This article describes the types of fabrics and preforms that are used in the manufacture of advanced composites and related selection, design, manufacturing, and performance considerations. The types of fabrics and performs include unidirectional and two-directional fabrics; multidirectionally reinforced fabrics; hybrid fabrics; woven fabric prepregs; unidirectional and multidirectional tape prepregs; and prepreg tow. The article discusses the three major categories of tape manufacturing processes, namely, hand lay-up, machine-cut patterns that are laid up by hand, and automatic machine lay-up. It provides a description of the two classes of prepregs. These include those suitable for high-performance applications and those suitable for lower-performance molding compounds.

Prepreg hand lay-up process is versatile, reliable, cost-effective, and high quality process for fabricating large or small components. This article discusses the technique characteristics and applications of prepreg hand lay-up process. It describes the stages involved in the process of lay-up, namely, lay-up definition, ply-kit cutting, layup, debulking, and preparation for curing. The article concludes with a discussion on the component properties and design guidelines of the prepreg hand lay-up process.

This article reviews the history of prepreg and ply cutting technologies as well as outlines the options available for creating the necessary data and for nesting, cutting, and kitting the plies. It discusses the ways in which these steps influence the workflow for various applications. The characteristics of prepreg and ply cutting methods are presented in a table.

This article focuses on epoxy because this resin category has widespread use and because it is tested using quality control measures typical of most resin systems. A typical resin system will consist of one or more epoxy resins, a curing agent, and a catalyst to control the rate of reaction. The article describes the component material tests, mixed resin system tests, and prepreg tests for the resin system. The tests include high-performance liquid chromatography, infrared spectroscopy, and gel permeation chromatography. The article contains a table that lists typical resin and prepreg property tests.

This article describes the dispersed-phase toughening of thermoset matrices by the development of multiphase-structure thermosetting matrices using rubber and/or thermoplastic materials. It discusses two main methods for manufacturing prepregs, namely, single-pass impregnation and double-pass impregnation. The article illustrates reflected-light optical microscopy techniques to evaluate the morphology of thermoplastic materials for determining the material quality and correlating key microstructural features with material performance.

Autoclave molding is a process used to impart a controlled heat and pressure cycle cure to a layup. This article describes the materials used for preparing a layup, including peel ply, separator, bleeder, barrier, breather, dam, and vacuum bag. It describes the major elements and functions of an autoclave system, including pressure vessel, gas stream heating and circulation sources, gas stream pressurizing systems, vacuum systems, control systems, and loading systems. The article includes information about modified autoclaves for specialized applications and safety practices in autoclave molding. It also describes the tooling configuration and type of tooling which includes aluminum and steel tooling, electroformed nickel tooling, graphite-epoxy tooling, and elastomeric tooling.

This article describes the most significant tests to characterize the properties of constituent materials. It discusses the chemical, physical, and mechanical tests for determining the properties of reinforcement fibers and fabrics. The article provides information on some of the basic materials used for thermoset and thermoplastic resin matrices. It reviews the identification of the individual characteristics of thermoset and thermoplastic resin along with the test methods normally used for their determination. The article contains a table that lists properties and tests for uncured and cured thermoset-matrix resins and prepregs.

This article focuses on the sample preparation methods for titanium honeycomb composites, boron fiber composites, and titanium/polymeric composite hybrids. These include mounting, sectioning, grinding, and polishing. The article also provides information on the sample preparation of unstaged and staged prepreg materials for optical analysis.

Analyzing the structure of composite materials is essential for understanding how the part will perform in service. Assessing fiber volume variations, void content, ply orientation variability, and foreign object inclusions helps in preventing degradation of composite performance. This article describes the optical microscopy and bright-field illumination techniques involved in analyzing ply terminations, prepreg plies, splices, and fiber orientation to provide the insight necessary for optimizing composite structure and performance.

This article addresses the types, properties, forms, and applications of fibers that are available for use in fiber-reinforced polymeric matrix composites, including glass, graphite, carbon, aramid, boron, silicon carbide, ceramic, continuous oxide and discontinuous oxide fibers. It describes the functions, types, and chemical composition of fiber sizing agents. The article discusses the styles, properties, applications, and weaving methods of unidirectional, two-directional and multidirectionally reinforced fabrics. The article also reviews the use of prepreg resins in aerospace and lower performance applications.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of a type of resin-matrix composites, carbon-epoxy composites. The fractographs illustrate the fracture modes found in composite prepregs, composite panels, solid rocket motor nozzles, and tension, flexural, compressive, and shear loadings.

Composite tooling is the making of tools from composite materials. This article focuses on wet lay-up methods and techniques that are used to fabricate prepreg tooling. It discusses the advantages and disadvantages of composite tools. The article describes the process considerations for composite tool design, such as master model or pattern design selection, fiber and fabric selection, resins, and surface coat and ply. Various tool laminate construction techniques, such as curing and demolding, and cutting and trimming, are reviewed. The article describes the substructure design for the construction of tool laminates.

This article describes the characteristics of thermoplastic composites and its material forms. It presents the steps and considerations in manufacturing the thermoplastic composites. The article provides a description of various techniques of manufacturing, such as consolidation, autoclave molding, diaphragm forming, compression molding, roll forming, bladder molding, liquid molding, filament winding, and pultrusion.

Voids in fiber-reinforced composite materials are areas that are absent of the composite components: matrix (resin) and fibers. Voids have many causes but generally can be categorized as voids due to volatiles or as voids that result from entrapped air. This article describes the analysis of various types of voids. It reviews techniques for analysis of voids at ply-drops, voids due to high fiber packing, and voids that occur in honeycomb core composites. The final section of the article discusses void documentation through the use of nondestructive inspection techniques and density/specific gravity measurement methods.

Honeycomb-cored sandwich panels increase part stiffness at a lower weight than monolithic composite materials. This article illustrates an area of a honeycomb-cored sandwich structure composite cross section that is viewed using transmitted polarized light. This area shows the differences in the constituents and resin intermingling. The article discusses the factors that govern the honeycomb core movement and honeycomb core crush, with illustrations. Some common tests performed on honeycomb composites to characterize the skin-to-core bond strength are the climbing drum peel and flatwise tensile tests. The article concludes with a description on the reasons for core failure, which are analyzed after these tests.

This article illustrates the polymer matrices used for composite materials. It describes the use of prepeg materials in manufacturing high-performance composites. The article discusses the various infusion processes for the development of fiber-reinforced composites, namely, resin transfer molding, vacuum-assisted resin transfer molding, and resin film infusion. It explains the composite- and matrix-toughening methods for fiber-reinforced composites, such as dispersed-phase toughening and interlayer toughening. The article concludes with information on optical microscopy, which provides an insight into the micro- and macrostructure of fiber-reinforced composites.

This article describes processes and equipment that are used to produce composite tubular parts. The processes include sheeting, pattern cutting, tube rolling, shrink tape debulking, and finishing. The article provides a discussion on materials that are most suitable for tube rolling. These include preimpregnated materials and unidirectional tapes. The article discusses the wrapping techniques, such as convolute and spiral wrapping, of cylindrical and tapered tubes.

In-process inspection during composite material lay-up is essential if the structural, dimensional, and environmental performance designed into a part is to be consistently achieved. This article discusses the requirements to be met by the facilities and equipment to produce high quality composites. It reviews the procedures that are allowed and prohibited in controlled-contamination areas of lay-up. The article discusses significant areas, such as material control and lay-up process, in which quality-control personnel can be effective in preventing production problems. It concludes with a discussion on automated tape laying and fiber placement, as well as numerically aided lay-up process.

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 to 20 m length for short coastal events, 20 to 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 tooling, laminating practice, curing, mold removal, and quality control, for manufacturing hulls, decks, masts, and appendages using composites.

This article describes the chemistry of phenolic resins and reviews their characteristics and properties for various composites fabrication processes. The fabrication processes include solution/hot-melt process, pultrusion, vacuum infusion, filament winding, sheet molding, and hand lay-up. The article illustrates the manufacturing process of phenolic honeycomb and provides information on the applications of phenolic composites.