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Smart design of hull forms through hybrid evolutionary algorithm and morphing approach
Published in Pentti Kujala, Liangliang Lu, Marine Design XIII, 2018
J.H. Ang, V.P. Jirafe, C. Goh, Y. Li
Performance evaluation assess each candidate solution produced from the optimiser based on the objective function. The most important performance parameters that are influenced by shape of the hull include resistance and sea-keeping behavior and hence selected as key objective functions in most hull form design optimisation applications. For evaluation of resistance, Computational fluid dynamic (CFD) are used extensively in hull form optimisation which had been proven as an effective means to simulate the fluid flow around vessel. Examples of CFD methods used for resistance evaluation include potential flow (Nowacki 1996) and Reynolds Averaged Navier-Strokes Equation—RANSE (Tahara et al. 2006, Zha et al. 2014). For sea-keeping analysis, there are several numerical methods which include strip theory, unified theory, green function method, etc. (Bertram 2000).
Research Vessel Construction—Terminology, Equipment, and Machinery
Published in George A. Maul, The Oceanographer's Companion, 2017
A ship of this size could be constructed of fiberglass, aluminum, steel, or some combination (e.g., steel hull and aluminum superstructure). In any case it would all start with the keel, and perhaps a keel-laying ceremony. The keel on such a vessel will be an interior “I beam” structure to reduce the draft and increase interior space. The bottom of the I is the keel plate, next the center vertical keel, capped by a rider plate at the top of the I; the rider plate often is at the height of the lowest deck, which is called the “A” deck, or inner bottom, or tank top if it covers spaces used for fuel or water. The fore-and-aft outer hull plate next to the keel plate is called the garboard strake, which is a holdover term from when ships were wooden plank construction. Figure 3.3 adds a few other structural member names such as the bilge strake, the floors (which are vertical transverse structures), the shear strake that defines the outer hull's shape, stringers running longitudinally, open pillars called stanchions to support the deck beams, and so forth. Ships have ceilings, but you walk on them; ships have girders, which run fore-and-aft, but not athwartships; ships have bulkheads, but no walls….
Introduction to Composites
Published in Manoj Kumar Buragohain, Composite Structures, 2017
Glass/polyester and glass/vinyl ester composites are routinely used in the production of different types of small and large yachts. In some cases, aramid fibers are also used these days. The primary attraction of composites is weight reduction, which leads to greater speeds, better maneuverability, and fuel efficiency. Hulls of these boats are made typically by contact molding. In some high-performance applications such as racing boats, high specific strength and stiffness are essential. In such cases, hulls, decks, masts, etc. are made using carbon/epoxy laminates and honeycomb sandwich construction with carbon/epoxy skins. There are other marine applications of composites that include submarines, offshore oil exploration, etc.
A just-in-time learning-based compensation prediction method for hull plate welding
Published in International Journal of Computer Integrated Manufacturing, 2023
Liang Chen, Yu Zheng, Kaipeng Lan, Yanjun Ma, Huade Su
The hull is an important part of a ship. The construction of the final hull, which is a large and complex structure, requires the assembly of a large number of parts with different shapes and sizes. The associated levels of assembly of the steel plates and blocks can be categorized into subassembly, unit block assembly (UBA), block assembly, and final hull levels. According to the size and weight of the subassembly (Cho, Sun, and Oh 1999), the subassembly levels may be further divided into small subassembly (SSA) levels and intermediate subassembly (ISA) levels. Due to the complex structure of the hull, its construction process is very complex, including pretreatment, parts processing, parts and block assembly, berth closing, and other processes. Parts of the hull structure must be processed via cold machining or hot treatment, which are known to induce errors, such as assembly and deformation errors. These errors are difficult to avoid (Mandal 2017). They would be propagated and accumulated throughout the subsequent construction procedures, ultimately affecting the accuracy of the final hull. The hull structure is mostly made of steel, and its elements are usually joined by welding. Errors caused by welding deformation should be considered and controlled during the construction procedures. This improves the quality of the hull, shortens the construction cycle, and reduces manufacturing costs.
A constrained localization algorithm for improving the efficiency and accuracy of forming curved hull plates in shipbuilding
Published in International Journal of Computer Integrated Manufacturing, 2019
Bao Zhao, Zhouqi Wu, Xijin Zhen, Juntong Xi
Efficient and accurate fabrication of curved plates is one of the most important steps in shipbuilding. It is because the shape of a ship hull has a large influence on the overall performance of a ship (e.g. fuel efficiency, operational performance, etc.). A ship hull consists of various curved plates in shapes and sizes. Each piece of curved plate is fabricated by either thermal forming or mechanical forming. The thermal forming is the most used method in shipyards and it is considered the only practical method for forming thick plates with thicknesses of 15–50 mm (Park et al. 2015).