Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
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Standard Deviation: See Sample Standard Deviation.<br />
Staple: Either naturally occurring fibers or lengths cut from filaments.<br />
Starved Area: It is an area in a plastic part, which has an insufficient amount of resin to wet out<br />
the reinforcement completely. This condition may be due to improper wetting or impregnation or<br />
excessive molding pressure.<br />
Starved Joint: It is a joint that does not have the proper amount of adhesive because of<br />
insufficient spread or excessive pressure.<br />
Step-Growth Polymerization: One of the two principal polymerization mechanisms. In sepgrowth<br />
polymerization, the reaction grows by combination of monomer, oligomer, or polymer<br />
molecules through the consumption of reactive groups. Since average molecular weight increases<br />
with monomer consumption, high molecular weight polymers are formed only at high degrees of<br />
conversion.<br />
Stiffness: The relationship of load and deformation; a term often used when the relationship of<br />
stress to strain does not conform to<br />
the definition of Young's modulus.<br />
Stop Motion: A device on a creel that quickly stops the winder when a strand breaks so that the<br />
strand can be repaired /replaced for further winding.<br />
Storage Life: The period of time during which a liquid resin or packaged adhesive can be stored<br />
under specified temperature conditions and remain suitable for use. Also see "shelf life”.<br />
Strain: the per unit change, due to force, in the size or shape of a body referred to its original<br />
size or shape. Strain is a non-dimensional quantity, but it is frequently expressed in inches per<br />
inch, meters per meter, or percent.<br />
Strand: Normally an untwisted bundle or assembly of continuous filaments used as a unit,<br />
including slivers, tow, ends, yarn, etc. Sometimes a single fiber or filament is called a strand.<br />
Strand Count: The number of strands in a plied yarn; the number of strands in a roving.<br />
Strand Integrity: The degree to which the individual filaments making up the strand or end are<br />
held together by the sizing applied.<br />
Strength, Flexural: The maximum stress that can be borne by the surface fibers in a beam in<br />
bending. The flexural strength is the unit resistance to the maximum load prior to failure by<br />
bending, usually expressed in pounds per square inch.<br />
Strength: the maximum stress which a material is capable of sustaining.