Definitions /Dictionary/Glossary - nptel

Static: Buildup of an electrical charge causing the chopper roving to "cling" or stick to the
chopper, line and/or people. The static level is quantified by measuring the electrical field
strength in kilovolts per inch.
Sticker: see Trapped End
Stiffness: The relationship of load to deformation; a term often used when the relationship of
stress to strain does not conform to the definition of Young's modulus.
Strand: In the roving process or shop, a primary group of bundles gathered together in a creel. A
strand is that which is pulled out of a doff; also a plurality of drawn and elongated individual
filaments combined together to form an individual strand. Strands are held together and protected
by sizing.
Strand Count: According to the U.S. Yardage System, the length in hundreds of yards of a
single strand having a mass of one pound. In the European TEX System, the mass in grams of a
strand 1000 meters in length.
Strand Integrity: The size’s ability to keep all filaments in a bundle stuck together during
chopping. Good strand integrity is required for good flow in or wet-through and wet-out on the
mold.
Strength, Flexural: Maximum stress that can be borne by surface fibers in a beam in bending.
Flexural strength is the unit resistance to maximum load prior to failure by bending, usually
expressed in pounds per square inch.
Stress-Strain: Stiffness, expressed in pounds per square inch or kilograms per square
centimeter, at a given strain.
Stress-Strain Curve: Simultaneous readings of load and deformation, converted to stress and
strain, plotted as ordinates and abscissa to obtain a stress-strain diagram.
Structural Reaction Injection Molding (S-RIM): Evolution of two other plastic molding
processes, RIM and RTM. S-RIM uses the fast polymerization reactions of RIM-type polymers,
its intensive resin mixing procedures and its rapid resin injection rates. S-RIM also employs
preforms like RTM to obtain composite mechanical properties.
Styrene/Acetone Solubility: Percentage of sizing on glass fiber dissolved off the strand in
styrene or acetone after soaking in the solvent.
Styrene Monomer: A water-thin liquid monomer used to thin polyester resins and act as the
cross-linking agent.
Surfacing Mat: Very thin mat, usually 180 to 510 mm thick, used primarily to produce a
smooth, resin-rich surface on a reinforced plastic laminate, or for precise machining or grinding.
See Veil