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1
Paik, Jeom Kee. "A Guide for the Ultimate Longitudinal Strength Assessment of Ships". Marine Technology and SNAME News 41, nr 03 (1.07.2004): 122–39. http://dx.doi.org/10.5957/mt1.2004.41.3.122.
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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.
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Zhang, Xiangming, Lingkai Huang, Libao Zhu, Yuhang Tang i Anwen Wang. "Ultimate Longitudinal Strength of Composite Ship Hulls". Curved and Layered Structures 4, nr 1 (26.01.2017): 158–66. http://dx.doi.org/10.1515/cls-2017-0012.
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Abstract A simple analytical model to estimate the longitudinal strength of ship hulls in composite materials under buckling, material failure and ultimate collapse is presented in this paper. Ship hulls are regarded as assemblies of stiffened panels which idealized as group of plate-stiffener combinations. Ultimate strain of the plate-stiffener combination is predicted under buckling or material failure with composite beam-column theory. The effects of initial imperfection of ship hull and eccentricity of load are included. Corresponding longitudinal strengths of ship hull are derived in a straightforward method. A longitudinally framed ship hull made of symmetrically stacked unidirectional plies under sagging is analyzed. The results indicate that present analytical results have a good agreement with FEM method. The initial deflection of ship hull and eccentricity of load can dramatically reduce the bending capacity of ship hull. The proposed formulations provide a simple but useful tool for the longitudinal strength estimation in practical design.
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Chen, Nian-Zhong, i C. Guedes Soares. "Ultimate Longitudinal Strength of Ship Hulls of Composite Materials". Journal of Ship Research 52, nr 03 (1.09.2008): 184–93. http://dx.doi.org/10.5957/jsr.2008.52.3.184.
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A progressive collapse analysis method is proposed to predict the ultimate longitudinal strength of ship hulls of composite materials. The load-average strain curve derived from a progressive failure nonlinear finite element analysis is adopted for representing the behavior of each stiffened composite panel forming a hull cross section. The bending moment of the ship hull under a prescribed curvature is achieved by integrating the reaction force of each stiffened panel over a hull cross section based on the load-average strain curves. The ultimate longitudinal strength of a ship hull is obtained from the moment-curvature relationship of the ship hull, which is established by imposing progressively increasing curvatures of a hull cross section. An all-composite ship is analyzed as an application.
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Zakerdoost, Hassan, Hassan Ghassemi i Mahmoud Ghiasi. "An evolutionary optimization technique applied to resistance reduction of the ship hull form". Journal of Naval Architecture and Marine Engineering 10, nr 1 (9.06.2013): 1–12. http://dx.doi.org/10.3329/jname.v10i1.12927.
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Hull form optimization from a hydrodynamic performance point of view is an important aspect of ship design. This paper presents a computational method to estimate the ship resistance (viscous & wave) in calm-water. In the optimization process the evolution strategy (ES) technique is linked to the computational method to obtain an optimum hull form by taking into account the displacement as design constraint. For allowing the large variation of hull form during optimization process the hull surface is represented by NURBS. New hull forms are obtained from the well-known S60 hull and the classical Wigley hull taken as initial hulls in the optimization process at Fn=0.316. The optimization variables are a combination of ship hull offsets and main dimensions. The benchmark results for two test cases indicate that the total resistance of optimized hulls is reduced significantly.DOI: http://dx.doi.org/10.3329/jname.v10i1.12927
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Matveev, Konstantin I. "Effect of Drag-Reducing Air Lubrication on Underwater Noise Radiation From Ship Hulls". Journal of Vibration and Acoustics 127, nr 4 (22.11.2004): 420–22. http://dx.doi.org/10.1115/1.1924646.
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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.
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Yastrebov, Dmitry Pavlovich, Oleg Aleksandrovich Belov, Vladimir Alekseevich Shvetsov, Bogdan Vladimirovich Tarabanov i Sergey Anatolevich Zaitsev. "Problem of using electrodes made of shipbuilding steel to protect ship hull from corrosion". Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2020, nr 2 (22.05.2020): 15–21. http://dx.doi.org/10.24143/2073-1574-2020-2-15-21.
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The article discusses the problem of corrosion that causes significant damage to the ship structures and mechanisms, reducing their service life. The experience of using different electrodes to control the electrochemical protection systems of steel hulls of auxiliary vessels is presented. The results of corrosion tests of PM-15 ship hull are presented, which included measurements of the hull potential at a given control point, using an electrical measuring device and two control electrodes. As the first electrode used an electric carbon product for electric machines. A ship hull steel plate was used as the second electrode. The investigated vessel stayed at the pier for a long time. Corrosion tests were carried out in the period within 10.10.2019-16.10.2019. The ship hull potential at the control point was controlled using 50 parallel measurements. Parallel measurements were performed with a specified time interval of 5 sec. between them. A qualified operator has been trained to perform corrosion studies. The accuracy of the measurements was determined on the basis of current regulatory documents. The test results show that the reliability of the control of electrochemical protection systems of the hull primarily depends on the type of electrode used. It has been demonstrated that the metrological characteristics of the results of control measurements depend on the period of using a steel plate. The results of scientific research help to select the right elements of the system of monitoring the effectiveness of electrochemical protection of the ships and ship crews.
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Pérez, F. L., J. A. Clemente, J. A. Suárez i J. M. González. "Parametric Generation, Modeling, and Fairing of Simple Hull Lines With the Use of Nonuniform Rational B-Spline Surfaces". Journal of Ship Research 52, nr 01 (1.03.2008): 1–15. http://dx.doi.org/10.5957/jsr.2008.52.1.1.
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This paper deals with the use of a simple parametric design method applied to simple hull lines, such as sailing ship hulls and round bilge hulls. The described method allows the generation of hull lines that meet hydrodynamic coefficients imposed by the designer, obtaining more flexibility than with normal affine transformations of a parent hull. First, a wire model of the ship stations is made with the use of explicit curves. The method is completed with an automatic surface modeling of the previ¬ously generated offsets. The construction of spline curves and their application in the definition of ship lines are reviewed. Approximation of spline curves fitting the data on the stations is made, with special emphasis on the choice of parametrization, which is relevant to increasing the accuracy of the splines. B-spline surface modeling of the hull and the fairing process adapted to maintain certain ship characteristics are described. Some examples of the generation, lofting, and fairing process are pre¬sented.
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Pranatal, Erifive, Gatot Basuki, Norita Prasetya, Maria Margareta Zau Beu i Minto Basuki. "Reparasi dan Perhitungan Tahanan Kapal Nelayan di Daerah Nambangan Kelurahan Kedung Cowek – Surabaya". JAST : Jurnal Aplikasi Sains dan Teknologi 4, nr 1 (9.06.2020): 1. http://dx.doi.org/10.33366/jast.v4i1.1456.
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Wooden hulls have been damaged and overgrown by fouling have negative impact on the service life and also increase the resistance of ship thereby increasing fuel consumption. Therefore the ship have to repaired regularly. The problem discussed is how to repair wooden ships such as replacing plank, cleaning hull and coating; and hull analysis to determine resistance of ship. Therefore the object of this paper is to repair wooden ships and analysis of the hull. The method used is training that is followed by demonstration and also science and technology simulation that explains the form hull and resistance of the ship with use of software Maxsurf. The result is replacement plank on the keel, and the side; clean the hull, putty and coating. The ship is measured and the main dimension is obtained and then makes line plans and 3D ship models. The calculation of the ship's resistance shows that ship use main engine Honda GX 160 with 5.5 hp will produce 6.325 knots.ABSTRAKKondisi lambung kapal kayu yang rusak dan ditumbuhi biota laut (fouling) berdampak negatif pada umur pakai kapal dan juga menambah tahanan kapal sehingga meningkatkan konsumsi bahan bakar. Oleh karena itu kapal harus diperbaiki secara berkala. Permasalah yang diselesaikan adalah bagaimana reparasi kapal kayu seperti penggantian papan kayu, pembersihan lambung, pengecatan dan juga analisa bentuk lambung kapal kayu untuk mengetahui tahanan kapal kayu. Sehingga tujuan penulisan ini adalah melakukan reparasi kapal kayu dan juga analisa lambung kapal. Sendangkan metode penelitian yang digunakan adalah adalah pelatihan yang diikuti demonstrasi dan juga simulasi ipteks yang menjelaskan bentuk lambung dan tahanan kapal dengan bantuan software Masurf. Kapal yang reparasi dilakukan pergantian papan pada lunas kapal, dan sisi kapal, pembersihan lambung, pendempulan dan pengecatan. Selanjutnya dilakukan pengukuran kapal untuk mendapatkan ukuran utama dan pembuatan gambar rencana garis dan model kapal 3D. Pada perhitungan tahanan kapal dengan menggunakan motor penggerak Honda GX 160 dengan daya 5,5 HP akan menghasilakan kecepatan 6,325 knot.
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Belov, O. A., A. O. Shuvaeva, S. A. Klementyev i A. V. Fedin. "OPERATIONAL CONTROL OF THE STATE OF ANTI-CORROSION PROTECTIONAS A FACTOR IN THE SAFETY OF TECHNICAL OPERATION OF MARINE VESSELS". Innovatics and Expert Examination, nr 1(29) (1.07.2020): 152–59. http://dx.doi.org/10.35264/1996-2274-2020-1-152-159.
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The technical operation of modern marine vessels is inevitably associated with the aggressive effects of electrochemical corrosion on hull structures and the ship as a whole. Corrosion processes have a destructive effect on hull elements, welded joints of metal structures, as a result of which there is a violation of water tightness, a decrease in the general and local strength of the hull, other operational characteristics of the vessel, reliability parameters of the hull structures and, as a result, a decrease in the safety of navigation and environmental safety, including at the points of basing ships and adjacent waters. This factor requires the introduction of special methods of corrosion protection, the main of which are the use of coatings and the use of electrochemical protection of ship hulls. Maintaining the integrity of coatings and a given level of hull electrochemical protection during the operation of the vessel involves the implementation of a set of interconnected engineering, technical and organizational measures, the basis of which is the operational control of the state of corrosion protection.
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He, Ngo Van, Keisuke Mizutani i Yoshiho Ikeda. "REDUCING AIR RESISTANCE ACTING ON A SHIP BY USING INTERACTION EFFECTS BETWEEN THE HULL AND ACCOMMODATION". ASEAN Engineering Journal 7, nr 1 (26.12.2014): 1–14. http://dx.doi.org/10.11113/aej.v7.15484.
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Nowaday, a study on saving energy as well as reducing resistance acting on a ship is important in maritime transportation. In this study, the authors present a study on reducing air resistance acting on a ship by using interaction effects between the hull and an accommodation. At first, air resistances acting on a hull and an accommodation of the ship are investigated by a commercial Computation Fluid Dynamic (CFD) code. Then, CFD results are compared with those of experimental results to validate the accuracy of the CFD. Secondly, air resistances acting on the ship with an accommodation on its deck are computed to obtain air resistances acting on the whole ships, on the hull and on accommodation. The results demonstrate that the interaction effects between the hull and its accommodation house be also shown how to reduce the total air resistance by using interaction effects between the hull and an accommodation house. The results can be applied in reducing the total resistances acting on a ship.
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Muthugala, M. A. Viraj J., Anh Vu Le, Eduardo Sanchez Cruz, Mohan Rajesh Elara, Prabakaran Veerajagadheswar i Madhu Kumar. "A Self-Organizing Fuzzy Logic Classifier for Benchmarking Robot-Aided Blasting of Ship Hulls". Sensors 20, nr 11 (5.06.2020): 3215. http://dx.doi.org/10.3390/s20113215.
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Regular dry dock maintenance work on ship hulls is essential for maintaining the efficiency and sustainability of the shipping industry. Hydro blasting is one of the major processes of dry dock maintenance work, where human labor is extensively used. The conventional methods of maintenance work suffer from many shortcomings, and hence robotized solutions have been developed. This paper proposes a novel robotic system that can synthesize a benchmarking map for a previously blasted ship hull. A Self-Organizing Fuzzy logic (SOF) classifier has been developed to benchmark the blasting quality of a ship hull similar to blasting quality categorization done by human experts. Hornbill, a multipurpose inspection and maintenance robot intended for hydro blasting, benchmarking, and painting, has been developed by integrating the proposed SOF classifier. Moreover, an integrated system solution has been developed to improve dry dock maintenance of ship hulls. The proposed SOF classifier can achieve a mean accuracy of 0.9942 with an execution time of 8.42 µs. Realtime experimenting with the proposed robotic system has been conducted on a ship hull. This experiment confirms the ability of the proposed robotic system in synthesizing a benchmarking map that reveals the benchmarking quality of different areas of a previously blasted ship hull. This sort of a benchmarking map would be useful for ensuring the blasting quality as well as performing efficient spot wise reblasting before the painting. Therefore, the proposed robotic system could be utilized for improving the efficiency and quality of hydro blasting work on the ship hull maintenance industry.
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Deng, Rui, Shigang Wang, Yuxiao Hu, Yuquan Wang i Tiecheng Wu. "The Effect of Hull Form Parameters on the Hydrodynamic Performance of a Bulk Carrier". Journal of Marine Science and Engineering 9, nr 4 (1.04.2021): 373. http://dx.doi.org/10.3390/jmse9040373.
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In this study, the effect of joint optimization of the principal dimensions and hull form on the hydrodynamic performance of a bulk carrier was studied. In the first part of the joint optimization process, fast principal-dimension optimization of the origin parent ship considering the integrated performance of ship resistance, seakeeping, and maneuverability, as well as their relationships with the principal dimensions were analyzed in detail based on the ship resistance, seakeeping qualities, and maneuverability empirical methods of Holtrop and Mennen, Bales, and K and T indices, respectively. A new parent ship was chosen from 496 sets of hulls after comprehensive consideration. In the remaining part, a further hull form optimization was performed on the new parent ship according to the minimum wave-making resistance. The obtained results demonstrate that: (a) For the case in which the principal dimension of the original parent-type ship is different from that of the owner’s target ship, within the bounds of the relevant constraints from the owner, an excellent parent ship can be obtained by principal-dimension optimization; (b) the joint optimization method considering the principal dimension and hull form optimization can further explore the optimization space and provide a better hull.
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Haro, Marco Polo Espinoza, Jong-Chun Park, Dong-Hyun Kim i Sung-Bum Lee. "CFD Simulation on Workability of a Seaweed Harvesting Boat Due to Wake-Wash". Journal of Marine Science and Engineering 8, nr 8 (22.07.2020): 544. http://dx.doi.org/10.3390/jmse8080544.
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In the present study, a 2-ton class seaweed harvesting boat was optimized by employing a W-shape hull form to reduce roll motion due to wake-wash from passing boats. A series of numerical simulations were conducted using Star-CCM+, a commercial CFD (computational fluid dynamics) software, to improve workability by optimizing the hull form from the conventional design (original hull form). The 2-dimensional roll decay motion of various hull forms with W-shape midsection were simulated and the hull form with the best performance in free roll decay test was selected. To evaluate stability of each hull in wake-wash, the original or optimized hull was alternately located at the middle of a computational domain as a target ship while an advancing ship (original hull) moved forward generating Kelvin waves which impact the original or optimized boat. Two kinds of working conditions, i.e., ballast and full loading conditions, of the target ship were considered with and without initial roll angle. It was observed through the comparison of motion between the original and optimized hulls a decrement of roll motion for the optimized ship demonstrating the effectiveness of the W-shape hull. Decrement of roll motion was observed for both working conditions. Additionally, the optimized W-shape hull showed an extraordinary performance under the ballast condition without initial roll angle.
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Gierusz, Witold, i Anna Waszkiel. "Determination of Suction Forces and Moment on Parallel Manoeuvring Vessels for a Future Control System". Solid State Phenomena 180 (listopad 2011): 281–87. http://dx.doi.org/10.4028/www.scientific.net/ssp.180.281.
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Vessels moving on parallel courses on the border of two mediums interact together. Ship to ship interactions are caused by irregular pressure distribution around the hull. Higher velocity of the fluid between hulls causes formation of the decreased pressure amidships. This is the base of suction forces and moments generation. Analytical computations and computer based CFD simulations were carried out on the basis of 3DOF models of two training ships - VLCC and Passenger Car Ferry. The results of both methods are comparable. Therefore the analytical semi-empirical equations can be implemented in a future control system, which requires ship to ship interactions estimations to ensure proper working conditions.
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Trisyaldi, Ar, Purwantono Purwantono, Waskito Waskito, Primawati Primawati i Syahril Syahril. "Study of Ship Design Maninjau Lake Tourism by Using Catamaran Hull Type and Fiberglass Material". Teknomekanik 2, nr 1 (2.06.2019): 24–28. http://dx.doi.org/10.24036/tm.v2i2.3072.
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Maninjau lake uses ships designed in a simple way without significant innovation from time to time. This case is caused by design methods that are based on hereditary knowledge from generations to generations, so that the ships that are made tend to have the same shape and size. Innovation is needed to get a higher level of efficiency and effectiveness on a ship. The innovation that needs to be done is the design of ships with a multi-hull shape or catamaran. The pre-design of the catamaran hull is based on using the comparation method as the dimension ratio of the ship, so that the dimensions of the ship are LWL = 4 m; LPP = 3.96 m; B = 1.7 m; B1 = 0.36 m; D = 0.7 m; d = 0.307 m. After that, testing the resistance (resistance) while determining the amount of Power needed. The next step is to analyze Stability and Seakeeping to determine the efficiency and effectiveness of the hull type. Analysis carried out on this type of hull was applied to several models, then the best hull design was found. Each design is distinguished by hull shape, but has the same displacement which is equal to 0.448 tons. The first model of the catamaran hull with the type of Flat Inside Symmetry; second with the type of symmetry Flat Outside; and the third type with gastric Asymmetry.
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Rassinot, P., i A. E. Mansour. "Ship Hull Bottom Slamming". Journal of Offshore Mechanics and Arctic Engineering 117, nr 4 (1.11.1995): 252–59. http://dx.doi.org/10.1115/1.2827231.
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A method is presented to evaluate the hull bending moment due to bottom slamming. Theoretical explanations and updates are given to the commonly used empirical results, and some observations are made on slamming. An energy approach combined with a strip theory is used to get the hydrodynamic load, and to analyze the effects of the forward velocity. Impacts of simple bodies are simulated numerically to describe these loads. The ship hull is represented as a nonuniform free-free beam, and its response is decomposed into normal modes; only the contribution of the first one is kept. In a numerical example, the bending moment during the impact is determined. It is shown that its value when the impact is over is much harder to predict. The maximum value of the bending moment, however, occurs during the impact, and is an increasing function of the vertical velocity, as expected. A simple expression is given for it.
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Jianping, Chen, Xu Jie, Gong You i Xu Li. "Ship Hull Principal Dimensions Optimization Employing Fuzzy Decision-Making Theory". Mathematical Problems in Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5262160.
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The paper presents an optimization method for the ship hull principal dimensions scheme employing the fuzzy decision-making theory. First of all, the paper establishes the fuzzy decision-making model of the ship hull principal dimensions optimization, and then a series of ship hull principal dimensions schemes are accordingly constructed by employing the variable value method. On the basis of this, the fuzzy decision-making method is employed to evaluate the series ship hull principal dimensions schemes. Finally, the optimal ship hull principal dimensions scheme is obtained. The example demonstration verified the proposed method’s validity for ship hull principal dimensions optimization economic performance.
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Sun, Jianglong, Xujian Lv, Weibin Liu, Hanwen Ning i Xianwen Chen. "Research on a method of hull form design based on wave-making resistance optimization". Polish Maritime Research 19, nr 3 (1.10.2012): 16–25. http://dx.doi.org/10.2478/v10012-012-0027-1.
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ABSTRACT In this paper, we consider an optimization of the hull shape in order to minimize the total resistance of a ship. The total resistance is assumed to be the sum of the wave resistance computed on the basis of the thin-ship theory and the frictional resistance. Smoothness of hull lines is proved with mathematical procedure, in which differentials of the hull lines functions are analyzed. The wave-making resistance optimization, involving a genetic algorithm, uses Michell integral to calculate wave resistance. A certain hull form is generated by the method using cross section information of a modified DTMB model ship 5415 and a comparative experiment is carried out. Experimental and calculation result show that the method is of good adaptability for designing certain types of ships with excellent resistance performance.
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Perez-Arribas, Francisco L., i Erno Peter-Cosma. "Parametric Generation of Planing Hulls with NURBS Surfaces". Journal of Ship Research 57, nr 04 (1.12.2013): 241–61. http://dx.doi.org/10.5957/jsr.2013.57.4.241.
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This article presents a mathematical method for producing hard-chine ship hulls based on a set of numerical parameters that are directly related to the geometric features of the hull and uniquely define a hull form for this type of ship. The term planing hull is used generically to describe the majority of hard-chine boats being built today. This article is focused on unstepped, single-chine hulls. B-spline curves and surfaces were combined with constraints on the significant ship curves to produce the final hull design. The hard-chine hull geometry was modeled by decomposing the surface geometry into boundary curves, which were defined by design constraints or parameters. In planing hull design, these control curves are the center, chine, and sheer lines as well as their geometric features including position, slope, and, in the case of the chine, enclosed area and centroid. These geometric parameters have physical, hydrodynamic, and stability implications from the design point of view. The proposed method uses two-dimensional orthogonal projections of the control curves and then produces three-dimensional (3-D) definitions using B-spline fitting of the 3-D data points. The fitting considers maximum deviation from the curve to the data points and is based on an original selection of the parameterization. A net of B-spline curves (stations) is then created to match the previously defined 3-D boundaries. A final set of lofting surfaces of the previous B-spline curves produces the hull surface.
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Dong, Yan Qiu, i Weixue Lin. "Hydroelasticity and Wave Loads for a Full-Form Ship with Shallow Draft". Journal of Ship Research 36, nr 03 (1.09.1992): 280–85. http://dx.doi.org/10.5957/jsr.1992.36.3.280.
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A shallow-draft full-form ship is a particular type of ship with a breadth-to-draft ratio higher than is conventional. To investigate the characteristics of such full forms in response to hull vibrations induced by waves, a special computer program based on the hydroelasticity theory of ships has been developed. In addition, an experimental investigation using a segmented elastic-keel model of the ship has been carried out in order to verify the theoretical calculations. It is found from calculation of the wave loads that the dynamic responses of this specific hull form cannot be accurately predicted by strip theory. It is concluded therefore that hydroelasticity theory should be used in the design of the hull structure.
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Toan, Ninh Cong, i Ngo Van He. "EFFECT OF HULL AND ACCOMMODATION SHAPE ON AERODYNAMIC PERFORMANCES OF A SMALL SHIP". Tạp chí Khoa học và Công nghệ biển 18, nr 4 (15.03.2019): 413–21. http://dx.doi.org/10.15625/1859-3097/18/4/13292.
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In marine transportation, aerodynamic performance is important for the ships, especially for the small passenger fast ships. It has affected the service speed, air resistance acting on hull, power energy as well as roll, pitch, yaw and stability of the ships. Moreover, the aerodynamic performance also directly affects the passengers, captains or employments who work on the ships. For a bad aerodynamic performance hull shape, it may make an accident in marine transportation. In this paper, the authors present a study on effect of hull shape on aerodynamic performance of a small passenger fast ship by using a commercial Computational Fluid Dynamics (CFD). Several hull forms with different shapes are proposed and computed to show their aerodynamic performances. From the comparison between different CFD results of the ships, the effects of hull shape on aerodynamic performances of the ships are understood.
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Li, Ya Nan, Jun Wei Zhou, Da Zheng Wang i Yong Gang Cui. "Resistance and Strength Analysis of Three Hulls with Different Knuckles". Advanced Materials Research 779-780 (wrzesień 2013): 615–18. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.615.
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Three FRP fishing vessel hulls with different knuckles, the two knuckles ship, the round bilge ship and the single knuckle ship (hereinafter using abbreviation the TKS, the RBS, and the SKS, respectively), are studied to reduce resistance and enhance strength. Here the TKS is a variation design from the RBS. And the knuckles on the hull were designed paralleled with the streamlines of the hull surface of the RBS at the design speed, and the SKS is applied as the comparison ship. The resistance of the three hulls is predicted using the CFD software FLOW-3D, at the same time, the midship section modulus of the three hulls is calculated in this paper. It shows that the resistance of the TKS is slightly lower than that of the RBS at the design speed, and about 50% lower than that of the SKS. On the other side, the strength of the TKS increased about 15% than the RBS, and 6.9% than the SKS.
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Iqbal, Muhammad, Parlindungan Manik, Eko Sasmito Hadi i Achmad Kurniawan. "PENGARUH POSISI CENTERBULB BERBENTUK FOIL TERHADAP KOMPONEN HAMBATAN KAPAL IKAN KATAMARAN MV. LAGANBAR". JURNAL INTEGRASI 12, nr 1 (22.04.2020): 64–71. http://dx.doi.org/10.30871/ji.v12i1.1885.
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Catamarans are double hull ships which have many advantages over single hull ships with the same displacement. To increase catches, fishermen in Cilacap converted ships from the original single hull with outrigger to double hull (catamaran). Displacement of ships has doubled. But the ship's resistance increased to almost 4 times. To reduce the resistance of catamarans, some researchers use the concept of center bulb. In this study, the center bulb form used foil. The purpose of this study was to determine the effect of center bulb position on ship resistance components by comparing 9 center bulb positions. The results stated that of the nine center bulb position configurations, Model 6 is the best model because at Fr 0.35 it can reduce ship resistance by up to 33%. For the viscous resistance component it is not significantly affected by the use of the center bulb. But on the wave resistance component, the use of this center bulb can reduce wave resistance by 47% at Fr 0.35.
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Liu, Yingfei, i Ruru Deng. "Ship Wakes in Optical Images". Journal of Atmospheric and Oceanic Technology 35, nr 8 (sierpień 2018): 1633–48. http://dx.doi.org/10.1175/jtech-d-18-0021.1.
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AbstractShip wakes are more distinct than the hulls and can be visually observed in optical images. In this paper the wakes of 2836 ships in 32 optical images with different resolutions are observed and summarized. The ships are divided into four types according to the hull and wake features: fishing vessels, motorboats, cargo ships, and warships. The results show that each ship type has characteristic wakes, and there are significant differences among the categories. The probabilities of occurrence of different types of wakes and their components are shown. Turbulent wakes are inevitable. The probability of occurrence of Kelvin wakes is small and less than 40%. The visibilities of internal waves that are generated by only cargo ships are very low as a result of the harsh formation conditions. Turbulent wakes should be preferentially detected. Low-resolution images are more suitable for the detection and positioning of hulls and wakes, while high-resolution images with more details are convenient for further analysis of the size, velocity, and draft of ships. The study on the cause of the formation of the features of ship wakes in optical images proves that the classification of the wakes is reasonable and that the features of wakes can be used to initially identify the type of ship.
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Amromin, Eduard, i Igor Mizine. "Partial Cavitation as Drag Reduction Technique and Problem of Active Flow Control". Marine Technology and SNAME News 40, nr 03 (1.07.2003): 181–88. http://dx.doi.org/10.5957/mt1.2003.40.3.181.
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Partial cavitation can substantially reduce the ship total drag in a wide range of her speed. Vented partial cavitation manifested certain advantages in comparison with other drag reduction techniques. Its successful employment, however, requires both a special hull design and development of an active flow control system. Such a system will stabilize the cavity under perturbations of incoming flow in seas. The paper includes an analysis of achievements in drag reduction, description of design fundamentals of ships with cavitating hulls/elements, and suggestions on application of ship drag reduction by cavitation.
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Salmat, Salmat, Arya Zulhendrik, Muhammad Iqbal Iski, Arifin Adli i Aulia Zulkanain Nasty. "Design of Hybrid Hull Ship by B-NINE TEAM to The National Unmanned Fast Boat Contest 2019". Teknomekanik 3, nr 1 (25.05.2020): 17–21. http://dx.doi.org/10.24036/tm.v3i1.5772.
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The Nastional Unmanned Fast Boat Contest 2019 is an event to discover colleger interests and talents about ships and as an event to hone and develop college competitions.B-NINE TEAM from Universitas Negeri Padang is very interested and interested to participating based on illegal fishing problem that occurs. Ship design through literature study and ship model analysis using computer simulations. Ship comparison methods and trial-error to determine the shape of the hull to be userd and numerical experiments.Dimensions of the ship are Length Overall 0.80 m; Length Waterline 0.79 m; Beam 0.05 m; Depth 0.24 m; Draft 0.05 m. The variable parameter used is the variation of catamaran hull type V asymmetric inner flat. There are two types of modification applied, that is modification hull type U asymmetric and modification hull type U symmetric. Based on result of computer simulation testing, based on result of computer simulation testing, it is found that modification hull type U asymmetric has a low resistance value is 5.31 N at a speed of 4.2 knots with effective is 0.04776 Kw and main engine power of 0.1.70 KW.
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Cole, S. L. "A Numerical Solution to the Three-Dimensional Low-Aspect-Ratio Flat Ship Problem". Journal of Ship Research 34, nr 04 (1.12.1990): 283–88. http://dx.doi.org/10.5957/jsr.1990.34.4.283.
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This paper defines a numerical procedure for solving the low-aspect-ratio flat ship problem and providesa sample solution using MAPLE, a symbolic manipulation software language, for the class of hulls with slope fx = -(a + bx + cy2 + dxy2 + ex2 + gy4)and parabolic planform y2< xfor 0 < x< 1. The lift and drag are computed as a function of the ship speed and arbitrary hull parameters a through g. To demonstrate the usefulness of these formulas, two simple optimizations are performed for three fixedhull speeds. First, the hull parameters are chosen so as to minimize the drag for the total lift fixed, and second, the hull parameters are chosen so as to minimize the drag for the volume of the hull fixed.
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Murawski, Lech. "Shaft Line Whirling Vibrations: Effects of Numerical Assumptions on Analysis Results". Marine Technology and SNAME News 42, nr 02 (1.04.2005): 53–60. http://dx.doi.org/10.5957/mt1.2005.42.2.53.
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Whirling (lateral, transverse, bending) vibration of a typical marine power transmission system is not usually dangerous for a shaft line. Nevertheless, the shaft line lateral vibration analysis is quite often performed, especially for a long, elastic shaft line or when a ship hull is elastic compared to the propulsion system (Camisetti 1982). Whirling vibrations are transferred to the ship hull through journal bearings and may be a source of excessive superstructure vibrations. During whirling vibrations analysis, some parameters have to be checked. Usually, a beam model of the power transmission system is isolated from the ship hull. Therefore, determining the correctness of the boundary conditions is one of the most important, difficult, and debated tasks. In the author's opinion, stiffness and damping characteristics of the journal bearings' oil film, ship hull, and bearings frame should be taken into account (Murawski 2001). Additionally, the influence of the gyroscopic force and thrust force on whirling vibrations is discussed. The presented numerical analysis method is compared and verified by measurements on real ships.
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Abramowski, Tomasz, Katarzyna Żelazny i Tadeusz Szelangiewicz. "Numerical analysis of influence of ship hull form modification on ship resistance and propulsion characteristics". Polish Maritime Research 17, nr 1 (1.01.2010): 10–13. http://dx.doi.org/10.2478/v10012-008-0060-2.
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Numerical analysis of influence of ship hull form modification on ship resistance and propulsion characteristics After signing ship building contract shipyard's design office orders performance of ship resistance and propulsion model tests aimed at, apart from resistance measurements, also determination of ship speed, propeller rotational speed and propulsion engine power for the designed ship, as well as improvement of its hull form, if necessary. Range of ship hull modifications is practically very limited due to cost and time reasons. Hence numerical methods, mainly CFD ones are more and more often used for such tests. In this paper consisted of three parts, are presented results of numerical calculations of hull resistance, wake and efficiency of propeller operating in non-homogenous velocity field, performed for research on 18 hull versions of B573 ship designed and built by Szczecin Nowa Shipyard.
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Belov, O. A., I. V. Maloletko, I. A. Romanenkov i S. A. Klementyev. "Analytical calculation of the potential for contact corrosion of metals in the marine environment". Innovatics and Expert Examination, nr 1(31) (18.06.2021): 119–28. http://dx.doi.org/10.35264/1996-2274-2021-1-119-128.
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One of the most common types of ship corrosion is contact corrosion, which occurs at the interface of dissimilar metals being washed. It poses a serious danger to the ship's hull and ship metal structures, as it leads to a sharp increase in the rate of corrosion damage to one of the contacting metals. Therefore, the fight against contact corrosion is one of the most urgent tasks in the field of anti-corrosion protection of ships. Protection of ships from contact corrosion requires solving a set of interrelated engineering problems that require a quantitative assessment of the rate of corrosion processes on ship structures and the effectiveness of anti-corrosion protection means used on ships [1, 2]. The article discusses an analytical approach in assessing the local rate of electrochemical corrosion processes of ship hull structures based on the phenomenon of polarization using polarization curves and approximation methods.
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Sun, Shuzheng, Wenlei Du i Hui Li. "Study on Green Water of Tumblehome Hull Using Dam-Break Flow and Ranse Models". Polish Maritime Research 24, s2 (28.08.2017): 172–80. http://dx.doi.org/10.1515/pomr-2017-0080.
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Abstract The tumblehome hull adopts some novelty designs such as low-tumblehome freeboard and wave-piercing bow. The new form design makes the ship have many special hydrodynamic performances. Especially the green water of tumblehome hull is different from that of hulls with flare free board. Green water is a strong nonlinear phenomenon of ship-wave interaction, the variation of free surface of liquid is complicated, and there are still some difficulties to solve green water problems well with numerical simulation method. In this paper firstly the motion responses of the tumblehome hull was calculated based on 3D potential theory, and then the dam-break flow model was used to calculate green water height and pressure distribution. According to the result of numerical simulation, some typical working conditions are chosen for 3D CFD simulation using RANS method. The results of numerical simulation methods are compared with the experimental results measured in towing tank. The influence of different ship form parameters and wave parameters to the green water of tumblehome hull is analyzed, and some regularities of green water on tumblehome hull in regular waves are summarized.
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Gavan, Eugen, Violeta Mihaela Hogas, Florin Renardo Teodor i Costel Iulian Mocanu. "Comparative study of the cutting shape from the reinforced elements on the ship body structure". Analele Universităţii "Dunărea de Jos" din Galaţi. Fascicula XI, Construcţii navale/ Annals of "Dunărea de Jos" of Galati, Fascicle XI, Shipbuilding 43 (15.12.2020): 45–52. http://dx.doi.org/10.35219/annugalshipbuilding.2020.43.06.
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"In order to achieve a lighter ship hull, solutions are required regarding the mass reduction of the structural elements, which are part of the ship hull. In the development of the ship hull, besides the shell, there is another series of system elements, the transverse and longitudinal frames, which ensure the rigidity, the strength and the stability of the ship. Depending on the building system of the ship hull, these structural elements have a more or less preponderance in the total mass of the ship. In this study paper using Finite Elements Method will be presented a comparative study of different cutting forms through the reinforced frame elements, which are a part of the structure of the ship hull. On the end will be some conclusions regarding the opportunity of adopting one form or the other."
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Li, Chun Tao, Xiang Qi, Jian Shi, Zhong Kun Shi i Huan Qi. "Ship Lines Modeling Theory of High-Speed Ship Based on the Partial Differential Equations". Advanced Materials Research 602-604 (grudzień 2012): 1827–30. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.1827.
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Based on the analysis of molded line geometrical characteristic and boundary conditions of high-speed frigate’s hull by using differential geometry, we report a curve modeling principle to express the hull line geometry through differential geometry application. The starting point of this molded-line automatic generation method is using the planar curve to express 3D surface shape. The first problem to be solved is how to get shape functions which describe every design ship curves via the the hull type curves geometry. The second problem to be solved is how the two-dimensional function, which describe ship lines, transformed to the hull shape function designed of three-dimensional hull surface, namely “mathematic ship”.
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An, Feng Bao, Ping Yang, Xin Ping Yan i Ming Li. "Influence Analysis of Hull Deformation on Dynamic Behavior of Propulsion Shafting". Advanced Materials Research 904 (marzec 2014): 432–36. http://dx.doi.org/10.4028/www.scientific.net/amr.904.432.
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The aim of this paper is to study the influence of hull deformation on dynamic behavior of ship propulsion shafting. Taking an 8530TEU container ship as an objective and using the finite element method, a global ship structure model is built up to evaluate the hull deformations under typical loading cases. Then the hull bottom-propulsion shafting integrated model is adopted to analyze the effect of hull deformation on shafting natural frequency under dry and wet mode. The results show that the natural frequencies of the shafting will increase due to the effect of hull deformation. Consequently, it is necessary to consider the effect of ship deformation when dealing with the dynamic behavior of ship propulsion shafting.
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Leduc, Daniel. "A new nematode species, Chromadorina tangaroa sp. nov. (Chromadorida: Chromadoridae) from the hull of a research vessel, New Zealand". PeerJ 8 (26.05.2020): e9233. http://dx.doi.org/10.7717/peerj.9233.
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Chromadorina is a globally distributed, largely marine nematode genus frequently found on a variety of organisms, including macro- and microalgae and crustaceans, as well as artificial substrates such as settlement plates and ship hulls. Here, Chromadorina tangaroa sp. nov. is described from filamentous seaweed growing on the hull of RV Tangaroa anchored in Wellington, North Island of New Zealand. It is characterized by body length 763–1,086 μm, and pore of secretory-excretory system located at or near level of teeth. Males have spicules with rounded capitulum followed by a narrower shaft and blade tapered distally, a gubernaculum as long as the spicules, and three cup-shaped precloacal supplements, and females are characterized by a cuticularized prevulvar pad, vagina located at 46–48% of body length from anterior, and vagina anteriorly directed. Chromadorina tangaroa sp. nov. is the first species of the genus to be described from New Zealand, but it is unclear whether it is native to the region because it may have dispersed as part of ship hull biofouling communities. Long-distance transport of nematodes through ship hull biofouling may be a common occurrence, but too little is known about the occurrence of nematodes on ship hulls to gauge the potential effect of shipping on nematode species distributions.
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Borchardt, John K. "Grooming the Fleet". Mechanical Engineering 132, nr 04 (1.04.2010): 33–35. http://dx.doi.org/10.1115/1.2010-apr-3.
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This article presents an overview of a robotic system, named Hull BUG, designed to remove deposits from the undersides of ships. The robot is the product of SeaRobotics, a company in Palm Beach Gardens, FL, USA, that develops unmanned vessels for jobs including deep-water research and coastal surveillance. The current developmental model of the Hull BUG uses a negative pressure vortex regenerative fluid movement assembly to attach itself to the hull. The robot is designed to work without using cleaning chemicals. It measures about 2-feet wide, 2-feet long, and 1-foot high. Weighing 30 pounds, it is designed to be neutrally buoyant in seawater, so it needs less propulsion to negotiate a ship’s hull underwater. The Hull BUG requires no human operator. Onboard sensors provide obstacle avoidance, path planning, and navigation capabilities. These capabilities include a biofilm detector that can distinguish between fouled and groomed surfaces. The Hull BUG has already been tested on many pieces of steel having different types of structures and shapes to model sections of ship hulls.
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Indiaryanto, Mahendra, Ahmad Syafi'ul Mujahid, Taufiq A. Setyanto i Navik Puryantini. "Hull Form Factor Prediction of Mini Submarine Model Using Prohaska Method". EPI International Journal of Engineering 3, nr 2 (1.02.2021): 160–64. http://dx.doi.org/10.25042/epi-ije.082020.12.
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Speaking of prisoners on mini-submarines is certainly different Fnom the type of surface vessels in general. This is related to differences in the shape of the sub's hull when compared to surface ship. In addition to differences in the shape of the hull, the difference in the operational area of the ship is also different, where the submarine's hull operates at full water depth, while the surface ship the ship hull partly operates at sea level. If the submarine model is tested then the value of the coefficient of resistance will be very different. Where the component of the coefficient of resistance (CT) consists of the coefficient of Fniction (CF), form factor (1+K), and Correlate Allowance (CA). Because the hull shape is different Fnom the surface ship, then the hull form factor coefficient is the focus of this study. The prediction of the hull form factor can be searched using the PROHASKA method. Where this method is done using a mini-submarine model test. By the known value of the hull form factor, then it can be used to find the value of the coefficient of resistance and can know the resistance of the ship
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Jang, Chang Doo, Ho Kyung Kim i Ha Cheol Song. "Optimum Structural Design of High-Speed Surface Effect Ships Built of Composite Materials". Marine Technology and SNAME News 40, nr 01 (1.01.2003): 42–48. http://dx.doi.org/10.5957/mt1.2003.40.1.42.
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A surface effect ship is known to be comparable to a high-speed ship. For the structural design of surface effect ships, advanced design methods are needed which can reflect the various loading conditions different from those of conventional ships. Also, minimum weight design is essential because hull weight significantly affects the lift, thrust powering and high-speed performance. This paper presents the procedure of optimum structural design and a computer program to minimize the hull weight of surface effect ships built of composite materials. By using the developed computer program, the optimum structural designs for three types of surface effect ships—built of sandwich plate only, stiffened single skin plate only, and both plates—are carried out and the efficiency of each type is investigated in terms of weight. The computer program, developed herein, successfully reduced the hull weight of surface effect ships by 15–30% compared with the original design. Numerical results of optimum structural designs are presented and discussed.
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Hunsucker, Kelli Z., J. Travis Hunsucker, Harrison Gardner i Geoffrey Swain. "Static and Dynamic Comparisons for the Evaluation of Ship Hull Coatings". Marine Technology Society Journal 51, nr 2 (1.03.2017): 71–75. http://dx.doi.org/10.4031/mtsj.51.2.9.
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AbstractStatic immersion tests are commonly used to evaluate the performance of marine coatings prior to use on ship hulls or for other applications. Although these tests provide valuable data, they do not expose the coatings to the hydrodynamic and fouling conditions that will be present when a ship is underway, thus making it difficult to extrapolate results to ship hull performance. The present study reports data for two commercially available ship hull coatings (one antifouling and one fouling release coating) exposed concurrently to static and dynamic ocean conditions for 4 months. Coatings that were exposed to static conditions developed macrofouling communities dominated by tubeworms, tunicates, and encrusting bryozoans. The coatings subjected to dynamic conditions were fouled only by biofilms and green macroalgae. The results show a difference in coating performance depending on immersion environment (static vs. dynamic) as well as coating type. This highlights the importance of utilizing dynamic testing concurrently with static immersion in coating evaluation to better understand how the system will respond to hydrodynamic stresses. Knowing how a coating performs under various real-world conditions can help drive ship hull management and determine which coating is appropriate for the ship's operational schedule.
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Бокатова, А. А., i Н. И. Герасимов. "Wear of hulls and hull structures of Russian NAVY auxiliary vessels". MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), nr 2(52) (5.06.2021): 64–68. http://dx.doi.org/10.37220/mit.2021.52.2.008.
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В статье рассматривается вопрос износа связей корпусных конструкций судов атомно-технологического обслуживания военно-морского флота, транспортирующих жидкие радиоактивные отходы. Как известно, определение технического состояния корпуса судна является основным параметром установления их пригодности к дальнейшей эксплуатации. Авторами были проанализированы исследования влияние гамма-облучения на лакокрасочные покрытия и установлено, что такое воздействие приводит к изменению основных характеристик лакокрасочных покрытий, вследствие чего наступает их отслаивание от поверхности корпусных конструкций. В связи с тем, что ускоренное разрушение лакокрасочных покрытий влечет за собой более раннее коррозионное разрушение корпусных конструкций, авторами настоящей работы проводилось изучение скоростей изнашивания корпусных конструкций, подверженных воздействию ионизирующего облучению, так и не подверженных агрессивному воздействию груза для судов атомно-технологического обслуживания и сопоставление их с известными данными скоростей изнашивания для конструкций гражданских судов. Результаты выполненного авторами исследования могут быть использованы в научно-обоснованном прогнозировании сроков службы и определении технического состояния корпусов судов атомно-технологического обслуживания. This article considers issues, related to wear of hulls and hull structures of Russian NAVY auxiliary vessels, used for transportation of liquid radioactive wastes. As is known, assessment of ship hull state is the main criteria of ship readiness for further exploitation. The authors analyzed surveys related to influence of gamma-irradiation on paint coatings and revealed alteration of their main characteristics followed by stripping from the ship hull. Since accelerated destruction of paint coatings leads to early corrosion damage of hull structures, the authors analyzed wear rate of nuclear-servicing vessels hulls exposed and non-exposed to nuclear radiation and compared it with known wear rates of civil vessels hulls. The obtained results may be used for scientifically-based forecasting of ship service life and assessment of technical state of nuclear-servicing vessels.
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Fernández-Isla, Carlos, Pedro J. Navarro i Pedro María Alcover. "Automated Visual Inspection of Ship Hull Surfaces Using the Wavelet Transform". Mathematical Problems in Engineering 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/101837.
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A new online visual inspection technique is proposed, based on a wavelet reconstruction scheme over images obtained from the hull. This type of visual inspection to detect defects in hull surfaces is commonly carried out at shipyards by human inspectors before the hull repair task starts. We propose the use of Shannon entropy for automatic selection of the band for image reconstruction which provides a low decomposition level, thus avoiding excessive degradation of the image, allowing more precise defect segmentation. The proposed method here is capable of on-line assisting to a robotic system to perform grit blasting operations over damage areas of ship hulls. This solution allows a reliable and cost-effective operation for hull grit spot blasting. A prototype of the automated blasting system has been developed and tested in the Spanish NAVANTIA shipyards.
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Davey, Kent. "Ship Component in Hull Optimization". Marine Technology Society Journal 39, nr 2 (1.06.2005): 39–46. http://dx.doi.org/10.4031/002533205787443953.
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This document outlines an optimization to define the size of the components in the power train of an electric ship, specifically one appropriate for an 80 MW Destroyer. The objective is to minimize the volume of the system, including the fuel. The size, number and speed of the gas turbines, the electric generators, and the power electronics are considered as unknowns in the analysis. At the heart of the procedure is the power mission profile. The gas turbine is by far the most important component in terms of influence on system volume. Integral to its selection is the specific fuel consumption as a function of power and turbine size. The proposed procedure outlines a nested optimization to define both the best spread of turbines as well as the proper scheduling with load demand. Including fuel in the system volume is the key to meaningful component identification. The optimized design has a system volume 603.5 m3 smaller than the base configuration, assuming both systems employ load scheduling among turbines. An optimized design can save as much as 600 m3.
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Townsin, R. L. "The Ship Hull Fouling Penalty". Biofouling 19, sup1 (styczeń 2003): 9–15. http://dx.doi.org/10.1080/0892701031000088535.
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Song, Soonseok, Yigit Kemal Demirel, Claire De Marco Muscat-Fenech, Tonio Sant, Diego Villa, Tahsin Tezdogan i Atilla Incecik. "Investigating the Effect of Heterogeneous Hull Roughness on Ship Resistance Using CFD". Journal of Marine Science and Engineering 9, nr 2 (16.02.2021): 202. http://dx.doi.org/10.3390/jmse9020202.
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Research into the effects of hull roughness on ship resistance and propulsion is well established, however, the effect of heterogeneous hull roughness is not yet fully understood. In this study, Computational Fluid Dynamics (CFD) simulations were conducted to investigate the effect of heterogeneous hull roughness on ship resistance. The Wigley hull was modelled with various hull conditions, including homogeneous and heterogeneous hull conditions. The results were compared against existing experimental data and showed a good agreement, suggesting that the CFD approach is valid for predicting the effect of heterogeneous hull roughness on ship resistance. Furthermore, the local distributions of the wall shear stress and roughness Reynolds number on the hull surface were examined to assess the flow characteristics over the heterogeneous hull roughness.
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Bian, Wen Feng, Jie Cheng, Yan Lin Liu i Bao Xian Jia. "The Influence of Composite Material’s Constituents on the Stiffness of the 70m Hull". Materials Science Forum 813 (marzec 2015): 109–15. http://dx.doi.org/10.4028/www.scientific.net/msf.813.109.
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It is widely believed that large composite materials are difficult to build a ship which is longer than 40 meters because of lack of structural stiffness. Up to now, the ships, 72-meter in length, made of glass fiber reinforced composite have been in serve abroad, while 35 meters in China. Therefore, it’s absolutely necessary to study the problem about the stiffness of the 70-metre composite materials hulls. Start from integration design and finite element analysis of composite materials and structure, the influences of material component, laminated angle and laminated sequences of composite materials’ hull on the dynamic stiffness and static stiffness of the ship are studied to explore the method of improving stiffness. The result show that, in the conditions of having the same molded surface, ship's weight and applied stress, it can improve the ship’s longitudinal stiffness to reach standard requirements by using the part of the high modulus fiber as well as the high modulus fiber laying on the outboard of the hull.
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Mansour, A. E., P. H. Wirsching, B. Ayyub i G. White. "Code Development for Ship Structures—A Demonstration". Journal of Offshore Mechanics and Arctic Engineering 119, nr 2 (1.05.1997): 114–19. http://dx.doi.org/10.1115/1.2829052.
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A demonstration summary of a reliability-based structural design code for ships is presented for two ship types: a cruiser and a tanker. One reason for the development of such a code is to provide specifications which produce ship structure having a weight savings and/or improvement in reliability relative to structure designed by traditional methods. Another reason is to provide uniform safety margin for ships within each type. For both ship types, code requirements cover four failure modes: hull girder bulkling, unstiffened plate yielding and buckling, stiffened plate buckling, and fatigue of critical detail. Both serviceability and ultimate limit states are considered. Because of limitation on the length, only hull girder modes are presented in this paper. Code requirements for other modes will be presented in future publication. A specific provision of the code will be safety check expression, which, for example, for three bending moments (still water Ms, wave Mw, and dynamic Md), and strength Mu, might have the form, following the partial safety factor format: γsMs+γwMw+γdMd≤φMu γs, γw, γd, and φ are the partial safety factors. The design variables (M’s) are to be taken at their nominal values, typically values in the safe side of the respective distributions. Other safety check expressions for hull girder failure that include load combination factors, as well as consequence of failure factors, are considered. This paper provides a summary of safety check expressions for the hull girder modes.
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Kamal, I. Z. Mustaffa, A. Imran Ismail, M. Naim Abdullah i Y. Adnan Ahmed. "Influence of the transom immersion to ship resistance components at low and medium speeds". Journal of Naval Architecture and Marine Engineering 17, nr 2 (30.12.2020): 165–82. http://dx.doi.org/10.3329/jname.v17i2.48494.
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The transom stern offered some advantages over the traditional rounded cruiser stern reducing the resistance of a ship. This can only be achieved if the transom stern is carefully designed with suitable transom immersion ratio. In this study, the influence of different transom area immersion ratios on the resistance components was investigated for a semi-displacement hull and a full displacement hull. The base hull was based on NPL hull form and KCS hull form for a semi-displacement and full-displacement hull respectively. The transom immersion ratios for the NPL hull were varied at a ratio of 0.5, 0.7, 0.8 and 1.0. The resistance of each of the NPL hull form was simulated at Froude number 0.3 up to 0.6. The transom immersion ratios for the KCS hull were varied at a ratio of 0.05, 0.1, 0.15 and 0.3. The resistance of each of the KCS hull form was simulated at Froude number 0.195, 0.23, 0.26 and 0.28. The transoms of both hulls were modified or varied systematically to study the influence of the transom shape or immersion on the total and wave resistance components. The investigation was carried out using a CFD software named SHIPFLOW 6.3 based on RANSE solver. These results on the NPL hull shows that the larger the transom immersion, the higher the resistance will be for a semi-displacement vessel. The increased resistance is contributed by additional frictional and wave resistance components. The results for the KCS hull seems to contradict with the results obtained from the NPL hull. The larger and deeper transom for the case of KCS hull form sometimes can be beneficial at higher Froude number.
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Boitsov, G. V., i M. A. Koudrin. "Drawbacks of the Present System of Unified Requirements for Ship Hull Global Strength and Potential Ways to Rectify Them". Marine Technology and SNAME News 37, nr 04 (1.10.2000): 185–90. http://dx.doi.org/10.5957/mt1.2000.37.4.185.
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This paper considers inadequacies in the formulas for ship global hull strength currently approved by members of the International Associations of Classification Societies (IACS). Citing the results of several experimental and numerical studies, the author proposes modifications to the Rules formulas on ship hull vertical bending moments. Wave loading on the hull under steady wave conditions is studied for long-term ship operations, and the existing fatigue strength standards for hull longitudinals are also examined.
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Dwiono, Aris Sasongko, Andi Hendrawan i Sri Pramono. "Perbaikan Lambung Kapal KM. Harima PT. CSFI-Cilacap". Dinamika Bahari 2, nr 1 (18.05.2021): 56–61. http://dx.doi.org/10.46484/db.v2i1.261.
Pełny tekst źródłaStreszczenie:
The purpose of a ship is for the transportation or transfer of goods, but what is no less important is safety. Therefore checking every part is very important. Repair of the hull is mandatory because damage to the hull can result in imbalance in ship operations and even ship accidents. This study aims to describe the repair of the ship's hull on the KM. Harima PT. CSFI Cilacap. The study used a survey method by observing and being directly involved in the ship repair process. Improvements that are in accordance with the research objectives are repairing the ship's hull KM Harima. The results show that ship repair is carried out through checking, welding, welding, or painting.
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Davydova, Svetlana V., i Ivan V. Andriyanov. "Principles of the tugboats’ surface systematization in the development of theoretical drawing by the interpolation method". Russian Journal of Water Transport, nr 63 (1.06.2020): 55–61. http://dx.doi.org/10.37890/jwt.vi63.76.
Pełny tekst źródłaStreszczenie:
The work is devoted to the issues of the tugboat’s surface development by the interpolation method at the early design stages. The developed theoretical drawing of the tugboat’s hull should correspond as much as possible to the specified parameters, namely, the calculated values of the overall completeness ratio and the relative abscissa of the magnitude center. The principles of the approach to existing ship hulls’ systematization are given and the possibility of their application for developing a theoretical surface with the specified parameters is evaluated. As a result of the analysis, systematization and selection of the most suitable hulls for processing were carried out. The variety of hull shapes has been successfully brought to a single system, which is necessary for interpolation, and consequently for creation of a new hull with the specified parameters. The adopted approach to the ship surface development can be used to automate the process of obtaining it.