Definitions /Dictionary/Glossary - nptel

Fracture: When a surface ruptures without the laminate completely separating, or where there is
complete separation of a body because of external or internal forces.
Fracture Stress: The true, normal stress on the minimum cross-sectional area at the beginning
of fracture.
Fracture Toughness: The damage tolerance of a material containing initial flaws or cracks.
Used in aircraft structural design and analysis.
FRP: Acronym for fiber glass-reinforced or fiber-reinforced plastic, polymer or polyester.
Fuzz: Creel Fuzz - In glass fiber manufacturing, the broken filaments found around and on a
roving creel. Chopper Fuzz - In Composite Fabrication, the broken filaments found around the
glasscutter or chopper. See Fines. In the field, the broken filaments found around a roving pallet.
Fuzz Plug: Small, broken, compacted filaments of glass that collect inside the guide eye tubes
feeding the chopper, preventing glass from running through.
Gate: Point at which molten thermoplastic enters the injection molding tool cavity.
Gel: A partial cure of plastic resins; a semisolid, jelly-like state similar to gelatin in consistency.
Gel: The initial jelly-like solid phase that develops during a resin’s formation from a liquid state.
It is a semisolid network of solid aggregates in which liquid is held.
Gelation: The point during resin cure when viscosity has increased so much that resin barely
moves when probed with a sharp instrument.
Gel Coat: Surface coat of a specialized, quick-setting polyester resin, either colored or clear,
providing cosmetic enhancement and weather ability to a fiberglass laminate. Gel coat is an
integral part of the finished laminate.
Gel Point: When a liquid begins to exhibit pseudo-elastic properties. This stage may be
conveniently observed from the inflection point on a viscosity time plot.
Gel Time: Time required to change a flowable liquid resin into a non-flowing gel.
GFRP: Glass fiber-reinforced plastic, polymer or polyester.
Glass Blends: When several different fiber types, i.e. different lengths and diameters, are
blended in the fiber slurry.
Glass Content: Percentage of glass in the compound.
Glass Fiber Wet-Process: Process of forming a glass mat on modified papermaking equipment.