Definitions /Dictionary/Glossary - nptel

Automated Tape Laying: It is a fabrication process in which prepreg tape is laid side by side or
overlapped in various configurations to form a structure.
Automatic Mold: A mold (for injection or compression molding) that cycles repeatedly through
the injection phase without human assistance.
Automatic Press: A press for compression molding or an injection machine that operates
continuously is being controlled mechanically, electrically or hydraulically.
Axial Strain: It is the linear strain in a plane parallel to the longitudinal axis of the specimen.
Axial Winding: In filament-wound reinforced plastics, a winding with the filaments parallel to,
or at a small angle to, the axis.
Axis of Braiding: The direction in which the braided form progresses.
Axial Winding: A type of filament winding in which the filaments are parallel to the axis.
B-Basis (or B-Value): A statistically-based material property; a 95% lower confidence
bound on the tenth percentile of a specified population of measurements. Also a 95% lower
tolerance bound for the upper 90% of a specified population.
B-Stage: An intermediate stage in the reaction of a thermosetting resin in which the material
softens when heated and swells when in contact with certain liquids but does not entirely fuse or
dissolve. Materials are usually precured to this stage to facilitate handling and processing prior to
final cure (Sometimes referred to as resitol). See A-stage, C-stage.
Back Pressure: Resistance of a material, because of its viscosity, to continued flow when mold
is closing.
Bagging: It is an operation consisting of thermocouple placement, bleeder cloth and blanket
arrangement over a laminate lay-up, installation of vacuum bag and vacuum lines and sealing of
the vacuum bag.
Bag Molding: It is a method of molding or laminating which involves the application of fluid
pressure to a flexible material which transmits the pressure to the material being molded or
bonded. Fluid pressure usually is applied by means of air, steam, water or vacuum.
Balanced Construction: Equal parts of warp and fill in fibre fabric.
Balanced Design: In filament-wound reinforced plastics, a winding pattern so designed that, the
stresses in all filaments are equal.
Balanced In-plane Contour: In a filament wound part, a head contour in which the filaments
are oriented within a plane and the radii of curvature are adjusted to balance the stresses along
the filaments with the pressure loading.