Definitions /Dictionary/Glossary - nptel

Braid, Jacquard: A braided design made with the aid of a jacquard machine, which is a
shedding mechanism by means of which a large number of ends may be controlled
independently and complicated patterns produced.
Braid, Regular: A braided fabric with an over two, under two weave pattern (2 x 2).
Braid, Square: A braided pattern in which the yarns are formed into a square pattern.
Braid, Two-Dimensional: Braided fabric with no braiding yarns in the through thickness
direction.
Braid, Three-Dimensional: Braided fabric with one or more braiding yarns in the through
thickness direction.
Braid, Tri-axial: A biaxial braided fabric with laid in yarns running in the axis of braiding.
Braiding: A textile process where two or more strands, yarns or tapes are intertwined in the bias
direction to form an integrated structure.
Breakout: Separation or breakage of fibers when the edges of a composite part are drilled or cut.
Breather: A loosely woven material that does not come in contact with the resin but serves as a
continuous vacuum path over a part in production.
Breathing: It is the opening and closing of a mold to allow gas to escape early in the molding
cycle. It is also called degassing.
Bridging: Fabric reinforcement extended over a curved edge that does not come into contact
with the rest of the composite.
Broadgoods: A term loosely applied to prepreg material greater than about 12 inches in width,
usually furnished by suppliers in continuous rolls. The term is currently used to designate both
collimated uniaxial tape and woven fabric prepregs.
Buckling (Composite): This is a mode of structural response characterized by an out-of-plane
material deflection due to compressive action on the structural element involved. In advanced
composites, buckling may take the form not only of conventional general instability and local
instability but also micro-instability of individual fibers.
Bulk Density: The density of the molding material in loose form expressed as a ratio of weight
to volume.
Bulk Modulus: It is the ratio of the hydrostatic pressure to the volume strain.