Search Results for Hulls (structures)

This article provides information on the potential applications of fiber-reinforced polymer (FRP) composites for maritime craft and offshore drilling platforms. The key benefits gained from using FRP materials together with an examination of the drawbacks and major issues impeding the more widespread use of composites in marine structures are presented.

Organic coatings are the principal means of corrosion control for the hulls and topsides of ships and for the splash zones on permanent offshore structures. This article describes surface preparation which is the most important consideration in determining the performance of organic coating systems. It contains a table that lists the uses and applicable standards for various surface preparation techniques. The article provides information on organic coatings in topside coating systems and reviews the importance of primers in the protection of steel substrates. It also explains the property requirements and the common types of immersion coatings.

Cathodic protection (CP) is an electrochemical means of corrosion control widely used in the marine environment. This article discusses two types of CP systems: impressed current systems and sacrificial anode (passive) systems. It describes the anode materials used in these systems and the CP criteria. The article examines the design considerations and procedures involved in the CP of marine pipelines, offshore structures, and ship hulls. An illustration of sacrificial anode calculation is also provided.

This article focuses on the design process, materials, and manufacturing techniques for one-off and low-volume production sailing craft. These include racing yachts of typically 10-20 m length for short coastal events, 20-25 m ocean racers, 24 m America's Cup racing craft, multihull racers of 35 m or more, and large luxury cruising craft. The article discusses the tooling, laminating practice, curing, mold removal, and quality control, for manufacturing hulls, decks, masts, and appendages using composites.

It is recommended that repairs be made whenever damage consists of delamination cracks or broken fibers. This article provides an overview of the repair classification, characterization, and cycle of the composite ship structure. The methods outlined in this article, which covers gel coat repairs, patching, scarfing, and step repairs, have undergone extensive development and rigorous testing for use on composite ship structures. Resin infusion repair, which is a relatively new method for repairing marine composites, is also described.

This article focuses on the corrosion and deterioration of components on recreational and small workboats. It discusses the materials selection and corrosion control for the components. These components include hulls, fittings, fasteners, metal deck gear, winches, backing plates, lifeline supports, inboard engines, cooling systems, propulsion systems, electrical and electronic systems, plumbing systems, masts, spars, and rigging.

This article focuses on marine coatings associated with protecting commercial and military vessels. It provides detailed information on the common issues and requirements encountered when coating ballast tanks, freeboard, topside, and decks of the vessel. The article describes the advent of ultra-high solids coatings technology, and reviews the marine-specific coatings such as antifouling and their mechanisms and common failure modes.

Stray-current corrosion is an accelerated form of corrosion caused by externally induced electric current. It can occur in unprotected pipelines and submerged metal structures located near electric power sources or anywhere voltage differences exist. This article describes common scenarios and sources of stray current along with ways to detect it and prevent the type of corrosion it can cause.

The selection of materials for welded construction applications involves a number of considerations, including design codes and specifications. Mobile structures have quite different materials requirements for weight, durability, and safety than stationary structures, which are built to last for many years. This article provides an overview of the service conditions. It offers guidance for material selection applications, including bridges and buildings, pressure vessels and piping, shipbuilding and offshore structures, aerospace systems, machinery and equipment, automobiles, railroad systems, and sheet metal. Material properties and welding processes that may be significant in meeting design goals are also described.

Vacuum infusion is a resin injection technique derived from resin transfer molding. This article discusses the characteristics of the technique and its applications. It presents the theory and background of the technique and provides an illustration of how parts are made. The article provides information on the equipment and material used for vacuum infusion. It describes the mechanical properties of components and summarizes the influence of production on the properties. The article concludes with a discussion on design guidelines.

The goal of design is to improve the overall performance of the metal or ceramic matrix rather than to create a material with different response than the base matrix. This article focuses on the design for manufacturing polymeric composites. Specially developed methods including contact molding, compression-type molding, resin-injection molding, and pultrusion are described. The article also discusses the various factors to be considered in designing for composite manufacturing.

This article describes the various environments affecting corrosion performance, corrosion protection, and corrosion control. These include freshwater environments, marine environments, and underground environments. The article provides information on corrosion in military environments and specialized environments, representing less-well-known environments with more limited applications.

This article discusses the historical background of composite construction in recreational equipment and sporting goods. It provides information on the applications of composites in baseball bats, tennis rackets, and golf clubs. The applications of composites in bicycling, winter sports, aquatic sports, track, field, and archery equipment are also discussed.

A phase diagram is a graphical representation of the phase equilibria of materials in terms of temperature, composition, and pressure. This article provides an overview on the background of phase diagram calculation software. It presents an algorithm to calculate binary stable phase equilibria. The article summarizes a rapid method to obtain a thermodynamic description of a multicomponent system. It also provides information on thermodynamically calculated phase diagrams.

Austenitic stainless steels exhibit a single-phase, face-centered cubic structure that is maintained over a wide range of temperatures. This article reviews the compositions of standard and nonstandard austenitic stainless steels. It summarizes the important aspects of solidification behavior and microstructural evolution that dictate weld-metal ferrite content and morphology. The article describes weld defect formation, namely, solidification cracking, heat-affected zone liquation cracking, weld-metal liquation cracking, copper contamination cracking, ductility dip cracking, and weld porosity. It discusses four general types of corrosive attack: intergranular attack, stress-corrosion cracking, pitting and crevice corrosion, and microbiologically influenced corrosion. The article concludes with information on weld thermal treatments such as preheat and interpass heat treatments and postweld heat treatment.

Mechanical properties are described as the relationship between forces (or stresses) acting on a material and the resistance of the material to deformation (i.e., strains) and fracture. This article briefly introduces the typical relationships between metallurgical features and the mechanical behavior of metals. It explains the deformation and fracture mechanisms of these metals. Typical properties measured during mechanical testing related to these deformation mechanisms and the microstructures of metals are discussed. The article reviews the various factors that affect the deformation response of the metal: strain rate, temperature, nature of loading, stress-corrosion cracking, and presence of notches.

Filament winding is a process for fabricating a composite structure in which continuous reinforcements, either previously impregnated with a matrix material or impregnated during winding, is placed over a rotating form or mandrel in a prescribed way to meet certain stress conditions. This article describes the advancements in filament winding and lists the advantages and disadvantages of filament winding. It discusses the effects of fiber tension in filament winding and the selection of fibers, resins, and materials for filament winding. The article emphasizes the three basic filament-winding patterns, such as helical, polar, and hoop. It presents information on the applications of filament winding, including rocket motors, natural gas vehicle (NGV) tanks, and sporting goods. The article presents recommendations for the basic design guidelines for filament-winding design/manufacturing process and concludes with a discussion on fabrication recommendations.

This article reviews corrosion problems in the U.S. Department of Defense (DoD) and discusses management and maintenance aspects of the practices that address the cost and readiness. It describes the plans to institute corrosion prevention and control strategies under DoD directives in engineering design, material selection, and fabrication processes for new acquisitions. The article also suggests a long-term strategy to reduce the cost of corrosion control.