Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
Definitions /Dictionary/Glossary - nptel
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Wet-Process: A process for forming a non-woven web from water slurry on "papermaking’<br />
equipment. It is also known as "wet-laid" or "wet-formed".<br />
Wet Strength: It is strength of paper when saturated with water, especially in discussions of<br />
processes whereby the strength of paper is increased by the addition, in manufacture, or plastic<br />
resins; the strength of an adhesive joint determined immediately after removal from a liquid in<br />
which it has been immersed under specified conditions of time, temperature and pressure.<br />
Wet-Through: The degree and/or rate of encapsulation of sized glass fiber bundles in a<br />
laminate. Also, the rate and/or degree of which the polymer matrix resin system can flow<br />
through a bed of sized glass bundles or strands and encapsulate each bundle of filaments.<br />
Wides: Term describing bundles of roving that are wider than most of the other bundles in a bed<br />
of chopped glass fibers. They usually contain 3 to 4 times more filaments than most of the other<br />
bundles in the roving (See Matchstick).<br />
Woven Roving Fabric: Heavy fabrics woven from continuous filament in roving form. It is<br />
usually in weights between 18-30 per square yard.<br />
Wrinkle: Surface imperfection pressed into laminated plastics similar to a crease or fold in<br />
paper, fabric or other base. Also occurs in vacuum bag molding when the bag is improperly<br />
placed, causing a crease.<br />
Yardage: Similar to Yield, but used to describe the linear density of "bare glass" or an un-sized<br />
product. Yardage specifies the number of yards of glass required to weigh one pound, measured<br />
in hundreds. For example, K18 is a K fiber diameter that has 180yards in one pound of glass.<br />
Yarn: Generic term for a continuous strand of textile fibers, filaments or material in a form<br />
suitable for knitting, weaving or intertwining to form a textile fabric.<br />
Yield: Linear density of a roving or yarn, measured by the number of yards per pound.<br />
Yield Point: First stress in a material, less than the maximum attainable stress, at which strain<br />
increases at a higher rate than stress. It is the point at which permanent deformation of a stressed<br />
specimen begins to take place. Only materials that exhibit yielding have a yield point.<br />
Yield Strength: Stress at the yield point. It is a stress at which a material exhibits a specified<br />
limiting deviation from the proportionality of stress to strain. It is the lowest stress at which a<br />
material undergoes plastic deformation. Below this stress, material is elastic; above it, material is<br />
viscous. Often it is defined as the stress needed to produce a specified amount of plastic<br />
deformation (usually a 0.2% change in length).<br />
Young's Modulus: Ratio of normal stress to corresponding strain for tensile or compressive<br />
stresses less than the proportional limit of the material.