bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analytical Approach to Modeling Thin, Pre-Cracked Specimens Using Traction-Separation: A Proof of Concept
Authors: Adly Mohammed A. , Walters Carey L. 
Published: August 2024

Abstract
Cohesive zone and eXtended Finite Element Modeling (xFEM) are promising methods for modeling the propagation of a crack using coarse meshes and hence saving considerable computational time. The Traction Separation Law (TSL) that is needed for such techniques is, however, mostly derived a posteriori using experiments. This prevents its widespread utilization in structures without high costs. For example, in the modeling of a compact tension test, the TSL is known to evolve as the crack grows. Qualitative physical explanations have been offered for this phenomenon. Necking ahead of the crack tip is thought to have a large effect on crack propagation, while the necking behavior in any given element is influenced by both the state of stress acting on it and the structural boundaries around it. However, a method to account for those explanations a priori in the TSL doesn’t exist. Here, TSLs are developed for the elements along the known crack path in a middle crack tension test and implemented as a damage model in Abaqus. They are derived solely from the material properties and the element dimensions, thus excluding the need for inverse engineering based on experiments. This paves the way for more general applications of traction separation laws within the maritime and offshore industry.
Residual Plastic Strain Effects on the Ultimate Capacity for a HSLA Stiffened Panel Subjected to Two Different Cyclic Load Conditions
Authors: Barsotti Beatrice , Gaiotti Marco 
Published: August 2024

Abstract
This paper delves into how plastic deformations accumulate in structures and their effect on the ultimate load strength. More precisely, the study examines how repeated cyclic loads cause plastic deformations, which could have some effects on the ultimate capacity of the structure, in contrast to a continuously rising load. The study suggests a numerical strategy, by means of finite element analyses, to investigate the structural responses of two different load cycle histories and emphasizes differences that arise due to the choice in the material hardening law (model describing material behaviour) like isotropic, kinematic, or the combined Chaboche model.
The researchers focus on a stiffened panel made of high-strength, low-alloy steel subjected to both uniaxial compression and alternating tension-compression cyclic loading. In order to capture the arise of the residual plastic strains, the study employs shell element modelling, while also considering initial imperfections.
The paper discusses how residual displacements magnitude change as the number of load cycles increases under different loading conditions and material hardening models. Ultimately, it analyses how these accumulated plastic deformations influence the ultimate strength, with a particular emphasis on whether different plastic strain inputs from the two load configurations lead to varying outcomes.
An Effective Method for Evaluating the Failure of Wind Turbine Blade Under Various Conditions
Authors: Sheng Fangyuan , Liang Xu , Wang Baoxuan , Liao Haiyan 
Published: August 2024

Abstract
Wind turbine blades are critical components of wind turbines. The behavior of a wind turbine blade when operating involves multi-field coupling, requiring a comprehensive and interdisciplinary understanding of its performance under various design load conditions (DLCs). This paper introduces an efficient algorithm for evaluating the strength failure of all finite elements within the blade components. The algorithm utilizes a distributed load application method. It identifies the maximum failure index value and its corresponding DLC for each individual finite element across all load angles of the load envelope. This novel approach rapidly identifies the primary failure DLC at different locations along the blade’s length. To validate the algorithm, a series of aeroelastic response simulations of a 5MW wind turbine blade are conducted. Then, all load angles in load envelope are thoroughly examined, conduct global failure index assessments based on the Hashin laminate failure theory for the skin’s triaxial ply layer and the shear web’s biaxial ply layer of the blade. In essence, this research offers a rapid and accurate algorithm of identifying potential weaknesses. The algorithm is employed to assess the blade’s vulnerability to strength failure, highlighting its practical value in blade strength failure assessment, ensuring the safety and durability of these critical components.
Rock-Fluid Interactions in a Tight Sandstone Reservoir
Authors: Wang Lianhe , Liu Guangfeng , Jiang Fan , Wang Hengli , Yang Daoyong 
Published: August 2024

Abstract
In this work, we present a comprehensive and practical framework to quantify the dynamic characteristics of pore-throat structure together with wettability alterations during a waterflooding process in a tight sandstone reservoir in addition to evaluating the impact of ionic composition and salinity on its performance. Thin section analysis, XRD analysis, SEM tests, PMI and RMI experiments, contact angle measurements, zeta potential tests, and displacement experiments with and without surfactants are integrated. In a reservoir, throats with a radius greater than 0.2 μm are found to control less than 40% of its porosity but contribute over 95% to its permeability. While pore size distribution remains relatively stable, average throat radius with the maximum frequency is decreased from 0.5 μm to 0.3 μm, resulting in a 13.9% decrease in average permeability. Compared to that of using pure brine, adding surfactants reduces the cutoff movable throat radius from 0.033 μm to 0.019 μm, leading to an incremental oil recovery of 4.26%. In a strongly water-wetting formation with its oil filling the center of a pore in the form of oil droplets, the movable water saturation in the two-phase flow zone on the relative permeability curves ranges from 22.5% to 55.1%. At the isotonic point, the water saturation is 43.6%, resulting in a waterflooding oil recovery of 42.1%. Conversely, in a weakly oil-wetting formation with its oil mainly distributing in the form of an oil film, water saturation in the two-phase flow zone varies from 22.3% to 48.1%. At the isotonic point, the water saturation is 38.1%, resulting in a waterflooding oil recovery of 33.2%. Experimental observations demonstrate that low salinity water (LSW) injection expands the electric double layer (EDL) on the oil/brine and rock/brine interfaces, altering the rock wettability; however, the presence of divalent ions in the LSW undermines such wettability alteration. On the other hand, permeability reduction resulting from salinity decrease can be alleviated by introducing divalent ions into the LSW, while continuous injection of monovalent brine reduces the ultimate oil recovery. Alternatively, a mixture of monovalent and divalent ions in LSW is utilized to revive permeability and maintain wettability alteration. Furthermore, an optimized divalent ion concentration is found to be conducive to reducing the cutoff throat radius and achieving a higher oil recovery in a tight sandstone reservoir.
Obstacle Avoidance Nonlinear Model Predictive Controller for Autonomous Surface Vessels With Variable Sampling Time Prediction
Authors: Fernando Eranga , Imtiaz Syed , Ahmed Salim , Murrant Kevin , Gash Robert , Islam Mohammed , Zaman Hasanat 
Published: August 2024

Abstract
This study proposes an innovative nonlinear model predictive control (NMPC) algorithm developed for obstacle avoidance in trajectory tracking of autonomous surface vessels (ASV). The proposed algorithm extends the prediction horizon to enhance situational awareness and enable the controller to calculate the best control actions. The novelty of the proposed algorithm is that it modifies the duration of the prediction by dynamically varying the prediction sampling time. The controller scans along the reference trajectory for potential obstacles and adjusts the prediction sampling time based on the vessel speed and the obstacle size. The simulation results show that the proposed algorithm improves the consistency of the execution time compared to the conventional NMPC and exhibits improved trajectory tracking with less speed variations.
Multi-Objective Optimization of Semi-Submersible Platforms Based on Genetic Algorithm
Authors: Chen Yuchao , Lu Zhen , Wu Xiaofei , Xiao Feng , Tang Minggang , Cheng Xiaoming 
Published: August 2024

Abstract
The main particulars of semi-submersible platforms are the key factor during the design process, which affects the construction cost and hydrodynamic performance. Therefore, it is of great engineering significance to find a design scheme of main particulars that meets the requirements of functional arrangement and construction cost limit and has a relatively good hydrodynamic performance. Aimed at the semi-submersible platform, eight main particulars were selected as input variables to establish the analysis process of grid generation, mass estimation, and hydrodynamic calculation. The hydrodynamic mesh was generated automatically after the parametric modeling of the platform, and the mass and rotational inertia parameters of the platform were obtained through mass estimation. The hydrodynamic performance was calculated by AQWA to obtain the stability, natural periods, and motion RAOs of the platform. Taking a semi-submersible scientific experimental platform as the optimization target, combined with the wave data of the target sea area, the optimization of the main particulars of the platform was carried out based on genetic algorithm. The natural periods and response level of roll, pitch, and heave Motions of the platform were taken as the optimization objectives, and the hydrodynamic performance evaluation function was created through the allocation of the weights of each objective. Meanwhile, with the constraints of the stability and light weight of the platform, the optimization scheme of the main particulars of the platform was obtained, which showed a significant improvement in hydrodynamic performance over the prototype.
An Indirect Measurement Methodology to Identify Fatigue Damage in The Structure of a 2800TEU Container Ship
Authors: Lang Xiao , Zhang Mingyang , Wu Da , Mao Wengang 
Published: August 2024

Abstract
Ships endure fatigue damage from continuous wave-induced stress. The spectral method, despite being a standard assessment tool, is fraught with uncertainties. However, a large segment of today’s maritime vessels abstains from embedding continuous, life-cycle-spanning sensor systems to monitor fatigue damage accumulation. This lacuna precipitates pronounced ambiguities in maintenance prediction, highlighting the urgent need for a rigorously systematic approach to address this knowledge void. To address these issues, this paper introduces a machine learning-based indirect measurement method for evaluating fatigue damage in a 2800TEU container vessel. Utilizing three years of cross-Atlantic voyage data, the study aims to predict fatigue damage more accurately. Our method, which leverages available navigational and environmental data, circumvents the need for intricate sensors. We benchmark our model’s predictions against full-scale measurements and conventional approaches, scrutinizing the accuracy and reliability of each. This indirect strategy not only promises to enhance maritime safety through a more lucid understanding of fatigue accumulation but also supports maintenance planning by estimating long-term fatigue impact. This research posits a simpler yet potentially more efficacious alternative for the surveillance and management of fatigue in maritime vessels.
A Comparison of Wave Directional Spreading Measurements Made With a Spotter Buoy and a Directional Waverider Buoy in Parallel
Authors: Ewans Kevin , Collins Clarence 
Published: August 2024

Abstract
The directional spreading is an important characteristic of a sea state. For example, the probability of extreme wave crests occurring within the sea state and the loading on offshore structures are both dependent on the amount of spreading. Accordingly, field measurements of waves that allow quantification of directional spreading provide valuable insight into the directional characteristics of sea states and consequently into wave crest and wave load modelling. Wave buoys that measure three orthogonal component of surface displacement permit directional spreading to be estimated; the Datawell Directional Waverider buoy and the Sofar Spotter buoy are two examples. The Directional Waverider is a 90 cm diameter buoy and has seen widespread use since its introduction some 35 years ago. The Spotter is a recent development, and due its small size, with a diameter of 38 cm, and relatively low-cost, it has become popular solution for wave measurements, particularly in remote regions of the ocean. The Directional Waverider wave measurements are based on its own acceleration measured with onboard accelerometers, whereas the Spotter wave measurements are based on its own velocity measured with GPS. In this paper we compare the relative performance of the Directional Waverider and the Spotter buoys, with particular focus on the directional spreading, using parallel data sets from measurements made at a near shore, 17 m water depth, location in the US Army Corps of Engineer’s field research facility at DUCK, on the east coast of USA.
Numerical Analysis of Overload/Underload Effect on Fatigue Crack Propagation Behavior of AH32 Steel
Authors: Qin Dong , Dai Qiansheng , Xu Geng 
Published: August 2024

Abstract
A numerical analysis has been done to investigate the effects of different overload conditions on crack propagation behavior of AH32 steel. The tensile overload ratios, overload-underload, underload-overload and underload are investigated in this study. The residual stress distribution in the region near the crack tip under different overload ratios and overload conditions are all the results of plastic deformation of the material near the crack tip during fatigue crack propagation, which shows that applying tensile overload postpone the crack growth, while underload promote the crack growth. Furthermore, it is also observed that the crack closure level shows a fast increase with the increase of overload ratio. Finally, the mechanism of residual stress at the crack tip and the mechanism of plastic deformation at the crack tip controlling the transient crack growth behavior under variable amplitude loading are essentially the same.
A Nonlinear Integrable Water-Wave System Model for Gravity and Surface-Tension Waves
Authors: Nabelek Patrik V. , Yim Solomon C. 
Published: August 2024

Abstract
The completely integrable case of the nonlinear Bousinesq abcd system describing 1+1-dimensional weakly nonlinear and weakly nondispersive model for gravity and capillary waves is developed. The case of gravity and surface-tension solutions for the wave elevation and transverse parcel velocity on the surface of the fluid is examined in detail. The total wave energy of the system is written in Hamiltonian canonical variables and can be used to generate the dynamics in this model from a Poisson bracket. The Poisson bracket and dynamics is defined explicitly using the calculus of variations. The energy is the first conservation law obtained immediately from the Hamiltonian formulation. An infinite number of additional conservation laws are derived using a matrix Lax pair formulation of the system. Analytical soliton solutions (a kind of travelling wave) are derived and are combined in nonlinear superposition via the nonlocal dbar dressing method. The forward and inverse scattering transform (IST) for this system is developed and applied to the calculations of analytical multi-soliton solutions, periodic solutions, and undular bore like solutions. The capabilities of this method are demonstrated via various numerical solutions with a variety of boundary conditions. This nonlinear system and other well-known nonlinear wave models such as the KdV equation are compared. Validation of this system for the description of head on collision of solitons in an experimental flume was conducted in 2019 by Redor et. al. is discussed. Potential practical engineering applications of this system are examined and discussed.
Numerical Investigations on the Influence of Stiffness of Floating Collar and Net Cage on the Hydrodynamic Response of a Quadrate Aquaculture Structure in Waves
Authors: Zhang Xueyan , Zhang Xiantao , Wei Handi 
Published: August 2024

Abstract
A method of investigating the hydrodynamic characteristics and deformation of a quadrate gravity fish farm is presented in this paper, which focus on two components: net cage and floating collar. First, lumped mass model and screen model are adopted to simulate the net structure and calculate the hydrodynamic force acting on the net; the discrete-module-beam (DMB) method is applied to analyze the hydroelastic response of the floating collar. And convergence analysis is conducted to determine a reasonable grid division form of the net cage and the floating collar. Then, drag forces of the rigid and flexible circular cylindrical net cage are investigated and show a good agreement with the experimental data, which verifies the accuracy of this numerical simulation method. Given the simplification of the calculation, the explicit coupling method was used to couple the net cage and the floating collar. Finally, the numerical model is used to study three combination forms of the fish farm in waves, which are flexible net cage with elastic floating collar, flexible net cage with rigid floating collar and rigid net cage with elastic floating collar. And calculation results show that the rigidity or elasticity of the floating collar and the rigidity and flexibility of the net has some influence on the motion amplitude and the mooring loads of the fish farm.
Fatigue Performance of Riser Quality Girth Welds: Fracture Mechanics Study of the Slope Transition Point Using DNV’s Girth Weld Database
Authors: Horn Agnes Marie , Johnston Carol 
Published: August 2024

Abstract
The fatigue design S-N curves for welded joints include a change in slope to enable fatigue life under variable amplitude loading to be calculated. In in DNV-RP-C203 [1] and BS7608[2] the slope changes from m to m+2, for most of the fatigue Classes for welded joints, this is a change from a slope of m = 3 to m = 5. The slope transition point (STP) is located at 1 × 107 cycles in DNV-RP-C203 but at 5 × 107 cycles in BS7608.
A method was proposed which uses fracture mechanics analysis and a variable amplitude loading spectrum to understand the most suitable location for the STP for girth welds in risers and pipelines. Different positions of the slope transition point (STP) were used in conjunction with two-slope S-N curves in the Miner’s damage sum. By comparing the number of blocks of the histogram applied in both analyses, a suitable position for the slope transition point (STP) in the bilinear S-N curves can be suggested, for the particular VA stress histogram applied. This paper describes the findings related to STP for VA loading for different VA stresses, including recommendations for further work.
Local Structural Response of Stiffened Steel Panels due to Wave Impact: Calculated Responses From Measured Slamming Pressures Vs. Hydroelastic Measurements
Authors: Abrahamsen Bjørn Christian , Hellan Øyvind 
Published: August 2024

Abstract
Design of offshore structures must be designed against wave impacts. The local structural integrity of the stiffened panels is often checked by finite element analysis (FEA). The design critical slamming loads used as input to the FEA is often obtained from model tests in ocean basins or towing tanks. The slamming pressure measurements and corresponding response calculations are not trivial and for practical reasons calculations do not normally account for any hydro-elastic effects, except perhaps added mass. So how accurate are such FEA calculations? This document describes a classical FEA procedure using a constant and uniform added mass. The wave impact pressures used as input to the FE response calculations were measured on a 9 × 5m2 area of a vertical column in SINTEF Ocean’s large wave tank. The FE response calculations are compared with measured responses from hydroelastic wave impacts, where the elastic panel covered the same area as the slamming force panels. The structural response is calculated for the 5 largest extreme total force events out of a total of 19 realizations of a critical sea state. The FE results of the calculations are compared statistically to measured extreme strains from the elastic panels. The FE calculation procedure is found to be conservative since calculated design strain values from FEA are significantly larger than the measured design strain values.
An Overview of the 2021 Tropical Cyclone Features in the Western North Pacific Region
Authors: Zhang Kewei , Meng Wenjian , Liu Haijiang 
Published: August 2024

Abstract
As extreme events are getting more frequent in a changing climate, attention has been paid to the anomalous tropical cyclone (TC) features within a single year. The 2021 TC features in the Western North Pacific (WNP) are analyzed in this study. The result shows that more than half of TCs in 2021 can only reach an intensity of the tropical storm category, and 2021 TCs preferred a northeastward drift direction. August 2021 is identified to be one of the major contributors to these scenarios. Influenced by the strong southwest monsoon in early August 2021, TCs Lupit, Mirinae and Nida kept drifting northeastward since their genesis. Although their tracks were nearly parallel, few interactions among them can be detected due to the instantaneous large mutual distance and low TC intensity. Regarding the relatively low TC intensity in August 2021, it is confirmed that the intensification of TCs Lupit and Mirinae was restrained by the terrain effects along the track, while with the insufficient moisture flux convergence perhaps caused by the adjacent subtropical high, TCs Nida and Omais lacked an environment favorable for the intensification. The present study provides an overview of the TC features in WNP with a special focus on the 2021 August scenario, which could enhance the academic community’s understanding of extreme climate events and provide potential assistance for future disaster prevention and mitigation efforts in coastal areas.
A Numerical Study on Swing Motion of Single Point Mooring Floating Vertical-Axis Wind Turbines With Variable-Pitch Blades
Authors: Fukunaga Yuta , Ikoma Tomoki , Tan Lei 
Published: August 2024

Abstract
Although vertical axis wind turbines have not been introduced into floating offshore wind turbine (FOWT), they have the advantage that the power generation mechanism such as nacelles can be installed in a low location, making it relatively easy to provide static stability to the FOWT and eliminating the need for work at high locations during maintenance. In addition to these advantages, this study examines the effect of the thrust control of a vertical wind turbine on the oscillating motion of a floating structure with several vertical wind turbines equipped with a variable pitch mechanism, which is expected to improve the turbine performance.
In this study, the thrust calculated using double multiple stream tube model was added as an external force to the equation of motion of the floating body to simulate the swing motion of the floating body. The moving position of the floating body also differs depending on the pitch control angle, suggesting that the floating body can be moved to any position in the future with appropriate control.