bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled Motion Analysis of a Ship-Shaped Floater and the Cold-Water Pipe for OTEC Implementation
Authors: Adiputra Ristiyanto , Imam Firdaus Muhamad , Firdaus Nurman 
Published: August 2024

Abstract
Ocean Thermal Energy Conversion (OTEC) utilizes the temperature difference between warm surface seawater and cold deep seawater to produce electricity. The system demands the installation of a cold-water pipe (CWP) to deliver the deep cold seawater into the plantship from a water depth of around 400–800 m in free-hanging conditions. Considering this novel condition, the present paper focuses on how the CWP affects the dynamic motion of the plantship to ensure its global stability. The main dimensions of the plantship and the cold-water pipe were adapted from the previous study. The analysis is conducted experimentally using the scaled model in a beam sea and head sea for the regular and irregular waves. The comparison results are analyzed based on the obtained response amplitude operator response in the time series of each case configuration where the floater is set with or without the CWP. Overall, the CWP installation changes the system’s natural frequency and stabilizes the floater’s motion, especially for the roll motion. In contrast, the installation effect is insignificant for pitch and heave motions regardless of the wave direction.
Computational Modelling of Repetitive Raindrop Impact and Resulting Fatigue Damage in Wind Turbine Blades
Authors: Kuthe Nikesh , Ahmad Suhail , Mahajan Puneet , Mishnaevsky Leon 
Published: August 2024

Abstract
Computational modelling of repetitive raindrop impact and predicting the ensuing damage in the coating and substrate due to fatigue is an essential step in determining the life of the wind turbine blade. The blade is multi-layered with a viscoelastic coating layer, a viscoelastic putty layer, and an elastic composite substrate with an interface between the layers. The damage usually takes the form of erosion of the coating and debonding at the various interfaces between the layers of the wind turbine blade.
The modelling of impact and damage involves several steps beginning with generating a stochastic rain scenario which provides information on raindrop size distribution and velocity hitting a volume of the blade. A Coupled Eulerian-Lagrangian (CEL) analysis of a single raindrop and a representative region of the blade provides impact forces on and resulting stresses in the blade. The CEL analysis is repeated for drops of different diameters to generate a library of stresses. This library, combined with a stochastic rain scenario, generates stresses at any location of the representative blade due to the repetitive impact of different-sized raindrops hitting arbitrary locations. Continuum damage mechanics is used to predict the damage evolution in the coating, and when damage reaches a critical value in any element within the developed finite element model of the multilayered blade sample represents the erosion of the coating. A cohesive zone model for fatigue debonding is employed for interfaces between coating, putty, and composite substrate. Both the Continuum damage mechanics model and a Cohesive zone model for fatigue are implemented through a user-defined subroutine in ABAQUS/Explicit.
Using the model, the interaction between erosion and debonding is studied. Using the properties of materials from the literature, the analysis shows that damage always initiates from the bottom portion of the coating layer close to the adhesive interface. This eventually creates displacement jumps at the interface of coating and putty, causing damage initiation at the interfaces. Repetitive raindrop impact of different sizes at arbitrary locations causes damage accumulation and propagation faster at the interface, finally damaging the coating layer.
Analysis on Vibration Suppression Performance of an Attached Acoustic Black Hole Composite Beam
Authors: Liu Xinru , Fu Junyong , Wan Zhiwei , Li Tianyun , Zhu Xiang 
Published: August 2024

Abstract
Attaching damping to structures is a common vibration suppression measure. Different from attaching uniform thickness damping, this paper proposes an acoustic black hole damping attached to a beam. There is an internal cavity between the beam and the damping layer. The thickness of the internal cavity is designed to vary according to a power index gradient, forming an attached acoustic black hole composite beam. Combined with the energy and virtual spring method, the theoretical model of the ABH beam following the Euler-Bernoulli beam theory is established to calculate its vibrational response. The vibration displacement response of the ABH beam is calculated using the finite element method again. The correctness of the theoretical model is confirmed by contrasting the theoretical results with the finite element results. From the comparison, it can be found that the peak frequency of the vibration displacement level at the output end of the ABH beam moves toward the higher frequency, and the peak response value is lower compared to that of the uniformly damped beam. The attenuation frequency interval shifts to the higher frequency in the vibration displacement transfer response curve. It can be concluded that the ABH beam exhibits better vibration suppression performance than that of the uniformly damped beam with identical damping thickness.
Reliability of Offshore Structures – Requirements to and Limitations of Calibrated Deterministic Code Design and Assessment Approaches
Authors: Tychsen Jesper , Zeeberg Allan , Nielsen Jørgen S. , Cholley Jean-Marc 
Published: August 2024

Abstract
This paper uses a new and validated SRA model based on Monte Carlo simulations to assess the performance of existing design and assessment approaches for offshore structures. Generic structures are designed to meet the ISO 19902 [5] code requirements in ULS and ALS limit states at three sites in the Danish North Sea sector. We then run the Monte Carlo time domain simulation to obtain the response statistics and evaluate the annual failure probability for each failure mechanism within each generic model. Looking across the range of failure mechanisms, generic structures, and sites (water depth) the performance of the ISO 19902 design approach can be evaluated. We also use the SRA model and the generic structures to test the accuracy and validity of an existing (Shell 1997) SRA model [6], which outlines a SRA principle widely used for offshore reliability analysis. We will generally refer to this as the old SRA model. We examine each parameter of the model and identify the critical design assumptions and limitations.
Low-Frequency Vibration Suppression Using a Piezoelectric Metamaterial Beam With Tunable Band Gap
Authors: Zhong Kexin , Wan Zhiwei , Liu Wenxuan , Li Tianyun , Zhu Xiang 
Published: August 2024

Abstract
Acoustic metamaterials have been widely studied in recent years. Generally, when a passive acoustic metamaterial for vibration suppression is designed and manufactured, its structure is difficult to adjust, and the corresponding vibration reduction characteristics are also difficult to change, which greatly limits their vibration isolation ability in complex dynamic vibration environments. In this study, we propose a piezoelectric metamaterial (PMM) beam with a tunable band gap based on Kirchhoff’s law. The structure is composed of piezoelectric ceramic materials, PMMA (Polymethyl Methacrylate), and aluminum, in which the piezoelectric ceramic materials with inductor-resistance-capacitor (LRC) shunting circuits utilize electromagnetic oscillation and electromechanical coupling properties to form a tunable local resonance (LR) band gap inside the metamaterial beam. The dispersion curve of the PMM beam was calculated using the transfer matrix method. Firstly, the energy bands of PMM beams with different compositions were compared, which demonstrated that the proposed structure had a lower frequency and wider band gap. Subsequently, the values of inductance, resistance, and capacitance in the LRC shunting circuit were changed to study the effects of its parameters on the band gap starting frequency, cutoff frequency, and bandwidth. The proposed piezoelectric metamaterial beam provided a new idea for suppressing variable vibration frequencies in the environment.
Vibration Transmission Assessment of Ship Auxiliary Machinery With Varying Mass Based on Power Flow Method
Authors: Xu Weiye , Dai Wei , Zhu Xiang , Li Tianyun , Wang Jianing , Han Wei 
Published: August 2024

Abstract
Compared to traditional shipboard auxiliary machinery, the mass and size of the newly designed equipment are significantly reduced, and the conventional acceleration-based evaluation method on vibration transmission from the equipment to the hull may not be suitable. This research applies a power-flow-based method for the comprehensive study of vibration transmission. Considering the intricate structures of the equipment, the vibration isolation system is initially simplified to a single degree of freedom (SDOF) model. This allows for a preliminary theoretical study. Then, a two degrees of freedom (2DOF) model is investigated to simulate the flexible base on board for comparison. Further theoretical derivations are undertaken to obtain the dynamic behavior of the system. In these two models, the equivalent method, based on equal power flow, is employed to inversely derive the corresponding expression of foot vibration level under changes in weight of the equipment excited by the same level of base motion. The results show that the foot acceleration of the device gradually increases with the decrease of the device mass at the same transmitted vibration power flow to the base. Notably, under the condition of transmitting the same energy to the base, the foot vibration level generated by the new equipment surpasses the foot vibration level index of the old equipment. This study furnishes theoretical guidance for evaluating vibration transmission of the latest developed auxiliary machinery on board from an energy perspective, which can be employed in the engineering design of ships.
Hydrodynamics of Off-Bottom Plug Placements in Deviated Wells
Authors: Ghazal Abdallah , Shakeri Amin , Karimfazli Ida 
Published: August 2024

Abstract
Wellbores come in various shapes, from vertical to deviated and horizontal configurations. Deviated or horizontal wells typically involve a vertical drilling phase before shifting towards the target direction. As oil and gas production becomes economically unviable, well abandonment is common, involving the deployment of multiple cement plugs. The off-bottom plugs, located above the lowermost plug, are strategically placed in the vertical or least deviated sections of the well.
We consider a representative 2D model for the early stages of cement placement, where slurry is injected from a concentric injector with the well, and explore the influence of well inclination on the placement process. In vertical wells, the injected fluid forms a central finger below the injector. However, in highly deviated wells, the fluid slumps towards one side of the casing walls. The transition between these two flow regimes occurs through a monotonic change with the inclination angle. In all cases, the buoyancy-driven flow is disrupted, resulting in a mixed layer below the injector, and the accumulation of the injected fluid above it. While the accumulated fluid remains primarily unmixed with wellbore fluids in vertical wells, intermittent mixing occurs in deviated wells. The frequency and magnitude of this mixing change non-monotonically with the inclination angle.
Effects of Wave Nonlinearity on Solute Migration in Deformable Sediments
Authors: Zhao Hongyi , Liu Xiaoli , Jeng Dong-Sheng 
Published: August 2024

Abstract
This study employs a two-dimensional numerical model, coupling Biot’s poro-elastic theory with advection-dispersion equations, to examine the impact of wave nonlinearity on solute transport in deformable seabed sediment. The simulations reveal that compared to the second-order Stokes waves, the first-order cnoidal waves exhibit significant nonlinear effects, effectively enhancing the longitudinal dispersion coefficient and solute transport rate in marine sediment. However, this enhancement diminishes as wave height increases and water depth decreases, highlighting the diminishing impact of cnoidal wave nonlinearity under such conditions.
Experimental Investigation on Wave Evolution and Seabed Response During the Long-Term Development of Sloping Beach
Authors: Yang Yunhan , Wang Guangsheng , Xiao Ziwei , Sui Titi , Zhang Chi , Wang Gang 
Published: August 2024

Abstract
Nonlinear wave action plays a crucial role in cross-shore sediment transport, significantly impacting various coastal engineering challenges. This is especially true when assessing beach processes for shore protection methods, demanding precise evaluations. The nonlinearity of waves can instigate near-bed sediment transport. Previous studies mainly focused on the evolution of wave nonlinearity within specific cross-shore profiles, often neglecting the corresponding seabed response. To gain a deeper understanding of hydrodynamics on a sloping beach, we conducted experiments at a small scale within a flume. These experiments aimed to investigate wave evolution and seabed response concerning cross-shore profile development. Over a period of up to 60 hours, we continuously recorded wave heights and analyzed characteristic wave patterns. We also discussed the seabed response at various horizontal positions along the beach. Our findings reveal a reciprocal relationship between cross-shore profiles and wave evolution. In general, wave nonlinearity gradually increases during propagation. However, the nonlinear indicators of waves remain relatively stable over time at the same water depth. Meanwhile, wave-induced seabed responses vary both over time and across different spatial positions. The excess pore pressure within the seabed gradually decreases with increasing depth at various horizontal positions.
Coupled Analysis of an Remora-Inspired AUV Docking to a Submarine During Recovery Process
Authors: Xu Yunxin , Shi Weichao , Song Yang 
Published: August 2024

Abstract
To enhance the cost-effectiveness and safety of offshore operations, the utilization of autonomous underwater vehicles (AUVs) has become popular across various industries. However, traditional docking or recovery methods for AUVs can be inefficient, requiring the mother vehicle to remain stationary. Consequently, there is a critical need to develop underwater dynamic recovery systems for AUVs to reduce operation costs, shorten redeployment times, and enhance overall operational efficiency compared to traditional docking methods.
Recent investigations into the ‘hitchhiking’ behaviour of remoras, which have a symbiotic relationship with sharks, have revealed that the low-velocity region around the shark can significantly reduce drag on the remora during attachment. Drawing inspiration from this phenomenon, an AUV was developed. To further support the feasibility study of the underwater dynamic recovery system for AUVs, this paper utilized the commercial computational fluid dynamics (CFD) software, STAR-CCM+, to analyse the hydrodynamic characteristics of the AUV in close proximity to a self-propulsion submarine during the recovery process. This analysis considered changes in the AUV’s attitude, which is important as the AUV enters the boundary layer of the submarine and approaches it. The boundary layer flow, influencing the AUV’s resistance, also generates a force that attracts the AUV toward the submarine.
This research delves into the effects on the AUV when two underwater vehicles of significantly different sizes are in close proximity, analysing various stages during the recovery process. It lays the groundwork for further studies aimed at developing dynamic underwater docking operations.
Numerical Simulation of Forced Oscillation for Added Mass and Damping Characteristics of the SWACH Floating Wind Platform
Authors: Zhang Yali , Wang Hongchao , Santo Harrif , Larsen Espen , Lim Chin Lee 
Published: August 2024

Abstract
This study delves into the intricate realm of forced oscillation Computational Fluid Dynamics (CFD) simulations, placing a particular emphasis on evaluating the added mass and damping characteristics of the SWACH floating wind platform. Specifically designed by Sevan SSP and featuring damping skirts and a large moonpool, the SWACH platform represents a cutting-edge innovation in the field of floating wind energy.
These simulations spanned across distinct scenarios, representing various environmental conditions. The focal point of this extensive simulation effort is to meticulously investigate the influence of oscillation period and amplitude on critical parameters such as added mass and damping. These parameters play a pivotal role in understanding the dynamic behavior of the platform in response to wave forces, providing essential insights for the platform’s performance evaluation. Moreover, the study conducts a detailed component-level analysis, scrutinizing the inner skirts, outer skirts, and hull of the SWACH floater individually. This component-level investigation offers valuable insights into the functionality and interaction of each component, contributing to an understanding of the platform’s overall behavior. This comprehensive investigation is crucial for ensuring the platform’s optimal performance in offshore wind energy applications, offering significant potential for informed design and optimization of floating structures. By unraveling complex hydrodynamic phenomena through CFD simulations, this study provides a robust foundation for informed design decisions and the ongoing optimization of floating structures in the pursuit of sustainable offshore energy solutions.
Probabilistic Data Envelopment Analysis Applied to Risk-Based Inspection of Flexible Pipes
Authors: Ferraz Caroline , Netto Theodoro A. , Souza Marcelo Igor L. , Honorato Henrique , Vaillant Alyson G. , Custódio Anderson B. , Ferreira Lucas R. S. , Meirelles Eduardo V. , Moita Joao V. 
Published: August 2024

Abstract
Flexible pipelines and risers are widely used by oil and gas operators in Brazil in their subsea systems for offshore operations. These operators have teams of multidisciplinary specialists working on the integrity management of their assets, as well as a large amount of inspection data, a database of real failures, and failure predictive tools. However, inspection scope planning is based on the judgment of the experts operating the assets. With the advent of new technologies, the use of data science and decision-making tools has helped engineers to make more assertive and less subjective decisions. To ensure the operational safety of flexible pipes and risers, identifying the main failure modes that can lead to the total loss of structural integrity and all the failure mechanisms that will lead to each failure mode is essential. This work will present a risk-based inspection methodology for offshore flexible pipes and risers based on data envelopment analysis (DEA). The present methodology considers the organization of each failure mechanism through event trees, allowing the visualization of the chronological occurrence of non-conformities in stages until the failure mode is reached. Recent work has shown risk analyses using data envelopment analysis based only on events (nonconformities) detectable by inspection. The proposed methodology establishes a relative risk ranking for a group of flexible pipes based on event trees, formed by events detectable or not during inspection, considering their probability of occurrence over time.
Preliminary Evaluation of the Supply Chain Capability for Offshore Wind Farm Development in Tasmania
Authors: Chen Peggy Shu-Ling , Cahoon Stephen , Fan Hongjun , Cooper Mark , Haward Marcus 
Published: August 2024

Abstract
Australia has set an ambitious goal of attaining 82% of its electricity generation from renewable energy sources by 2030, with offshore wind energy expected to play a pivotal role in achieving this target. Australia has identified six priority offshore wind areas, with two officially announced, three in the proposal stage, and one under assessment. Establishing a reliable and resilient supply chain is paramount to developing Australia’s offshore wind farms. This paper focuses on offshore wind development in Tasmania, an island State of Australia. The purpose of the paper is to provide a preliminary evaluation of the offshore wind supply chain. Key variables integrated into the evaluation model encompass the offshore wind targets, the installed power capacity of individual turbines, international supply chain constraints, port capacity, vessel availability, and workforce considerations. This paper firstly assesses the demand for components of Tasmanian offshore wind projects based on the baseline and ambitious targets. Subsequently, it examines the corresponding demands and requirements for ports, vessels, and workforce. The paper also discusses the supply chain for Tasmanian offshore wind farm development and concludes with the opportunities and challenges for the future development of Tasmania’s offshore wind industry.
Dynamic Responses of Composite Sandwich Panels Under Air Blast Loading
Authors: Lu Yue , Liu Kun , Shi Shengzhao , Ke Li , Wang Zili 
Published: August 2024

Abstract
Sandwich plates have been widely used in shipbuilding industry due to its superior protective capability when subjected to extreme loads, and it has become an excellent candidate to replace conventional stiffened plates. This research investigates the blast response of composite sandwich panels with high density polyethylene (HDPE) core. Explosion tests are performed to reveal the primary failure characteristics of composite sandwich panels. Attention is focused on the effects of core arrangements. Meanwhile, numerical simulations are performed to examine the blast responses of sandwich panels. Coupled effects of strain rate and temperature are considered in the constitutive model. In combination with the validated numerical models, multiple failure patterns can be captured, including the perforations of front face, petalling or cracking of backface, plugging of filling core and debonding failure between cores and facesheets. Results indicate that introducing the HDPE core is beneficial to alleviating the damage extent of the sandwich panels. Under explosive loadings, composite sandwich panels with full-filling HDPE core possess more desirable anti-explosion capacity. Besides, more obvious debonding failure can be observed in sandwich panels when subjected to severe explosive loadings, and this phenomenon can be adequately captured in all numerical models with the developed material model.