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Kurniawan, Akhmad Reinaldy, Adi Kurniawan, Sardono Sarwito, Ahlur Roi Novanto Gumilang et Firman Budianto. « Power flow analysis of DC distribution system in a ship with non-electric propulsion ». International Journal of Electrical and Computer Engineering (IJECE) 13, no 1 (1 février 2023) : 9. http://dx.doi.org/10.11591/ijece.v13i1.pp9-16.
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<span lang="EN-US">Direct current (DC) shipboard power distribution system offers higher power efficiency and voltage stability compared to the alternating current (AC) systems due to lower impedance. The implementation of DC distribution system in all-electric ship seems to be worthy since the reduction of power loss and voltage drop could overcome the drawback of DC system. However, the effectiveness of DC distribution system in ship with non-electric propulsion has not been investigated yet. Unlike in an all-electric ship, electric power flow in the distribution system of a ship with mechanic propulsion is considerably lower. The study aims to provide numerical analysis of power loss and voltage drop reduction on DC distribution system that applied to a ship with mechanic propulsion. The power flow analysis is performed on a tanker ship. Contrary to the hypothesis, the results show that the DC power distribution increase the power losses about 15% compared to AC system due to the addition of rectifier and inverter. However, the voltage drops are decreased in DC distribution system. Further investigation in the other aspects should be performed before concludes whether DC distribution system is worthy to be used in the aforementioned ship.</span>
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Wang, Chuan, Hui Long Ren et Hui Li. « A Finite Element Method to Simulate Ice Based on Multi-Surface Failure Criterion ». Applied Mechanics and Materials 623 (août 2014) : 90–96. http://dx.doi.org/10.4028/www.scientific.net/amm.623.90.
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A finite element method is introduced to simulate ice failure based on multi-surface criterion. The effects of porosity, temperature and strain rates on the ice mechanic property are taken into consideration. The main principle to simulate environment is explained. Through second developed to the finite element software, the process of ship-ice interaction is simulated. And the ship motion, ice force and ice failure mode are predicted by this method. The result is compared with other papers. the numerical simulation phenomenon is nearly same with the actual process. It suggests that simulation is reasonable, and the model has potential value in simulations of assessing ship strength. The fatigue damage is pointed out to be a special problem in ice-going ship design.
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Mazur, E., P. Shcherban et V. Mazur. « Research and evaluation of the operating characteristics of used ship engine oil using the process parameter matrix method ». FME Transactions 51, no 4 (2023) : 497–503. http://dx.doi.org/10.5937/fme2304497m.
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The marine engine circulating oil change interval suggested by manufacturers is a guideline based on general scale statistics and laboratory testing. At the same time, the actual remaining oil life can significantly correct the time and money spent by the chief mechanic service on system maintenance. In the present work, a method has been developed that makes it possible to increase the service life of mechanisms and the reliability of ship equipment under operating conditions. The effect is achieved by identifying and analyzing the most significant and influential parameters of the lubricant used. An array of physical and chemical data on lubricants, taking into account the equipment's time to failure, is processed by a special computer program for monitoring the state of a marine engine in operating mode. The developed software package allows more accurate and timely maintenance of the SPP (ship power plant).
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Elmardi Suleiman, Osama Mohammed, et Surag Mohammed Saeed Ali. « INTRODUCTION AND LITERATURE REVIEW OF CORROSION AND BIOFOULING IN MARINE ENVIRONMENT ». International Journal of Engineering Applied Sciences and Technology 7, no 8 (1 décembre 2022) : 41–61. http://dx.doi.org/10.33564/ijeast.2022.v07i08.005.
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This study aims to increase the power and the performance of marine structures by protecting them from corrosion and biofouling, which cause reduction of the vessels power. There are many factors in marine environment such as salinity, pH, temperature, and velocity, which cause corrosion. There are three main reasons concerning the study of corrosion. These reasons are safety, economics, and conservation. In addition, there exists the aquatic organism bio-film, which covers the vessels hull. This phenomenon called fouling and it results in increasing hydrodynamic drags, lower the maneuverability of the vessels and increase the fuel consumption. All these factors lead to the deficiency of ships performance. There are many methods that can be used to prevent vessels from the results of fouling and corrosion, among these methods coating i.e. using a highly corrosion resistant material on the ship hull and cathodic method i.e. using zinc for electro mechanic interaction could be effective if implemented properly.
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Sibryaev, Konstantin Olegovich, Maxim Michailovich Gorbachev et Adel Damirovich Ibadullaev. « DEVELOPING INFORMATION PROCESSING UNIT USED IN SOFTWARE AND HARDWARE COMPLEX MONITORING SHIP SHAFT LINE TORSIONAL VIBRATIONS ». Vestnik of Astrakhan State Technical University 2021, no 1 (31 mai 2021) : 22–28. http://dx.doi.org/10.24143/1812-9498-2021-1-22-28.
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The article considers torsional vibrations in combination with other technical factors, which remain a cause of damages and breakdowns of the ship's propeller shafts, intermediate shafts and crankshafts. Torsional vibrations inevitably occur in the ship plants. It can be explained by the uneven torque of the engine and the torque on the propeller (exposure of the propeller, uneven movement of the water flow, stormy weather, etc.), which leads to alternating twisting of the shaft. To reduce torsional vibrations, dampers are used, which require periodic performance testing by using the torsiography procedure. In contrast to the existing monitoring systems of the technical condition of the damper, it is planned to install an information processing unit for the software and hardware complex for monitoring torsional vibrations of the ship's shaft line and the parameters associated with them (vibration and temperature changes of the flexible elements of the connecting couplings). The unit under development will allow to constantly monitor the level of torsional vibrations and, if they increase, to signal the ship's mechanic to switch to another operational mode of the main engine, which will increase the reliability and automation of the ship power plants, the safety of navigation, and reduce the economic costs of ship operating
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Karczewski, Artur, et Janusz Kozak. « Variants method approach to the preliminary ship design ». Mechanik 90, no 12 (11 décembre 2017) : 1196–98. http://dx.doi.org/10.17814/mechanik.2017.12.206.
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Typical ship designing is an iterative method based on the accumulated experience of already built ships. In the case of a completely new type of ship, without the „dowry of previous experience”, the design consists in developing a series of parallel variant solutions using the optimization. The paper identifies selected designing methods applying the optimizations used in the preliminary ship design. The optimization methods used in the ship design are discussed.
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Jokosisworo, Sarjito. « PENGARUH BESAR ARUS LISTRIK DENGAN MENGGUNAKAN ELEKTRODA SMAW TERHADAP KEKUATAN SAMBUNGAN LAS BUTT JOINT PADA PLAT MILD STEEL ». Kapal : Jurnal Ilmu Pengetahuan dan Teknologi Kelautan 6, no 2 (28 mars 2012) : 118–22. http://dx.doi.org/10.14710/kpl.v6i2.2725.
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The influence of mechanic disposition, is one of the factor influence ship strength. This influence can be test by mechanical test in welding butt joint. The result test database analysis can be conclude that very helpful to increase safety and quality butt joint. With steel specification C= 0,15%, Si= 0,24%, Mn= 0,88%,P= 0,018%, S= 0,034%. This material give a 90, 110, 125 ampere with SMAW AC electrode diameter 3,2 mm x 350 mm with V root and 600 angle In the fabrication of mild steel products, components or equipment, manufacturers employ welding as the principal joining method. Mild steel are weldable materials, and a welded joint can provide optimum corrosion resistance, strength, and fabrication economy. However, designers should recognize that any metal, including stainless steels, may undergo certain changes during welding. It is necessary, therefore, to exercise a reasonable degree of care during welding to minimize or prevent any deleterious effects that may occur, and to preserve the same degree of corrosion resistance and strength in weld zone that is an intheren part of the base metal
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Родионов, А. А. « The science of strength before and after I.G. Bubnov. To the 150th anniversary of the founder of the ship's structural mechanics ». MORSKIE INTELLEKTUAL`NYE TEHNOLOGII)</msg> ; 2, no 3(61) (28 août 2023) : 10–18. http://dx.doi.org/10.37220/mit.2023.61.3.022.
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Рассмотрены истоки строительной механики, которые ведут свое начало с возведения величественных инженерных сооружений древности. Развитие строительного дела в древней Греции стимулировало разработку статики, составляющую основу строительной механики. Богатейший опыт возведения инженерных сооружений Римской империи обобщен в десятитомном трактате Витрувия об архитектуре. Эпоха возрождения сформировала устойчивый интерес к науке о прочности. Начало XVIII ознаменовано поиском путей применения нового математического аппарата интегро-дифференциального исчисления Ньютона-Лейбница в физике и механике. Значительные результаты в этом направлении получены Яковом и Иоганном Бернулли, Эйлером, Лагранжем. Применение железа в создании инженерных сооружений при обустройстве путей сообщения способствовало окончательному формирования науки о прочности, на базе которой трудами И.Г. Бубнова – математика, механика и корабельного инженера создана наука - строительная механика корабля. Фундаментальные основы строительной механики корабля постоянно совершенствовались и совершенствуются последующими поколениями ученых и практиков, но сохраняют в себе главные положения, сформулированные ее основателем. Перспективные направления развития строительной механики определяются широким применением высокоточных математических моделей, применением новых композиционных материалов, аддитивных технологий изготовления деталей и конструкций для создания надежных объектов, с требуемыми характеристиками эффективности. The origins of construction mechanics, which originate from the construction of majestic engineering structures of antiquity, are considered. The development of the construction business in ancient Greece stimulated the development of statics, which forms the basis of construction mechanics. The richest experience in the construction of engineering structures of the Roman Empire is summarized in Vitruvius' ten-volume treatise on architecture. The Renaissance era forms a steady interest in the science of strength. The beginning of the XVIII century was marked by the search for ways to apply the new mathematical apparatus of the Newton-Leibniz integro-differential calculus in physics and mechanics. Significant results in this direction were obtained by Yakov and Johann Bernoulli, Euler, Lagrange. The use of iron in the creation of engineering structures in the arrangement of communication routes contributed to the final formation of the science of strength, on the basis of which the works of I.G. Bubnov, a mathematician, mechanic and ship engineer created the science of ship construction mechanics. The fundamental foundations of the ship's structural mechanics have been constantly improved and are being improved by subsequent generations of scientists and practitioners, but they retain the main provisions formulated by its founder. Promising areas of development of structural mechanics are determined by the widespread use of high-precision mathematical models, the use of new composite materials, additive manufacturing technologies for parts and structures to create reliable objects with the required performance characteristics.
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Kovalchuk, Tetiana. « Legal status of ship mechanics of the merchant navy of the Azov-black sea region of the XIX - early XX centuries ». Bulletin of Mariupol State University. Series : History. Political Studies 11, no 30 (2021) : 51–58. http://dx.doi.org/10.34079/2226-2830-2021-11-30-7-51-58.
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This article reveals the problems of the personnel of the crews of sea-going merchant vessels of the Azov-Black Sea region. The unrestrained development of domestic and foreign trade in the conditions of a shortage of professional personnel of the merchant navy pushed the Russian Empire to the legal regulation of the competencies of ship mechanics in the early XX century. Until 1903, the legal status of mechanics in the Russian merchant navy was uncertain. Ship mechanics in the Trade Charter of 1893 were listed as members of the crew of free hire and were not part of the command staff. This created serious inconveniences both for ship captains, who found it difficult to cooperate with mechanics, and for mechanics who had no legal basis to manage their immediate subordinates (drivers and firemen). In addition, in the Russian Empire at that time there was no clear system of ship mechanics training for both cabotage and long-distance navigation due to the low level of population’s education, and insufficient attention from the state to the problems of the merchant navy. «Regulations about mechanics on ships of the merchant navy», approved in 1903 defined the state benefits to ship mechanics − deprivation from military service and enlistment in the command of the ship, provided an opportunity to obtain the rights of honorary citizen. It defined the requirements for those who aspired to obtain the positions of ship mechanics: reaching the age of majority, passing the tests of the qualification commission and the presence of a practical qualification. The regulation of the legal status of ship mechanics at the legislative level has influenced on the organization of their training in the Russian Empire. In 1901, a mechanical department for the training of ship mechanics was opened at the Odessa School of Merchant Shipping, for the first time in the Russian Empire. There were no educational institutions in which they could receive higher education in the early XX century. The appearance of the «Regulations on Mechanics on Merchant Navy Ships» in 1903 corrected the negative situation caused by the legal uncertainty of the rights and responsibilities of merchant navy mechanics. The provision raised the prestige of ship mechanics, who received officer's rights and, at the same time, increased their salaries.
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Zen, Hardi, Indra Ranu Kusuma et Endang Widjiati. « Robust Laboratory Scale Seakeeping Test Wave Measurement Method Use Ultrasonic Sensor ». IOP Conference Series : Earth and Environmental Science 1081, no 1 (1 septembre 2022) : 012042. http://dx.doi.org/10.1088/1755-1315/1081/1/012042.
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Abstract The seakeeping test is one of the tests done in the Indonesia Hydrodynamic Laboratory (IHL) test tank on a model ship or floating unit. In the test tank, a wave can be generated by using electric and mechanic wave flaps that are pre-programmed on a certain condition of the wave, i.e. different frequencies and amplitude. To measure waves, produced by a wave generator, a wave measuring instrument is needed that can measure changes in water level in the test tank. The current wave measuring instrument is in the form of a 600 mm twin wire wave probe. This instrument is can be used to measure waves in the test tank but has limitations because it is only placed in one location without being moved. Another method is developed to be used in making alternative measuring instruments using ultrasonic sensors. In this paper, this alternative wave measuring instrument shows that measuring waves even when moving the measurement point to a new point location or following a towing carriage can be done and gives better measurement results. Based on these results, this new measuring instrument can be used in a more complex configuration test in the tank.
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Kononova, Olena. « Formation of communicative competence of future ship engineers using critical thinking technologies based on the “World Café” method ». Scientific Bulletin of Mukachevo State University Series “Pedagogy and Psychology” 9, no 4 (28 novembre 2023) : 27–34. http://dx.doi.org/10.52534/msu-pp4.2023.27.
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The transition to a new educational model that will ensure the independence of thinking and speech activity of the future mechanic-officer is a strategic vector of improvement and change in the educational space, which will help maintain the competitiveness of both the teacher and the student. The purpose of this study was to exchange experience of theoretical and practical application of the World Café method as a tool for critical thinking in the context of formation of communicative competence of future ship engineers. To fulfil this purpose, the survey method was used to collect and analyse information on the development of productive critical thinking of education students during discussion in English language classes for professional orientation. The main characteristics and requirements for critical thinking in the professional training of future ship engineers were defined, namely: clarity, accuracy, validity, logic, impartiality. It was proved that the process of forming critical thinking is a necessary condition for independent and responsible actions of maritime specialists in problematic situations. Critical skills such as analysis, evaluation, explanation, and summarisation were highlighted, which are important when discussing professional situations. It was substantiated that critical thinking requires active learning and does not tolerate passive learning, and therefore classes should be interesting and exciting, productive, and motivational. It was emphasised that the main purpose of modern maritime education is not just the accumulation of knowledge and skills, but the training of cadets as independent subjects of educational activities capable of learning and improving their knowledge. The study described the advantages of the World Café method. It was noted that in distance education, “the world cafe” method is widely used in online classes on the Moodle, Zoom, Google Classroom, Whiteboard Miro platforms for group work and knowledge sharing. The practical value of this study is that its results can be used by teachers in preparation for classes in English (for professional purposes), literature, history, etc
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Lamb, Thomas, Nathaniel Beavers, Thomas Ingram et Anton Schmieman. « The Benefits and Cost Impact of Aluminum Naval Ship Structure ». Journal of Ship Production and Design 27, no 01 (1 février 2011) : 35–49. http://dx.doi.org/10.5957/jspd.2011.27.1.35.
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Due to budget pressure and a growing diversity of mission requirements, the US Navy is in need of affordable and operation-flexible ships. This paper presents an acquisition and total life cycle cost comparison of steel and aluminum equivalent naval ship designs. A common perception is that aluminum ships cost significantly more than steel ships. This paper illustrates that even though the cost of the equivalent aluminum ship structure is 40% more than the steel structure, the equivalent aluminum naval ship can be built within just 7.5% of the acquisition price of the steel ship. This is possible because of the cascading benefits of the aluminum ship's significantly lighter weight. Advances in aluminum technology and new facilities in the shipyards for aluminum production are further improving the acquisition cost of aluminum ship. From a total life cycle cost perspective, aluminum ships enjoy a clear advantage over steel ships, the details of which are provided in this paper. Based on the findings presented in the paper, it is suggested that the US Navy should consider broadening its use of aluminum ships.
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Hauge, Audun, Roger M. Konieczny, Per Ø. Halvorsen et Arild Eikum. « Remediation of contaminated sediments in Oslo harbour, Norway ». Water Science and Technology 37, no 6-7 (1 mars 1998) : 299–305. http://dx.doi.org/10.2166/wst.1998.0765.
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During the past 60-70 years, contaminated sediments from local rivers have been settling in the harbour basin of Oslo. This contamination, combined with that from other harbour activities, has developed into a serious pollution problem with both organic and inorganic contaminants. Since 1992 dredging activities have been restricted until the effect of dredging was determined and a safe disposal was found for the sediments. Because of this restriction, a conflict situation arose in terms of decreasing sailing depths, and dispersal of large quantities of contaminated sediments into the water column each day from ship traffic. A complete plan of action to remediate Oslo Harbour was started in 1994 and delivered to the State Pollution Control Authority (SFT) in August 1996. An evaluation of environmental risks connected to the remediation work has been carried out along with the determination of the requirements for the monitoring programme during and after the work. Preliminary evaluation of dredging techniques indicates that mechanic/hydraulic equipment will cause the least dispersion of sediment. Several options for treatment of the sediments have been evaluated. Study results point out that conditioning prior to disposal of the sediments in a confined disposal site in the harbour area, is the most cost effective solution. Seven disposal sites with a capacity of 0.5 mill. m3 have been identified. Two of the sites are integrated with a subsea road tunnel crossing the harbour basin. The other disposal sites will serve as new dock area after closure.
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Guk, Junu, Daesu Park, Seongjin Kim, Hyoseop Lim et Sokhee P. Jung. « Current Status and Perspectives of Eco-friendly Electric Ships ». Journal of Korean Society of Environmental Engineers 45, no 5 (31 mai 2023) : 256–66. http://dx.doi.org/10.4491/ksee.2023.45.5.256.
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Recently, there has been an increasing national interest in air pollutants including fine dust due to worsening air quality. As more people become interested in the environment, policies that consider the environment are being implemented in various fields as regulations also change. It can be seen that regulations are being strengthened as the MARPOL standards for air pollutants such as sulfur oxides, nitrogen oxides, carbon dioxide, EEDI are being lowered. According to the United Nations Conference on Trade and Development, 80% of goods trade is transported by ships and the amount of air pollutants emitted by ships cannot be overlooked. Therefore, there is a growing need to transition from traditional fossil fuel-powered mechanical ships to eco-friendly ships. In this review, we analyze one type of eco-friendly ship, the electric ship. We compare the economic viability of electric ships with traditional mechanical ships and investigate the current status and commercialization cases of electric ships. We also provide insights into the future prospects of electric ships.
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Gao, Jianjie, et Yuquan Zhang. « Ship collision avoidance decision-making research in coastal waters considering uncertainty of target ships ». Brodogradnja 75, no 2 (1 mars 2024) : 1–16. http://dx.doi.org/10.21278/brod75203.
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Ship collision avoidance has always been a concern and it is crucial for achieving safe navigation of ships at sea. There are many studies on ship collision avoidance in open water, but less attention on coastal waters considering the uncertainty of target ships due to the complexity of the environment and traffic flow. In this paper, collision avoidance decision-making research in coastal waters considering the uncertainty of target ships was proposed. Firstly, accurate ship trajectories are obtained by preprocessing the raw Automatic Identification System (AIS) data. Subsequently, the processed trajectories are clustered using the Ordering Points to Identify the Clustering Structure (OPTICS) algorithm and Hausdorff distance, acquiring a dataset for trajectory prediction of target ships. Then, a mixed Gaussian model is utilized to calculate the prior probability distribution of the prediction model, thus establishing a trajectory prediction model that considers the uncertainty of the target ship. Finally, ship maneuverability is simulated using the Mathematical Model Group (MMG) and Proportion Integration Differentiation (PID) models, and a collision avoidance decision-making model for ships is constructed. The proposed algorithm has been tested and verified in a case study. The results show that the approach effectively predicts the trajectory of the target ship and facilitates informed collision avoidance decision-making.
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Garbatov, Yordan, et Petar Georgiev. « Principal component analysis of containership traffic in the Black Sea ». Brodogradnja 74, no 4 (1 septembre 2023) : 73–87. http://dx.doi.org/10.21278/brod74404.
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A novel quantitative analysis employing the Principal Component Analysis (PCA) of containership traffic in the Black Sea from 2018 to 2021 is performed. The study uses a matrix covering five ship size classes from A to E for four years of operation, from 2018 to 2021, accounting for ship traffic, CO2, fuel consumption (FC), shipping intensity, and eco and traffic efficiency. Only the first two principal factors are analysed because of their total variation weight. Shipping intensity, FC intensity, and CO2 intensity plays a significant role in the first factor, while Eco efficiency, FC efficiency, and Traffic efficiency are considered for the second factor. Notably, the set of parameters pertains to time and is strongly associated with DWT. Two principal components were identified, F1 and F2, where F1 integrates efficiency and intensity. At the same time, F2 separates the intensity from the efficiency conditional on the ship size and the year of operations. In the principal component F1 the activities of ships A and C differ from B, D and E, separating more efficiently from less efficiently used ships, and in F2, the activities of class sizes of ships C and D and E contrast A and B ships, distinguishing the big-size class ships from small ones. It was concluded that the most intensively used ships are the ship size classes C and D, and the most efficient are ship size classes A and B. The most intensive use of the ships was in 2020, followed by 2021, and the most efficient were in 2018, 2019. Based on the ship activities and using the Within-class variance, ships are grouped into two clusters of similar activities, where the first one, with lower variance and more homogeneous, includes only the ship size class A. The second one with a relatively large variance consists of the rest size of the ships. Linear relationships considering the intensity and efficiency are derived as a function of the main variables, where the factor loading represents the variable’s coefficient, given as a relative weight to any factor.
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Ma, ZhongXin. « Influence of scale effect on flow field offset for ships in confined waters ». Brodogradnja 75, no 1 (1 janvier 2024) : 1–22. http://dx.doi.org/10.21278/brod75106.
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To investigate the flow field characteristics of full-scale ships advancing through confined waters, the international standard container ship (KRISO Container Ship) was considered as a research object in this study. Using the RANS equation, the volume of fluid method and the body force method were selected to investigate the hydrodynamic characteristics of a model-scale ship (the model-scale ratio λ=31.6) and a full-scale ship advancing through confined waters at low speed. A virtual disk was used in the full-scale model to determine the influence of the propeller on the ship’s flow field. First, the feasibility of the numerical calculations was verified. This proves the feasibility of the numerical and grid division methods. The self-propulsion point of the full-scale ship at Fr=0.108 is determined. The calculation cases of model-scale and full-scale ships (with or without virtual disks) at different water depths and distances between the ship and the shore were calculated, and the changes in the hull surface pressure, the flow field around the ship, and the wake fraction near the ship propeller disk in different calculation cases were determined and compared. The variations in the surge force, sway force, and yaw moment between the model- scale and full-scale ships were generally consistent. In very shallow water (H/T=1.3), the non-dimensional force and moment coefficients for model-scale ships increase more rapidly with decreasing distance from shore, suggesting that using model-scale ships to investigate the wall effect in very shallow water will result in predictions that are biased towards safety. By comparing full-scale ships with and without propellers, it was discovered that the surge force, sway force, and yaw moment were marginally greater in the propeller-equipped ship due to the suction effect, and the accompanying flow before and after the propeller was slightly smaller, with less asymmetry.
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ALAM, MOHAMMAD-REZA, et CHIANG C. MEI. « Ships advancing near the critical speed in a shallow channel with a randomly uneven bed ». Journal of Fluid Mechanics 616 (10 décembre 2008) : 397–417. http://dx.doi.org/10.1017/s0022112008004035.
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Effects of random bathymetric irregularities on wave generation by transcritical ship motion in a shallow channel are investigated. Invoking Boussinesq approximation in shallow waters, it is shown that the wave evolution is governed by an integro-differential equation combining features of Korteweg–deVries and Burgers equations. For an isolated ship, the bottom roughness weakens the transient waves radiated both fore and aft. When many ships advance in tandem, a steady mount of high water can be formed in front and a depression behind. Wave forces on both an isolated ship and a ship in a caravan are obtained as functions of the mean-square roughness, ship speed and the blockage coefficient.
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Franz von Bock und Polach, Rüdiger U., Sören Ehlers et Stein Ove Erikstad. « A Decision-based Design Approach for Ships Operating in Open Water and Ice ». Journal of Ship Production and Design 31, no 04 (1 novembre 2015) : 209–19. http://dx.doi.org/10.5957/jspd.2015.31.4.209.
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Designing ships for open water and ice requires a suitable design method to account for the distinct challenges in open water and ice. Ships with multi environment capabilities are of high complexity as a result of design-coupling, which is illustrated by design matrices. In this context, this article presents a method that includes a ship performance evaluation method based on the Ship Merit Factor (SMF). The method combines the SMF with a route specific ship-dependent productivity and allows to compare the technoeconomic performance of ships operating in open water and ice. Consequently, the method is applied to a case study comparing the performance of different ship designs operating along the route Rotterdam to Yokohama through the Suez Canal and the Northern Sea Route. The resulting design approach indicates the necessity to include and develop novel simulation-based methods for the reliable assessment of ice-capable ships is discussed.
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Paulauskas, Vytautas, Donatas Paulauskas et Joep Wijffels. « SHIP SAFETY IN OPEN PORTS ». TRANSPORT 24, no 2 (30 juin 2009) : 113–20. http://dx.doi.org/10.3846/1648-4142.2009.24.113-120.
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Ports and terminals open to prevailing winds can cause problems to moored ships with a high freeboard. Such ships, i.e. ship and berth mooring systems, have to deal with significant aerodynamic loads.This paper addresses the theoretical approach of the influence of aerodynamic loads on a mooring system for ship and investigates whether windscreens can reduce aerodynamic loads on ships in ports.
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Lee, Joohee, Jiheon Ryu et Hyun Chung. « Liquefied natural gas ship-to-ship bunkering chain planning : Case studies of Busan, Singapore, and Rotterdam ports ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 231, no 2 (16 juillet 2016) : 511–20. http://dx.doi.org/10.1177/1475090216659838.
Texte intégralRésumé :
Liquefied natural gas–fuelled ships, beginning with small-sized ships produced in the 2000s to large merchant ships, are expected to show a rapid increase in number. According to Lloyd’s Register, liquefied natural gas shows great promise as fuel for new ships. In line with this trend, it is necessary to establish adequate infrastructure for liquefied natural gas fuelling systems. In the bunkering chain, bunkering shuttles retrieve fuel from the terminals to fuel liquefied natural gas–fuelled ships berthing at the ports. Many researches have dealt with the technical feasibility or the necessity of ship-to-ship bunkering considering the liquefied natural gas bunkering processes, but none has covered them at the same time. This study examines the liquefied natural gas ship-to-ship bunkering chain considering the technically feasible combinations of liquefied natural gas storage and boil off gas treatment system. The suggested method decomposes this large infrastructure problem into two steps, which are pre-processing to estimate port statistics and integer programming model. The model can represent any port as long as the port’s ship statistics and their data are provided. We select three major ports with high liquefied natural gas bunkering potential as case studies to verify the proposed model.
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Varela, Jose Miguel, et C. Guedes Soares. « Geometry and visual realism of ship models for digital ship bridge simulators ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 231, no 1 (3 août 2016) : 329–41. http://dx.doi.org/10.1177/1475090216642470.
Texte intégralRésumé :
This article addresses the main requirements and the process of creating the geometry of ship models that fulfil the highly demanding request for realism and performance of the virtual environments currently used in modern ship bridge simulators. It starts with a classification of the ships based on their role in the simulation and on the type of simulator used, and defines the main characteristics of the models. It also discusses the importance of a well-defined workflow and its impact on the modelling time and on the quality of the final product. The article provides contributions in the following areas: identification of the main requirements of polygonal models of ships for ship simulators; effective workflow for ship three-dimensional modelling and identification of most suitable modelling techniques for efficient creation of ship models. The study is supported by real examples of three-dimensional modelling of ships with different sizes and characteristics currently used by the ship manoeuvring simulator in the Centre for Marine Technology and Ocean Engineering of the University of Lisbon.
23
Matveev, Konstantin I. « Effect of Drag-Reducing Air Lubrication on Underwater Noise Radiation From Ship Hulls ». Journal of Vibration and Acoustics 127, no 4 (22 novembre 2004) : 420–22. http://dx.doi.org/10.1115/1.1924646.
Texte intégralRésumé :
As the speed and power of surface ships rise, the reduction of ship acoustic signature and self-noise is becoming an important task of naval engineering. A significant decrease in underwater noise can be achieved by using gaseous layers on the ship hull. Two mechanisms for sound radiation from low-drag air-lubricated hulls are discussed.
24
Meler-Kapcia, Maria. « Algorithm for searching out similar ships within expert system of computer aided preliminary design of ship power plant ». Polish Maritime Research 15, no 3 (1 octobre 2008) : 92–96. http://dx.doi.org/10.2478/v10012-007-0089-7.
Texte intégralRésumé :
Algorithm for searching out similar ships within expert system of computer aided preliminary design of ship power plant This paper presents an algorithm for searching out similar ships, implemented in a hybrid system for aiding preliminary design of ship power plant, based on new similarity functions as well as those adapted from literature sources. For searching out similar ships a multicriterial optimization method of weighed profits was applied.
25
Paik, Jeom Kee. « A Guide for the Ultimate Longitudinal Strength Assessment of Ships ». Marine Technology and SNAME News 41, no 03 (1 juillet 2004) : 122–39. http://dx.doi.org/10.5957/mt1.2004.41.3.122.
Texte intégralRésumé :
The aim of the present paper is to establish a practical guide for the ultimate longitudinal strength assessment of ships. The ultimate hull girder strength of a ship hull can be calculated using either the progressive collapse analysis method or closed-form design formulas. In the present paper, both the progressive collapse analysis method and the design formulas are presented. A comparison between the progressive collapse analysis results and the design formula solutions for merchant cargo ship hulls is undertaken. The total design (extreme) bending moment of a ship hull is estimated as the sum of the still-water and wave-induced bending moment components as usual. The safety measure of a ship hull is then defined as a ratio of the ultimate longitudinal strength to the total design bending moment. The developed guidelines are applied to safety measure calculations of merchant ship hulls with respect to hull girder collapse. It is concluded that the guidance and insights developed from the present study will be very useful for the ultimate limit state design of newly built ships as well as the safety measure calculations of existing ship hulls. The essence of the proposed guide shall form ISO code 18072-2: Ships and Marine Technology— Ship Structures—Part 2: Requirements of Their Ultimate Limit State Assessment.
26
Wang, Hui-Chiao, et Chien-Hsing Wu. « A Scenario Simulation - Evaluating Evacuation Analysis for ro-ro Passenger Ship in MV Tai Hwa ». Journal of Ship Production and Design 36, no 04 (13 novembre 2020) : 240–49. http://dx.doi.org/10.5957/jspd.05190026.
Texte intégralRésumé :
The ro-ro passenger ship is a type of passenger ship which is commonly seen in Europe. After the tragedy of MV Estonia, an effective evaluation of escape routes in passenger ship in the initial stage of ship design has been required by International Convention for the Safety of Life at Sea (SOLAS) Convention. To reduce the loss of life in passenger ships at sea, the International Maritime Organization (IMO) has created the revised guidelines on evacuation analyses for new and existing passenger ships. This article followed IMO's mandatory guidelines via using the hydraulic model of emergency egress to scrutinize the evacuation routes, congestion points, and the total evacuation duration of MV Tai Hwa.
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Yilmaz, Hüseyin, et Abdi Kükner. « An Approximate Method for Intact Stability of Fishing Vessels ». Marine Technology and SNAME News 36, no 03 (1 juillet 1999) : 171–74. http://dx.doi.org/10.5957/mt1.1999.36.3.171.
Texte intégralRésumé :
It is well known that stability is the most important safety requirement for ships. One should have some information on ship stability at the preliminary design stage in order to reduce risk. Initial stability of ships is an important criterion and can be closely evaluated in terms of form parameters and vertical center of gravity. In this study, using some sample ship data, approximate formulations are derived by means of regression analysis for the calculations expressed in terms of ship preliminary design parameters that can easily provide approximate GM calculations. Thus designers can be provided with ship stability at the preliminary design stage, and also a set of appropriate design parameters for improving vessel stability can easily be determined.
28
Zhang, Wenjun, et Yingjun Zhang. « Research on classification and navigational risk factors of intelligent ship ». Brodogradnja 74, no 4 (1 septembre 2023) : 105–28. http://dx.doi.org/10.21278/brod74406.
Texte intégralRésumé :
Based on combing the concept and development of intelligent ship, this paper brings forward the summary and classification of intelligent ships proposed by different institutions, and the main classification schemes are compared accordingly. Then one of these classification schemes is selected to study what are the key navigational risks under each grading level, with a detailed analysis of these risk factors. Finally, the index system of navigational risk factors for intelligent ships under different classification standards is constructed to lay a foundation for a further study of intelligent ship safe navigation, and at the same time avoid some risk factors in advance for the maritime management department, ship management companies, and ship design and research institutes.
29
Paulauskas, Vytautas. « SHIP PASSING THROUGH STRAITS ». TRANSPORT 25, no 4 (31 décembre 2010) : 345–51. http://dx.doi.org/10.3846/transport.2010.42.
Texte intégralRésumé :
All ports and a number of waterways have straits to optimize investments in developing such systems reaching the maximum results with minimum expenditures. New high accuracy port navigational systems have a possibility of high precision ship positioning and any time should guarantee shipping safety in port waters which makes a good basis for the optimization of port development. A new type of ships with good steering equipment and ship steering knowledge and methods in combination with very high accuracy port navigational systems such as E‐Sea Fix and horizontal/vertical port channel bottom scanning possibilities guaranteeing real port water bottom conditions could stimulate dramatically increasing ship sizes at the port entrance in case of guaranteed shipping safety. With reference to straits, a theoretical study and experimental results received by simulators and real ships under much the same conditions have delivered a new knowledge of the limit of big ship sailing in straits and the possibilities of increasing ship size under similar sailing conditions. The Klaipeda strait is taken as the case study for practical testing. The paper presents the results, conclusions and recommendations of a theoretical and practical study for the ships of an increased size at strait ports.
30
Martin, John P. « Roll Stabilization of Small Ships ». Marine Technology and SNAME News 31, no 04 (1 octobre 1994) : 286–95. http://dx.doi.org/10.5957/mt1.1994.31.4.286.
Texte intégralRésumé :
The effect of ship size on the roll response of smaller vessels is reviewed. Particular attention is paid to the prevalence of the shorter wave heights and lengths that will cause heavy, resonant rolling of ships with short natural roll periods. The choices of various stabilizer types for the general classifications of small ships are reviewed. Model basin and full-scale test results of these ships with and without any type of stabilizer are presented. Particular attention is paid to ship types recently bid or delivered.
31
Karn, A. R., et E. Runnerstrom. « Expanded Planning Yard Concept and Configuration Accounting, or Improving Navy Ship Engineering ». Journal of Ship Production 2, no 04 (1 novembre 1986) : 238–44. http://dx.doi.org/10.5957/jsp.1986.2.4.238.
Texte intégralRésumé :
For several years the Navy has been systematically analyzing problems with its ship engineering and improving its organization and processes for ship engineering. This paper briefly discusses the Navy organization for ship engineering and some of the major initiatives to improve ship engineering. These initiatives have led to an expanded role for the planning yard in supporting, maintaining, and modernizing Navy ships. The paper focuses on the two primary functions of the planning yard: ship alteration engineering and ship configuration identification.
32
Michalski, Jan P. « Parametric Method For Evaluating Optimal Ship Deadweight ». Polish Maritime Research 21, no 2 (1 avril 2014) : 3–8. http://dx.doi.org/10.2478/pomr-2014-0013.
Texte intégralRésumé :
Abstract The paper presents a method of choosing the optimal value of the cargo ships deadweight. The method may be useful at the stage of establishing the main owners requirements concerning the ship design parameters as well as for choosing a proper ship for a given transportation task. The deadweight is determined on the basis of a selected economic measure of the transport effectiveness of ship - the Required Freight Rate (RFR). The mathematical model of the problem is of a deterministic character and the simplifying assumptions are justified for ships operating in the liner trade. The assumptions are so selected that solution of the problem is obtained in analytical closed form. The presented method can be useful for application in the pre-investment ships designing parameters simulation or transportation task studies.
33
Zhang, Jinfen, Tiago A. Santos, C. Guedes Soares et Xinping Yan. « Sequential ship traffic scheduling model for restricted two-way waterway transportation ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 231, no 1 (3 août 2016) : 86–97. http://dx.doi.org/10.1177/1475090215621580.
Texte intégralRésumé :
A good ship traffic scheduling mode can enhance traffic efficiency to a large degree, especially in restricted waterways such as approach channel of ports and straits. A ship scheduling model for restricted two-way waterways is proposed in this article. The assumption is made in the model that two-way transportation is not allowed for cases in which there is at least one large ship. Based on this assumption, a mathematical model is proposed to minimize the weighted average of the mean and the maximum waiting time given several safety restrictions. A sequential scheduling algorithm is proposed to solve such problem, in which the ships are divided into rounds. The ships in each round are scheduled simultaneously to enhance traffic efficiency by the trade-off between the priorities of small and large ships. Experiments are carried out by comparing sequential scheduling method with first-come-first-serve model. The results indicate that the proposed algorithm can reduce ships’ waiting time, whereas a lot of ships need to wait for long time with first come first serve. The distinctions are more evident with a higher proportion of large ships, and the proposed algorithm can keep ships’ waiting time to an acceptable level.
34
Kim, Seong Jong, et Seok Ki Jang. « A Slow Strain Rate Test Experiment to Evaluate the Characteristics of High-Strength Al-Mg Alloy for Application in Ships ». Materials Science Forum 510-511 (mars 2006) : 162–65. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.162.
Texte intégralRésumé :
Recently, there has been increased interest in using aluminum alloys in ship construction instead of fiber-reinforced plastic (FRP). This is because aluminum alloy ships are faster, have a greater load capacity, and are easier to recycle than FRP ships. In this study, we investigated the mechanical and electrochemical properties of aluminum alloys using the slow strain rate and potentiostatic tests under various potential conditions. The optimum protection potential range with regards to hydrogen embrittlement and stress corrosion cracking was determined to lie between -1.5 and -0.7 V (SSCE). These results can be used as reference data for ship design.
35
Kilner, F. A. « MODEL TESTS ON THE MOTION OF MOORED SHIPS PLACED ON LONG WAVES ». Coastal Engineering Proceedings 1, no 7 (29 janvier 2011) : 40. http://dx.doi.org/10.9753/icce.v7.40.
Texte intégralRésumé :
The equation of motion for a moored ship, subject to stationary wave action, is presented and discussed. The moorings are longitudinal, the ship is considered to be aligned to the direction of wave motion and positioned at a node, and the wave length is assumed long compared with the ship length. If the motion of the ship is assumed to be simple harmonic, and frictional forces between the ship and the water are neglected, an elementary analysis gives the required relation between the amplitudes of the ship's movement and of the water particle motion associated with the wave, A description is given of some tests carried out on model ships moored in a flume where stationary waves can be generated, and the amplitude and period can be varied independently. In these experiments, the amplitude of ship movement could be measured visually, or inferred from strain gauge readings, and the water motion was also observed. The results of these tests are compared with the simple theory. A table tilting harmonically is shown to be a mechanical analogy to stationary wave action on ships. The hydrodynamic mass for a ship moving in surge or sway motion is measured and is found to depend on the depth of water in which the ship is moored.
36
Xie, Haibo, Zhengjiang Liu, Xingkang Xu et Jiping Zhang. « Research on the safe distance between passing ship and offshore drilling platform based on theory and statistics ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 234, no 3 (4 mars 2020) : 642–50. http://dx.doi.org/10.1177/1475090220902305.
Texte intégralRésumé :
The offshore drilling platform is the main equipment for oil and gas exploration. The increase in offshore drilling platform results in the apparently increased contradiction between oilfield exploitation and safe navigation of ships. In order to ensure safe navigation and the normal exploitation of oil and gas fields in a limited space, it is necessary to quantify the distance between ships and coastal drilling platforms. In this investigation, the relevant theoretical calculation models were developed, including a drift model for ship out of control and a ship emergency stopping model. By selecting appropriate ship samples, theoretical safe distances under different models can be obtained. With the use of statistical correlation theory based on the Automatic Identification System data of ship, the safe distance between passing ship and platform was further studied. Finally, the recommended safe distance in different waters was summarized by comparing different model calculation results and data statistics results. Research results are beneficial for the safety of ship navigation, safe operation of the platform, and the revision of relevant standards.
37
Dubrovskiy, V. A. « Complex Comparison of Seakeeping : Method and Example ». Marine Technology and SNAME News 37, no 04 (1 octobre 2000) : 223–29. http://dx.doi.org/10.5957/mt1.2000.37.4.223.
Texte intégralRésumé :
A method of seakeeping comparison, proposed originally by author in 1978, offers the possibility of taking into account all limitations of speed in waves and other ship characteristics, including motion amplitudes, accelerations at any point, slamming, deck wetness and bending moments for every type of ship. General characteristics of seakeeping are presented as one number for needed sea or for average conditions of the world's oceans. An example of the comparison is presented for two small-sized ships: a catamaran and a twin-hulled ship of small waterplane area (SWATH). Results of systematic calculations for naval ships in the North Atlantic are also presented.
38
Michalski, Jan. « A method for selection of parameters of ship propulsion system fitted with compromise screw propeller ». Polish Maritime Research 14, no 4 (1 octobre 2007) : 3–6. http://dx.doi.org/10.2478/v10012-007-0032-y.
Texte intégralRésumé :
A method for selection of parameters of ship propulsion system fitted with compromise screw propeller This paper concerns an algorithmic method for preliminary selection of parameters of ship propulsion system fitted with fixed screw propeller in the case when the ship's operation is associated with significant changes of waterway depth and width, hull resistance of the ship and its service speed. Mathematical model arguments of the considered design problem are main ship design parameters identified in the preliminary design stage. Structure of the formulated model complies with formal requirements for continuous- discrete mathematical optimization problems. The presented examples of application of the method concern an inland waterways ship fitted with compromise screw propeller optimized in the sense of minimization of fuel consumption for passing a given route distance within a given time. The elaborated method may be especially useful in designing such ships as: coasters, inland waterways ships, tugs, pushers, trawlers, mine sweepers, icebreakers etc.
39
Kim, Sang Jin, Jung Min Sohn, Pentti Kujala et Spyros Hirdaris. « A simplified fluid structure interaction model for the assessment of ship hard grounding ». Journal of Marine Science and Technology 27, no 1 (12 décembre 2021) : 695–711. http://dx.doi.org/10.1007/s00773-021-00862-6.
Texte intégralRésumé :
AbstractThe structural damage of ships in navigational accidents is influenced by the hydrodynamic properties of surrounding water. Fluid structure interactions (FSI) in way of grounding contact can be idealized by combining commercial FEA tools and specialized hydrodynamic solvers. Despite the efficacy of these simulations, the source codes idealizing FSI are not openly available, computationally expensive and subject to limitations in terms of physical assumptions. This paper presents a unified FSI model for the assessment of ship crashworthiness following ship hard grounding. The method uses spring elements for the idealization of hydrostatic restoring forces in 3 DoF (heave, pitch, roll) and distributes the added masses in 6 DoF on the nodal points in way of contact. Comparison of results against the method of Kim et al. (2021) for the case of a barge and a Ro–Ro passenger ship demonstrate excellent idealization of ship dynamics. It is concluded that the method could be useful for rapid assessment of ship grounding scenarios and associated regulatory developments.
40
Cole, S. L. « Low-Aspect-Ratio Flat Ship Theory for Moderate Froude Numbers ». Journal of Ship Research 35, no 04 (1 décembre 1991) : 325–30. http://dx.doi.org/10.5957/jsr.1991.35.4.325.
Texte intégralRésumé :
Low-aspect-ratio flat ship theory models ships whose dimensions satisfy draft << beam <<length. This paper systematically derives the inner and outer linearized problems for moderate Froude number potential flow past such a ship and their solutions. These solutions are matched through an intermediate region. It is found that the leading-order term for the wave resistance for moderate speed low-aspectratio flat ship theory is the same as found in slender ship theory for ships with equivalent cross-sectional areas. Flat ship theory, however, predicts singularities in the flow along the outside of the ship's leading edge which are not present in slender ship theory. A simple example demonstrating these spurious singularities is worked out.
41
Paulauskas, Vytautas, Valdas Lukauskas, Birute Plačiene et Raimondas Barzdžiukas. « SHIPS LEAVING A PORT UNDER EMERGENCY CONDITIONS ». TRANSPORT 27, no 4 (21 décembre 2012) : 345–50. http://dx.doi.org/10.3846/16484142.2012.720278.
Texte intégralRésumé :
Emergency conditions in a port request special precaution measures taken by ships when in the majority of cases they necessitate leaving port waters in the shortest time. Good management, awareness and timely actions can help with avoiding difficulties encountered by ships under emergency conditions at ports. The conducted research suggested in the article has been based on investigation into ship maneuverability considering complicated weather conditions, theoretical methods for the feasibility of ship maneuverability referring to difficult conditions, experimental tests using the calibrated Simulator and evaluation of real ships under similar conditions. The results of the presented research could be used for analyzing the situation in different ports with different ships regarding practical preparation for vessels to leave the port under emergency conditions without any delay.
42
Michalski, Jan. « A parametric method for evaluation of resistance of swath ships ». Polish Maritime Research 15, no 1 (1 janvier 2008) : 3–10. http://dx.doi.org/10.2478/v10012-007-0045-6.
Texte intégralRésumé :
A parametric method for evaluation of resistance of swath ships This paper contains formulation of a parametric method for evaluation of SWATH ship's hull resistance. The method was elaborated on the basis of numerical calculation results obtained by using structural methods based on ship hydrodynamic theory and performed for sufficiently large series of body forms with systematically changing ship form parameters. Also, results of verifying investigations dealing with features of the method in question are presented by comparing the obtained resistance characteristics with those achieved by other authors as well as with ship model experimental test results. The obtained results of the verification indicate that the elaborated method can be useful in preliminary designing the SWATH ships.
43
Li, Wenjie, Hao Wang, Yu Wan, Hongbo Du, Yi Xiao et Shengfa Yang. « Quantitative Assessment on Navigation Impact of the Controlled Waterway in the Upper Yangtze River Using Queuing Model ». Transportation Research Record : Journal of the Transportation Research Board 2676, no 4 (4 décembre 2021) : 421–35. http://dx.doi.org/10.1177/03611981211061127.
Texte intégralRésumé :
As an important transportation link between eastern and western economic zones of China, the Yangtze River waterway has been globally ranked first in relation to freight volume since 2010, and the density of ship traffic has also increased significantly. However, the inland navigation system has been increasingly threatened by traffic congestion, which is more serious in the controlled waterways of the upper Yangtze River. In this study, the distribution laws of ship traffic flow and service time in the controlled waterway were analyzed, indicating that the traffic flow obeys the Poisson distribution, and the service time obeys a negative exponential distribution. Thereafter, by simplifying the queuing processes and rules, the M/M/1 queuing service model was established to calculate ship queuing indicators in a controlled waterway. It was found that the ship queuing indicators varied greatly among different controlled waterways. Compared with downstream ships, upstream ships usually had longer queuing lengths and times, which were also more affected by the increasing number of ship arrivals and service times. Consequently, a dimensionless loss coefficient was proposed to quantify the influence of the controlled waterway on the navigation capacity. As the service time and number of ships increased, the loss coefficient also increased. The results of this study could provide references for understanding the ship queuing problem, and thereby the assessment of navigation capacity and anchorage constructions in a controlled waterway.
44
Schellin, Thomas E., et Ould el Moctar. « Numerical Prediction of Impact-Related Wave Loads on Ships ». Journal of Offshore Mechanics and Arctic Engineering 129, no 1 (8 novembre 2006) : 39–47. http://dx.doi.org/10.1115/1.2429695.
Texte intégralRésumé :
We present a numerical procedure to predict impact-related wave-induced (slamming) loads on ships. The procedure was applied to predict slamming loads on two ships that feature a flared bow with a pronounced bulb, hull shapes typical of modern offshore supply vessels. The procedure used a chain of seakeeping codes. First, a linear Green function panel code computed ship responses in unit amplitude regular waves. Ship speed, wave frequency, and wave heading were systematically varied to cover all possible combinations likely to cause slamming. Regular design waves were selected on the basis of maximum magnitudes of relative normal velocity between ship critical areas and wave, averaged over the critical areas. Second, a nonlinear strip theory seakeeping code determined ship motions under design wave conditions, thereby accounting for the nonlinear pressure distribution up to the wave contour and the frequency dependence of the radiation forces (memory effect). Third, these nonlinearly computed ship motions constituted part of the input for a Reynolds-averaged Navier–Stokes equations code that was used to obtain slamming loads. Favorable comparison with available model test data validated the procedure and demonstrated its capability to predict slamming loads suitable for design of ship structures.
45
V. Spyropoulos, Dionysios, et Epaminondas D. Mitronikas. « A Review on the Faults of Electric Machines Used in Electric Ships ». Advances in Power Electronics 2013 (5 mars 2013) : 1–8. http://dx.doi.org/10.1155/2013/216870.
Texte intégralRésumé :
Electric propulsion systems are today widely applied in modern ships, including transport ships and warships. The ship of the future will be fully electric, and not only its propulsion system but also all the other services will depend on electric power. The robust and reliable operation of the ship’s power system is essential. In this work, a review on the mechanical and electrical faults of electric machines that are used in electric ships is presented.
46
Dong, G. H., L. Sun, Z. Zong, H. W. An et Y. X. Wang. « Numerical Analysis of Ship-Generated Waves Action on a Vertical Cylinder ». Journal of Ship Research 53, no 02 (1 juin 2009) : 93–105. http://dx.doi.org/10.5957/jsr.2009.53.2.93.
Texte intégralRésumé :
In this paper, the action of ship-generated waves on a nearby vertical cylinder is considered in pure theory. Intensive demands of modern sea transportation result in larger and larger ships. These ships generate high waves as they move in calm water. The ship-generated waves can travel long distances without much attenuation. They are so strong that they might cause damage to nearby marine structures (e.g., platforms, river banks, breakwaters, etc.). Therefore, it is necessary to evaluate the forces of ship-generated waves acting on nearby marine structures. The problem turns out to be composed of two problems: evaluation of waves generated by a moving ship (ship-wave problem) and evaluation of the action of ship waves on a cylinder (wave-action problem). Here the wave-action problem is computed in detail with a boundary element method in time domain. And the ship-wave problem is evaluated in the well-known Michell thin-ship theory. Thus, the problem posed in this paper is finally solved using numerical methods by combining the ship-wave and wave-action problems. The numerical analyses of the result are: The resultant forces and moments acting on the cylinder are surprisingly large, characterized by being highly oscillatory. The periods of the oscillations are proportional to ship speed. The actions of ship-generated waves on nearby structures are not negligible. This is a new factor necessary to be considered for design of both marine structures and ships. Meanwhile, the potential fatigue damage resulting from oscillations of the forces and moments should be considered, too.
47
Hirdaris, S. E., et P. Temarel. « Hydroelasticity of ships : Recent advances and future trends ». Proceedings of the Institution of Mechanical Engineers, Part M : Journal of Engineering for the Maritime Environment 223, no 3 (12 juin 2009) : 305–30. http://dx.doi.org/10.1243/14750902jeme160.
Texte intégralRésumé :
Investigations into hydroelasticity of ships commenced in the 1970s. Since then the theory has been employed to predict the responses of a wide range of marine structures, such as mono- and multihulled ships, offshore structures, and VLFS. In recent years, with increasing market demands for new buildings of slender ocean going carriers and the continuously updated high-speed and unconventional multihulled designs, the maritime industry began to notice the advantage of assessing the usefulness and applicability of hydroelasticity in ship design. At first instance, the aim of this paper is to illustrate some of the applications of hydroelasticity theory to ships, with particular reference to recent and ongoing developments focusing on ship design applications and the effects of non-linearities and viscous flows. The paper also discusses the longer term potential use of weakly and fully non-linear fluid—structure interaction, as well as Navier—Stokes based fluid dynamic methods, for the improved modelling of ship dynamic response problems.
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Hofmann, Hans A., Raymond S. Grant et Siu Fung. « Producibility in U.S. Navy Ship Design ». Journal of Ship Production 6, no 03 (1 août 1990) : 139–50. http://dx.doi.org/10.5957/jsp.1990.6.3.139.
Texte intégralRésumé :
Recent NAVSEA studies of a twin-skeg hull form design applied to a T-AO type ship indicated many areas of possible improvement in producibility. This paper reviews the findings of producibility studies and attempts to indicate specific areas where an improvement in producibility and attendant cost savings for Navy ships are possible without any degradation in ship performance and survivability. Most available studies on producibility have an inherent trait of elaborating on details of shipyard producibility. This paper attempts to confine itself to the producibility aspect of the design phase, ending with the completion of contract design. It was determined that the concept of the producible, designed-to-build ship was worth further investigation for incorporation into future designs because of potential cost savings. The paper concludes with recommendations for a method of application of producibility to the Navy ship design process for MSC-operated T-ships.
49
Weng, Jinxian, Shiguan Liao et Guorong Li. « Bayesian Regression Model for Estimating Economic Loss Resulting from Two-Ship Collisions ». Transportation Research Record : Journal of the Transportation Research Board 2673, no 1 (janvier 2019) : 164–72. http://dx.doi.org/10.1177/0361198118821599.
Texte intégralRésumé :
This study aims to develop a Bayesian regression model to evaluate the economic loss resulting from two-ship collisions using ten years’ ship collision data for occurrances in Fujian waters. The model results show that the involvement of passenger/cruise ships could cause the largest increment on economic loss in ship collisions. Interestingly, it is found the involvement of fishing ships could greatly increase the ship collision consequence in terms of economic loss. Results also reveal that the higher economic loss is associated with the collisions in the straits/sea areas, under the strong wind/wave conditions, during nighttime period, and in poor visibility conditions. The impact analysis results highlight that judgment errors play a decisive role in increasing the economic loss as compared with the other two types of human errors: lookout failure and operation errors. The results of this study are useful for policy-makers in proposing efficient strategies to mitigate the economic loss from two-ship collisions. The developed model is also beneficial for insurance companies in determining the appropriate ship insurance rates.
50
Reid, Alan R., David S. Huff et John C. Cameron. « Conversion of San Clemente Class Tankers to Hospital Ships for the U.S. Navy ». Marine Technology and SNAME News 24, no 03 (1 juillet 1987) : 193–204. http://dx.doi.org/10.5957/mt1.1987.24.3.193.
Texte intégralRésumé :
This paper describes a program—unique in the history of U.S. Navy ship procurement—to convert two 90 000-dwt crude oil carriers into hospital ships. The San Clemente class tankers, of 894 ft length overall, proved ideally suited to the conversion because (1) the long, parallel midbody design offered large, open spaces for the installation of modularized hospital and habitability units; (2) the ships' hydrostatic characteristics were favorable to the addition of new upper deck structures; and (3) the ships' hydrodynamic characteristics provided excellent seakeeping qualities with reduced ship motions critical during casualty reception and underway medical operations. Under the programmatic direction of Naval Sea Systems Command, the conversions were accomplished by National Steel and Shipbuilding to meet U.S. Coast Guard and American Bureau of Shipping regulatory requirements for passenger ships. The ships will be operated by the Military Sealift Command in support of authorized medical missions.