Definitions /Dictionary/Glossary - nptel

Filler: A relatively inert material added to a plastic mixture to reduce cost, to modify mechanical
properties, to serve as a base for color effects, or to improve the surface texture.
Filler Ply: Additional patch to fill in a depression in repair or to build up an edge.
Fillet: A rounded filing of the internal angle between two surfaces of a plastic molding.
Filling Yarn: It is the transverse threads (or fibres) in a woven fabric. These are the fibres,
which running perpendicular to the warp.
Film Adhesive: An adhesive in the form of a thin, dry, resin film with or without a carrier,
commonly used for adhesion between layers of laminates.
Final Entry Point: The spot where the lightning flash channel last enters the aircraft (usually a
trailing edge).
Final Exit Point: The spot where the lightning flash channel last exits .the aircraft (usually a
trailing edge).
Finish (or Size System): A material, with which filaments are treated, which contains a coupling
agent to improve the bond between the filament surface and the resin matrix in a composite
material. In addition, finishes often contain ingredients which provide lubricity to the filament
surface, preventing abrasive damage during handling, and a binder which promotes strand
integrity and facilitates packing of the filaments.
First Return Stroke: The high current surge that occurs when the leader completes the
connection between the two charge centers. The current serge has a high peak current, high rate
of change of current with respect to time and a high action integral.
Fixed Effect: A systematic shift in a measured quantity due to a particular level change of a
treatment or condition
Finite Element Analysis (FEA): A process of selecting the optimum combination of materials
in a composite based on software analysis.
Fire Point: The lowest temperature at which a liquid in an open container will give off enough
vapors to continue to burn once ignited. Fire point generally is only slightly higher than flash
point.
Fish Eye: It is a circular separation in a gel coat film generally caused by contamination such as
silicone, oil, dust, and/or water.
Flame Resistance: It is ability of a material to extinguish flame once the source of heat is
removed.