust solution for riser installation. The technology has been proven safe in operations and efficient in saving installation time and cost.
This paper focuses on the technical aspects of the riser installation technology, from concept development, technical qualification, to numerical simulations. Vessel positioning and riser-hull clearance during all steps of riser pull-in and installation, as well as planning for ballast water transfer required throughout the process, is prepared with an in-house program based on rigid body rotation. Numerical simulations are performed to identify critical stages of the riser pull-in and to examine the clearance from the pull-in wire or the riser to the hull. The dependence of the minimum clearance on a few parameters related to riser installation is determined and discussed. More numerical simulations are performed to assess the vessel motion response and its dynamic effect on riser-hull clearance and to establish environmental limits for riser installation operation. Discussions are provided for potential challenges of the technology when it is applied to different production and export risers in various water depths.
Real-Time Well Monitoring and Engineering Analysis of Drilling Activities: Intelligent Rig State Detection and Prediction With Uncertainty
Authors: Kemajou Vanessa , Samuel Robello 
Published: December 2020

Abstract
Drilling activities are risky and costly, especially when performed offshore. Careful monitoring and real time data analysis are required for safe and efficient operations with minimized down-time. Drilling operations, being fast-paced and not visible, often lead to transient and unforeseen issues. The synchronous assessment and prediction of drilling quality has historically been a challenge. It relies on a prompt collection, analysis and prediction of the multiple sensors data, as well as an immediate comparison to the original drilling plan. Another challenge is achieving real-time well engineering, and automatically and instantaneously providing valuable insights to the engineering and operations teams. A system was successfully developed to tackle these challenges. It is a cloud-based application, made with an event-driven streaming architecture to automatically retrieve real-time drilling data and compare it with planned data. The real-time data is automatically made available to determine the current well operation or rig state, and trigger the subsequent engineering analysis. Next, a forecast model is trained with the engineering calculation outputs and it returns predictions on these outputs while considering their inherent uncertainty. As a result, these predictions enable alerts to be sent when the system detects approaching anomalous conditions. The proposed system is a DecisionSpace® 365 cloud-native application on an open architecture. It is flexible, accessible from anywhere, can be automatically updated for continuous improvement, and can be deployed easily and quickly. It can also be extended to further applications.
Black-Box Modeling of Ship Maneuvering Motion Using System Identification Method Based on BP Neural Network
Authors: He Hong-Wei , Zou Zao-Jian 
Published: December 2020

Abstract
This paper deals with the black-box modeling of 3-DOF nonlinear maneuvering motion of surface ships by using system identification method based on BP neural network. A Mariner Class vessel is taken as the study object. The time series used in training and testing the network is the simulated data of a series of maneuvers, which is obtained by numerically solving the Abkowitz model using fourth-order Runge-Kutta method. A three-layer neural network is built to solve this multivariable regression fitting problem, and only one network model is trained to predict various ship maneuvers. Taking the mean squared error (MSE) as the loss function, the network’s weights are optimized by Levenberg-Marquardt (LM) algorithm effectively. The trained network is evaluated by several simulation tests, and it is shown that the network achieves good prediction ability and can predict the maneuvering motion as long as the control inputs and initial states of the ship motion are known.
Experiments on Fluid Placement in a Confined Pipe: Fluid Mechanics Analysis for Plug and Abandonment Applications
Authors: Akbari Soheil , Taghavi Seyed Mohammad 
Published: December 2020

Abstract
Plug and abandonment (P&A) of oil and gas wells is an essential process to prevent the oil and gas reservoir fluids migration over time and possibly contaminating other formations and also fresh water resources. In order to plug and abandon a well, a high quality cement plug placement is required. One of the most common methods of cement plug placement is the dump bailing method. In this method, a fixed volume of cement is dumped using a bailer on a mechanical plug in the wellbore. The cement slurry occupies the wellbore and also the annular region outside the dump bailer. In the processes of cement slurry placement, an extensive range of Newtonian or non-Newtonian fluids is used to remove the in-situ fluid (drilling fluid or water) in the wellbore. Based on the large number of parameters such as the density and viscosity differences between the fluids, the geometry type (pipe, annulus, etc.), the operation conditions (velocity, geometry inclination, dumping height), various kinds of placement and mixing flows can occur, and different flow regimes (e.g. inertial, viscous) can develop. In this paper, we experimentally study the placement of a heavy fluid to replace an in-situ light fluid in an inclined closed-end pipe (representative of the dump bailing method). The two fluids are Newtonian and miscible, and they have the same viscosity. We investigate the effects of some of the flow parameters such as the dumping height, the pipe inclination, and the inflow velocity of the heavy fluid on the degree of mixing and the placement quality and efficiency. Our results show that the the most efficient displacement happens with the shortest dumping height and at lower inclination from vertical. Also, a high inflow velocity displaces the light fluid promptly with more mixing in comparison with a low inflow rate. The results can help us to develop strategies for improving the dump bailing method in the P&A of the oil and gas wells.
Performance Analysis of a Three-Axis Gyroscope Composite Anti-Rolling Device
Authors: Zhou Yuefa , Li Tao , Liu Zhiyuan , Zheng Kexin 
Published: December 2020

Abstract
In the ocean environment, the ship is prone to motions in six directions of roll, pitch, yaw, sway, surge, and heave under the influence of the waves. It will affect not only the airworthiness of the ship, but also have an adverse impact for the crew and the board’s equipment. In view of this situation, a new type of ship anti-rolling device has been proposed, which is based on the structural characteristics of the Stewart platform with precise adjustment of the position of the load platform and the stability of the gyroscope under the high-speed rotation of the rotor. Firstly, theoretical analysis of the device conducted with theorem of moment of momentum method shows that the device has practical feasibility and effectiveness. Then, a solid model has been established in Creo2.0 software, and the model has been imported into the dynamic analysis software MSC.ADAMS. Finally, using torque as the exciting force to simulate the impact of the wave, the dynamic simulation of the overall model has been analyzed. The simulation results show that such device has good anti-rolling performance under certain waves, indicating that the new anti-rolling device based on the Stewart platform and the three-axis gyroscope has effective reliability and practicability.
Numerical Study on the Resistance and Sinkage of Inland Vessels Passing Through Navigable Tunnel
Authors: Chen Xuehua , Wang Lizheng , Chen Shunhuai , Xiong Aokui 
Published: December 2020

Abstract
While passing through a navigable tunnel, a vessel usually undergoes a steady forward motion at low speed. Due to the limited size of the navigable tunnel, the restricted water conditions of small section-coefficient will have an adverse impact on vessel navigation safety. A bottom suction effect on vessels may occur for the risk of grounding and harming the maneuvering performance. Thus, it is particularly important to reveal the effect of the navigable tunnel scale on the vessel sinkage.
In this paper, a numerical model of the representative 1000-ton vessel of the Wujiang channel under construction is established. Numerical simulations of the vessel are conducted based on RANS equations in deep water, both in fixed condition and free condition (i.e. the trim and sinkage are allowed). And the validity of the method is verified by comparing the calculation results with the experimental ones. Subsequently, for diverse water depths, water widths and vessel speeds, the parameters such as the vessel resistance and sinkage are predicted and compared. The calculation results are analyzed to obtain the trend of vessel motion at different tunnel scales. In addition, the effect of the tunnel scale on vessel navigation performance is also investigated.
Numerical Simulation of Multi-Layer-Liquid Sloshing by Multiphase MPS-GPU Method
Authors: Wen Xiao , Chen Xiang , Wan Decheng 
Published: December 2020

Abstract
In this paper, a new multiphase MPS-GPU method is proposed through the combination of moving particle semi-implicit (MPS) method and Graphics Processing Unit (GPU) acceleration technique. The new method not only inherits the advantage of MPS method in capturing complex interface deformations, but also overcomes the limitations of huge computational cost in three-dimensional MPS simulation. By this method, both the two-layer-liquid and three-layer-liquids sloshing problems are simulated three-dimensionally on the GPU device, in which more than one million of particles are included. In simulations, the sloshing patterns of each liquid layer under different external excitations are accurately captured. From the interface elevations and impacting pressures calculated by present method, it is found that an obvious discrepancy exists between the deformations of free surface and phase interfaces. Then, the results obtained by multiphase MPS-GPU method are compared with experimental data and other numerical results in open literature and a good agreement is achieved, which validates the accuracy and applicability of the present method in three-dimensional simulations of multi-layer-liquid sloshing flows.
Study on the Architecture of a Zero Emission Hydrogen Fuel Cell Vessel Power Generating Unit
Authors: Balestra Lorenzo , Schjølberg Ingrid 
Published: December 2020

Abstract
This study focuses on providing design guidelines for a vessel’s power-plant in the multi-megawatt range, equipped with a hybrid fuel cell and battery system. Background information is provided on the challenges to realizing such a system, spanning from a literature review on studies looking into energy management, to the technical limitations of state-of-the-art fuel cells and batteries. The central part of the work consists of the description of the model used to calculate the size of the hybrid power generating unit, including a case study on a single, real-world scenario. The Plant Analysis Balance with Operational Profile (PABOP) model, developed by the author and presented in the paper, is used to calculate the resources needed to retrofit a vessel operating on fossil fuels with a hybrid zero-emission power-plant. The model aim is to achieve a 1:1 replacement for diesel-electric configurations, both in terms of range and power, using fuel cell and battery power. In the case study, the model is applied to analyze the operational data of a double-ended ferry operating with diesel-electric propulsion. Emphasis is put on the I/O needed and produced by the model, and how this tool can be used by shipyard engineers to estimate the footprint required, the necessary storage capacity, lifetime of components and other parameters. The presented solutions could help manufacturers estimate the economical viability of hydrogen vessels, filling a gap in current maritime fleets where zero-emission systems are gaining increasing importance.
A Stress Magnification Factor for Plates With Welding-Induced Curvatures
Authors: Mancini Federica , Remes Heikki , Romanoff Jani 
Published: December 2020

Abstract
The fatigue strength of thin-walled structures can be reduced significantly by non-linear secondary bending effects resulting from geometrical imperfections such as axial and angular misalignments. The welding-induced distortions can cause a critical increase of the structural hot-spot stress in the vicinity of the weld. Traditionally, the classification society rules for the fatigue strength assessment of welded ship structures suggest an analytical formula for a stress magnification factor km for axial and angular misalignment under axial loading condition. Recently, the well-known analytical solution for the angular misalignment has been extended to account for the curvature effect. The present paper analyses the effect of non-ideal, intermediate boundary conditions between fixed and pinned ends. In this regard, the fixity factors ρ (with 0 ≤ ρ ≤ 1 from ideally pinned to clamped conditions) are introduced in order to model the actual constraint on the rotation close to the ends. Under tension, a non-negligible decrease of the km factor is observed in relation to the reduction of the fixity factor at the welded end, while the fixity factor related to the loaded end has a minor effect on the km factor. Under compression, the reduction of the beam end fixity factors results into lower buckling resistance.
Feasibility Study of Lateral Buckling Using Residual Curvature Method for Deep Water Pipelines
Authors: Bai Qiang , Xu Fengbin , Brunner Mark 
Published: December 2020

Abstract
In recent years the residual curvature (RC) method has been used to provide buckle initiators to control and mitigate the lateral buckling of pipelines for some shallow water projects. With the appropriate planning of the controlled buckles using RC sections, an acceptable design of the pipeline in-place behavior is achieved. However, the RC method has not yet been applied to deep-water pipelines. The twist of RC sections in the sagbend during installation has been observed, and the orientation of as-laid RC section on the seabed is difficult to control in deep-water pipelines. The effects of as-laid RC-section orientation on in-place lateral buckling in deep water are unknown.
The FRIC user subroutine in the Abaqus finite-element software suite has been developed for modelling pipe-soil interactions based on uncoupled axial and lateral soil resistances that are assumed to be independent of vertical pipe penetration after initial embedment into the soil surface. However, the penetration of a twisted RC section can vary dramatically from a normal pipeline on the seabed. The UINTER user subroutine in Abaqus was selected for presenting 3D pipe-soil interactions that incorporate the variations of independent axial and lateral soil resistances as a function of pipe penetration more accurately. UINTER is used in the present study to account for the effects of soil penetration on the lateral buckling performance of a pipeline with RC sections in soft clay.
The analysis results show that the RC section twists in the sagbend area during installation, and the twist angle reaches its maximum value just prior to the RC section touching the seabed. The in-place lateral buckling analysis is carried out after the installation analysis is finished. The analysis results demonstrate the feasibility of applying the RC method as the primary buckle triggering mechanism for deep water pipelines, and it shows how the RC orientation affects the pipeline in-place performance in terms of strength and fatigue damage (only the stress ranges for use in fatigue calculations are shown in the paper).
Nonlinear Dynamic and Bilinear Fatigue Performance of Composite Marine Risers in Deep Offshore Fields
Authors: Khan Rizwan A. , Ahmad Suhail 
Published: December 2020

Abstract
Composite materials have drawn considerable consideration from the offshore business, basically because of their high explicit quality. Notwithstanding weight decrease, composites offer extra advantages, for example, fatigue resistance, damping, and thermal (protection) properties, and high erosion resistance. As a part of design procedure there are requirements of mechanical strength based on criteria referring to failure modes, such as rupture by over loading, fatigue failures, buckling or an unstable fracture. Three dimensional nonlinear assessment of riser is carried out in time domain using ABAQUS/Aqua. The response time histories so obtained are used for the study of fatigue safety assessment of riser. It is based on a bi-linear approach to model fatigue crack growth and incorporates a failure limit to describe the interaction between rupture and plastic failure. Using Monte Carlo Simulation, tests of fatigue reliability and fatigue crack size evolution are obtained. It is observed that bilinear S-N curve and crack growth models leads to higher estimate of fatigue life. Sensitivity behavior pertinent to limit state adopted has been thoroughly examined. These outcomes implicate assessment of components of the marine structures to ensure minimization of the surprises due to wide scatter of the fatigue phenomenon in marine environment.
Influence of Ice Floe Shape and Distribution on Ship Resistance
Authors: Cahay Marc , Fabiano de Lima Gabriel 
Published: December 2020

Abstract
Many ice basin tests have been performed on ships to assess the ice resistance of the hull in an ice floe field. During these tests, many parameters are studied, the most important of them being the transit speed, the thickness and the concentration of ice. Given the cost and the time required to carry out these basin test campaigns, it is imperative to keep the number of tests to the strict minimum, whilst still making it possible to draw conclusions about the sizing of the vessel. Hence, the influence of ice floe shape and their distribution in the field are generally not considered.
A way to achieve sensitivity studies regarding these parameters is to use numerical simulations in addition to a basin test. There are few advanced numerical design tools available in the market, especially those able to cope with any kind of structure geometry and a large variety of ice interaction & failure mechanisms. In 2012 TechnipFMC, Cervval and Bureau Veritas initiated a common development program to offer a new tool for the design of offshore structures interacting with ice combining a variety of models and approaches such as analytical, numerical and empirical. This numerical tool called Ice-MAS (www.ice-mas.com) uses a multi-agent technology and has the possibility to combine, in a common framework, multiple phenomena from various natures and heterogeneous scales (i.e. drag, friction, ice-sheet bending failure, local crushing and rubble stack up).
The study presented in this paper compares the simulation results for different ice floe fields not only in terms of concentration, maximum size of floe and their distribution but also in the way to generate the ice floe and its shape.
An Ontology-Based Approach for Simplified FMU Variable Connections With Automatic Verification of Semantically Correct Configuration
Authors: Nordahl Håvard , Rindarøy Martin , Skjong Stian , Kyllingstad Lars T. , Walther Dirk , Brekke Tore 
Published: December 2020

Abstract
Simulation is increasingly used as an engineering tool in the maritime industry. Currently, there is a particular focus on digital twins, where a supplier of equipment should also supply a simulation model of the equipment. Today, the person configuring the simulator must manually connect all required signals between these models, interpreting the meaning of each signal name to determine which signal can be connected together (e.g., connecting “pressure out” to “pressure in”, while ensuring that their units match). This is a tedious and error-prone process.
In this paper, we present a method for automatically connecting variables of different models while complying with the FMI standard in co-simulations. This also includes a method for unit conversions. The methods for both automatic connections and unit conversions are based on ontologies. The key idea is to build an ontology, based on existing ontologies, which enables structuring model input and output variables into groups and hierarchies, and assign them a defined type. This enables reasoning about connections between models, and simplifies the model connections. The focus in this paper is to present the ontology, how FMI interface signals can be connected to the ontology, and how this can be used to simplify model connections.
Study on 2nd-Order Wave Loads With Forward Speed Through Aranha’s Formula and Neumann-Kelvin Linearization
Authors: Xie Zhitian , Falzarano Jeffery 
Published: December 2020

Abstract
The 2nd-order wave loads consist of difference frequency, sum frequency components and a steady drift component that is also called the mean drift load. The first two components are usually not of interest, because of their small amplitudes compared with the 1st-order wave loads. The remaining mean drift load should be taken into consideration due to its steady effect on floating bodies. In the previous research, the full derivation and expression of the 2nd-order wave loads applied to a floating structure was presented. Moreover, numerically estimated quadratic transfer function was also illustrated with both off-diagonal elements and diagonal elements called the mean drift coefficients. Most research topics in this scenario consider the wave only case. In this paper, the mean drift wave loads applied to a floating structure with forward speed or current velocity has been numerically estimated through Aranha’s formula, a far field method and Neumann-Kelvin linearization, a near field method. Therefore, the effect of the floating structure’s forward speed or current velocity on the 2nd-order mean drift loads that is also called the wave drift damping has been discussed through these two methods. This work will provide a meaningful reference and numerical basis for the ongoing projects of the floating structure’s seakeeping and maneuvering problems.