Definitions /Dictionary/Glossary - nptel

Hoop Stress: It is a circumferential stress in a cylindrically shaped part as a result of internal or
external pressure.
Horizontal Shear: Sometimes used to indicate inter-laminar shear. This is not an approved term
for use in this handbook.
Hot Bond Repair: Repair made on a hot-patch bonding machine to cure and monitor curing.
Typically includes heat and vacuum source.
Hot Bond Repair: Repair made on a hot patch bonding machine to cure and monitor curing.
Typically includes heat and vacuum source.
Hot Melt Adhesive: An adhesive that is applied in a molten state and forms a bond after cooling
to a solid state.
Hot Pot: Catalyst is mixed with the gel coat or resin in the material container prior to spraying,
as opposed to internal or external gun mixing.
Hot Setting Adhesive: An adhesive that requires a temperature at or above 100°C (212°F) to
set.
Hot Working Any form of mechanical deformation process carried out on a metal or alloy
above its re-crystallization temperature but below its melting point.
Humidity: Moisture content of the air.
Humidity, Relative: The ratio of the pressure of water vapor present to the pressure of saturated
water vapor at the same temperature.
Hybrid: A composite laminate comprised of laminae of two or more composite material
systems. Or, a combination of two or more different fibers such as carbon and glass or carbon
and aramid into a structure (tapes, fabrics and other forms may be combined).
Hybrid Composite: A composite with two or more types of reinforcing fibers.
Hybrid Resin: What we call a modified resin. For example, we sometimes add a rubber
modifier to an epoxy resin in order to achieve cured properties with a higher impact resistance.
Hydraulic Press: A press in which the molding force is created by the pressure exerted on a
fluid.
Hydro-mechanical Pressure: A press in which the molding forces are created partly by the
mechanical system and partly by the hydraulic system
Hydrophilic: Capable of absorbing water.