Definitions /Dictionary/Glossary - nptel

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 fibers eliminated.
Bi-Directional Laminate: A reinforced plastic laminate with the fibers oriented in two
directions in the plane of the laminate; a cross laminate.
Binder: A bonding resin used to hold strands together in a mat or preform during manufacture of
a molded object. The resin or cementing constituent of a plastic compound which holds the other
components together; the agent applied to glass mat or preform to bond the fibers prior to
laminating or molding.
Binomial Random Variable: The number of successes in independent trials where the
probability of success is the same for each trial.
Birefringence: The difference between the two principal refractive indices (of a fiber) or the
ratio between the retardation and thickness of a material at a given point.
Bisected Core: Corrugated honeycomb that 'has flat sheets in between the corrugated ribbons;
same as reinforced core.
Bismalcimide - (BMI): A type of thermoset polyimide that cures by an additional reaction,
avoiding formation of volatiles, and has temperature capabilities between those of epoxy and
polyimide.
Bisphenol A: A condensation product formed by reaction of two (bis) molecules of phenol with
acetone (A). This polyhydric phenol is a standard resin intermediate along with epichlorohydrin
in the production of epoxy resins.
Blanket: Fibre or fabric plies that have been laid up in a complete assembly and placed on or in
the mold all at one time. Also, it is the type of bag in which the edges are sealed against the
mold.
Bleeder Cloth: A nonstructural layer of material used in the manufacture of composite parts to
allow the escape of excess gas and resin during cure. The bleeder cloth is removed after the
curing process and is not part of the final composite.
Bleeder Ply: Layer of porous material placed in a vacuum bag to absorb excess resin and allow
air and gas to escape.
Bleeding: -The removal of excess resin from a laminate during cure.
Bleed-out: The excess liquid resin appearing at the surface, primarily occurring during filament
winding.