Definitions /Dictionary/Glossary - nptel

Winding Pattern: The regularly recurring pattern of the filament winding after a certain number
of mandrel revolutions.
Winding: It is a process in which continuous material is applied under controlled tension to a
form in a predetermined geometric relationship to make a structure.
Discussion: A matrix material to bind the fibers together may be added before, during or
after winding. Filament winding is the most common type.
Work Life: The period during which a compound, after mixing with a catalyst, solvent, or other
compounding ingredient, remains suitable for its intended use.
Woven Fabric Composite: It is a major form of advanced composites in which the fiber
constituent consists of woven fabric. A woven fabric composite normally is a laminate
comprised of a number of laminae, each of which consists of one layer of fabric embedded in the
selected matrix material. Individual fabric laminae are directionally oriented and combined into
specific multi-axial laminates for application to specific envelopes of strength and stiffness
requirements.
Woven Roving: It is a heavy glass fiber fabric made by the weaving of roving.
Woven Roving Fabric: Heavy fabrics woven from continuous filament in roving form. They
drape well, are quickly impregnated, and intermediate in price between mats and yarn cloths.
Woven Tape: Tape of various thicknesses woven from continuous filament yarns.
Wrinkle: An imperfection in the surface of a laminate that looks like a crease in one of the outer
layers; it occurs in a vacuum bag molding due to improper placement of the bag.
X-Axis: In composite laminates, an axis in the plane of the laminate which is used as the 0
degree reference for designating the angle of a lamina.
X-Y Plane: In composite laminates, the reference plane parallel to the plane of the laminate.
Y-Axis: In composite laminates, the axis in the plane of the laminate which is perpendicular
to the x-axis.
Yarn: A generic term for strands or bundles of continuous filaments or fibers, usually twisted
and suitable for making textile fabric.
Yarn, Plied: Yarns made by collecting two or more single yarns together. Normally, the yarns
are twisted together though sometimes they are collected without twist.
Yield Strength: The stress at which a material exhibits a specified limiting deviation from the
proportionality of stress to strain; the lowest stress at which a material undergoes plastic
deformation. Below this stress, the material is elastic; above it, viscous.