In an FRP context, acetone is primarily useful as a cleaning solvent for removal of un-cured matrix from applicator equipment and clothing. VERY FLAMMABLE LIQUID. Top

ADDITIVES

Ingredients mixed into matrix to improve properties. Top

ADHESION

The state in which two surfaces are held together at an interface by forces or interlocking action or both. Top

ADHESION FAILURE

A rupture of an adhesive bond that appears to be a separation at the adhesive/adherent interface. Top

ADHESIVE

A bonding substance which creates a molecular attraction, holding tow surfaces together. Top

AGING

The effect, on materials, of exposure to an environment for an interval of time; the process of exposing materials to an environment for an interval of time. Top

AIR SPLICE

The coupling between two roving doffs which is made by a jet of air entwining/snarling two strands together. Air splice is used instead of a knot. Top

AIR VENT

Small outlet, to prevent entrapment of gases. Top

AIR-BUBBLE VOID

Air entrapment within and between the plies of reinforcement; non-interconnected, spherical in shape. Top

ALLOY

Made by mixing traditional polymers, which have already been formed. The mixing results in a single-phase material because the polymers have some interaction that combines them together. The properties of the alloy depend upon the physical interactions of the polymers. Top

AMBIENT

The surrounding environmental conditions such as pressure or temperature. Top

AMORPHOUS

Describes polymers that have no order to their molecules, thus no crystalline component. Top

ANISOTROPIC

The tendency of a material to exhibit different properties in response to stresses applied along axes in different directions. Top

ANISOTROPY OF LAMINATES

The difference of the properties along the directions parallel to the length or width into the lamination planes; or parallel to the thickness into the planes perpendicular to the lamination. Top

ANTI-STATIC AGENTS

Agents which, when added to the moulding material or applied on the surface of the moulded object, make it less conducting (thus hindering the fixation of dust). Top

ANTIMONY TRIOXIDE

An additive used to give special flammability characteristics to a polyester. Top

ARAMID

(Twaron(R)/Kevlar(R)) Aromatic polyamide fibres characterized by excellent flame-resistance, high-temperature, and electrical properties. Aramid fibres are used to achieve high-strength, high-modulus reinforcement in plastic composites. Top

AREAL WEIGHT

The weight of fibre per unit area (width times length) of tape or fabric. Top

ARTIFICIAL WEATHERING

Exposure to laboratory conditions, which may be cyclic, involving changes in temperature, relative humidity, radiant energy, and any other elements found in the atmosphere in various geographical areas. Top

ASH CONTENT

The solid residue remaining after a reinforcing substance has been incinerated (or strongly heated). Top

ASPECT RATIO

The ratio of length to diameter of a fibre. Top

ASTM

American Society of Test Methods. Top

ATOMS

The smallest possible unit of an element, which combines with another to form larger units; i.e., molecules. Top

AUTO- IGNITION TEMPERATURE

The lowest temperature required to initiate or cause self-sustained combustion in the absence of a spark or a flame. Top

AUTOCLAVE

A closed vessel that permits application of pressure and heat used for curing composites. Top

AUTOCLAVE MOULDING

A moulding technique in which an entire assembly (lay up) is placed into an autoclave at 50 to 100 psi, in order to consolidate layers of the part by removing entrapped air and volatiles Top

AUTOMATED TAPE LAYING

A fabrication process in which prepreg tape is laid side by side or overlapped in various configurations to form a structure. Top

AXIAL WINDING

A type of filament winding in which the filaments are parallel to the axis. Top

Twintex®

Twintex® is a hybrid yarn copyright Saint-Gobain Vetrotex International Top

B

BAG MOULDING

A moulding technique in which the composite material is placed in a rigid mould and covered with a flexible bag, with pressure applied by vacuum, autoclave, press, or by inflating the bag. Top

BALANCED LAMINATE

All lamina except those at 0/90( are placed in plus/minus pairs (not necessarily adjacent) symmetrically about the lay up centreline. Top

BARCOL HARDNESS

Hardness value obtained by measuring the resistance to penetration of a sharp steel point under a spring load. The instrument, called the Barcol Impressor, gives a direct reading on a 0-100 scale. The hardness value is often used as a measure of the degree of cure of a plastic. Top

BARE GLASS

Glass (yarns, roving, fabrics) from which the sizing or finish has been removed; also, such glass before the application of sizing or finish. Top

BASKET WEAVE

Woven reinforcement where two or more warp threads go over and under two or more filling threads in a repeat pattern. This weave is less stable than the plain weave but produces a flatter, stronger, more pliable fabric. Top

BATCH (or LOT)

Material made with the same process at the same time having identical characteristics throughout. Top

BEARING AREA

The product of the pin diameter and the specimen thickness. Top

BEARING LOAD

A comprehensive load on an interface. Top

BEARING STRENGTH

The maximum bearing stress that will not fail a composite when applied through a cylindrical fastener surface. Top

BEARING STRESS

Applied load divided by bearing area (hole diameter times thickness). Top

BEND TEST

A test of ductility by bending or folding usually with steadily applied forces. In some instances the test may involve blows to a specimen having a cross section that is essentially uniform over a length several times as great as the largest dimension of the cross section. Top

BI-DIRECTIONAL LAMINATE

A reinforced plastic laminate with the fibres oriented in two directions in the plane of the laminate; a cross laminate. Top

BIAS CUT

Fabric cut at an angle (45o) to the warp & fill fibres. Top

BIAS FABRIC

A fabric in which warp and fill fibres are at an angle to the length. Top

BIAXIAL WINDING

In filament winding, a type of winding in which the helical band is laid in sequence, side by side, with the crossover of the fibres eliminated. Top

BINDER

The matrix or cementing constituent of a plastic compound which holds the other components together; the agent applied to glass mat or preforms to bond the fibres prior to laminating or moulding. Top

BLEEDER CLOTH

A layer of woven or non-woven material, not a part of the composite, that allows excess gas and matrix to escape during vacuum bagging. Top

BLEEDER PLY

Layer of porous material placed in a vacuum bag to absorb excess matrix and allow air and gas to escape. Top

BLEEDOUT

The excess liquid matrix appearing at the surface, primarily occurring during filament winding. Top

BLEND

Made by mixing traditional polymers which have already formed. The mixing results in a multi-phase system. Physical interactions between the polymers are responsible for the properties of the blend. Top

BLISTER

Undesirable rounded elevation of the surface of a plastic, whose boundaries may be more or less sharply defined, resembling in shape a blister on the human skin. The blister may burst and become flattened. Top

BMC

Bulk Moulding Compound. Top

BOND PLY

The ply or fabric patch that comes in contact with the honeycomb core during repair. Top

BOND STRENGTH

The amount of adhesion between bonded surfaces; a measure of the stress required to separate a layer of material from the base to which it is bonded. The amount of adhesion between bonded surfaces. Top

BORON fibre

A fibre usually of a tungsten-filament core with elemental boron vapour deposited on it to impart strength and stiffness. Top

BRAID

A system of three or more yarns which are interwoven in such a way that no two yarns are twisted around each other. Top

BRAID ANGLE

The acute angle measured from the axis of braiding. Top

BRAID, THREE-DIMENSIONAL

Braided fabric with one or more braiding yarns in the through thickness direction. Top

BRAID, TWO-DIMENSIONAL

Braided fabric with no braiding yarns in the through thickness. Top

BRAIDED, TRIAXIAL

A biaxial braided fabric with laid in yarns running in the axis of braiding. Top

BRAIDING

Weaving fibres into a tubular shape. Top

BREAKOUT

Separation or breakage of fibres when the edges of a composite part are drilled or cut. Top

BREATHER

A loosely woven material that does not come in contact with the matrix but serves as a continuous vacuum path over a part in production. Top

BRIDGING

Fabric reinforcement extended over a curved edge that does not come into contact with the rest of the composite. Top

BUCKLING (composite)

A failure mode usually characterized by fibre deflection rather than breaking because of compressive action. Top

BURST STRENGTH

(1) Hydraulic pressure required to burst a vessel of given thickness. Commonly used in testing filament-wound composite structures. (2) Pressure required to break a fabric by expanding a flexible diaphragm or pushing a smooth spherical surface against a securely held circular area of fabric. Top

BUTT JOINT

A joint in which parts are joined with no overlap. Top

C

CAD/CAM

Computer-aided design/computer-aided manufacturing. Top

CARBON fibre

Fibres produced by the pyrolysis of organic precursor fibres such as rayon, polyacrylonitrile (PAN), and pitch in an inert atmosphere. The term is often used interchangeably with "graphite"; however, carbon fibres and graphite fibres differ in the temperature at which the fibres are made and heat-treated, and the amount of carbon produced. Carbon fibres typically are carbonized at about 2400(F (1300(C) and assay at 93 to 95% carbon, while graphite fibres are graphitized at 3450 to 5450(F (1900 to 3000(C) and assay at more than 99% elemental carbon. Top

CARBON/CARBON

A composite of carbon fibre in a carbon matrix. Top

CARBONFIBRE REINFORCED PLASTICS (CFRP)

Term used to designate carbon fibre reinforced composites. Top

CAROXYL

The chemical group characteristic of organic acids, which are incorporated into the polyester reaction process. Top

CASTING

The process of pouring a mixture of matrix, fillers and/or fibres into a mould as opposed to building up layers through lamination. This technique produces different physical properties from laminating. Top

CATALYST

A substance which changes the rate of a chemical reaction without itself undergoing permanent change in its composition; a substance which markedly speeds up the cure of a compound when added in minor quantity as compared to the amounts of primary reactants. Top

CAUL PLATE

Plate or sheet the same size and shape as the composite lay-up with which it will be used. The caul plate is placed in immediate contact with the lay-up during curing to transmit normal pressure and provide a smooth surface on the finished part. Top

CAUL SHEET

Plate or sheet the same size and shape used in contact with a composite lay up to transmit normal pressure and temperature during cure. Top

CAULK

An elastic material used to protect joints or connections from external elements, particularly moisture. Top

CAVITY

Depression in mould; the space inside a mould wherein a matrix is poured; the moulded article; which forms the outer surface of the moulded article (often referred to as the die); also, the space between matched moulds. (Depending on number of such depressions, moulds are designated as Single-Cavity or Multiple-Cavity). Top

CENTIPOISE

Measurement of viscosity as compared to water (1 centipoises). Top

CERAMIC-MATRIX COMPOSITES

Materials consisting of a ceramic or carbon fibre surrounded by a ceramic matrix, usually SiC (silicon carbide). Top

CHAIN-GROWTH POLYMERIZATION

One of the two principal polymerization mechanisms. In chain-growth polymerization, the reactive groups are continuously regenerated during the growth process. Once started, the polymer molecule grows rapidly by a chain of reactions emanating from a particular reactive initiator which may be a free radical, cat ion or anion. Top

CHALKING

Dry, powder-like appearance or deposit on gel coat surface. Top

CHEMICAL VAPOR DEPOSITION (CVD)

A process in which desired reinforcement material is deposited from vapour phase onto a continuous core; boron on tungsten, for example. Top

CIRCUIT

One complete traverse of the fibre feed mechanism of a filament-winding machine. Top

CIRCUMFERENTIAL WINDING

A type of filament winding in which the filaments are perpendicular to the axis. Top

CLOTH

another word for fabric, which can be a woven, knitted or processed yarn in another way Top

COEFFICIENT of EXPANSION (COE)

Measure of the change in length or volume of an object. Top

COEFFICIENT of THERMAL EXPANSION

A material's fractional change in length for a given unit change of temperature. Top

COEFFICIENT OF VARIATION

The ratio of the population (or sample) standard deviation to the population (or sample) mean. Top

COHESION

Tendency of a single substance to adhere to itself. Also, the force holding a single substance together. Top

COIN TAP

Tapping a laminate with a coin in different spots to detect a change in sound, indicating the presence of a defect that may require repair. Top

COLD PRESS MOULDING

Compression Moulding – A technique for moulding thermoplastic material in which a part is shaped by placing the preheated fibre and matrix into an open mould cavity, closing the mould fast, and wait until the material has achieved its final form. Top

COLOR STABILITY

The ability of a surface coating or pigment to resist degradation due to environmental exposure. Top

COMMINGLED YARN

A hybrid yarn made with two types of material intermingled in a single yarn; for example, thermoplastic filaments intermingled with carbon filaments to form a single yarn. Top

COMPATIBLE

The ability of different matrix systems to be processed in contact with each other without degradation of end product properties. Top

COMPOSITE

A homogeneous material created by the synthetic assembly of two or more materials (a selected filler or reinforcing elements and compatible matrix binder) to obtain specific characteristics and properties. Composites are subdivided into classes on the basis of the form of the structural constituents; Laminar: Composed of layer or laminar constituents; Particular: The dispersed phase consists of small particles; Fibrous: The dispersed phase consists of fibres; Flake: The dispersed phase consists of flat flakes; Skeletal: Composed of a continuous skeletal matrix filled by a second material. Top

COMPOUND

An intimate mixture of polymer or polymers with all the materials necessary for the finished product. Top

COMPRESSION MOULD

A mould which is open when the material is introduced and which shapes the material by heat and by the pressure of closing. See also Compression moulding. Top

COMPRESSION MOULDING

A technique for moulding thermo set plastics in which a part is shaped by placing the fibre and matrix into an open mould cavity, closing the mould, and applying heat and pressure until the material has cured or achieved its final form. Top

COMPRESSIVE MODULUS

A mechanical property description which measures the compression of a sample at a specified load. Top

COMPRESSIVE STRENGTH

The ability of a material to resist a force that tends to crush; the crushing load at the failure of a specimen divided by the original sectional area of the specimen. Top

CONDUCTIVITY

Reciprocal of volume resistivity; the conductance of a unit cube of any material. Top

CONNECTION

Where two panels are attached to each other or a panel is attached to the building. Top

CONSOLIDATION

A processing step that compresses fibre and matrix to reduce voids and achieve a desired density using of heat and pressure. Top

CONTAMINANT

Impurity or foreign substance that affects one or more properties of composite material, particularly adhesion. Top

CONTINUOUS FILAMENT

An individual , small-diameter reinforcement that is flexible and indefinite in length. Top

CONTINUOUS HEAT RESISTANCE

This is the maximum temperature the material should be subjected to in a continuous application. Below this temperature the material is acceptable. Above this temperature the material may decompose, melt, or otherwise fail in an application. Units - degrees Fahrenheit ((F) - degrees Centigrade ((C). Higher numbers mean that the material can be used continuously at higher temperatures. Top

CONTINUOUS LAMINATING

A process for forming panels and sheeting in which fabric(s) and layers in a build-up is passed through heating zones and cooling zones, all under pressure, for consolidation. Top

CONTINUOUS ROVING

Parallel filaments coated with sizing, gathered together into single or multiple strands, and wound into a cylindrical package. It may be used to provide continuous reinforcement in woven roving, filament winding, pultrusion, prepregs, or high-strength moulding compounds. Top

CONTINUOUS-FILAMENT YARN

Yarn that is combined by two or more continuous filaments into a single continuous strand. Top

COPOLYMER

A large chemical chain composed of two or more dissimilar groups. Top

CORE

The central component of a sandwich construction to which the sandwich faces or skins are attached; also, part of a complex mould that forms undercut parts. Top

CORE CRUSH

Compression damage of the core. Top

CORE DEPRESSION

A gouge or indentation in the core material. Top

CORE ORIENTATION

Used on a honeycomb core to line up the ribbon direction, thickness of the cell depth, cell size and transverse direction. Top

CORE SPLICING

Joining two core segments by bonding them together. Top

COUPLING AGENT

Any chemical substance designed to react with both the reinforcement and matrix phases of a composite material to form or promote a stronger bond at the interface; a bonding link. Top

COWOVEN FABRIC

A reinforcement fabric woven with two different types of fibres in individual yarns; for example, thermoplastic fibres woven side by side with carbon fibres. Top

CRAZING

Fine cracks, which may extend in a network on or under the surface of a plastic material. Top

CREEL

A device for holding the required number of roving balls or supply packages in desired position for unwinding onto the next processing step. Top

CREEP

The change in dimension of a plastic under load over a period of time, not including the initial instantaneous elastic deformation. (Creep at room temperature is called 'cold flow.') Top

CREEP, RATE OF

The slope of the creep-time curve at a given time. Top

CRIMP

A fibre's waviness, which determines the capacity of the fibre to cohere. Top

CRITICAL LENGTH

The minimum length of a fibre necessary for matrix shear loading to develop fibre ultimate strength by matrix. Top

CROSS LAMINATED

Material laminated so that some of the layers are oriented at various angles to the other layers with respect to the laminate grain. A cross-ply laminate usually has plies oriented only at 0/90. Top

CROSSPLY

Any filamentary laminate which is not uniaxial. Same as Angleply. In some references, the term cross ply is used to designate only those laminates in which the laminate are at right angles to one another, while the term angle ply is used for all others. Top

CRYSTALLINITY

The quality of having a molecular structure with atoms arranged in an orderly, three-dimensional pattern. Top

CYCLE

The complete, repeating sequence of operations in a process or part of a process. In moulding, the cycle time is the period (or elapsed time) between a certain point in one cycle and the same point in the next. Top

D

DAMAGE TOLERANCE

A measure of the ability of structures to retain load-carrying capability after exposure to sudden loads (for example, ballistic impact). Top

DAMPING

Diminishing the intensity of vibrations. Top

DAYLIGHT

The distance in the open position, between the moving and fixed tables or the platens of a hydraulic press. In the case of a multi-daylight press, daylight is the distance between adjacent platens. Top

DEBOND

An unplanned non-adhered or un-bonded region in an assembly. Top

DECITEX

A numbering system for yarn and filament in which yarn number is equal to weight in grams of 10000 meters of yarn Top

DEEP-DRAW MOULD

A mould having a core which is long in relation to the wall thickness. Top

DEFLECTION TEMPERATURE UNDER LOAD

The temperature at which a simple beam has deflected a given amount under load (formerly called heat distortion temperature). Top

DEFORMATION UNDER LOAD

The dimensional change of a material under load for a specific time following the instantaneous elastic deformation caused by the initial application of the load. (Also, 'cold flow' or 'creep'.) Top

DEGRADATION

A deleterious change in chemical structure, physical properties or appearance. Top

DELAMINATE: DELAMINATION

To split a laminated plastic material along the plane of its layers. Physical separation or loss of bond between laminate plies. Top

DEMOULD

To remove a part from a tool, or a tool from an intermediate model. Top

DENSITY

This is defined as the weight of a material per unit volume. Units - grams/cubic centimetre. Higher numbers indicate heavier materials. Top

DENSITY, fibres

Mass per unit volume of the solid matter of which a fibre is composed, measured under specified conditions. Top

DEVIATION

Variation from a specified dimension or requirement, usually defining the upper and lower limits. Top

DIELECTRIC

A non-conductor of electricity. The ability of a material to resist the flow of an electric current. Top

DIELECTRIC CONSTANT

The ratio of the capacity of a condenser having a dielectric constant between the plates to that of the same condenser when the dielectric is replaced by a vacuum; a measure of the electrical charge stored per unit thickness at unit potential. Top

DIELECTRIC STRENGTH

1) This is an electrical property and gives an indication of how well the material acts as an electrical insulator. It describes how much of an electrical voltage can be built up on one side of the material before it is communicated to the other side. Units - Volts per mil of thickness (volts/mil). Higher numbers indicate materials which are better insulators. C means that the material conducts electricity and therefore has no dielectric strength. 2) The average potential per unit thickness at which failure of the dielectric material occurs. Top

DIMENSIONAL STABILITY

Capability of an item to maintain its constructed dimensions without distorting. Top

DIRECT ROVING

A roving made directly at the bushing that does not go through a roving process. Typical characteristics are: single-end roving, coreless, 6-inch diameter centres and no catenaries. Top

DISPERSION

The means of incorporating pigments into a fluid. Top

DISTRIBUTION

A formula which gives the probability that a value will fall within prescribed limits. Top

DRAPE

The ability of textiles to conform to an irregular shape; textile conformity. Top

DRY fibre AREA

Area of fibre not totally encapsulated by matrix. Top

DRY SPOT

Area of incomplete surface film on laminated plastics; in laminated glass, an area over which the interlayer and the glass have not become bonded. Top

DRY WINDING

A type of filament winding in which pre-impregnated roving is used. Top

DUCTILITY

The ability of a material to deform plastically before fracturing. Top

DUPLICATION MOULD

A mould made by casting over or duplicating another article. Top

E

E-GLASS

"Electrical glass" A borosilicate glass; the type most used for glass fibres for reinforced plastics; -suitable for electrical laminates because of its high resistivity. (Also called 'electrical glass.') Top

EJECTION / DEMOULDING

The process of removing a moulding from the moulding impression; by mechanical means, by hand, or by the use of compressed air. Top

EJECTION PLATE

A metal plate used to operate ejector pins; designed to apply a uniform pressure to them in the process of ejection. Top

ELASTIC DEFORMATION

The part of the total strain in a material under stress that recovers upon removal of the stress. Top

ELASTIC LIMIT

The greatest stress which a material is capable of sustaining without permanent strain remaining upon the complete release of the stress. A material is said to have passed its elastic limit when the load is sufficient to initiate plastic, or non-recoverable, deformation. Top

ELASTICITY

The property of materials to recover their original size and shape after deformation. Top

ELASTOMER

A polymeric material which has a high modulus of elasticity and toughness. Urethane elastomer is an example. Top

ELONGATION

Standard measure for the amount a sample can stretch as a percentage of original length before it fails or breaks. Top

ELONGATION AT BREAK

Elongation recorded at the moment of rupture of the specimen, often expressed as a percentage of the original length. Top

END

A strand of roving consisting of a given number of filaments gathered together. Top

END COUNT

An exact number of ends supplied on a ball or roving. Top

EXTENSOMETER

A device for measuring linear strain. Top

F

FABRIC, NONWOVEN

A material formed from fibres or yarns without interlacing. Top

FABRIC, WOVEN

A material constructed of interlaced yarns, fibres, or filaments. Top

FATIGUE

The failure or decay of mechanical properties after repeated applications of stress. Top

FATIGUE LIFE

The number of cycles of deformation required to bring about failure of the test specimen under a given set of oscillating conditions. Top

FATIGUE LIMIT

The stress below which a material can be stressed cyclically for an infinite number of times without failure. Top

FATIGUE STRENGTH

The maximum cyclic stress a material can withstand for a given number of cycles before failure occurs; the residual strength after being subjected to fatigue. Top

FEA

Finite element analysis, a process of selecting the optimum combination of materials in a composite based on software analysis. Top

FELT

a fibrous material made up of interlocking fibres by mechanical or chemical reaction, pressure or heat. Felts may be made of cotton, glass, or other fibres. Top

FEMALE MOULD

A concave mould used to precisely define the convex surface of a moulded part. Top

FIBRE

Very small normally round cross sections (in micron)of various materials. For commingling process endless filamntes are used. More fibres together form a yarn or roving. Also known as FIBER in USA Top

FIBRE ARCHITECTURE

The design of a fibrous preform or part in which the fibres are arranged (braided, stitched, woven, etc.) in a particular way in order to achieve the desired result. Top

FIBRE CONTENT

Amount of fibre present in a composite expressed as a ratio to the matrix. The ratio can either be by volume or by weight. Top

FIBRE DIAMETER

The measurement (expressed in micron) of the diameter of individual filaments. Top

FIBRE GLASS

Fibres made by continuing Glass filaments Top

FIBRE ORIENTATION

Fibre alignment in a laminate where the majority of fibres are in the same direction, resulting in a higher strength in that direction. Top

FIBRE PLACEMENT

A continuous process for fabricating composite shapes with complex contours and/or cut-outs by means of a device that lays pre-impregnated fibres (in tow form) onto a non-uniform mandrel or tool. It differs from filament winding (below) in several ways: there is no limit on fibre angles; compaction takes place on-line via heat, pressure, or both; and fibres can be added and dropped as necessary. The process produces more complex shapes and permits a faster put-down rate than filament winding. Top

FIBRE REINFORCED PLASTICS (FRP)

Term used to designate glass fibre reinforced composites. Top

FIBRE SYSTEM

The type and arrangement of fibrous material which comprises the fibre constituent of an advanced composite. Examples of fibre systems are collimated filaments or filament yarns, woven fabric, randomly oriented short-fibre ribbons, random fibre mats, whiskers, etc. Top

FILAMENT

The smallest unit of a fibrous material. The basic units formed during spinning and which are gathered into strands of fibre for use in composites. Filaments usually are of extreme length and of very small diameter. Filaments normally are not used individually. Some textile filaments can function as a yarn when they are of sufficient strength and flexibility. Top

FILAMENT WINDING

A process for fabricating a composite structure in which continuous reinforcements (filament, wire, yarn, tape, or other) either previously impregnated with a matrix material or impregnated during the winding are placed over a rotating and removable form or mandrel in a previously prescribed way to meet certain stress conditions. Generally the shape is a surface of revolution and may or may not include end closures. When the right number of layers are applied the wound form is cured and the mandrel removed, if it is not manufactured in a continuing laminating process. Top

FILAMENT WOUND

Pertaining to an object created by the filament winding method of fabrication. Top

FILAMENT YARN

A yarn composed of continuous filaments assembled with or without twists. Top

FILAMENTARY COMPOSITES

A major form of advanced composites in which the fibre constituent consists of continuous filaments. Specifically, a filamentary composite is a laminate comprised of a number of lamina, each of which consists of a nonwoven, parallel, uniaxial, planar array of filaments (or filament yarns) embedded in the selected matrix material. Individual lamina are directionally oriented and combined into specific multiaxial laminates for application to specific envelopes of strength and stiffness requirements. Top

FILAMENTS

Individual glass fibres of indefinite length, usually as pulled from a stream of molten glass flowing through an orifice of the bushing. In the operation, a number are gathered together to make a strand or end of roving or yarn. Top

FILL

yarn running from selvage to selvage at right angles to the warp in a woven fabric. Top

FILL THREADS

Also known as the weft. These are the crosswise fibres woven at 90 degrees to the warp fibres. Top

FILLER

A relatively inert material added to a plastic mixture to reduce cost, to modify mechanical properties, to serve as a base for colour effects, or to improve the surface texture. Top

FILLER PLY

Additional patch to fill in a depression in repair or to build up an edge. Top

FILM ADHESIVE

An adhesive in the form of a thin, dry, matrix film with or without a carrier, commonly used for adhesion between layers of laminates. Top

FINISH

Material applied to fibres, after sizing is removed, to improve matrix-to-fibre coupling. Top

FINITE ELEMENT ANALYSIS (FEA)

A process of selecting the optimum combination of materials in a composite based on software analysis. Top

FIRE POINT

The lowest temperature at which a liquid in an open container will give off enough vapours to continue to burn once ignited. Fire point generally is only slightly higher than flash point. Top

FLAME RETARDENT matrix

A matrix which is compounded with certain chemicals to reduce or eliminate its tendency to burn. Top

FLAME RETARDENTS

Certain chemicals that are used to reduce or eliminate a matrices tendency to burn. Top

FLAMMABILITY

A measure of how fast a material will burn under controlled conditions. Top

FLANGE

An extension around the perimeter of a mould or part for the purpose of remoulding, stiffening or connecting two components. Top

FLASH POINT

The lowest temperature at which a substance gives off enough vapours to form a flammable or ignitable mixture with air near the surface of the substance being tested. Top

FLEXURAL MODULUS

This is a number associated with the stiffness of materials. It is used to calculate how far a bar will bend when a bending load is applied to it. Units are normally millions of pounds per square inch. (106 Psi) - Giga Pascal (gPa). Higher numbers for materials mean that they are more resistant to deflection when equal thickness are being compared. Top

FLEXURAL STRENGTH

The resistance of a material to being broken by bending stresses; the strength of a material in bending, expressed as the tensile stress of the outermost fibres of a bent test sample at the instant of failure. (With plastics, this value is usually higher than the straight tensile strength.) Top

FLOW

The movement of matrix under pressure, allowing it to fill all parts of a mould; flow or creep - the gradual but continuous distortion of a material under continued load, usually at high temperature. Top

FOAM

A lightweight, cellular plastic material containing gas-filled voids. Typical foams include urethane, PVC and polyester. Top

FOAM-IN-PLACE

The process of creating a foam by the combination of two liquid polymers. See In-Situ. Top

FRACTURE

A rupture of the surface of a laminate because of external or internal forces, with or without complete separation. Top

FRACTURE DUCTILITY

The true plastic strain at fracture. Top

FRACTURE TOUGHNESS

A measure of the damage tolerance of a material containing initial flaws or cracks. Top

FREE RADICALS

Highly reactive molecular fragments capable of initiating chemical reactions, such as polymerization of polyester matrices. Top

FRP

Fibrous-glass reinforced plastic; a general term covering any type of plastic reinforced cloth, mat, strands, or any other form of fibrous glass. Top

G

GFRP

Glass fibre-reinforced plastic, polymer or polyester. Top

GLASS

An inorganic product of fusion which has cooled to a rigid condition without crystallizing. Top

GLASS CLOTH

Conventionally-woven glass fibre material (see Scrim). Top

GLASS FIBRES

A fibre spun from an inorganic product of fusion which has cooled to a rigid condition without crystallizing. Top

GLASS RICH

An area of moulded part that has an overabundance of glass reinforcement. The reinforcement may appear dry and unwet with the matrix. Top

GLASS TRANSITION

The reversible change in an amorphous polymer between a viscous or rubbery condition and a hard, relatively brittle one. Top

GLASS-TRANSITION TEMPERATURE (Tg)

The approximate temperature at which increased molecular mobility results in significant changes in properties of a cured matrix. The measured value of Tg can vary, depending on the test method. Top

GLASS/matrix RATIO

The amount of glass by weight compared to the amount of matrix by weight in a finished laminate or moulding Top

GRAPHITE FIBRES

See Carbon Fibres Top

GRAPHITIZATION

The process of pyrolization at very high temperatures (as high as 5400(F) that converts carbon to its crystalline allotropic form. Top

GRP

Glass-reinforced plastic, polymer, polyester. Top

GUIDE PIN

A pin, which guides mould halves into alignment on closing. Top

H

HARD TOOL

A tool made of metallic or any "hard" material that is generally impervious to damage during normal use. Top

HEAT-DISTORTION TEMPERATURE

Temperature at which a test bar deflects a certain amount under specified temperature and a sated load. Top

HONEYCOMB

Material manufactured in, usually, hexagonal cells that serve as a core material in sandwich constructions. Honeycomb may be metallic, matrix-impregnated or polymer materials in a rigid, open structure. Top

HONEYCOMB CORE

Strips of paper, plastic metal, etc., joined together to form a honeycomb pattern. Used as a lightweight core in sandwich mouldings. Top

HOOP STRESS

Circumferential stress in a cylindrically shaped part as a result of internal or external pressure. Top

HORIZONTAL SHEAR

Sometimes used to indicate interlaminar shear. Top

HOT BOND REPAIR

Repair made on a hot-patch bonding machine to cure and monitor curing. Typically includes heat and vacuum source. Top

HUMIDITY

Moisture content of the air. Top

HUMIDITY, RELATIVE

The ratio of the pressure of water vapour present to the pressure of saturated water vapour at the same temperature. Top

HYBRID COMPOSITE

A composite with two or more types of matrix, systems or reinforcing fibres . Top

HYBRID YARN

A hybrid yarn is a textured or a commingled yarn consisting of structural fibres and thermoplastic polymer fibres. The hybrid yarn is a so-called prostpreg material (opposite prepreg) since the fibres are impregnated with the matrix in a post-process. The hybrid yarn is "soft" and drape able, and therefore very suitable for producing fibre preforms by almost any textile technology. Top

HYDRAULIC PRESS

A press in which the moulding force is created by the pressure exerted on a fluid. Top

HYDROPHOBIC

Moisture resistant capability, moisture repelling. Top

HYGROSCOPIC

Capable of absorbing and retaining atmospheric moisture. Top

I

IGNITION LOSS

The difference in weight before and after burning; as with glass, the burning off of the binder or size. Top

ILSS

See INTERLAMINAR SHEAR STRENGTH Top

IMPACT STRENGTH

The ability of a material to withstand shock loading; the work done in fracturing a test specimen in a specified manner under shock loading. Top

IMPREGNATE

In reinforced plastics, the saturation of the reinforcement with a matrix. Top

IMPREGNATED FABRIC

See Prepreg. Top

IN-SITU

In the position which it will finally occupy, e.g. moulding or forming foam. Top

INCLUSION

A physical and mechanical discontinuity occurring within a material or part, usually consisting of solid, encapsulated foreign material. Inclusions are often capable of transmitting some structural stresses and energy fields, but in a noticeably different manner from the parent material. Top

INHIBITOR

A substance which retards a chemical reaction. Top

INSERT

An integral part of a plastics moulding consisting of metal or other material which may be moulded into position or pressed into the moulding after the moulding is completed. Top

INTEGRAL COMPOSITE STRUCTURE

Composite structure in which several structural elements, which would conventionally be assembled by bonding or with mechanical fasteners after separate fabrication, are instead laid up and cured as a single, complex, continuous structure: e.g., spars, ribs, and one stiffened cover of a wing box fabricated as a single integral part. The term is sometimes applied more loosely to any composite structure not assembled by mechanical fasteners. Top

INTEGRAL HEATING

A system in which heating elements are built into a tool, forming part of the tool and usually eliminating the need for an oven or autoclave as a heat source. Top

INTERFACE

The junction point or surface between two different media; on glass fibres, the contact area between glass and sizing or finish; in a laminate, the contact area between the reinforcement and the laminating matrix. Top

INTERLAMINAR SHEAR

The shearing force tending to produce displacement between two lamina along the plane of their interface; usually the weakest element of a composite. Top

INTERLAMINAR SHEAR STRENGTH

The maximum shear stress existing between layers of a laminated material. Top

INTRALAMINAR

Descriptive term pertaining to some object (e.g., voids), event (e.g., fracture), or potential field (e.g., temperature gradient) existing entirely within a single, lamina without reference to any adjacent lamina. Top

ISO

Short for International Standards Organization or abbreviated terminology for the isophthalic acid type matrices . Top

ISOTROPIC

Having uniform properties in all directions-independent of the direction of load application. Top

IZOD IMPACT TEST

A destructive test designed to determine the resistance of a plastic to the impact of a suddenly applied force. Top

JIG

Any fixture for holding parts in position, while joining them together or to maintain their shape. Top

JOINT

A line or distinction formed when two panels are connected. Also referred to as a seam. Top

K

KEVLAR

Trademark of DuPont for aramid fibres used as a reinforcement fibre. Top

KNITTING

A method of constructing fabric by interlocking series of loops of one or more yarns. Top

L

Technique for producing long runs of identical parts with two finished sides. Top

LAMINA

A single ply or layer in a laminate made up of a series of layers. Top

LAMINATE

To unite layers of material by a bonding material usually with pressure and heat Top

LAMINATE ORIENTATION

The configuration of a cross-plied composite laminate with regard to the angles of cross-plying, the number of laminate at each angle, and the exact sequence of the lamina lay-up. Top

LAMINATE PLY

One layer of a laminated product. Top

LAND

The portion of a mould which provides the separation or cut-off of the flash from the moulded article; in the screw of an extruder, the bearing surface along the top of the flights; in an extrusion die, the surface parallel to the flow of material; in a semi-positive or flash mould, the horizontal bearing surface; in a two-piece mould, a platform build up to the split line. Top

LAP JOINT

A joint made by bonding overlapped portions of two adherents. Top

LAY-UP

As used in reinforced plastics, the reinforcing material place in position in the mould; the process of placing the reinforcing material in position in the mould; the matrix-impregnated reinforcement; a description of the component materials, geometry, etc. of a laminate. Top

LAYER

A single ply of lay up or laminate. Top

LENGTHWISE DIRECTION

Refers to the cutting of specimens and to the application of loads. For rods and tubes, lengthwise is the direction of the long axis. For the other shapes of materials that are stronger in one direction than in the other, lengthwise is the direction that is stronger. For materials that are equally strong in both directions, lengthwise is an arbitrarily designated direction that may be with the grain, direction of flow in manufacture, longer direction, etc. Top

LIQUID-CRYSTAL POLYMERS

A newer type of thermoplastic, melt processible, with high orientation in moulding, improved tensile strength, and high-temperature capability. Top

LOAD-DEFLECTION CURVE

A curve in which the increasing flexural loads are plotted on the ordinate axis and the deflections caused by those loads are plotted on the abscissa axis. Top

LOFT

The height of the dry lay-down "laminate". Top

LOI

See LOSS ON IGNITION Top

LOSS ON IGNITION

Weight loss, usually expressed as percent of total, after burning off an organic sizing from glass fibres, or an organic matrix from a glass fibre laminate. Top

LOW-PRESSURE LAMINANTS

In general, laminates moulded and cured

THERMOPLASTIC COMPOSITES

Glossary

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B

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D

E

F

G

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