bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wave Riding Through Time – The Contributions of Günther F. Clauss to the Field of Ocean Wave Research
Authors: Sprenger Florian , Kosleck Sascha , Klein Marco 
Published: October 2022

Abstract
Günther F. Clauss is one of the most influential and distinguished international experts in the field of ocean engineering. With 50 years of activities in the field, often in collaboration with national and international colleagues, he has contributed significantly to the visibility and progress of ocean engineering as a research discipline. In his scientific contributions, he has repeatedly established new ideas and set standards. His research contributions include the design, installation and decommissioning of offshore structures, the analysis of loads and motions on floating structures and ships, the development of SAR and oil spill response systems and deep-sea technology.
Across all areas, from fundamental to application driven research, one topic always stood out — the investigation, simulation and experimental modelling of natural waves aiming at a comprehensive deterministic analysis of offshore structures and ships in natural sea states and extreme waves.
From linear superposition of regular waves to the generation of highly nonlinear wave phenomena, from wave-structure interaction to marine oil spill response technologies this paper attempts the almost impossible task: to deliver an overview over 50 years of research by highlighting selected topics, telling the story of Günther F. Clauss who has conquered the inner space.
Structural Optimization of Ships: Benchmark Study of Metaheuristic Algorithms and Constraint Handling Approaches
Authors: Cai Yuecheng , Jelovica Jasmin 
Published: October 2022

Abstract
Optimization of ship structures can be performed using swarm and evolutionary algorithms in search for global optima, which is useful to maximize performance and minimize costs. There is a wide variety of such algorithms available and some have been proposed recently, but tested on mathematical problems. Thus, a benchmark study is performed here to assess their performance on structural optimization of a 180 m long chemical tanker which needs to fulfil class society’s requirements. Main frame is optimized considering firstly structural weight as a single objective and secondly weight and deck adequacy as two concurrent objectives. Optimization of deck adequacy leads to decrease of stresses in the deck. Artificial neural network is used as surrogate model to reduce the computational time. Following swarm and evolutionary algorithms are considered: PSO, NSGA-II, MOEA/D, MVO, MOMVO, MOGWO, IGWO and GSA. Following constraint handling techniques (CHTs) are used within: static and dynamic penalty, adaptive threshold and repair method. All algorithms are run for 30 times and the statistical results are presented. Results are compared in terms of objective values and speed of convergence. Results reveal that recently proposed swarm algorithms perform worse than well-known evolutionary algorithms in terms of the convergence rate and spread of the non-dominated front. In addition, algorithms’ performance is strongly influenced by CHT used. Among the ones tested, the best CHT is the repair method.
Safety Distance During Escort and Convoy Based on Channel Breakout Simulation and Model Tests
Authors: Li Fang , Puolakka Otto , Goerlandt Floris , Kujala Pentti 
Published: October 2022

Abstract
Escort and convoy are typical operations when a merchant ship navigates in ice beyond its own ice-going capability. In such scenarios, a safety distance between the front ship and the following ship is maintained. The leading vessel may suddenly decelerate or even come to a halt if it encounters a heavy ridge or thick ice floe. When this happens, the following ship needs to take actions to avoid collision with the leading vessel. An evasive operation for such collision avoidance is to break out of the channel. The safety distance can be defined as the minimum distance which is needed for successful collision avoidance. This depends on various parameters such as ice thickness, ship speed, channel width, the ship’s icebreaking capability and its manoeuvrability in ice. This paper investigates safety distance during escort and convoy by model-scale experiments and numerical simulation of a ship breaking out of ice channel. The experiments are carried out at Aalto Ice Tank and the numerical simulations are conducted via the in-house simulation software package of Aalto University Marine Technology group. The dependencies of the safety distance on ice thickness, channel width and initial speed are identified via multiple experimental and simulation runs. The simulation proves to provide accurate estimation on breakout distance through comparison with model test results, and reveals the influence of ice thickness, channel width and initial speed on the breakout distance.
Compressive Failure of Ice During Indentation by Rock Particles
Authors: Fitzpatrick Thomas , Taylor Rocky S. , Thijssen Jan 
Published: October 2022

Abstract
The indentation of rock particles into ice is an important aspect of understanding subsea interactions involving ice features and gravelly soil. This paper investigates the indentation of rock particles into an ice specimen, where observations are made to study the effect of changes in indentation rate and the relative spacing from previously formed damage zones on resulting force and pressure trends. Experiments were conducted for three indentation rates: 10 mm/s, 0.5 mm/s, and 0.01 mm/s. Observations were also completed for three unique spacing distances (as multiples of mean rock diameter) between the rock particle and previous damage zones. These setpoint spacings were taken as 2D (26 mm), 5D (65 mm), and 7D (96 mm), where the diameter D was based on a mean rock diameter of 13 mm. Maximum observed forces and pressures exerted onto the ice by the rock particles are examined and compared based on changes in the noted test parameters. The behavior observed during these tests is also compared with results from prior ice indentation tests with steel spherical indenters. The research outlined in this paper will additionally inform future research on the nature of subsea interactions of icebergs with the ocean floor, and how this may affect potential risks related to subsea installations.
A Trawl Net Model Tailor-Made for Simulation of Pipeline and Trawl Board Pull-Over Interaction
Authors: Longva Vegard , Levold Erik , Ilstad Håvar 
Published: October 2022

Abstract
This paper proposes a new trawl net model tailor-made for simulation of trawl board and pipeline pull-over interaction. The trawl net is connected to the trawl board by a steel rope referred to as the sweepline. It is crucial that the correct tension level is simulated for the sweepline during the trawl board and pipeline interaction phase. In previous work, this was achieved by using a single node with quadratic drag properties for the trawl net. However, it was necessary to apply a time-consuming approach where the drag properties were tuned on a case-to-case basis and also stepwise changes of the drag properties throughout the analysis had to be applied in some cases. These drawbacks were avoided in the present work by developing a new trawl net model consisting of 4 nodes and 4 lines. The number of degrees of freedom (DOFs) is very small which makes the proposed model an attractive alternative compared to detailed net structure models consisting of numerous DOFs. Further, the model is applicable for use in standard commercial software since it employs basic structural elements and a quadratic Morison load model. This paper also presents a numerical study where the developed model is validated against model test results of trawl board and pipeline interaction. The trawl net model was found to predict sweepline tension levels in very good agreement with the model tests performed for velocities of 1.5 m/s and 2.06 m/s. The trawl net model was further applied to study the validity of a flume tank test method that applies a constant sweepline tension during trawl board and pipeline interaction. The study showed that non-conservative pipeline interaction loads resulted for the constant sweepline tension model. It is therefore recommended to include the complete trawl net in flume tank testing of trawl board and pipeline pull-over interaction.
Indentation Test Implementation for Rock Strength Correlation by Experimental Method and Simulation Using Distinct Element Method
Authors: Premraj Prajit , Li Zijian , Abugharara Abdelsalam , Butt Stephen 
Published: October 2022

Abstract
Rock strength is an important parameter for the drilling penetration estimation, which is usually determined through standard destructive strength tests, which are known to be sophisticated, expensive, and time-consuming. In addition, the accuracy of these tests has a high standard on the rock sample dimension. As a non-conventional method, the rock indentation test is reviewed and conducted in this study to solve these problems. The sample preparation and test method of the rock indentation test are validated to standardize the test. Based on the stress-strain behavior of the test samples, the correlation between the rock indentation hardness index (IHI) and the rock UCS strength is developed based on different lithology. Then the rock indentation test is simulated in the distinct element method (DEM) in PFC2D software. The robustness of the DEM simulation is validated, and the sample failure pattern is studied. The significance of the process is that it very closely matches with the process a rock fails under the cones of a roller cone drilling bit penetrating the rock.
Development of an Online Ship Simulator to Represent the Dynamic Ship Responses in Regular Waves Using an Inertial Measurement Unit
Authors: Zorrilla Gomez Luis A. , Miranda Sandoval Beatriz K. , Hinostroza Miguel A. , Ramos Quiñonez Saida M. , Ramos Alvarez Nain M. 
Published: October 2022

Abstract
Nowadays, it has been observed a vertiginous growth of technological implementations in the naval and offshore industry, implementations such as online ship simulators that represent the state of the vessel in real-time for a certain sea condition, motion amplification methods to monitor vibrations of the ship propulsion system, virtual shore stations to control autonomous vessels, among others. This work presents the implementation of an inertial measurement unit (IMU) in a scaled-down vessel to observe the dynamic responses of a ship in an online simulator called ShipSim. The implementation considers the responses of the ship in its six degrees of freedom and its behavior in regular waves. The simulator responds to a parametric variation, which considers the direction, amplitude, period of the waves, among other geometric parameters. The scaled-down model of the vessel is fabricated on a 3D printer and is designed to place the IMU system at the geometrical center of the vessel. The IMU is a 6DOF OCTANS surface which is used to measure the ship motions. In addition, real-time results of the different movements of the scaled-down vessel in the time domain are displayed, which are observed in the simulator in the form of time-series graphs.
Offshore Wind Power Construction Efficiency Assessment in Fujian Sea Area Based on the Mixed Integer Linear Programming
Authors: Yang Zihao , Lin Yifan , Dong Sheng 
Published: October 2022

Abstract
China has become the world second largest energy consumer, and IEA predicted that its primary energy demand will double from 2025 to 2030. Offshore wind power construction is difficult and carries high risk. It is extremely difficult to control the cost, of which the construction period is the biggest variable. As to meet the requirements of cost reduction and efficiency increase in the coming era of flat rate, the construction procedures, primary vessels, and equipment need to be properly planned prior to the project startup. For this purpose, an algorithm based on Mixed Integer Linear Programming (MILP) for accurately calculating weather window and construction efficiency of offshore wind power was firstly proposed in this study, which comprehensively takes the complex construction procedures, duration of each link and environmental restrictions into account. Focusing on the offshore seas of Fujian province, utilizing the 1-hour hindcast wind and wave data respectively from the validated reanalysis wind field and SWAN model with a time span of 25 years (1996–2020), the weather window and construction efficiency for monopile foundation construction and offshore wind turbine installation were evaluated both on spatial and temporal scope. With respects to the specific wind farms that will be constructed, the detailed analysis and construction suggestions were provided.
An Experimental Study on the Wave Force on the Slope of Smoothed Mound Breakwater With and Without Crown Wall Under Medium-Long Period Waves
Authors: Han Xinyu , Dong Sheng 
Published: October 2022

Abstract
A Mound breakwater is a common coastal defence against waves. The wave force has greatly related to the stability of the armour blocks. Medium-long period waves have greatly impact on coastal structures and are attracting more and more attention. In this work, the wave force and pressure distribution on the slope of smoothed mound breakwater were studied by experiments. Total of 140 tests were carried out, in which 70 sets are breakwaters with crown wall, and the other 70 sets are breakwaters without crown wall. In the scope of medium-long period waves, the wave force on slope of the breakwater with crown wall is similar to that without crown wall. Neelamani method is more suitable for the breakwater without crown wall and its top submerged. Under short period waves, the maximum pressure on the slope is different. The pressure on the slope with and without crown wall is similar. Pressure at berm with crown wall is greater than that without crown wall. The maximum ratio of the horizontal velocity in front of breakwater with and without crown wall is about 2. A formula was proposed to predict the difference of pressure at the berm with and without crown wall through the difference of reflection coefficient Cr.
Automatic Tsunami Barrier
Authors: Hamada Eigai 
Published: October 2022

Abstract
The Anti-Tsunami Laboratory (ATL) invented and developed the Anti-Tsunami Door (ATD) barrier as an automatic tsunami barrier. In September 2018, ATL and Kyoto University tested a mid-scale model of a three-stage ATD unit and confirmed its performance: (1) functioning automatically (refer to Figure 9); (2) achieving reasonable wave height reduction, which is approximately 40%–80% that of a solid barrier of the same height; and (3) demonstrating reasonable strength for a wooden structure under the mid-scale model test conditions. ATL had firstly planned to test a large-scale model of an ATD unit in Oregon State University (OSU) in May 2020, but that test has been delayed owing to the COVID-19 pandemic. Currently ATL plan to do it in March 2022. Because the wave pressure on the ATD unit is expected to be high during the large-scale model test, ATL requested that the Explosion Research Institute (ERI) simulate the wave pressure on a large-scale model ATD unit, and based on the results, ATL will reinforce the ATD unit. After testing the large-scale model unit, ATL will install ATD barriers along the coast of Japan, customizing the barrier for specific tsunami hazards.
A Study on the Construction of the Tsunami Hazard Database for Mooring Vessels in the Ports
Authors: Masuda Mitsuhiro 
Published: October 2022

Abstract
When a tsunami attacks a coastal area, vessels moored at the wharf suffer serious damage. In fact, more than 20,000 vessels have been damaged, such as landing on a wharf, drifting, or colliding due to the tsunami caused by the Tohoku earthquake in 2011. Tsunamis are significant disasters in Japan. Many researchers have studied the prediction of tsunami damages and the tsunami damage protection measures. However, there are various approaches for studying tsunami damage prediction and tsunami protection measures for each researcher. This means that the tsunami damages and tsunami protection measures are evaluated using various methods in each area and port. Accordingly, when tsunami damages are evaluated, there is currently no unified evaluation method in Japan as a whole. This study proposes a tsunami hazard database for major Japanese ports using the unified evaluation method. The moving particle simulation (MPS) method was used as a tsunami hazard simulation method. Target ports are 23 major Japanese ports. The landing on a wharf and breakage of mooring lines were evaluated as hazard cases for the mooring vessel. In evaluating the landing of vessels on a wharf, the tsunami height in each port, the draft of vessels, and the crown heights by the difference in tidal levels were considered. The tsunami hazard database was constructed based on these results. Finally, tsunami hazards in major Japanese ports were evaluated using the tsunami hazard database.
Integrity Assessment of Electrically Heat Traced Pipe-in-Pipe Plug Weld
Authors: Zhou Daowu , Cao Lingjun 
Published: October 2022

Abstract
To ensure the integrity of three recent electrically heat traced flowline (EHTF) projects, an innovative engineering critical assessment (ECA) of the vacuum plug weld has been performed. Vacuum plug welds are used to seal the annulus of the EHTF pipe in pipe (PiP) after vacuum draw down operations. Plug welds are a high focus area for the EHTF system study.
EHTF PiP in offshore application is installed by a reel-lay method. The plug weld in the carrier pipe is subjected to large plastic deformation, followed by cyclic fatigue in lay-down and operation. These loading conditions pose significant challenges to plug weld integrity management. Due to the unique design and function of the EHTF plug weld, a fit-for-purpose ECA is crucial for demonstrating the weld quality is sufficient to guarantee the integrity of the carrier pipe throughout the entire EHTF life cycle. The allowable defect size from the ECA is also crucial to validate the accuracy of the inspection method.
This paper presents the development of the plug weld ECA methodology. The complexity of the plug weld requires a bespoke ECA to address defect tearing during plastic deformation from reeling, as well as fracture check against operational conditions. In terms of fatigue crack growth for installation and operational phases, there is no off-the-shelf empirical stress intensity factor (SIF) solutions for a plug weld. A bespoke SIF solution for plug weld was developed and verified via 3D FEA. A case study of plug weld ECA in an EHTF using the developed methodology is presented. Segment testing of plug weld to ascertain the reeling defect growth is also described in case study.
Experimental Strain Field Assessment of Pressure Armor Profiles Subjected to Compression Loads via Digital Image Correlation
Authors: Santos Caio C. P. , Pesce Celso P. , Savioli Rafael G. , Burgos Diego S. , Carneiro Campello George , Brun Coser Thiago , de Souza Rodolfo F. 
Published: October 2022

Abstract
The pressure armor layer of a flexible pipe is designed mainly to resist radial loads. Despite the diversity of analytical and numerical studies, some absence of experimental results to evaluate the behavior of this reinforcement layer may be noted. One of the reasons for this lack of experimental studies is the difficulty in accessing and instrumenting this structural layer, particularly when internal contact strain fields are concerned. This study proposes a simple experiment to assess the strain fields of typical pressure armor wire profiles subjected to compressive loads. Using a DIC (Digital Image Correlation) system, the experimental campaign aims to map the strain distribution in a 2:1 scaled sample of a typical wire profile. This technique allows identifying maximum strain values in the cross-sections and more specifically in the contact regions between the pressure armor wires. The obtained experimental results are not yet conclusive. Nonetheless, they provide some interesting insights for a better understanding of the structural behavior of the pressure armor layer. Its findings are valuable for academia and the industry and could serve as a starting point to assess the complex problem of determining cross-sectional strains (and stresses) in pressure armors.
Experimental Investigation of Roughness Effect on Flow Field Around Cylinder in Steady Flow
Authors: Suzuki Masahiro , Ikoma Tomoki , Rheem Chang-Kyu , Aida Yasuhiro 
Published: October 2022

Abstract
In this paper, the velocity distribution around a rotating cylinder in a flow is investigated, and the effect of the roughness of the cylinder surface on the flow field is also investigated. As a research method, we measure the fluid force acting on a rotating cylinder and the flow velocity around the cylinder in a water tank experiment. The tank experiment was conducted under two conditions: in static fluid and in flow. In the flow, we measured both the speed-up side and the speed-down side due to the rotation of the cylinder. For the roughness of the cylinders, the roughness of the cylinder surface was changed by attaching water-resistant abrasive paper to the cylinder. Calculate mean flow velocity, Reynolds stress, and eddy kinematic viscosity from the measured flow velocity. In the case where only the cylinder is rotating in a stationary fluid, the effect of the cylinder surface roughness is strongly observed, the coarser the cylinder surface grain size, the stronger the velocity gradient in the circumferential mean flow velocity, and the overall Reynolds stress increases. In the flow, the effect of the cylinder surface roughness is small and the flow field does not change much.
Advanced Data Analytics Based Hybrid Engine-Propeller Combinator Diagram for Green Ship Operations
Authors: Perera Lokukaluge P. , Belibassakis Kostas , Filippas Evangelos , Premasiri Maneesha 
Published: October 2022

Abstract
Ship owners should comply with the forthcoming IMO legislations that mandates a reduction of ship emissions of at least 40% by 2030 compared with the 2008 baseline. However, it is unlikely that the shipping industry will be able to achieve its 2030 and 2050 emission reduction targets relying only on existing vessel technologies. Hence, the required green ship technologies that relate to industrial digitalization and AI applications should be utilized onboard vessels to achieve these emission reduction targets. This study proposes to analyze a hybrid engine-propeller combinator diagram from both theoretical calculations, i.e. from the vessel hull design, as well as data driven calculations, i.e. from ship performance and navigation data sets, to compare their performance in a single model framework. That would consist of various machine learning applications to create AI. It is expected that such combinations will support to understand the variations among system-model uncertainties in vessels and ship systems as a system of systems and that can also support industrial digitalization in shipping. Furthermore, the hybrid engine-propeller combinator diagram can be utilized to establish the basis for advanced data analytics that will be used to identify optimal vessel navigation and ship system operational conditions.