Definitions /Dictionary/Glossary - nptel

Heat-Convertible Resin: A thermosetting resin convertible by heat to an infusible and insoluble
mass.
Heat-Distortion Temperature: Temperature at which a test bar deflects a certain amount under
specified temperature and a sated load.
Heat Resistance: The property or ability of plastics and Elastomer to resist the deteriorating
effects of elevated temperatures.
Heat-Pressure Laminants: Laminants molded and cured at pressures not lower than 1000 psi.
Heat Sink: A device for the absorption or transfer of heat away from a critical element or part.
Helical Winding: In filament winding, a winding in which a filament band advances along a
helical path.
Helical: Ply lay onto a mandrel at an angle, often a 45-degree angle.
Het-Acid Resin: Polyester resin with exceptional fire qualities.
Heterogeneous: Descriptive term for a material consisting of dissimilar constituents separately
identifiable; a medium consisting of regions of unlike properties separated by internal
boundaries. (Note that all non-homogeneous materials are not necessarily heterogeneous).
High Pressure Laminate: -Laminate molded and cured at pressures not lower than 6.9 MPa
(1000 psi) and in the range of 6.9-14 MPa (1000-2000 psi).
High Pressure Molding: A molding process wherein pressure is in excess of 6.9 MPa (1000
psi).
HOBE: Honeycomb before Expansion, the solid block of bonded sheets.
Homogeneous: Descriptive term for a material of uniform composition throughout; a medium
which has no internal physical boundaries; a material whose properties are constant at every
point, in other words, constant with respect to spatial coordinates (but not necessarily with
respect to directional coordinates).
Honeycomb: Resin-impregnated material manufactured in, usually, hexagonal cells that serve as
a core material in sandwich constructions. Honeycomb may also be metallic or polymer
materials in a rigid, open structure.
Honeycomb Core: Strips of paper, plastic metal, etc., joined together to form a honeycomb
pattern. Used as a lightweight core in sandwich moldings.
Hoop: Ply lay onto a mandrel at a 90-degree angle.