bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viscosity Modeling of Solvent-Heavy Oil/Bitumen Systems at High Pressures and Elevated Temperatures
Authors: Hu Bingge , Yang Daoyong 
Published: August 2024

Abstract
This work presents a novel framework for reproducing the measured viscosity of solvent-heavy oil/bitumen systems by integrating the Peng-Robinson equation of state (PR EOS) with binary interaction parameters (BIPs) and modified alpha functions. The oil samples are treated as either as a single pseudocomponent (PC) or multiple PCs. Also, the six most common mixing rules (i.e., Arrhenius’ mixing rule, Cragoe’s mixing rule, double-log mixing rule, Lobe’s mixing rule, power law mixing rule and Shu’s mixing rule) have been evaluated and compared. By adopting the effective density concept, the volume-based power law, weight-based power law, and weight-based Cragoe’s mixing rules reproduce the measured viscosity from 4.3–15000.0 mPa·s within the pressure and temperature range from 1.1 to 10.9 MPa and from 287.9 to 463.4 K. When utilizing one PC, the overall absolute average relative deviation (AARD) for viscosity prediction is found to be 16.0%, 16.5%, and 29.4% for the aforementioned mixing rules. When utilizing four PCs, the AARDs decrease to 13.9%, 14.8%, and 19.3% for the same mixing rules. It is evident that such framework has ability to predict solvent-heavy oil mixture viscosity reasonably accurate under various conditions, while it can be easily incorporated into any reservoir simulators within a given reservoir.
Finite Element Modelling of Residual Stresses in Flexible Pipe Pressure Armor Z Profiles
Authors: Provasi Rodrigo , Toni Fernando Geremias , de Arruda Martins Clovis , Ramos Junior Roberto , Campello George Carneiro , Figueira de Souza Rodolfo , Coser Tiago Brun 
Published: August 2024

Abstract
In the manufacturing of flexible pipes, the pressure armor wires are submitted to successive folding and unfolding processes to achieve its final form. This process results in residual stresses that must be taken into account when calculating the total stresses, they are subjected to in operational situations and in fatigue life calculations. After the manufacturing, the flexible pipe is submitted to the so-called Factory Acceptance Test (FAT), in which a huge internal pressure is applied and then removed. In this latter process, a part of the residual stresses is alleviated, resulting in the residual stress field that must be considered in subsequent mechanical analysis. This paper presents finite element models developed to simulate all the folding and unfolding operations, besides the internal pressure application and removal during the Factory Acceptance Test for Z-shaped pressure armor profiles. This modelling contributes to a more representative manufacturing process, leading to a more assertive stress evaluation.
An Intelligent Failure Data Analysis Framework for Failure Data Management of Wind Turbines
Authors: Li He , Guedes Soares Carlos , Ding Yi 
Published: August 2024

Abstract
This paper proposes an intelligent failure data analysis framework to identify failure features of wind turbines intelligently and automatically, requiring few interactions with analysts. Initially, two operation and maintenance datasets in terms of wind turbine failure and maintenance onshore (LGS-Onshore) and offshore (LGS-Offshore) are introduced. Subsequently, an intelligent failure data analysis model is developed based on Bidirectional Encoder Representations from Transformers and the Conditional Random Field model with the assistance of the proposed adaptive resampling mechanism. The advantage of the proposed framework is validated by the better performance in extracting failure features of wind turbines from the LGS-Onshore and LGS-Offshore datasets. Failure properties of the wind turbines are revealed together with the recommendation for failure prevention actions. Overall, this paper proposes a new concept of failure data analysis and contributes to the operation and maintenance of onshore and offshore wind turbines.
Artificial Intelligence for Cooperative Collision Avoidance of Ships Developed by Multi-Agent Deep Reinforcement Learning
Authors: Yoshioka Hitoshi , Hashimoto Hirotada , Matsuda Akihiko 
Published: August 2024

Abstract
Most ship collisions are caused by human error, making them unpreventable as long as humans operate a ship. Autonomous navigation technology is expected to prevent these accidents. Collision avoidance is a key issue in the realization of autonomous ships. To date, rule- and artificial intelligence (AI)-based collision avoidance algorithms have been studied. However, most of them assumed a simple environment in which other ships maintain their speed and course. During actual navigation in congested waters, safe and efficient collision avoidance are achieved through cooperative maneuvers between ships that obey the COLREGs. To realize cooperative maneuvers of ships, multi-agent deep reinforcement learning was applied to learn collision avoidance maneuvers considering the motions of other ships and COLREGs. Then, the developed multi-agent AI was evaluated with typical one-on-one encounters. The multi-agent AI performed cooperative collision avoidance maneuvers in head-on and crossing situations. Furthermore, the influence of reward setting regarding the degree of compliance with COLREGs on the cooperative collision avoidance was investigated. These results demonstrated that the multi-agent AI was promising for realizing cooperative collision avoidance maneuvers similar to those performed by humans.
Study on the Hydrodynamic Interaction Between Two Floating Bodies of Different Dimensions Undergoing Heave Motion in Regular Waves
Authors: Meng Wei , Li Dan , Kang Zhuang 
Published: August 2024

Abstract
When two floating bodies work side-by-side, the close spacing between them can cause hydrodynamic interactions, resulting in large wave oscillations in the gap and motions of the two bodies, seriously threatening the safety of the operation. This paper uses a hybrid two-way coupled field-domain decomposition method to establish a numerical wave tank, where the incident wave part is computed explicitly, and the diffraction and radiation parts are solved on a two-way coupled potential-viscous flow field. Further, the overset method is applied to simulate the body motions. The computational method is first validated by simulating the motions of a floating box heaving in regular waves, and the numerical results are compared with experimental data. The hydrodynamic interaction problem of two floating bodies with different principal dimensions undergoing heave motion in regular waves is then studied, and different wave directions and gap widths are considered. The results show that the two bodies move in phase for low-frequency waves, resulting in smaller relative motions between them. On the other hand, under high-frequency wave conditions, the two bodies move in an inverted phase, enlarging the relative motions. Further, when the larger floating body is located upstream, there is a significant shielding effect on the downstream small body.
Analysis of Hydrodynamic Performance and Mooring Dynamic Response of Offshore Dual-Module Floating Photovoltaic Platform
Authors: Wu Fanlei , Zhang Kai , Cheng Xiaoming , Wang Jingxiang , Xie Chunmei , Yu Jun , Gu Yujie 
Published: August 2024

Abstract
Floating photovoltaic (FPV) systems, as an emerging solar photovoltaic technology, have great development prospects. In order to investigate the adaptability of offshore multi-connected floating photovoltaic platforms under specific sea conditions, hydrodynamic performance research was conducted. A frequency domain hydrodynamic performance analysis of the floating photovoltaic platform was performed using the hydrodynamic analysis software AQWA, which includes platform RAOs (Response Amplitude Operators), hydrodynamic interaction characteristics, and shielding effects. Using the hydrodynamic analysis software Orcaflex, a time domain analysis was performed to investigate the influence of hydrodynamic interactions on the motion response of a multi-connected photovoltaic platform under extreme sea conditions. To ensure model consistency between the AQWA and Orcaflex, the platform model was simulated with six degrees of freedom for free decay under time domain analysis. In shallow water environments, the response generated by mooring dynamics cannot be ignored. In order to investigate the effect of mooring dynamics on the platform in shallow water environments, sensitivity analysis was performed for two cases: considering mooring dynamics and not considering mooring dynamics. Finally, the influence of the wave direction on the floating photovoltaic platform was investigated under normal operating sea conditions. The results show that the peaks of the platform RAOs are mainly clustered in the low frequency range. Hydrodynamic interaction on the two-body platform inhibits the platform motion response. Mooring dynamics have little effect on platform motion response in shallow water environments. Waves in the 60° direction exert the greatest force on the mooring chain and should be avoided as much as possible in practical engineering.
Optimization Design of the Jacket Support Structure for Offshore Wind Turbine Using Golden-Sine Dynamic Marine Predator Algorithm
Authors: Han Muxuan , Du Zunfeng , Zhu Haiming , Zhu Haitao , Yang Yuan 
Published: August 2024

Abstract
Jacket support structure is the main support form for bottom fixed offshore wind turbine. Weight optimization is critical importance due to the substantial volume of material used in the components of jacket support structures. A metaheuristic algorithm is a powerful tool that allows many parameters in a structural optimization design to be considered simultaneously. As a nature-inspired metaheuristic algorithm, Golden-Sine dynamic marine predator algorithm (GDMPA) has been proved to be competitive in multi-modal and high-dimension optimization problems. In this study, a type of offshore wind turbine composed of the Offshore Code Comparison Collaboration Continuation (OC4) reference jacket structure and the NREL 5 MW baseline turbine was optimized using GDMPA. The forces applied to the structure are realistic ensuring that the simulations are accurate and realistic. The inner problem which consists of member sizing is solved using a robust and efficient GDMPA. An innovative jacket structure with ultimate strength, stiffness, stability, and natural frequency constraints was optimized. Moreover, ultimate limit state analysis, eigen analysis and fatigue analysis are used to evaluate the optimized structure. The results indicate that the proposed optimization method is an effective way to reduce the weight and stress concentration. The final design is a low mass jacket support structure that fully complies with offshore structural standard requirements for all design limit states, while meeting the fatigue life of the welding points, thus being best suited for long operating life.
The Safety Analysis of a FPSO Temporary Mooring System at Quayside With One Line Failure
Authors: Liang Mingxiao , Wang Chao , Liu Haidong , Teng Yanjun , Yang Shangjun 
Published: August 2024

Abstract
The Floating Production Storage and Offloading (FPSO) has a long outfitting period at the dock, which will coincide with the typhoon season. In general, the prediction of temporary mooring system safety does not consider the impact of transient stage of mooring line failure. Instead, the failed mooring line is removed from the mooring system before carrying out the simulation to analysis the mooring safety. However, ignoring the transient stage of mooring line failure will underestimate the damage caused by line failure. In this case, the safety of a temporary mooring system of a large FPSO is investigated in this paper. The failed mooring line is disconnected with the FPSO during the simulate process to achieve the simulation of transient stage. The results of FPSO and mooring system motion response in transient stage and steady state shows that the impact of mooring line failure can be considered as an impact load, which will lead to a rapid increase of the FPSO motion and mooring line tension in transient stage. The underestimated damage of line failure may cause insufficient safety redundancy when design a temporary mooring system for typhoon condition. Thus, with one line failure, the tension of the remaining line in the may exceed the tolerable limit and the mooring system may lose the station keeping ability.
Linear and Nonlinear Pitch Response of a Floating Wind Turbine
Authors: Ma Yueyuan , Cheng Zhengshun , Zhao Wenhua , Wang Shuaishuai , Xiao Longfei , Peng Tao 
Published: August 2024

Abstract
Wave-induced pitch motion of a semi-submersible floating wind turbine (FWT) is of practical significance, particularly in conditions involving shallow and intermediate water depths. These conditions often feature more complex and robust nonlinear wave characteristics, which can potentially trigger pitch resonance more readily. To address this, this study focuses on the analysis of pitch motion for a 5-MW semi-submersible FWT in a water depth of 42 m. A series of experiments are conducted in a large wave basin. The linear and nonlinear pitch responses of a semi-floating wind turbine are examined based on the experimental data. The investigation delves into the pitch response generated by diverse wave loads in both operational and parked wave conditions. Certainly, a well-matched linear correlation can be observed between linear wave loads and linear pitch motion across all wave conditions. The analysis also demonstrates that, in the presence of irregular waves, the nonlinear pitch response, induced by the second-order difference-frequency wave loads and taking place at the pitch natural frequency, becomes increasingly prominent and cannot be disregarded as the wave height grows. The excitation at the second-order difference-frequency holds significant practical implications for offshore operations.
VIV Responses of an Elastic Pipe With Staggered Buoyancy Elements: a Combine CFD and Empirical Time Domain VIV Analysis
Authors: Jiang Fengjian , Wu Jie , Lie Halvor 
Published: August 2024

Abstract
This study examines the influence of buoyancy elements on the VIV responses of a flexible riser using a combined method involving the non-linear time domain VIV prediction program VIVANA-TD and Computational Fluid Dynamics (CFD). Detailed analysis of the flow physics around buoyancy elements was firstly made through visualizations from CFD simulations on a rigid cylinder equipped with staggered buoyancy elements. The CFD results suggest that the vortex shedding behind buoyancy elements is suppressed in the configuration with a diameter ratio 5:1 and a length ratio 1:3, because of the complex wake interactions between the thin cylinder and thick buoyancy elements. This indicates a reduced likelihood of resonance and excitations. Hydrodynamic coefficients respectively for the buoyancy elements and bare cylinder are then derived from forced oscillation CFD simulations, and the values align with above-mentioned flow visualizations, such that buoyancy elements primarily play as a damper in the investigated configuration. These derived hydrodynamic coefficients were further applied in non-linear time domain analysis using VIVANA-TD for a 38m long flexible pipe equipped with buoyancy elements. The results were compared with those from model tests carried out in SINTEF Ocean’s ocean basin, demonstrating promising comparisons.
CFD-Based Consequence Modeling for Jet Fire Release on the LNG Bunkering Ship During Replenishment: Predicting Personnel Injuries and Structural Damage
Authors: Nubli Haris , Jung Dongho , Choi Byung Chul , Sohn Jung Min 
Published: August 2024

Abstract
Liquefied Natural Gas (LNG) remains a popular choice due to its widespread availability. However, LNG, stored in a volatile liquid phase, is susceptible to evaporation and highly flammable, which raises concerns regarding its safe transportation, storage, and utilization. Consequently, accidental releases of this flammable fuel pose potential risks to surrounding structures, including fires and vapor cloud explosions. Furthermore, it is crucial to address the risks to individuals and assets, particularly during bunkering or replenishment processes, which are critical events.
This paper aims to identify the impacts of a jet fire release on both personnel and the ship’s structure during LNG replenishment at an LNG port facility. The study presents a case study involving the use of a Computational Fluid Dynamics (CFD) model to simulate an immediate ignition of fire, employing the OpenFOAM solver. This approach enables the acquisition of a temperature profile within the ship’s structure. Subsequently, a regression tool, Random Forest, was employed to construct the temperature profile. This temperature profile can be utilized to identify potential structural failures. Various regression techniques were also employed for comparison with the Random Forest regression. Additionally, a heat dose profile emitted from the fire was used to estimate the probability of injury in the surrounding area. This paper outlines the entire procedure, encompassing CFD analysis, temperature load mapping, and the assessment of injury probability. The findings and recommendations are comprehensively addressed and discussed.
Impact of Hydrogen Concentration Distribution in Hydrogen-Blended Gas on Fatigue Crack Growth Rate of Pipeline Steels
Authors: Zheng Tingsen , Chen Nian-Zhong 
Published: August 2024

Abstract
The methods to achieve large-scale and long-distance hydrogen transport are primarily to blend hydrogen with another gas, such as natural gas. Due to the significant difference of the densities of hydrogen and those of other gases, the distribution of hydrogen-blended gas becomes uneven during pipeline transportation. Mechanical properties of pipeline steels are normally degraded due to the internal hydrogen environment, and thus fatigue and fracture of pipelines that transport hydrogen-blended gases are likely to occur. This paper aims to investigate the impact of the heterogeneous hydrogen volume fraction of hydrogen-blended gas on the hydrogen induced fatigue crack growth rate of pipeline steels using the cyclic cohesive zone model (CCZM). A dynamic surface hydrogen concentration is used to simulate the heterogeneous hydrogen volume fraction of hydrogen-blended gas during transportation. In the CCZM, not only the degradation of cohesive strength but also the degradation of accumulated cohesive length is considered to incorporate the impact of hydrogen embrittlement (HE) on the fatigue crack growth. The predicted results are compared with the fatigue crack growth rate where the hydrogen volume fraction is constant and the most prone locations in pipeline steels where HE may occur are discussed. The results tend to provide a valuable reference for future designs of hydrogen-blended gas pipelines.
The Sympathetic Implosion of Multiple Titanium Alloy Spheres Under Various Inductive Conditions
Authors: Zheng Jiancai , Li Mingyi , He Tengwu , Zhao Min 
Published: August 2024

Abstract
When a pressure hull implodes in the deep-sea environment, it generates a shock wave that propagates at an exceptionally high speed and releases immense energy accumulated due to ultra-high pressure differences. The phenomenon can potentially induce a chain-type implosion of nearby pressure hulls, posing a significant threat to the reliability and safety of the entire underwater vehicle. Therefore, this study aims to investigate the effect of sympathetic implosion between two titanium alloy spheres under different inducing conditions. Firstly, a self-developed numerical method for three-phase fluid-structure interaction involving compressible multiphase flow is implemented based on an open-source solver. This method ensures the conservation properties and accurately captures and tracks gas-liquid interfaces during simulations. Subsequently, the differences in impulse pressure are compared when sphere I implodes due to local impacts or large geometric defects. Furthermore, the sympathetic implosion phenomena and failure mechanisms are extensively discussed under two inducing conditions, including damage characteristics observed in deformed structures, high-speed movement of compressed fluids, and evolution and balance of energy during fluid-structure interactions. The results demonstrate that when the sympathetic implosion occurs due to the local impact, sphere II fractures under the combined effect of the shock wave, expanding bubble, and structural fragments from sphere I. However, sphere II fractures primarily due to dynamic pressure difference when the larger geometric defect induces the sympathetic implosion. Moreover, when the sympathetic implosion is caused by local impact, there is a greater release of energy through shock waves and a higher absorption of energy through structural plastic strain.
Designing for the Animal: Reimagining Offshore Fish Structures
Authors: Black Suzanne , Vennell Ross , Kregting Louise , Moran Damian , Cook Denham , Janssen Gerard 
Published: August 2024

Abstract
The offshore marine environment has the potential to play a significant role in meeting the projected global demand for high quality protein from finfish aquaculture. However, moving aquaculture structures to open ocean locations poses technical and engineering challenges due to increased environmental loads from larger waves and current velocities. Several global initiatives are exploring this opportunity, but none is tackling the ambitious goal of developing soft-structure, mobile solutions. Our aim is to re-imagine the entire approach to finfish aquaculture by considering the key variables, temperature, water motion and husbandry, to understand the requirements for optimal fish wellbeing and growth. This knowledge will enable the design and future implementation of radically new Mobile Aquaculture Production Systems (MAPS). These systems will be flexible, mobile enclosures, readily customizable to support optimal conditions throughout the fish grow-out production cycle, addressing the design challenges for growing, transporting and harvesting fish offshore. The long-term goal is to create an optimal culture system for fish that supports fish wellbeing and growth while enabling increased production, reduced capital outlay and operating costs in a novel, scalable, low-impact, sustainable aquaculture system.
Non-Contact Dynamic Testing of a Next-Generation Helical Crossflow Tidal Turbine Foil Using a Laser Scanning Vibrometer
Authors: Munaweera Thanthirige Tenis Ranjan , Flanagan Michael , Kennedy Ciaran , Jiang Yadong , Fakhari Vahid , Bachour Carlos , Courade Clement , Cronin Patrick , Dillon Conor , McEntee Jarlath , Flanagan Tomas , Goggins Jamie , Finnegan William 
Published: August 2024

Abstract
The renewable energy sector is strategically focused on mitigating risks associated with tidal energy converters to lower the cost of tidal energy to allow it to become a significant contributor to the renewable energy mix. In this study, dynamic testing was used to assess the structural performance of a next-generation helical crossflow tidal turbine foil made with carbon fibre prepreg composite material. Utilizing a Laser Scanning Vibrometer (LSV) expedites testing and data processing. A 5-metre foil prototype underwent dynamic testing in accordance with DNVGL-ST-0164 and IEC DTS 62600-3 standards. Two dynamic testing setups, with and without an unbalanced rotating mass system, were conducted before and after a series of static and fatigue tests. The research highlights the impact of altering tidal turbine system mass on dynamic response, offering crucial insights for designers. This study establishes the groundwork for a standardized LSV testing protocol for small to large scale tidal turbines, contributing to the optimization of next generation designs and performance. Ultimately, it paves the way for more efficient and sustainable marine energy solutions in the future.