bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ice-Induced Frequency Lock-in Vibration Analysis of Bottom Fixed Wind Turbine Structure
Authors: Yin Haoyang , Wang Bin , Gao Shan , Chuang Zhenju , Qu Yan , Chen Diyi 
Published: September 2023

Abstract
Ice induced vibration is a serious problem for offshore structures in the ice-covered sea area. Especially when ice moves at low speeds against structures, the coupling of the ice crushing failure process and structural vibration will induce lock-in between ice loads and structural vibration. The strong vibration of the structure has been found in the lock-in process and the loading scenario has been named as frequency lock-in (FLI) vibration, which is a dangerous loading condition that needs to be considered in the design. However, no practical analysis method for FLI vibration is available in existing industry standards due to the lack of understanding of the underlying mechanism. To solve this problem, an FLI analysis method is proposed in this paper based on the ductile damage-collapse mechanism for offshore wind turbine structures. The sample study of a 5MW fixed monopile wind turbine shows that the probability of FLI occurrence on an offshore wind turbine is less than that on an oil platform and lighthouses because the wind turbine has a high rise and low-frequency characteristics. The analysis also shows that the magnitude of the FLI vibration is larger than the random vibration caused by continuous brittle ice crushing.
Study on Robust Design for Navigation Dynamics Test for Small Catamaran
Authors: Lin Chun-Cheng , Liang Wei-Li 
Published: September 2023

Abstract
With the trend of science and technology development, unmanned autonomous guidance and navigation requirements are critical. Recently, the advanced worldwide countries have been developing unmanned surface vessels (USVs) as well as possible; they applied these USVs to investigate the marine science, surveillance, transportation, and other civilian fields. Its advantages, including saving human resources, reducing the operation risks, increasing the flexibility and efficiency of mission execution. In this study, application a small catamaran with Global Position System (GPS), Lidar, PID controller and two-thrusters, etc. Through series of experiments and analyses were carried out using Taguchi’s experimental design methods, Taguchi orthogonal array (L9), ANOVA, and obtained the optimal factor-level combination and approached robust design. Based on the previous study results of resistance and payload for the catamaran, this study selected two control factors: the width of the catamaran (factor-A), and thruster positions (factor-B). The study results presented that Taguchi’s optimal configuration design in manual remote mode and waypoint navigation model is A2B1, and the accuracy is also A2B1 in 85% confidence level. The impact of accuracy is analyzed using Taguchi’s experimental design method, which is expected to improve unmanned surface vessels’ tracking and navigation accuracy and be applied by relevant research agencies.
Decommissioning Analyses for Suction Caisson Foundations
Authors: Sharma Lupamudra , Bubel Julian 
Published: September 2023

Abstract
Suction caisson foundations are an economic alternative to piled foundations to support offshore jackets, especially in situations where there is shallow bedrock. Over the last few years significant advances in the design of suction caissons have developed, leading to a strong increase in installed suction caissons, particularly for offshore wind energy. One ecological benefit of this type of foundation is the possibility of a complete removal at the end of its lifetime with today’s technology.
The removal of suction caissons follows a reverse installation procedure. The CPT-based method with site-specific soil resistance factors is preferably calibrated using trial installations. However, the decommissioning needs to also consider the soil’s aging effects and marine growth, which can result in yet unknown additional forces.
This paper presents the methodology of the decommissioning analysis for suction caissons in sandy and layered soils, which was applied to an Offshore Wind Farm in the North Sea. Due to data restrictions, the method is explained using artificially generated CPT logs and synthetic trial installation recordings. The frictional forces are assessed using a simple CPT-approach [1] with back-calculated soil resistance factors from synthetic on-site trials. The aging effects considered are soil type specific with an approach for sand following [2] and for clay based on [3].
Novel Solution for Mitigating Sloshing in Floating Closed-Containment Aquaculture Tanks
Authors: Wiegerink Johannes , Baldock Tom , Callaghan David , Wang Chien Ming 
Published: September 2023

Abstract
Marine aquaculture in floating closed containment tank systems is a promising proposition for the seafood farming industry as it addresses many farming problems associated with open net pens. Current floating closed containment systems typically have a relatively large free surface area and the contained fluid makes up most of the total mass. A major challenge is sloshing of water in the tanks when they are sited at more exposed farming sites. Significant sloshing affects the structural integrity of the containment tank, the day-to-day operation and fish well-being. As fish benefit from a calm and controlled environment with a free surface for air and sunlight, it is necessary to find an engineering solution to mitigate sloshing while live fish are in the tanks. A novel solution developed by University of Queensland (UQ) researchers is to install a slosh suppression block at the top end of the tank. These suppression blocks may be fabricated from HDPE material, and they form an annular slab with its top surface in line with the internal water surface. These suppression blocks contract the free water surface and interfere with resonance by letting sloshing fluid overtop onto them. Experiments were carried out on a floating containment tank model fitted with slosh suppression blocks in UQ’s wave flume. The experimental results demonstrated that appropriately designed slosh suppression blocks can mitigate resonant sloshing and sloshing amplitude. The sloshing flow associated with slosh suppression blocks reduces interference with the main fluid volume where the fish reside to facilitate a calm and controlled environment for fish well-being.
Dynamic Analysis of Launching and Recovering ROV
Authors: Deng Yulin , Ren Xiudi , Nuernberg Martin , Tao Longbin 
Published: September 2023

Abstract
During operation and maintenance of the offshore wind farms, some regular inspections for the wind turbines are performed by remotely operated underwater vehicles (ROV) and service operation vessels (SOV). However, the ROV often experiences excessive motions as it passes through wave zone due to wave-ROV interaction combined with free surface effects. These movements can cause rope slack and sudden loading, which may damage umbilical components and endanger ROV operation.
This study focuses on experimental measurements and numerical prediction of the dynamic tension in the umbilical during launch and recovery of ROV passing through wave zone under different environmental conditions combined with winching process and ship motions. A coupled offshore vessel, umbilical and ROV hydrodynamic analysis for launching and recovering ROV, which is a typical offshore wind farm service operation, is carried out with coupling characteristics being examined.
The numerical results are validated by the 1:10 scale model test measurements on the ROV. The numerical simulation shows ROV experiences larger umbilical tension in recovery process than that in launch process in general. It is found that the tension in the cable is primarily determined by the strength and direction of wind and wave, and the change of winch speed does not significantly impact on the maximum tension in umbilical within the operational range examined.
Impact of Wake Effect on the Levelized Cost of Energy for a Wind Farm Offshore Rio De Janeiro
Authors: Maali Amiri Mojtaba , Osmar de Almeida Jeferson , Bergman-Fonte Clarissa , Shadman Milad , F. Estefen Segen 
Published: September 2023

Abstract
The present paper aims at investigating the impact of the wake effect on the levelized cost of energy (LCOE) of a wind farm located offshore Rio de Janeiro. The study is performed using the reference 15-megawatt (MW) offshore wind turbine of the International Energy Agency (IEA). The wind farm is defined over a square area, where initially 5 × 5 × 15MW wind turbines are placed uniformly over this area. To investigate the impact of the wake effect on the LCOE, the wind farm buildable area is varied systematically from (4 × 3D) × (4 × 3D) to (4 × 15D) × (4 × 15D), where D is the rotor diameter. To perform the wind farm layout optimization, a symmetrical layout optimization algorithm available within the WindFarmer: Analyst software of DNV GL is used. Further, the wake effect is considered by using a simplified CFD-based model. Moreover, the wind data are predicted by Weather Research & Forecasting (WRF) Model at the hub height of the wind turbine. The results show that considering the optimum layout the wake effect is responsible for an increase of about 2% to 30% in the LCOE values for the studied wind farm buildable areas.
Improved Reliability Assessment Methods for Subsea Cables on Rocky Seabed Using NPV Calculation
Authors: McGrath Nicholas , Griffiths Terry , Jorgensen Jack , Pistani Fabrizio , Draper Scott , Cheng Liang 
Published: September 2023

Abstract
To date, the offshore renewables industry has drawn substantially on prior design guidance and recommended practices from the oil and gas industry. This includes the extension of the existing DNV-RP-F109 to cover on-bottom stability of subsea power cables for offshore wind.
However the overwhelming focus of oil and gas design practice is to avoid loss of containment events which represent potentially catastrophic safety, health and environmental consequences. In contrast, the mechanical failure of subsea power cables in an offshore wind farm represents in practice a purely economic consequence. The inherited factors of safety are therefore entirely inappropriate.
A more relevant approach to provide the most reliably cost-effective product is to quantitatively consider the lifetime design risk through an assessment of the relative net present value (NPV) of different options. This allows comparison between increased upfront costs to reduce the probability of component failure versus the future cost of additional maintenance and repair. NPV reliability methods are recommended in ISO 2394 and the new BS10009 Bottom stability of cables on rocky seabeds.
In this paper the NPV of two on-bottom stability risk management strategies are quantitatively compared for subsea cables on rocky seabeds that are being designed to BS10009. Drawing on recent research findings from The University of Western Australia together with published field data, an example cable is analysed to determine that the probability of cable mechanical failure across the design life is around 3.54 × 10−3. This is roughly half an magnitude lower than the limit detailed in IEC 61400-1.
This scenario is compared to the same cable with the addition of filter units (rock bags), which reduces the overall and annual probabilities of failure. The increased upfront cost is compared against the reduced risk of replacing a segment of cable after failure. Based on the low cable probability of failure it is found that, for this worked example, there is no positive NPV benefit to place filter units on the cable from an on-bottom stability perspective.
Empirical Mode Decomposition for Noise Detection and Filtration of Ice-Induced Load Measurements
Authors: Suominen Mikko , BahooToroody Ahmad , Valdez Banda Osiris 
Published: September 2023

Abstract
Structure-ice interaction is a complex process. The related failure process may include intermediate failures of ice, e.g. flacking, that decreases the load level temporarily before larger failures like bending failure occurs. Simultaneously, loads on a frame move and can reach a level of MN. The loads are commonly determined from the structural response with strain gauge measurements where the noise may be few kNs. As the changes in load level related to intermediate failures may be at the same level as noise, it is difficult to separate noise from the measurements.
Empirical Mode Decomposition is a relatively new method in engineering that considers the measurement signal to be composed of a set of functions. The method parses the measurement data into Intrinsic Mode Functions that represent the true data and noise. Removing the modes related to noise enables the use of the method as a filter. This study applies the described filtration technique to the full-scale measurements conducted onboard S.A. Agulhas II in the Baltic Sea. The results demonstrate a good applicability of the method for the filtration of the data that can be applied in the load identification from the measurement data in the future studies.
Numerical Analysis of Ice Blocks Impact on Stiffened Plates According to a Mohr-Coulomb Material and Node Splitting Technique
Authors: Yoon Sungwon , Herrnring Hauke , Müller Franciska , von Bock und Polach Franz 
Published: September 2023

Abstract
Due to the surge of interest and use in Artic, much research has been done over the years on ice-interaction issues. A reliable ice material model is essential to study ice-structure interactions. The ice model in this analysis uses the Mohr-Coulomb mathematical model, which well expresses the behavior of brittle materials. In addition, the ice model was expanded using the node splitting technique to preserve mass and energy, in opposite to the commonly used element erosion technique. In this paper a numerical analysis of a collision between ice blocks with masses of around 100 kg and 600 kg and stiffened steel plates was carried out using the explicit solver LS-DYNA R11.1.0. To validate the simulation, kinetic energy and maximum dent on stiffened steel plates were compared with experimental data performed at the Norwegian University of Science and Technology and the Aalto University. The impact speed is around 4 and 7 m/s, which is frequently observed in ship collisions with ice. As a result of numerical analysis, MCNS ice blocks with particularly high kinetic energy were analyzed to be consistent with the NTNU and Aalto experimental results. In terms of energy balance, it was consistent with previous study in which 20 to 30 % of collision energy was dispersed in the structure. This proves that MCNS ice model can be used to accidental limits scenarios.
Third-Order Steady-State Solutions of Bichromatic Bi-Directional Water Waves
Authors: Gao Zhe , Liu Yi , Jia L. S. , Teng Yunfei , Wang Dejun , Jia Xu 
Published: September 2023

Abstract
In the context of potential flow theory, the resonance mechanism leads to energy transfer between primary waves, resulting in a series of dynamic physical phenomena. However, for the analytical solutions of surface gravity waves, resonance interactions become an obstacle in solving the steady-state solution of surface gravity waves, resulting in a small divisor problem. Due to the small divisor problem caused by harmonic resonances, the classical perturbation method fails when solving third-order solutions of bichromatic bi-directional water waves. In this paper, a novel method is proposed to solve third-order solutions of bichromatic bidirectional water waves, which successfully overcome the small division problem caused by harmonic resonance and is applicable to resonance and non-resonance cases. Finally, the third-order steady-state solutions provide explicit expressions for the surface elevation, surface potential and nonlinear dispersion relations.
A Computational Study to Predict Seakeeping Performance of a Surfaced Submarine in Irregular Waves
Authors: Jung Doojin , Kim Sanghyun 
Published: September 2023

Abstract
In general, submarines are designed to optimize operation below the water surface because they spend most of their time in an underwater condition. However, the performance in free surface condition is also important because submarines face a variety of scenarios to complete operational missions and the free surface condition is unavoidable for port departure and arrival. In case of submarine, a numerical accuracy of potential theory for seakeeping analysis is excellent in submerged condition, but it is poor in free surface condition because of nonlinear effects near the free surface area. In this study, Star-CCM+ was used as a Reynolds-averaged Navier Stokes (RANS) solver to estimate the seakeeping performance of Canadian Victoria Class submarine in irregular waves, and the results were compared to those of model tests from a published paper. In addition, the potential theory code was also used for seakeeping performance to compare with Computational Fluid Dynamics (CFD) results. From the calculation results, the motion responses in irregular waves by using CFD showed similar trends to experimental results, while motion responses from potential code showed significantly larger values than experimental results. In conclusion, CFD simulations with irregular waves can be good solution to predict the seakeeping performance of submarines in free surface condition.
Motion Response Study of the Floating Dock During the Spar Installation
Authors: Pani Soumyashree , Saha Nilanjan , Sundaravadivelu R. 
Published: September 2023

Abstract
Floating wind turbines are an evolving renewable energy source, but installing them offshore is difficult due to weather conditions. A new approach called the floating dock concept has been developed to address this issue. The dock makes the process more reliable by shielding the installation process from weather disturbances. This study examines a floating dock of 60 m diameter used to install a 5 MW wind turbine on a spar of 15 m diameter. The dock has a gate that allows for establishing a spar at the desired location. The system is analyzed under two conditions: with the gates closed and open since the latter has a risk of instability. The paper uses the ANSYS-AQWA software to study the heave and pitch response of the structures. Free decay tests were conducted numerically to obtain the total damping matrix, from which the viscous damping matrix was derived. This matrix was also incorporated in the analysis of the structures. The behavior of the system was analyzed, and the results ensured that the floating dock was effective in reducing the responses of the spar foundation.
Review on Feasibility of Bottom-Fixed Offshore Wind Development in the Arctic Focusing on Icing Problems
Authors: Gu Yingjie , Ong Muk Chen , Janocha Marek Jan , Blomgren Atle 
Published: September 2023

Abstract
The Arctic is a resource-rich region, especially concerning hydrocarbons, minerals, and fisheries abundance. Due to remoteness and harsh environment, communities in some parts of the Arctic rely heavily on diesel-based power generation. In addition to the challenge of maintaining reliable sustainable supply chains for fossil fuels, the generator emissions also have an undeniable negative impact on the vulnerable Arctic ecosystems. Low-cost, efficient, clean energy sources are required to support the sustainable development of the most remote communities. Comprehensive comparison and evaluation of the advantages and disadvantages of known energy generation and storage technologies suitable for cold climate deployment are presented in this study. Among analyzed solutions, hybrid power systems that incorporate bottom-fixed offshore wind turbines (BFOWTs) have great advantages of providing green energy and reducing land occupation and energy generation costs. Many challenges and risks require further investigation before BFOWTs can be commercially deployed in the Arctic. The main risks of BFOWTs deployed in the Arctic are the structural interaction with sea ice and ice accretion on wind turbine elements. To address issues about ice accretion, this study provides reviews of state-of-the-art research on ice detection and ice mitigation technology. Important knowledge gaps related to the BFOWT development in the Arctic are identified and future research recommendations are made.
Study on Deformation Analysis and Prediction Method of Multi-Function FPSO Hull
Authors: Yuan Hongtao , Ren Huilong , Chen Gang , Yin Yan , Wang Chao , Wu Bin 
Published: September 2023

Abstract
The total longitudinal bending deformation of the hull girder will affect the static function of the ship equipments and the dynamic response of the hull girder structure, while the influence of the deformation of the FPSO hull girder on the design of the Topside module support structure can not be ignored. Therefore, in addition to the conventional design load, the influence of the displacement of the Topside module support structure caused by the hull girder deformation should also be considered in the design of the FPSO Topside module. There are cumbersome calculation steps and troublesome solution process in the calculation of FPSO Hull Beam Deformation based on the undetermined coefficient method, continuous subsection integration method proposed based on the single span beam theory and the total longitudinal bending deformation theory of ship hull girder. Aiming at the shortcomings of the traditional prediction methods of FPSO hull girder deformation, a simplified deflection calculation formula is proposed based on engineering experience, which is convenient for the rapid analysis of the FPSO hull girder deformation, and compared with the numerical simulation results of Finite Element Analysis to verify the applicability of the empirical formula in the front-end engineering design and basic design.
Ice Resistance Prediction Using Explainable Deep Learning Method
Authors: Sun Qianyang , Zhou Li , Ding Shifeng , Liu Renwei , Wang Aimin , Chen Jiaming 
Published: September 2023

Abstract
Accurate prediction of ice resistance plays an important role in ensuring the safety of ship navigation when sailing in ice regions. In recent years, machine learning has been widely applied in the field of ships, among which deep learning is a common method. This study combines the scientific problems of ice resistance for ice-ship design closely, focusing on the design of a deep learning network for predicting the resistance of ice-sailing ships, proposes a Graph Neural Network method to predict ship resistance in ice area based on different data preprocessing methods. The predicted response and real response of the network, the feature weight relationship of the network and the prediction error are shown in the form of a graph. This study refers to the traditional semi-empirical formula, selects appropriate input features (ship design parameters and ice mechanic properties). The neural network is trained through the ship model test data. Different data preprocessing methods are selected to analyze the error of network prediction results, and the generalization ability and fitting effect of the network are evaluated. This work will provide reference for ice-sailing ship.