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Terminology Their are many commonly used composite terms. The terms in this briefing are the common terms and the ones we will use in this course. This section is designed to help you with terminology that will be used in this course. It is by no means complete and while you should become familiar with these terms total recall for all is not necessary.

Terminology Abrasion: the wearing away of a portion of the surface by either natural (rain), mechanical (rubbing), man-made (sanding) means; penetrates only the surface finish. Activator: an additive or substance used to initiate the curing process, sometimes know as Part “B” Adhere: to cause two surfaces to be held together by adhesion Adhesion: the sticking together of two parts with an adhesive.

Terminology Adhesive: a substance capable of holding two materials together by surface attachment. Advanced Composites: advanced composites materials are made by embedding high-strength, high-modulus fibers within an essentially homogeneous matrix. Aging: the effect on materials, of exposure to an environment for an interval of time. Ambient: the surrounding environmental conditions. May be pressure or temperature.

Terminology Aramid Fiber: Dupont trade name for this fabric is “Kevlar”. Assembly Time: the time interval between spreading of the adhesive and the application of pressure and/or heat to the assembly. Autoclave: a heated and pressurized vessel to cure laminates and bonded parts/processing composite materials.

Terminology Barrier Film: the layer of film used to permit removal or air and volatiles from a composite lay-up during the cure cycle while minimizing resin loss. Barrier Ply: a ply (usually fiberglass) placed between aluminum and carbon to eliminate electrolysis. Also know as a corrosion barrier. Bias Fabric: warp and fill fibers at an angle to the length of the fabric.

Terminology Bleed: to extract or drain off resin from a part or tool in a controlled manner. Bleeder cloth: a material used to absorb excess resin and to allow escape of gas during the cure process. Bond: The adhesion of one surface to another. Bond strength: amount of adhesion between bonded surfaces.

Terminology Breather: a porous material, such as a fabric or mat, used between the barrier film and the vacuum bag that provides an escape path for air and volatiles. Carbon Fiber: the term is often used inter-changeably with the term graphite; however, carbon fibers and graphite fibers differ. The basic differences lie in the temperature at which the fibers are made and heat treated, and in the amount of elemental carbon produced.

Terminology Caul plates: smooth plate, free of surface defects, used to transmit pressure to the laminate. Cell: in honeycomb core, a cell is a single honeycomb unit, usually in a hexagonal shape. Coin Test: using a coin to tap a laminate in different spots while listening for change in sound. Core: the central layer of a sandwich type construction to which the faces of the sandwich are bonded.

Terminology Cure: to permanently change the properties of a thermosetting resin system as a result of a controlled chemical reaction, usually involving heat and pressure. This is a nonreversible process. Cure cycle: the time/temp/pressure cycle used to cure a thermosetting resin system or prepreg. Delamination: the separation of layers of materials in a laminate

Terminology Dwell time: the period of time that a material is held at a constant temperature or pressure. Fabric: a cloth woven in an established weave pattern from advanced fiber yarns and used as the fibrous constituent in an advanced composite laminate. FRP: Fiber Reinforced Plastic, a general term for a composite that is reinforced with cloth, mat, strands, or any other fiber form.