bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel design of a hybrid glulam-steel substructure for the IEA 15-MW floating wind turbine
Authors: Yousef H H , Ma Y , Patel K S , Xing Y 
Published: December 2023

Abstract
Wind energy has become increasingly recognised as a very promising type of renewable energy. In addition, floating offshore wind turbines have facilitated the development of electricity production in intermediate (45-150 m) and deep sea (>150 m) depths. Despite this, wind turbine manufacturing, installation, and operation may generate substantial greenhouse gas emissions. A novel hybrid glulam-steel floating substructure design is presented in this research, intended for the IEA 15 MW floating wind turbine. The objective is to contribute to advancing floating wind energy while minimising costs and carbon dioxide emissions. The objective of the novel design is to substitute steel with glued laminated lumber (glulam). It showcases an altered iteration of the UMaine VolturnUS-S semi-submersible platform originally created for the IEA 15 MW turbine. Before selecting one of three preliminary hybrid wood-steel models, the Ansys Workbench 2020 R1 is used to evaluate and appraise them per a set of criteria extracted from pertinent timber and steel standards. The chosen hybrid design conserves about 590 metric tonnes of steel mass compared to the UMaine VolturnUS-S semi-submersible platform. The selected model is then validated by executing a fully coupled aero-hydro-servo-elastic dynamic analysis with OpenFAST. Consideration is limited to the ultimate limit state design (ULS) for normal and severe operating situations. The utilisation factor of the glulam supporting structure for the IEA 15 MW turbine ranges from 74% to 94%, indicating that it is an effective load-bearing solution.
Numerical analysis of semiconductor-based energy conversion technologies for offshore applications
Authors: Choi T , Lee J H , Kim T Y 
Published: December 2023

Abstract
This study analyzes the physical principles and characteristics of thermoelectric energy conversion phenomena utilizing p-n semiconductor couples to propose a design methodology for thermoelectric generators (TEGs) capable of energy recovery in marine environments. To design TEGs with practical power generation and energy conversion efficiency, the development of a numerical analysis model that can predict and analyze the behavior characteristics of TEGs is required. We present the necessary conditions for a numerical analysis model that simulates the generation characteristics of TEGs at the system level, along with a comparison and analysis of experimental results. The electrical connection method of the thermoelectric modules (TEMs) significantly affects the power generation performance of TEGs; however, there is a lack of research on the electrical connections between TEMs in existing studies. This paper examines the reasons for performance changes due to electrical connections between TEMs and proposes an optimal electrical connection method. Additionally, it is demonstrated that improving the thermal flow distribution within the TEG can enhance system performance and maximize the effects of electrical connections between TEMs. We analyze the characteristics of technologies that can improve the level of thermal flow distribution within the TEG, such as finned and porous structures, and present optimal utilization strategies.
Selecting the inlet configuration for gas-liquid cylindrical cyclone separator
Authors: Sy L V , Lan N T 
Published: December 2023

Abstract
Gas-Liquid Cylindrical Cyclone Separator (short for GLCC) is a compact separator that has been widely used in petroleum production. The inlet configuration has significant impact of the GLCC capacity separation. By utilization of both FEM simulation and practical experiments, three inlet configurations and twelve inclined angles are investigated to find the steadily operating inlet configuration for industrial applications. In this study, the flow pattern and kinematic behaviour of each configuration are thoroughly analysed. Besides, the distribution of three velocity components of the body flow in GLCC is compared with one of the practical experiments. The result shows that the current inclined-inlet angle of 27° is not the steadily operating angle for industrial applications. In steady, it is a range of inclined inlet angle from 0° to 35° for three inlet configurations. The dual-inlet configuration indicates better properties for separating efficiency.
Assessment of a novel PTO system for swell energy convertors using digital twin modelling
Authors: Ren C , Xing Y , Moen L 
Published: December 2023

Abstract
There is no lack of ideas and prototypes for wave energy converters (WECs). However, existing WECs are designed to extract energy from waves at normal to high frequencies and typically focus on close-to-shore steep waves and short wavelengths to gain a frequent movement of interactive components. This limits the size of the buoyancy structure and results in the need to use many generating units to achieve a high-power output. We reverse this focus in small and coastal WECs mentioned above by harvesting swell energy through the Swell Energy Convertor (SWC). SWC uses an innovative power take-off (PTO) system, which Ocean Energies AS invented. This patented crankshaft mechanism transforms the linear motion from ocean waves into rotation for rotating a generator. When combined with a large buoy structure, this PTO system allows the SWC to focus on the swells (large wavelengths and low to high wave heights) further offshore and reduce/remove the drawbacks associated with the abovementioned coastal areas. The SWC (i) focuses on the high energy swells offshore, (ii) uses large buoy structures in combination with slight vertical movement, and (iii) can optimally extract energy in any direction. This results in SWC being a far less complex system with a much higher power output than existing WECs, which will significantly lower the cost of WECs. The SWC will target the area between Greenland and Scotland, with significantly high wave energy above 60 kW/m. This paper will present the design and analysis of the proposed PTO system in the SWC. First, the PTO model and working mechanism will be described. Second, a digital model of the PTO system will also be introduced. Third, three optimal design candidates are selected and analysed further to provide a deeper insight into the PTO design. Last, discussions and planned future works are presented.
Research on dynamic responses of mooring line system of semi-submersible platforms in Vietnam sea conditions using random model
Authors: Pham H H , Mai T , Liu Y 
Published: December 2023

Abstract
Recently, due to the nearshore oil fields in Vietnam were nearly exhausted, oil and gas extraction proceeds to deeper water areas using the mooring floating offshore structures. Therefore, the durability of the mooring system in deep water should be studied through determining the dynamic tension of the mooring line system using random wave models. However, full stochastic dynamics analysis for mooring line system takes up a lot of time and requires large computing resources. This paper is going to study the hydrodynamic interaction of random waves onto a semi-submersible platform, thereby analysing the dynamic responses in time domain of the mooring system using the “time window” method to optimize computational time and computing resources. This method performs the dynamic simulations around the maximum quasi-dynamic tension values to determine the dynamic tension and the dynamic amplification factor (DAF) of a maximum load-bearing mooring line, thereby evaluating the dynamic responses for the whole mooring system. The method is applied to calculate for a semi-submersible platform in Dai Hung field in Vietnam Sea.
Numerical study on the de-ballasting operation of a floating dock with a malfunctioning pump
Authors: Zhang J , Wen X , Ong M C 
Published: December 2023

Abstract
In normal de-ballasting operations of floating docks, each ballast pump manages a specific group of ballast tanks, independently of the others. However, if one pump is malfunctioning, a connection valve between the group and its adjacent group is opened, allowing its adjacent pump to control two groups of tanks simultaneously. This study aims to investigate the de-ballasting dynamic process in the event of a ballast pump malfunction by utilizing a numerical model of a full-scale digital floating dock. In the present numerical model, the dock is represented as a rigid body with six degrees of freedom and is subjected to hydrostatic, hydrodynamic, and mooring forces. To maintain pitch and roll angles within predefined limits, a modified P-controller is employed to regulate the valve opening angles at all the ballast tanks. Hydraulic calculations for the ballast water system with a malfunctioning pump are conducted, and the numerical results demonstrate the effectiveness of the present modified P-controller when dealing with a malfunctioning Pump No. 1.
Fixed type-oscillating water column front wall angle variation and impact on chamber performance: CFD numerical wave tank assessment
Authors: Samitha Weerakoon A H , Thilan W , De Silva H A , Assadi M 
Published: December 2023

Abstract
This study investigates optimizing the front wall geometry of an Oscillating Water Column (OWC) chamber to enhance turbine performance and output efficiency when harnessing energy from progressive waves with consistent periods and wavelengths. Numerical Wave Tank (NWT) adopted simulations carried out using ANSYS-Fluent ® package, VOF method with multiphase flow (air-water) where 2-D wave motion of NWT implemented using a C+ computer code. Frontal wall angle of the air/water chamber changed from 0° to 80°, for 10 cases. OWC system was most effective in harnessing and converting wave energy at 0° angle, reaching the maximum power output of 605.08 W/m. In contrast, 80° angle exhibited lower efficiency, with the lowest power output of 26.55 W/m. The average power output over time reflects consistent energy conversion, with the 0° angle demonstrating the highest average power output of 123.72 W/m, while the 80° case exhibited less efficient pneumatic power potential with an average of 3.5 W/m. A uniform cross section provides higher pneumatic power when with PTO in OWC. The efficiency of power generation can be increased by approximately 10 to 20% by keeping 0 to 10° angle of front wall without any appendages fitted with into the wall.
Optimization of bend stiffeners of a suspended inter-array power cable between two floating offshore wind turbines
Authors: Liu D , Ahmad I , Janocha M J , Nystrøm P , Ong M C 
Published: December 2023

Abstract
The concept of a suspended inter-array power cable assumes that the cable floats within the water column instead of being laid on the seabed. This setup requires additional equipment, such as buoyancy modules or buoys, to achieve the desired cable configuration. The implementation of buoyancy modules introduces abrupt changes in stiffness between the cable sections with clamped-on buoyancy modules and bare cable sections. Large stiffness variations can negatively impact cable bending, causing excessive curvature and fatigue damage. In order to form a smooth transition in stiffness between the buoyancy sections and the bare cable, bend stiffeners can be equipped. The study aims to optimize the bend stiffener design for a representative suspended power cable between two floating offshore wind turbines (FOWTs). The inter-array power cable system is simulated in OrcaFlex. Two parameters, including the outer diameter and the length of the bend stiffener, are adjusted to generate different cases. Eight environmental conditions are applied to the dynamic analysis of the cases. The fitness factor approach is used as a criterion to assess the overall performance of different bend stiffener designs. Adjusting the outer diameter of bend stiffeners clearly influences the maximum effective tension and the minimum bending radius by changing the stiffness profile of the bend stiffener and its submerged weight. In the investigated range of parameters, increasing the overall length of bend stiffeners is found to be less effective than adjusting the outer diameter of the bend stiffener.
Effect of a rotational damper on a moored and articulated multibody offshore system in waves
Authors: Zhang Qi , Moctar Ould el , Jiang Changqing 
Published: December 2023

Abstract
Motions and loads of an articulated and moored floating platform consisting of multiple bodies in waves are investigated through numerical analysis. The wave–structure interaction (WSI) problem is solved using a high-fidelity viscous–flow solver that couples nonlinear rigid body motions, multibody interactions with an internal connection, and mooring dynamics. The study focuses on two modular floating structures (MFSs) connected by a flexible joint, with and without a rotational damper, and positioned using four symmetrical mooring lines. Multibody responses and the corresponding loads acting on the mooring lines and hinged joints are analyzed. Our results reveal that the influence of the damper on heave motions is less significant. Notably, the presence of the rotational damper has a noticeable impact on pitch motions between the two hinged MFSs. Introducing a rotational damper on the flexible joint effectively dampens the highly dynamic pitch motions while not imposing additional loads on the flexible joints.
A parametric study on the initial transverse stability of suspension ships
Authors: Han J , Murai M 
Published: December 2023

Abstract
Suspension ships are a novel type of ships that utilize a suspension system as an integral part of their structure. One critical aspect of a suspension ship is its stability characteristics. The parameters that affect the initial transverse stability of these ships include the ship’s mass ratio, loaded height of suspension, placement location height of suspension, and beam. It is found that designing a suspension ship in monohull configuration is more difficult than in a catamaran configuration. Special attention is required when the static mass ratio is below 2 for both monohulls and catamarans.
Numerical analysis of centrifugal water pump impeller under varying loads
Authors: Yadeta L , Lemu H G , Tadese A K/M 
Published: December 2023

Abstract
Centrifugal pumps are widely used to move liquids from one place to another at varying pressure and flow rate, and to an elevated height for irrigation, water supply plants, and steam power plants. The load variations often lead to unpredictable performance of the impeller. The objective of this study is to investigate the performance of a three-stage centrifugal water pump impeller under varying loads using numerical methods. To conduct the investigation, a water pump used by Jimma town water treatment station, which operates with head of 191 m and discharges 439.2 m3/hr water was used as a case study. Computational fluid dynamics analysis of the pump was conducted using ANSYS 19.0 CFX to get the pressure distribution at different flow rates (60%, 100% and 140% of the design flow rate). The fluid pressure was then used to make static stress analysis of the impeller employing one way fluid structural interaction analysis for three different materials. The finding of the study shows that the fluid pressure on the impeller has great impact on the impeller performance causing high stress and deformation of the impeller.
Design optimization of small fishing vessel structures: A case study
Authors: Putra G L , Rizqillah F , Yatim A , Liu Y 
Published: December 2023

Abstract
The cost of vessel operations poses a significant challenge for fishermen in Indonesia, with 60% - 70% of their operational expenses being allocated to fuel. To address this issue and decrease fuel consumption in fishing vessels, one possible solution is to construct lighter boat designs. Through careful optimization of the construction process and the selection of suitable materials, it becomes feasible to achieve such a lighter design, leading to reduced operational and construction costs. The optimization process involves considering various frame spacing variations, like 400 mm, 500 mm, and 600 mm, and utilizing materials such as mild steel and AH32. Additionally, optimizing the plate thickness ensures that the vessel’s stress and deformation remain within the limits set by the rules. As a result of this optimization, a weight reduction of up to 20% is observed.
Non-linear buckling analysis of ship hull stiffened panels
Authors: Hacihamud E , Dahl K , Gabrielsen O , Lemu H G , Siriwardane S C 
Published: December 2023

Abstract
Stiffened panels are crucial in maritime applications, where buckling is a primary structural failure concern. Typically, assessing the buckling capacity of these panels relies on established guidelines like DNV-RP-C201 and NS-EN 1993-1-5. Alternatively, non-linear finite element methods, guided by DNV-RP-C208, can be used. However, there’s a significant research gap in calibrating buckling capacities for large ship-hull stiffened panels. This paper bridges that gap by employing non-linear finite element analysis to evaluate the buckling capacity of ship hull stiffened panels and compare the results with DNV-RP-C201. It establishes a capacity benchmark by thoroughly comparing results for a plated panel. Subsequently, it develops a validated model using ABAQUS, introducing material and geometric nonlinearities, including a mid-stiffener span imperfection ranging from 0.06% to 1% of the stiffener span length for 99.7% calibration. The validated non-linear model then assesses the impact of holes on buckling capacity under uniaxial and gravity loads, revealing a clear correlation between reduced buckling capacity.
Spatial and temporal crack initiation prediction in steels based on residual stress tensor distribution monitoring
Authors: Mangiorou E , Damatopoulou T , Angelopoulos S , Vourna P , Ktena A , Hristoforou E 
Published: December 2023

Abstract
We have developed a method and the corresponding instruments, able to provide the spatial and temporal determination of crack initiation in ferromagnetic steels and their welds. The method is based on the monitoring of the differential magnetic permeability µr along the length of the steel, since a sigmoid monotonical dependence of µr on residual stresses has been determined in the past. Thus, the magnetic stress calibration (MASC) curves can inform on the localized residual stresses. Therefore, the temporal stress monitoring at different areas of interest can inform about the status of residual stresses. Then, the tendency of the residual stress value can inform about reaching the positive (tensile) or negative (compressive) yield point of the steel. As an example, a quasi-parabolic temporal dependence of µr offers the tendency to determine the time, or the time window, required to reach yield point. This way, the temporal prediction of the crack initiation is provided for the given point in space, since reaching the yield point results in crack initiation.
Experimental assessment of cracked tubular joints repaired with crack-deflecting holes and weld-toe grinding
Authors: Riise S , Atteya M , Mikkelsen O , Ersdal G 
Published: December 2023

Abstract
Tubular joints in offshore structures for energy production are exposed to cyclic loading and may experience fatigue cracking. Presently, the inspection method commonly used for such structures will primarily detect whether a member is flooded, which is an indication of through thickness cracks. As a result, repair methods suitable for repairing through thickness cracks that are cost-effective and quick to implement are needed. One such repair method could be crack arrest by hole drilling. However, the validity of such a repair method is at present not sufficiently proven. Hence, this paper presents the results of an experimental fatigue test of pre-cracked tubular joint repaired with crack-deflecting holes combined weld-toe grinding. One tubular double T joint was tested and underwent three-phases comprising of a pre-cracking phase, a repair phase and a post-repair testing phase. The through-thickness fatigue crack was achieved by subjecting the intact test joint to cyclic axial loading within the high-cycle fatigue domain. In the repair phase, crack-deflecting holes were drilled in front of each crack tip to arrest the crack ends. In addition, the weld-toe behind these holes were grinded to enhance the fatigue life of the repaired joint. The performances of the repaired test joint were then investigated in the last phase by subjecting it to further cyclic loading within the high cycles fatigue domain. In the test, the crack was successfully arrested in the crack-deflecting holes. Furthermore, the repair method indicated an apparent enhancement of the fatigue endurance of the cracked tubular joint when subjected to stress ranges within the high-cycle fatigue domain.
Optimization of the routing problem using the physics-based electromagnetism-like algorithm
Authors: Jao J R , Vallar E A 
Published: December 2023

Abstract
Waste collection is considered as a first objective in planning a sustainable waste management, and provision of substantial collection coverage in urban and rural areas should be satisfied before investing in more sophisticated infrastructure. Therefore, good waste collection service is essential to upgrade further the next levels of a municipal solid waste system. One of the ways to enhance performance on waste collection is to plan effective routing of trucks. The study formulated a Waste Collection Arc Routing Problem to model the waste collection routing problem of Parang, Marikina City. The study revealed that the EM-like with local search and selection strategy mechanism displayed significant minimization abilities of distance values, and the capacity consideration of truck is important to attain better efficiency and cost savings of route.
Bio-inspired design trends for sustainable energy structures
Authors: Regassa Y , Dabasa T , Amare G , Lemu H G. 
Published: December 2023

Abstract
Researchers and engineers are constantly looking to nature for design inspiration as they work to create novel and effective energy conversion structures. Engineers are developing durable and resilient materials to survive extreme weather conditions and environmental issues using inspiration from the Nenuphar’s durability in adverse aquatic environments and the Sunflower’s adaptation to vary climatic situations. The analysis of new design ideas in renewable energy systems in this research was inspired by the Nenuphar (Water Lily) and the Sunflower. The Nenuphar’s exceptional capacity to float and large leaf surface make it a model for enhanced water-based energy conversion systems. Researchers have been looking into novel concepts like floating solar farms and wave energy collecting platforms after being inspired by the Nenuphar’s buoyancy and ability to efficiently use sunlight. Solar panel integration with water features can boost overall energy output while preserving precious land resources. The Sunflower, known for its phototropism and effective sun-tracking mechanism, offers suggestions for improving solar energy harvesting. Advanced heliotropic solar panels have demonstrated promising results in boosting energy production throughout the day by mimicking the Sunflower’s ability to follow the trajectory of the Sun. These designs maximize energy outputs and boost overall system efficiency by maximizing solar exposure. Embracing these bio-inspired concepts can lead to the development of sustainable and efficient energy solutions, contributing to a greener and more sustainable future. Furthermore, the integration of smart technology and artificial intelligence is on the rise to optimize energy conversion structures.