HOME > Technical Information > Glossary

Glossary

You can download the PDF file of this page. → 

Glossary

AFW
Areal Fiber Weight of prepregs (unit:g/m2).
Aging
The process /effect of exposing materials to an environment for an interval of time.
Aspect ratio
The ratio of length to diameter of a fiber.
ASTM
American Society for Testing and Materials. A standards development organization that serves as an open forum for the development of international standards.
Autoclave molding
A molding process in which a prepreg lay-up with tooling sealed with an airtight film is placed into the autoclave and subjected to heat and elevated pressure for curing while removing entrapped air and volatiles.
B stage
An intermediate stage in the reaction of thermoset resins. Uncured prepregs or premix is usually in this stage.
BMC
Bulk Molding Compound: An intermediate material for compression or injection molding, thermosetting resin mixed with chopped fibers and / or fillers.
C-stage
The final step in the curing process for thermoset resins.
C/C Composites
Carbon / Carbon Composite: Composite of carbon fiber in a carbon matrix.
CAI
Compression After Impact: A test applied to assess damage tolerance of composites.
CFRP
Carbon Fiber Reinforced Plastics: A composite material of carbon fibers and a thermoset resin matrix.
CFRTP
Carbon Fiber Reinforced Thermo-Plastics: A composite material of carbon fibers and a thermoplastic matrix.
Chopped fiber
Continuous tows that are chopped into short lengths for use in mats, spray up or molding compounds.
CMC
Ceramic Matrix Composite: A composite made of a ceramic or carbon fiber surrounded by a ceramic matrix, primarily silicon carbide.
CME
Coefficient of Moisture Expansion: Measures dimensional change of a material when absorbs moisture. Measured in inches per inch per degree.
Co-curing
A molding process of composites which are concurrently cured and bonded to another prepared surface (e.g.: to form a sandwich panel with surface sheets and a core).
Composite materials
The combined material made from two or more materials (usually reinforcing fiber and resin matrix). The properties and performances are superior to the individual materials.
Compression molding
Press Molding; A molding process to form a composite in a closed mold under heat and pressure, using a compound or prepreg.
Core
A low density material used for sandwiched composite. Examples of core materials are urethane foam, PVC foam and various honeycomb materials.
CTE
Coefficient of Thermal Expansion: Measures dimensional change of a material when heated or cooled. Measured in inches per inch per degree.
Delamination
The exfoliation of composite layers from each other. Separation of plies in a laminate due to adhesive failure. It includes the separation of layers of fabric from the core structure.
Drapeability
The ability of fabric or prepreg to conform to a contoured surface.
Elongation
The stretching percentage of original length of a sample before it breaks.
Fatigue Strength
The strength under the maximum cyclic stress before failure of a sample; The residual strength after fatigue.
FAW
Fiber Areal Weight of a fabric / weaving (unit:g/m2)
Fiber placement
A process for fabricating composite shapes by lay-upping impregnated fibers onto a complex mandrel or tool. The process can produce bigger complex shapes with a faster put-down operation than filament winding.
Filament winding
A molding process to form a composite which involves winding a resin-impregnated tow around a rotating mandrel (a pipe/rod or a vessel) and cured under heat.
FRM
Fiber Reinforced Metal. Also called MMC(Metal Matrix Composites).
Hand lay-up
The molding process of manual works to build up layers of reinforcing fiber material and resin (usually with hand rollers, brushes and spray equipment.
ILSS
InterLaminar Shear Strength: The maximum shear stress existing between layers of a laminated material.
LOI
Limited Oxygen Index: Index of flame retardancy. Oxygen concentration at burning point.
Matrix
Material in which reinforcing fiber of a composite is embedded. Includes thermosetting and thermoplastic resins, metals and carbon/ceramic compounds.
Milled fiber
Continuous glass or carbon tows which is hammer-milled into very short fibers, usually several hundreds micron meter or less.
MMC
Metal Matrix Composite: FRM(Fiber Reinforced Metal)
Peel ply
A base material on the surface of composites which removed by gliding to improve adhesiveness.
Postcure
Curing process by application of heat after the chemical exothermic reaction has subsided to get higher Tg.
pot life
The time during which the resin /prepreg remains "workable."; Work life.
Preform
A three dimensional reinforcing fiber material to apply RTM or C/C Composites.
Pultrusion
A molding process applying resin-impregnated roving and mats in the manufacture of rods, tubes and structural shapes of a uniform cross-section. The rovings, after passing through the resin dip tank, is drawn through a die to form the desired cross-section.
Residual stress
A tension or compression which exists in the composite without application of an external load after molding process.
RTM
Resin Transfer Molding: A low pressure, closed molding process, using liquid thermoset resins reinforced with various forms of fiber reinforcement.
Shelf life
The allowable storage time before a product must be used.
Sizing
To add sizing agents etc. in order to make handling easier in production process and in higher processing steps (weaving process, prepreg process, other molding processes) of Carbon Fiber. Such sizing agent itself is also called "sizing".
SMC
Sheet Molding Compound: A process to form a composite with sheet layers made of reinforcing fibers and resins (thermo-plastics or thermo-setting) in a hot-press.
Specific modulus
Modulus divided by weight on unit volume is called Specific Modulus.
Specific tensile strength
Tensile strength divided by weight on unit volume is called Specific Tensile Strength. CFRP has larger Specific Tensile Strength and Specific Modulus as compared with Steel or GFRP.
Surface treatment
Surface of Carbon Fiber is oxidized for better adhesion to matrix resins. As the method of such surface treatment, electrochemical oxidation is generally used where we send electric current to Carbon Fiber dipped in electrolyte.
Tack
Surface stickiness of prepregs. Important property for laminate molding process.
TEX
Weight of a tow or a strand per 1000 m. (unit: g/1000m)
Tg
Glass Transition Temperature; Heat-resisting temperature.
TOS
Thermal Oxidative Stability: A measure of heat resistance. A mass attrition rate of a material at a high temperature for a specified time.
Tow prepreg
An intermediate material in a form of half-hardened tows made of Carbon Fibers impregnated with thermo-setting resin.
Vacuum Bag molding
A molding process of laminated layers sealed by an airtight film applying atmospheric force by vacuum.
VARTM
Vacuum Assisted RTM: An infusion process to form a composite by which vacuum draws resin into reinforcing fiber forms set on a one-sided rigid mold, covered with a vacuum-tight seal.
Vf
Fiber volume content of a prepreg / composite (%).
Volume resistivity
A measurement of the resistance to the conduction of electricity provided by a unit cube of a material. (unit: Ω・m).