An
Advanced Composite Primer
Advanced composites are truly remarkable and diverse materials. They fall into three basic categories: polymers, metals, and ceramics.
They are classified according to their matrix phase. There are polymer matrix composites (PMC's), ceramic matrix composites (CMC's), and metal matrix composites (MMC's). Materials within these categories are often called "advanced" if they combine the properties of high strength and high stiffness, low weight, corrosion resistance, and in some cases special electrical properties. This combination of properties makes advanced composites very attractive for aircraft and aerospace structural parts.
Our discussion here is limited to the segment of the polymer composite industry known as advanced polymer matrix composites, or advanced composites. Information is presented here on the technology as practiced in current operations and the technology of advanced composites manufacture is continually evolving.
Overview
Polymer-matrix composites manufacturing is a multibillion dollar industry and one of the few in which the U.S. is conceded to be slightly more advanced than competitors abroad. Composite products range from skateboards to components of the space shuttle. The industry can be generally divided into two basic segments, industrial composites and advanced composites. Several of the composites manufacturing processes are common to both segments. The two basic segments are described below.
Industrial Composites
The industrial composites industry has been in place for over 40 years in the U.S. This large industry utilizes various resin systems including polyester, epoxy, and other specialty resins. These materials, along with a catalyst or curing agent and some type of fiber reinforcement (typically glass fibers) are used in the production of a wide spectrum of industrial components and consumer goods: boats, piping, auto bodies, and a variety of other parts and components.
Advanced Composites
This sector of the composites industry is characterized by the use of expensive,
high-performance resin systems andhigh-strength, high-stiffness fiber reinforcement. The aerospace industry, including military and commercial aircraft of all types, is the major customer for advanced composites. These materials have also been adopted for use by the sporting goods suppliers who sellhigh-performance equipment to the golf, tennis, fishing, and archery markets.While aerospace is the predominant market for advanced composites today, the industrial and automotive markets will increasingly see the use of advanced composites in 2002 and beyond. At present, both manual and automated processes are employed in making
advanced-composite parts. As automated processes become more predominant, the costs of advanced composites are expected to decline to the point at which these materials will be used widely in electronic, machinery, and surface transportation equipment.Suppliers of advanced composite materials tend to be larger companies capable of doing the research and development necessary to provide the
high-performance resin systems used in this segment of the industry, yet there are numerous smaller fabricators.End-users tend to be large, and many are in the aircraft and aerospace businesses.Advanced composite systems are divided into two basic types, thermosets and thermoplastics. Thermosets are by far the predominant type in use today. Thermosets are subdivided into several resin systems including epoxies, phenolics, polyurethanes, and polyimides. Of these, epoxy systems currently dominate the advanced composite industry.
For an overview of advanced composite processes, click the links below.
Composites Primer Composite Processes Composite Glossary Carbon-Carbon Metal-Matrix
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