Glossary of terms


Adhesive  A thermoset resin (e.g., epoxy, phenolic or BMI) in the form of a thin film or paste, cured under heat and pressure to bond a wide range of composite, metallic and honeycomb surfaces.

Aramid  A high strength, high stiffness fiber derived from polyamide. Kevlar ® and Nomex ® are examples of aramids.

Carbon Fiber  Fiber produced by carbonizing precursor fibers based on PAN (polyacrylonitrile), rayon and pitch to eliminate non-carbon atoms. The term is often used interchangeably with graphite. However, carbon fibers and graphite fibers are made and heat treated at different temperatures and have different carbon contents.

Composite Material  Product made by combining two or more dissimilar materials such as fibers and resins to create a product with exceptional structural properties not present in the original materials.

Copper Clad  Laminate The basic building material for printed wiring boards. The laminate uses resin-coated fiberglass and external plies of copper foil which are cured in high-pressure flat presses.

Cowls or Cowling  The outside protective shell of a jet engine, traditionally made out of metal. Cowls or cowling mainly provide the engine with protection from the elements and with structural support.

Dimensional Stability  A measure of an electrical laminate’s dimensional movement (in three dimensions) when exposed to temperature cycles.

Engineered Products  Completed composite components that typically are manufactured from prepregs, honeycomb, adhesives and assembled hardware. These parts are ready for direct attachment to a structure (e.g., aircraft) or to subassemblies. Emerging manufacturing processes allow the fabrication of engineered products directly from reinforcing fibers/fabrics and matrix resins.

Fairing  A secondary structure of an airplane providing enhanced aerodynamics. Typically, fairings are found where the wing meets the body or at various locations on the leading or trailing edge of the wing.

Fiberglass  Filaments made by drawing molten glass, commonly used to reinforce composite materials.

Filament Winding  A process to manufacture composite materials components such as rocket casings and cylinders. Fiber filaments are impregnated in a resin matrix and then wound in a predetermined pattern over a form with the shape of the desired component.

Honeycomb  A unique, lightweight, cellular structure made from either metallic sheet materials or nonmetallic materials (e.g., resin-impregnated paper or woven fabric) and formed into hexagonal nested cells, similar in appearance to a cross-section of beehive.

Interiors  Finished internal aircraft components, such as overhead stowage compartments, lavatories, sidewalls, floor panels and ceilings.

Kevlar®  An aramid fiber from DuPont. Woven Kevlar ® fabrics are used in both ballistic and composite materials applications.

Modulus  The physical measurement of stiffness in a material. A high modulus indicates a stiff material.

Multilayer Laminate  An electrical laminate that uses three or more layers of circuitry. These laminates are used in complex, high-density circuit designs.

Nacelle  The protective shell of a jet engine housed within the cowling, usually made from honeycomb. Provides noise absorption, insulation, structural support and can aid heat dissipation.

Nomex®  DuPont’s registered trade name for its high temperature resistant aramid papers, pressboard, staple fibers and filament yarns. Nomex ® aramid paper is used in the manufacture of honeycomb.

PAN (Polyacrylonitrile)  A polymer which when spun into fiber is used as a precursor material in the manufacture of certain carbon fibers.

Precursor  The PAN, rayon or pitch fibers from which carbon or graphite fibers are derived.

Prepreg (Pre-impregnated)  A composite material made from combining high performance reinforcement fibers or fabrics with a ther-moset or thermoplastic resin matrix. When cured under high temperature and pressure, exceptional structural properties are achieved.

Printed Circuit Board  An electronic platform containing etched copper circuitry and multiple layers of interconnected circuitry, and assembled with microprocessors, passive devices and other electronic components.

Radome  The housing which protects the aircraft radar system from the elements while allowing transmission of radar signals.

Reinforcement  A strong material which when combined with a resin matrix forms a composite material. Reinforcements are usually continuous fibers, which may be woven. Fiberglass, aramid and carbon fibers are typical reinforcements.

Reinforcement  Fabrics Woven fiberglass, carbon or aramid fabrics used in production of prepregs and honeycomb.

Repair and Retrofit  The reinforcement or repair of existing structures to strengthen them or increase their ability to withstand an earthquake or other forces. Until recently, repair and retrofit was done with traditional materials like steel, but now it can also be done with composite materials.

Resin Matrix  In reinforced fiber composites, the formulated polymeric substrate.

Rigid Laminate  A one-sided or two-sided copper clad standard electrical laminate used in low cost applications. Usually uses eight plies of 7628 fiberglass fabric.

Sandwich Panels  A stiff and lightweight panel consisting of thin sheets such as aluminum or cured prepreg laminate bonded to a low density, rigid core material (e.g., foam or honeycomb).

Special Process  The forming, shaping, machining or bonding of sheets or blocks of honeycomb into profiled and complex shapes for use as semifinished components in the fabrication of composite parts and structures.

Structures  Finished components for aircraft and industrial applications. For aircraft, these may be for primary or secondary external structures.